Manipulating motions of targeted single cells in solution by an integrated double-ring magnetic tweezers imaging microscope

NASA Astrophysics Data System (ADS)

Wu, Meiling; Yadav, Rajeev; Pal, Nibedita; Lu, H. Peter

2017-07-01

Controlling and manipulating living cell motions in solution hold a high promise in developing new biotechnology and biological science. Here, we developed a magnetic tweezers device that employs a combination of two permanent magnets in up-down double-ring configuration axially fitting with a microscopic objective, allowing a picoNewton (pN) bidirectional force and motion control on the sample beyond a single upward pulling direction. The experimental force calibration and magnetic field simulation using finite element method magnetics demonstrate that the designed magnetic tweezers covers a linear-combined pN force with positive-negative polarization changes in a tenability of sub-pN scale, which can be utilized to further achieve motion manipulation by shifting the force balance. We demonstrate an application of the up-down double-ring magnetic tweezers for single cell manipulation, showing that the cells with internalized paramagnetic beads can be selectively picked up and guided in a controlled fine motion.

Joint-space adaptive control of a 6 DOF end-effector with closed-kinematic chain mechanism

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Zhou, Zhen-Lei

1989-01-01

The development is presented for a joint-space adaptive scheme that controls the joint position of a six-degree-of-freedom (DOF) robot end-effector performing fine and precise motion within a very limited workspace. The end-effector was built to study autonomous assembly of NASA hardware in space. The design of the adaptive controller is based on the concept of model reference adaptive control (MRAC) and Lyapunov direct method. In the development, it is assumed that the end-effector performs slowly varying motion. Computer simulation is performed to investigate the performance of the developed control scheme on position control of the end-effector. Simulation results manifest that the adaptive control scheme provides excellent tracking of several test paths.

Slow Orbit Feedback at the ALS Using Matlab

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

Portmann, G.

1999-03-25

The third generation Advanced Light Source (ALS) produces extremely bright and finely focused photon beams using undulatory, wigglers, and bend magnets. In order to position the photon beams accurately, a slow global orbit feedback system has been developed. The dominant causes of orbit motion at the ALS are temperature variation and insertion device motion. This type of motion can be removed using slow global orbit feedback with a data rate of a few Hertz. The remaining orbit motion in the ALS is only 1-3 micron rms. Slow orbit feedback does not require high computational throughput. At the ALS, the globalmore » orbit feedback algorithm, based on the singular valued decomposition method, is coded in MATLAB and runs on a control room workstation. Using the MATLAB environment to develop, test, and run the storage ring control algorithms has proven to be a fast and efficient way to operate the ALS.« less

Sensing And Force-Reflecting Exoskeleton

NASA Technical Reports Server (NTRS)

Eberman, Brian; Fontana, Richard; Marcus, Beth

1993-01-01

Sensing and force-reflecting exoskeleton (SAFiRE) provides control signals to robot hand and force feedback from robot hand to human operator. Operator makes robot hand touch objects gently and manipulates them finely without exerting excessive forces. Device attaches to operator's hand; comfortable and lightweight. Includes finger exoskeleton, cable mechanical transmission, two dc servomotors, partial thumb exoskeleton, harness, amplifier box, two computer circuit boards, and software. Transduces motion of index finger and thumb. Video monitor of associated computer displays image corresponding to motion.

A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

PubMed

Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Bin Aziz, Mohamed Fareez; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M; Sato, Hirotaka

2014-01-01

In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot).

Development of virtual reality exercise of hand motion assist robot for rehabilitation therapy by patient self-motion control.

PubMed

Ueki, Satoshi; Nishimoto, Yutaka; Abe, Motoyuki; Kawasaki, Haruhisa; Ito, Satoshi; Ishigure, Yasuhiko; Mizumoto, Jun; Ojika, Takeo

2008-01-01

This paper presents a virtual reality-enhanced hand rehabilitation support system with a symmetric master-slave motion assistant for independent rehabilitation therapies. Our aim is to provide fine motion exercise for a hand and fingers, which allows the impaired hand of a patient to be driven by his or her healthy hand on the opposite side. Since most disabilities caused by cerebral vascular accidents or bone fractures are hemiplegic, we adopted a symmetric master-slave motion assistant system in which the impaired hand is driven by the healthy hand on the opposite side. A VR environment displaying an effective exercise was created in consideration of system's characteristic. To verify the effectiveness of this system, a clinical test was executed by applying to six patients.

Fine pointing of the Solar Optical Telescope in the Space Shuttle environment

NASA Astrophysics Data System (ADS)

Gowrinathan, S.

Instruments requiring fine (i.e., sub-arcsecond) pointing, such as the Solar Optical Telescope (SOT), must be equipped with two-stage pointing devices, coarse and fine. Coarse pointing will be performed by a gimbal system, such as the Instrument Pointing System, while the image motion compensation (IMC) will provide fine pointing. This paper describes work performed on the SOT concept design that illustrates IMC as applied to SOT. The SOT control system was modeled in the frequency domain to evaluate performance, stability, and bandwidth requirements. The two requirements of the pointing control, i.e., the 2 arcsecond reproducibility and 0.03 arcsecond rms pointing jitter, can be satisfied by use of IMC at about 20 Hz bandwidth. The need for this high bandwidth is related to Shuttle-induced disturbances that arise primarily from man push-offs and vernier thruster firings. A block diagram of SOT model/stability analysis, schematic illustrations of the SOT pointing system, and a structural model summary are included.

A biomechanical modeling-guided simultaneous motion estimation and image reconstruction technique (SMEIR-Bio) for 4D-CBCT reconstruction

NASA Astrophysics Data System (ADS)

Huang, Xiaokun; Zhang, You; Wang, Jing

2018-02-01

Reconstructing four-dimensional cone-beam computed tomography (4D-CBCT) images directly from respiratory phase-sorted traditional 3D-CBCT projections can capture target motion trajectory, reduce motion artifacts, and reduce imaging dose and time. However, the limited numbers of projections in each phase after phase-sorting decreases CBCT image quality under traditional reconstruction techniques. To address this problem, we developed a simultaneous motion estimation and image reconstruction (SMEIR) algorithm, an iterative method that can reconstruct higher quality 4D-CBCT images from limited projections using an inter-phase intensity-driven motion model. However, the accuracy of the intensity-driven motion model is limited in regions with fine details whose quality is degraded due to insufficient projection number, which consequently degrades the reconstructed image quality in corresponding regions. In this study, we developed a new 4D-CBCT reconstruction algorithm by introducing biomechanical modeling into SMEIR (SMEIR-Bio) to boost the accuracy of the motion model in regions with small fine structures. The biomechanical modeling uses tetrahedral meshes to model organs of interest and solves internal organ motion using tissue elasticity parameters and mesh boundary conditions. This physics-driven approach enhances the accuracy of solved motion in the organ’s fine structures regions. This study used 11 lung patient cases to evaluate the performance of SMEIR-Bio, making both qualitative and quantitative comparisons between SMEIR-Bio, SMEIR, and the algebraic reconstruction technique with total variation regularization (ART-TV). The reconstruction results suggest that SMEIR-Bio improves the motion model’s accuracy in regions containing small fine details, which consequently enhances the accuracy and quality of the reconstructed 4D-CBCT images.

A closed-loop neurobotic system for fine touch sensing

NASA Astrophysics Data System (ADS)

Bologna, L. L.; Pinoteau, J.; Passot, J.-B.; Garrido, J. A.; Vogel, J.; Ros Vidal, E.; Arleo, A.

2013-08-01

Objective. Fine touch sensing relies on peripheral-to-central neurotransmission of somesthetic percepts, as well as on active motion policies shaping tactile exploration. This paper presents a novel neuroengineering framework for robotic applications based on the multistage processing of fine tactile information in the closed action-perception loop. Approach. The integrated system modules focus on (i) neural coding principles of spatiotemporal spiking patterns at the periphery of the somatosensory pathway, (ii) probabilistic decoding mechanisms mediating cortical-like tactile recognition and (iii) decision-making and low-level motor adaptation underlying active touch sensing. We probed the resulting neural architecture through a Braille reading task. Main results. Our results on the peripheral encoding of primary contact features are consistent with experimental data on human slow-adapting type I mechanoreceptors. They also suggest second-order processing by cuneate neurons may resolve perceptual ambiguities, contributing to a fast and highly performing online discrimination of Braille inputs by a downstream probabilistic decoder. The implemented multilevel adaptive control provides robustness to motion inaccuracy, while making the number of finger accelerations covariate with Braille character complexity. The resulting modulation of fingertip kinematics is coherent with that observed in human Braille readers. Significance. This work provides a basis for the design and implementation of modular neuromimetic systems for fine touch discrimination in robotics.

Global motion perception is related to motor function in 4.5-year-old children born at risk of abnormal development

PubMed Central

Chakraborty, Arijit; Anstice, Nicola S.; Jacobs, Robert J.; Paudel, Nabin; LaGasse, Linda L.; Lester, Barry M.; McKinlay, Christopher J. D.; Harding, Jane E.; Wouldes, Trecia A.; Thompson, Benjamin

2017-01-01

Global motion perception is often used as an index of dorsal visual stream function in neurodevelopmental studies. However, the relationship between global motion perception and visuomotor control, a primary function of the dorsal stream, is unclear. We measured global motion perception (motion coherence threshold; MCT) and performance on standardized measures of motor function in 606 4.5-year-old children born at risk of abnormal neurodevelopment. Visual acuity, stereoacuity and verbal IQ were also assessed. After adjustment for verbal IQ or both visual acuity and stereoacuity, MCT was modestly, but significantly, associated with all components of motor function with the exception of gross motor scores. In a separate analysis, stereoacuity, but not visual acuity, was significantly associated with both gross and fine motor scores. These results indicate that the development of motion perception and stereoacuity are associated with motor function in pre-school children. PMID:28435122

New Worlds Observer Formation Control Design Based on the Dynamics of Relative Motion

NASA Technical Reports Server (NTRS)

Luquette, Richard J.

2008-01-01

The New Worlds Observer (NWO) mission is designed for the direct detection and characterization of extrasolar planets. The NWO mission concept employs a two spacecraft leader-follower formation on a trajectory around the Earth/Moon-Sun L(sub 2) Libration Point. The leader spacecraft is baselined as a 4 meter optical telescope. The follower, Starshade spacecraft, is designed to suppress light from a central body star permitting direct detection of a surrounding exoplanetary system. The current design requires a nominal leader-follower separation range of 72 Megameters. NWO poses many challenges including formation control. NWO cycles between three principal control modes during the nominal mission timeline: science (fine pointing), realignment and transition. This paper examines formation control strategies in the context of dynamics of relative motion for two spacecraft operating in the vicinity of the Earth/Moon-Sun L(sub 2)libration point. The paper presents an overview of the equations of relative motion followed by a discussion of each of the control modes. Discussion and analysis characterize control strategies for each of the mission control modes, including requirements, implementation challenges and project fuel budgets.

Motion Simulation Analysis of Rail Weld CNC Fine Milling Machine

NASA Astrophysics Data System (ADS)

Mao, Huajie; Shu, Min; Li, Chao; Zhang, Baojun

CNC fine milling machine is a new advanced equipment of rail weld precision machining with high precision, high efficiency, low environmental pollution and other technical advantages. The motion performance of this machine directly affects its machining accuracy and stability, which makes it an important consideration for its design. Based on the design drawings, this article completed 3D modeling of 60mm/kg rail weld CNC fine milling machine by using Solidworks. After that, the geometry was imported into Adams to finish the motion simulation analysis. The displacement, velocity, angular velocity and some other kinematical parameters curves of the main components were obtained in the post-processing and these are the scientific basis for the design and development for this machine.

Coherent random lasing controlled by Brownian motion of the active scatterer

NASA Astrophysics Data System (ADS)

Liang, Shuofeng; Yin, Leicheng; Zhang, ZhenZhen; Xia, Jiangying; Xie, Kang; Zou, Gang; Hu, Zhijia; Zhang, Qijin

2018-05-01

The stability of the scattering loop is fundamental for coherent random lasing in a dynamic scattering system. In this work, fluorescence of DPP (N, N-di [3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide) is scattered to produce RL and we realize the transition from incoherent RL to coherent RL by controlling the Brownian motion of the scatterers (dimer aggregates of DPP) and the stability of scattering loop. To produce coherent random lasers, the loop needs to maintain a stable state within the loop-stable time, which can be determined through controlled Brownian motion of scatterers in the scattering system. The result shows that the loop-stable time is within 5.83 × 10‑5 s to 1.61 × 10‑4 s based on the transition from coherent to incoherent random lasing. The time range could be tuned by finely controlling the viscosity of the solution. This work not only develops a method to predict the loop-stable time, but also develops the study between Brownian motion and random lasers, which opens the road to a variety of novel interdisciplinary investigations involving modern statistical mechanics and disordered photonics.

On Motion Planning and Control of Multi-Link Lightweight Robotic Manipulators

NASA Technical Reports Server (NTRS)

Cetinkunt, Sabri

1987-01-01

A general gross and fine motion planning and control strategy is needed for lightweight robotic manipulator applications such as painting, welding, material handling, surface finishing, and spacecraft servicing. The control problem of lightweight manipulators is to perform fast, accurate, and robust motions despite the payload variations, structural flexibility, and other environmental disturbances. Performance of the rigid manipulator model based computed torque and decoupled joint control methods are determined and simulated for the counterpart flexible manipulators. A counterpart flexible manipulator is defined as a manipulator which has structural flexibility, in addition to having the same inertial, geometric, and actuation properties of a given rigid manipulator. An adaptive model following control (AMFC) algorithm is developed to improve the performance in speed, accuracy, and robustness. It is found that the AMFC improves the speed performance by a factor of two over the conventional non-adaptive control methods for given accuracy requirements while proving to be more robust with respect to payload variations. Yet there are clear limitations on the performance of AMFC alone as well, which are imposed by the arm flexibility. In the search to further improve speed performance while providing a desired accuracy and robustness, a combined control strategy is developed. Furthermore, the problem of switching from one control structure to another during the motion and implementation aspects of combined control are discussed.

The Function and Organization of the Motor System Controlling Flight Maneuvers in Flies.

PubMed

Lindsay, Theodore; Sustar, Anne; Dickinson, Michael

2017-02-06

Animals face the daunting task of controlling their limbs using a small set of highly constrained actuators. This problem is particularly demanding for insects such as Drosophila, which must adjust wing motion for both quick voluntary maneuvers and slow compensatory reflexes using only a dozen pairs of muscles. To identify strategies by which animals execute precise actions using sparse motor networks, we imaged the activity of a complete ensemble of wing control muscles in intact, flying flies. Our experiments uncovered a remarkably efficient logic in which each of the four skeletal elements at the base of the wing are equipped with both large phasically active muscles capable of executing large changes and smaller tonically active muscles specialized for continuous fine-scaled adjustments. Based on the responses to a broad panel of visual motion stimuli, we have developed a model by which the motor array regulates aerodynamically functional features of wing motion. VIDEO ABSTRACT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Relations between Automatically Extracted Motion Features and the Quality of Mother-Infant Interactions at 4 and 13 Months

PubMed Central

Egmose, Ida; Varni, Giovanna; Cordes, Katharina; Smith-Nielsen, Johanne; Væver, Mette S.; Køppe, Simo; Cohen, David; Chetouani, Mohamed

2017-01-01

Bodily movements are an essential component of social interactions. However, the role of movement in early mother-infant interaction has received little attention in the research literature. The aim of the present study was to investigate the relationship between automatically extracted motion features and interaction quality in mother-infant interactions at 4 and 13 months. The sample consisted of 19 mother-infant dyads at 4 months and 33 mother-infant dyads at 13 months. The coding system Coding Interactive Behavior (CIB) was used for rating the quality of the interactions. Kinetic energy of upper-body, arms and head motion was calculated and used as segmentation in order to extract coarse- and fine-grained motion features. Spearman correlations were conducted between the composites derived from the CIB and the coarse- and fine-grained motion features. At both 4 and 13 months, longer durations of maternal arm motion and infant upper-body motion were associated with more aversive interactions, i.e., more parent-led interactions and more infant negativity. Further, at 4 months, the amount of motion silence was related to more adaptive interactions, i.e., more sensitive and child-led interactions. Analyses of the fine-grained motion features showed that if the mother coordinates her head movements with her infant's head movements, the interaction is rated as more adaptive in terms of less infant negativity and less dyadic negative states. We found more and stronger correlations between the motion features and the interaction qualities at 4 compared to 13 months. These results highlight that motion features are related to the quality of mother-infant interactions. Factors such as infant age and interaction set-up are likely to modify the meaning and importance of different motion features. PMID:29326626

Relations between Automatically Extracted Motion Features and the Quality of Mother-Infant Interactions at 4 and 13 Months.

PubMed

Egmose, Ida; Varni, Giovanna; Cordes, Katharina; Smith-Nielsen, Johanne; Væver, Mette S; Køppe, Simo; Cohen, David; Chetouani, Mohamed

2017-01-01

Bodily movements are an essential component of social interactions. However, the role of movement in early mother-infant interaction has received little attention in the research literature. The aim of the present study was to investigate the relationship between automatically extracted motion features and interaction quality in mother-infant interactions at 4 and 13 months. The sample consisted of 19 mother-infant dyads at 4 months and 33 mother-infant dyads at 13 months. The coding system Coding Interactive Behavior (CIB) was used for rating the quality of the interactions. Kinetic energy of upper-body, arms and head motion was calculated and used as segmentation in order to extract coarse- and fine-grained motion features. Spearman correlations were conducted between the composites derived from the CIB and the coarse- and fine-grained motion features. At both 4 and 13 months, longer durations of maternal arm motion and infant upper-body motion were associated with more aversive interactions, i.e., more parent-led interactions and more infant negativity. Further, at 4 months, the amount of motion silence was related to more adaptive interactions, i.e., more sensitive and child-led interactions. Analyses of the fine-grained motion features showed that if the mother coordinates her head movements with her infant's head movements, the interaction is rated as more adaptive in terms of less infant negativity and less dyadic negative states. We found more and stronger correlations between the motion features and the interaction qualities at 4 compared to 13 months. These results highlight that motion features are related to the quality of mother-infant interactions. Factors such as infant age and interaction set-up are likely to modify the meaning and importance of different motion features.

Inflight redesign of the IUE attitude control system

NASA Technical Reports Server (NTRS)

Femiano, M. D.

1986-01-01

The one- and two-gyro system designs of the International Ultraviolet Explorer (IUE) attitude control system (ACS) are examined. The inertial reference assembly that provides the primary attitude reference for IUE consists of six rate sensors which are single-axis rate integrating gyros. The gyros operate in a pulse rebalanced mode that produces an output pulse for 0.01 arcsec of motion about the input axis. The functions of the fine error sensor, fine sun sensor (FSS), the IUE reaction wheels, the onboard computer, and the hold/slew algorithm are described. The use of the hold/slew algorithm to compute the control voltage for the ACS based on the Kalman filter is studied. A two-gyro system was incorporated into IUE following gyro failure. The procedures for establishing attitude control with the two-gyro design based on the FSS is analyzed. The performance of the two-gyro system is evaluated; it is observed that the pitch and yaw gyro control is 0.24 arcsec and the control is sufficient to permit extended periods of observation.

Six degree of freedom fine motion positioning stage based on magnetic levitation

NASA Technical Reports Server (NTRS)

Arling, R. W.; Kohler, S. M.

1994-01-01

The design of a magnetically suspended six degree of freedom positioning system capable of nanometer positioning is presented. The sample holder is controlled in six degrees of freedom (DOF) over 300 micrometers of travel in the X, Y, and Z directions. A design and control summary and test results indicating stability and power dissipation are included in the paper. The system is vacuum compatible, uses commercially available materials, and requires minimal assembly and setup.

Temporal and Fine-Grained Pedestrian Action Recognition on Driving Recorder Database

PubMed Central

Satoh, Yutaka; Aoki, Yoshimitsu; Oikawa, Shoko; Matsui, Yasuhiro

2018-01-01

The paper presents an emerging issue of fine-grained pedestrian action recognition that induces an advanced pre-crush safety to estimate a pedestrian intention in advance. The fine-grained pedestrian actions include visually slight differences (e.g., walking straight and crossing), which are difficult to distinguish from each other. It is believed that the fine-grained action recognition induces a pedestrian intention estimation for a helpful advanced driver-assistance systems (ADAS). The following difficulties have been studied to achieve a fine-grained and accurate pedestrian action recognition: (i) In order to analyze the fine-grained motion of a pedestrian appearance in the vehicle-mounted drive recorder, a method to describe subtle change of motion characteristics occurring in a short time is necessary; (ii) even when the background moves greatly due to the driving of the vehicle, it is necessary to detect changes in subtle motion of the pedestrian; (iii) the collection of large-scale fine-grained actions is very difficult, and therefore a relatively small database should be focused. We find out how to learn an effective recognition model with only a small-scale database. Here, we have thoroughly evaluated several types of configurations to explore an effective approach in fine-grained pedestrian action recognition without a large-scale database. Moreover, two different datasets have been collected in order to raise the issue. Finally, our proposal attained 91.01% on National Traffic Science and Environment Laboratory database (NTSEL) and 53.23% on the near-miss driving recorder database (NDRDB). The paper has improved +8.28% and +6.53% from baseline two-stream fusion convnets. PMID:29461473

Image motion compensation on the Spacelab 2 Solar Optical Universal Polarimeter /SL2 SOUP/

NASA Technical Reports Server (NTRS)

Tarbell, T. D.; Duncan, D. W.; Finch, M. L.; Spence, G.

1981-01-01

The SOUP experiment on Spacelab 2 includes a 30 cm visible light telescope and focal plane package mounted on the Instrument Pointing System (IPS). Scientific goals of the experiment dictate pointing stability requirements of less than 0.05 arcsecond jitter over periods of 5-20 seconds. Quantitative derivations of these requirements from two different aspects are presented: (1) avoidance of motion blurring of diffraction-limited images; (2) precise coalignment of consecutive frames to allow measurement of small image differences. To achieve this stability, a fine guider system capable of removing residual jitter of the IPS and image motions generated on the IPS cruciform instrument support structure has been constructed. This system uses solar limb detectors in the prime focal plane to derive an error signal. Image motion due to pointing errors is compensated by the agile secondary mirror mounted on piezoelectric transducers, controlled by a closed-loop servo system.

Vortex Filaments in Grids for Scalable, Fine Smoke Simulation.

PubMed

Meng, Zhang; Weixin, Si; Yinling, Qian; Hanqiu, Sun; Jing, Qin; Heng, Pheng-Ann

2015-01-01

Vortex modeling can produce attractive visual effects of dynamic fluids, which are widely applicable for dynamic media, computer games, special effects, and virtual reality systems. However, it is challenging to effectively simulate intensive and fine detailed fluids such as smoke with fast increasing vortex filaments and smoke particles. The authors propose a novel vortex filaments in grids scheme in which the uniform grids dynamically bridge the vortex filaments and smoke particles for scalable, fine smoke simulation with macroscopic vortex structures. Using the vortex model, their approach supports the trade-off between simulation speed and scale of details. After computing the whole velocity, external control can be easily exerted on the embedded grid to guide the vortex-based smoke motion. The experimental results demonstrate the efficiency of using the proposed scheme for a visually plausible smoke simulation with macroscopic vortex structures.

Tracking and Predicting Fine Scale Sea Ice Motion by Constructing Super-Resolution Images and Fusing Multiple Satellite Sensors

DTIC Science & Technology

2013-09-30

COVERED 00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Tracking and Predicting Fine Scale Sea Ice Motion by Constructing Super-Resolution Images...limited, but potentially provide more detailed data. Initial assessments have been made on MODIS data in terms of its suitability. While clouds obscure...estimates. 2 Data from Aqua, Terra, and Suomi NPP satellites were investigated. Aqua and Terra are older satellites that fly the MODIS instrument

Projectile Motion on an Inclined Misty Surface: I. Capturing and Analysing the Trajectory

ERIC Educational Resources Information Center

Ho, S. Y.; Foong, S. K.; Lim, C. H.; Lim, C. C.; Lin, K.; Kuppan, L.

2009-01-01

Projectile motion is usually the first non-uniform two-dimensional motion that students will encounter in a pre-university physics course. In this article, we introduce a novel technique for capturing the trajectory of projectile motion on an inclined Perspex plane. This is achieved by coating the Perspex with a thin layer of fine water droplets…

Scanning electron microscope fine tuning using four-bar piezoelectric actuated mechanism

NASA Astrophysics Data System (ADS)

Hatamleh, Khaled S.; Khasawneh, Qais A.; Al-Ghasem, Adnan; Jaradat, Mohammad A.; Sawaqed, Laith; Al-Shabi, Mohammad

2018-01-01

Scanning Electron Microscopes are extensively used for accurate micro/nano images exploring. Several strategies have been proposed to fine tune those microscopes in the past few years. This work presents a new fine tuning strategy of a scanning electron microscope sample table using four bar piezoelectric actuated mechanisms. The introduced paper presents an algorithm to find all possible inverse kinematics solutions of the proposed mechanism. In addition, another algorithm is presented to search for the optimal inverse kinematic solution. Both algorithms are used simultaneously by means of a simulation study to fine tune a scanning electron microscope sample table through a pre-specified circular or linear path of motion. Results of the study shows that, proposed algorithms were able to minimize the power required to drive the piezoelectric actuated mechanism by a ratio of 97.5% for all simulated paths of motion when compared to general non-optimized solution.

Instrument Pointing Control System for the Stellar Interferometry Mission - Planet Quest

NASA Technical Reports Server (NTRS)

Brugarolas, Paul B.; Kang, Bryan

2006-01-01

This paper describes the high precision Instrument Pointing Control System (PCS) for the Stellar Interferometry Mission (SIM) - Planet Quest. The PCS system provides front-end pointing, compensation for spacecraft motion, and feedforward stabilization, which are needed for proper interference. Optical interferometric measurements require very precise pointing (0.03 as, 1-(sigma) radial) for maximizing the interference pattern visibility. This requirement is achieved by fine pointing control of articulating pointing mirrors with feedback from angle tracking cameras. The overall pointing system design concept is presentcd. Functional requirements and an acquisition concept are given. Guide and Science pointing control loops are discussed. Simulation analyses demonstrate the feasibility of the design.

Training in cortical control of neuroprosthetic devices improves signal extraction from small neuronal ensembles.

PubMed

Helms Tillery, S I; Taylor, D M; Schwartz, A B

2003-01-01

We have recently developed a closed-loop environment in which we can test the ability of primates to control the motion of a virtual device using ensembles of simultaneously recorded neurons /29/. Here we use a maximum likelihood method to assess the information about task performance contained in the neuronal ensemble. We trained two animals to control the motion of a computer cursor in three dimensions. Initially the animals controlled cursor motion using arm movements, but eventually they learned to drive the cursor directly from cortical activity. Using a population vector (PV) based upon the relation between cortical activity and arm motion, the animals were able to control the cursor directly from the brain in a closed-loop environment, but with difficulty. We added a supervised learning method that modified the parameters of the PV according to task performance (adaptive PV), and found that animals were able to exert much finer control over the cursor motion from brain signals. Here we describe a maximum likelihood method (ML) to assess the information about target contained in neuronal ensemble activity. Using this method, we compared the information about target contained in the ensemble during arm control, during brain control early in the adaptive PV, and during brain control after the adaptive PV had settled and the animal could drive the cursor reliably and with fine gradations. During the arm-control task, the ML was able to determine the target of the movement in as few as 10% of the trials, and as many as 75% of the trials, with an average of 65%. This average dropped when the animals used a population vector to control motion of the cursor. On average we could determine the target in around 35% of the trials. This low percentage was also reflected in poor control of the cursor, so that the animal was unable to reach the target in a large percentage of trials. Supervised adjustment of the population vector parameters produced new weighting coefficients and directional tuning parameters for many neurons. This produced a much better performance of the brain-controlled cursor motion. It was also reflected in the maximum likelihood measure of cell activity, producing the correct target based only on neuronal activity in over 80% of the trials on average. The changes in maximum likelihood estimates of target location based on ensemble firing show that an animal's ability to regulate the motion of a cortically controlled device is not crucially dependent on the experimenter's ability to estimate intention from neuronal activity.

Optical pseudomotors for soft x-ray beamlines

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

Pedreira, P., E-mail: ppedreira@cells.es; Sics, I.; Sorrentino, A.

2016-05-15

Optical elements of soft x-ray beamlines usually have motorized translations and rotations that allow for the fine alignment of the beamline. This is to steer the photon beam at some positions and to correct the focus on slits or on sample. Generally, each degree of freedom of a mirror induces a change of several parameters of the beam. Inversely, several motions are required to actuate on a single optical parameter, keeping the others unchanged. We define optical pseudomotors as combinations of physical motions of the optical elements of a beamline, which allow modifying one optical parameter without affecting the others.more » We describe a method to obtain analytic relationships between physical motions of mirrors and the corresponding variations of the beam parameters. This method has been implemented and tested at two beamlines at ALBA, where it is used to control the focus of the photon beam and its position independently.« less

Development of Young Adults' Fine Motor Skills when Learning to Play Percussion Instruments

ERIC Educational Resources Information Center

Gzibovskis, Talis; Marnauza, Mara

2012-01-01

When playing percussion instruments, the main activity is done with the help of a motion or motor skills; to perform it, developed fine motor skills are necessary: the speed and precision of fingers, hands and palms. The aim of the research was to study and test the development of young adults' fine motor skills while learning to play percussion…

A fuzzy neural network sliding mode controller for vibration suppression in robotically assisted minimally invasive surgery.

PubMed

Sang, Hongqiang; Yang, Chenghao; Liu, Fen; Yun, Jintian; Jin, Guoguang

2016-12-01

It is very important for robotically assisted minimally invasive surgery to achieve a high-precision and smooth motion control. However, the surgical instrument tip will exhibit vibration caused by nonlinear friction and unmodeled dynamics, especially when the surgical robot system is attempting low-speed, fine motion. A fuzzy neural network sliding mode controller (FNNSMC) is proposed to suppress vibration of the surgical robotic system. Nonlinear friction and modeling uncertainties are compensated by a Stribeck model, a radial basis function (RBF) neural network and a fuzzy system, respectively. Simulations and experiments were performed on a 3 degree-of-freedom (DOF) minimally invasive surgical robot. The results demonstrate that the FNNSMC is effective and can suppress vibrations at the surgical instrument tip. The proposed FNNSMC can provide a robust performance and suppress the vibrations at the surgical instrument tip, which can enhance the quality and security of surgical procedures. Copyright © 2016 John Wiley & Sons, Ltd.

Improving Attachments of Non-Invasive (Type III) Electronic Data Loggers to Cetaceans

DTIC Science & Technology

2015-09-30

animals in human care will be performed to test and validate this approach. The cadaver trials will enable controlled testing to failure or with both...quantitative metrics and analysis tools to assess the impact of a tag on the animal . Here we will present: 1) the characterization of the mechanical...fine scale motion analysis for swimming animals . 2 APPROACH Our approach is divided into four subtasks: Task 1: Forces and failure modes

Quantitation of Fine Displacement in Echography

NASA Astrophysics Data System (ADS)

Masuda, Kohji; Ishihara, Ken; Yoshii, Ken; Furukawa, Toshiyuki; Kumagai, Sadatoshi; Maeda, Hajime; Kodama, Shinzo

1993-05-01

A High-speed Digital Subtraction Echography was developed to visualize the fine displacement of human internal organs. This method indicates differences in position through time series images of high-frame-rate echography. Fine displacement less than ultrasonic wavelength can be observed. This method, however, lacks the ability to quantitatively measure displacement length. The subtraction between two successive images was affected by displacement direction in spite of the displacement length being the same. To solve this problem, convolution of an echogram with Gaussian distribution was used. To express displacement length as brightness quantitatively, normalization using a brightness gradient was applied. The quantitation algorithm was applied to successive B-mode images. Compared to the simply subtracted images, quantitated images express more precisely the motion of organs. Expansion of the carotid artery and fine motion of ventricular walls can be visualized more easily. Displacement length can be quantitated with wavelength. Under more static conditions, this system quantitates displacement length that is much less than wavelength.

Planetary Ring Simulation Experiment in Fine Particle Plasmas

NASA Astrophysics Data System (ADS)

Yokota, Toshiaki

We are experimenting on the planetary ring formation by using two component fine particle plasmas generated by a boat method. Two component plasmas which were composed of positively charged particles and negatively charged particles were generated by UV irradiation of fine aluminum particles. A small insulator sphere in which a small permanent magnet was inserted was put into the fine particle plasmas, and was connected using insulator rods and rotated by a small motor. We were able to create a ring form of fine particle plasmas just like the Saturn ring by unipolar induction. The ring formation process was recorded on VTR and its motion was analyzed by using a computer. The experimental parameters for ring formation coincides almost with the estimated values. The particles had charges of ±25 electrons from analysis of the particle beam splitting after passage through a static electric and a static magnetic field. It is estimated that the fine particle plasmas were in strongly coupled state (Γ>1) in these experimental conditions. The charges of particles increased and Γ also increased when the power of the halogen lamp was increased. The relations between the rotating frequency and the motion of ring and charge dependency were investigated mainly by using an optical method

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection.

PubMed

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-12-21

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection †

PubMed Central

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-01-01

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate. PMID:26703612

Intelligent Systems Approach for Automated Identification of Individual Control Behavior of a Human Operator

NASA Technical Reports Server (NTRS)

Zaychik, Kirill B.; Cardullo, Frank M.

2012-01-01

Results have been obtained using conventional techniques to model the generic human operator?s control behavior, however little research has been done to identify an individual based on control behavior. The hypothesis investigated is that different operators exhibit different control behavior when performing a given control task. Two enhancements to existing human operator models, which allow personalization of the modeled control behavior, are presented. One enhancement accounts for the testing control signals, which are introduced by an operator for more accurate control of the system and/or to adjust the control strategy. This uses the Artificial Neural Network which can be fine-tuned to model the testing control. Another enhancement takes the form of an equiripple filter which conditions the control system power spectrum. A novel automated parameter identification technique was developed to facilitate the identification process of the parameters of the selected models. This utilizes a Genetic Algorithm based optimization engine called the Bit-Climbing Algorithm. Enhancements were validated using experimental data obtained from three different sources: the Manual Control Laboratory software experiments, Unmanned Aerial Vehicle simulation, and NASA Langley Research Center Visual Motion Simulator studies. This manuscript also addresses applying human operator models to evaluate the effectiveness of motion feedback when simulating actual pilot control behavior in a flight simulator.

Humanoid Mobile Manipulation Using Controller Refinement

NASA Technical Reports Server (NTRS)

Platt, Robert; Burridge, Robert; Diftler, Myron; Graf, Jodi; Goza, Mike; Huber, Eric; Brock, Oliver

2006-01-01

An important class of mobile manipulation problems are move-to-grasp problems where a mobile robot must navigate to and pick up an object. One of the distinguishing features of this class of tasks is its coarse-to-fine structure. Near the beginning of the task, the robot can only sense the target object coarsely or indirectly and make gross motion toward the object. However, after the robot has located and approached the object, the robot must finely control its grasping contacts using precise visual and haptic feedback. This paper proposes that move-to-grasp problems are naturally solved by a sequence of controllers that iteratively refines what ultimately becomes the final solution. This paper introduces the notion of a refining sequence of controllers and characterizes this type of solution. The approach is demonstrated in a move-to-grasp task where Robonaut, the NASA/JSC dexterous humanoid, is mounted on a mobile base and navigates to and picks up a geological sample box. In a series of tests, it is shown that a refining sequence of controllers decreases variance in robot configuration relative to the sample box until a successful grasp has been achieved.

Humanoid Mobile Manipulation Using Controller Refinement

NASA Technical Reports Server (NTRS)

Platt, Robert; Burridge, Robert; Diftler, Myron; Graf, Jodi; Goza, Mike; Huber, Eric

2006-01-01

An important class of mobile manipulation problems are move-to-grasp problems where a mobile robot must navigate to and pick up an object. One of the distinguishing features of this class of tasks is its coarse-to-fine structure. Near the beginning of the task, the robot can only sense the target object coarsely or indirectly and make gross motion toward the object. However, after the robot has located and approached the object, the robot must finely control its grasping contacts using precise visual and haptic feedback. In this paper, it is proposed that move-to-grasp problems are naturally solved by a sequence of controllers that iteratively refines what ultimately becomes the final solution. This paper introduces the notion of a refining sequence of controllers and characterizes this type of solution. The approach is demonstrated in a move-to-grasp task where Robonaut, the NASA/JSC dexterous humanoid, is mounted on a mobile base and navigates to and picks up a geological sample box. In a series of tests, it is shown that a refining sequence of controllers decreases variance in robot configuration relative to the sample box until a successful grasp has been achieved.

Linear phase conjugation for atmospheric aberration compensation

NASA Astrophysics Data System (ADS)

Grasso, Robert J.; Stappaerts, Eddy A.

1998-01-01

Atmospheric induced aberrations can seriously degrade laser performance, greatly affecting the beam that finally reaches the target. Lasers propagated over any distance in the atmosphere suffer from a significant decrease in fluence at the target due to these aberrations. This is especially so for propagation over long distances. It is due primarily to fluctuations in the atmosphere over the propagation path, and from platform motion relative to the intended aimpoint. Also, delivery of high fluence to the target typically requires low beam divergence, thus, atmospheric turbulence, platform motion, or both results in a lack of fine aimpoint control to keep the beam directed at the target. To improve both the beam quality and amount of laser energy delivered to the target, Northrop Grumman has developed the Active Tracking System (ATS); a novel linear phase conjugation aberration compensation technique. Utilizing a silicon spatial light modulator (SLM) as a dynamic wavefront reversing element, ATS undoes aberrations induced by the atmosphere, platform motion or both. ATS continually tracks the target as well as compensates for atmospheric and platform motion induced aberrations. This results in a high fidelity, near-diffraction limited beam delivered to the target.

A biomechanical modeling guided simultaneous motion estimation and image reconstruction technique (SMEIR-Bio) for 4D-CBCT reconstruction

NASA Astrophysics Data System (ADS)

Huang, Xiaokun; Zhang, You; Wang, Jing

2017-03-01

Four-dimensional (4D) cone-beam computed tomography (CBCT) enables motion tracking of anatomical structures and removes artifacts introduced by motion. However, the imaging time/dose of 4D-CBCT is substantially longer/higher than traditional 3D-CBCT. We previously developed a simultaneous motion estimation and image reconstruction (SMEIR) algorithm, to reconstruct high-quality 4D-CBCT from limited number of projections to reduce the imaging time/dose. However, the accuracy of SMEIR is limited in reconstructing low-contrast regions with fine structure details. In this study, we incorporate biomechanical modeling into the SMEIR algorithm (SMEIR-Bio), to improve the reconstruction accuracy at low-contrast regions with fine details. The efficacy of SMEIR-Bio is evaluated using 11 lung patient cases and compared to that of the original SMEIR algorithm. Qualitative and quantitative comparisons showed that SMEIR-Bio greatly enhances the accuracy of reconstructed 4D-CBCT volume in low-contrast regions, which can potentially benefit multiple clinical applications including the treatment outcome analysis.

A coarse-to-fine kernel matching approach for mean-shift based visual tracking

NASA Astrophysics Data System (ADS)

Liangfu, L.; Zuren, F.; Weidong, C.; Ming, J.

2009-03-01

Mean shift is an efficient pattern match algorithm. It is widely used in visual tracking fields since it need not perform whole search in the image space. It employs gradient optimization method to reduce the time of feature matching and realize rapid object localization, and uses Bhattacharyya coefficient as the similarity measure between object template and candidate template. This thesis presents a mean shift algorithm based on coarse-to-fine search for the best kernel matching. This paper researches for object tracking with large motion area based on mean shift. To realize efficient tracking of such an object, we present a kernel matching method from coarseness to fine. If the motion areas of the object between two frames are very large and they are not overlapped in image space, then the traditional mean shift method can only obtain local optimal value by iterative computing in the old object window area, so the real tracking position cannot be obtained and the object tracking will be disabled. Our proposed algorithm can efficiently use a similarity measure function to realize the rough location of motion object, then use mean shift method to obtain the accurate local optimal value by iterative computing, which successfully realizes object tracking with large motion. Experimental results show its good performance in accuracy and speed when compared with background-weighted histogram algorithm in the literature.

Leap motion controlled videogame-based therapy for rehabilitation of elderly patients with subacute stroke: a feasibility pilot study.

PubMed

Iosa, Marco; Morone, Giovanni; Fusco, Augusto; Castagnoli, Marcello; Fusco, Francesca Romana; Pratesi, Luca; Paolucci, Stefano

2015-08-01

The leap motion controller (LMC) is a new optoelectronic system for capturing motion of both hands and controlling a virtual environment. Differently from previous devices, it optoelectronically tracks the fine movements of fingers neither using glows nor markers. This pilot study explored the feasibility of adapting the LMC, developed for videogames, to neurorehabilitation of elderly with subacute stroke. Four elderly patients (71.50 ± 4.51 years old) affected by stroke in subacute phase were enrolled and tested in a cross-over pilot trial in which six sessions of 30 minutes of LMC videogame-based therapy were added on conventional therapy. Measurements involved participation to the sessions, evaluated by means of the Pittsburgh Rehabilitation Participation Scale, hand ability and grasp force evaluated respectively by means of the Abilhand Scale and by means of the dynamometer. Neither adverse effects nor spasticity increments were observed during LMC training. Participation to the sessions was excellent in three patients and very good in one patient during the LMC trial. In this period, patients showed a significantly higher improvement in hand abilities (P = 0.028) and grasp force (P = 0.006). This feasibility pilot study was the first one using leap motion controller for conducting a videogame-based therapy. This study provided a proof of concept that LMC can be a suitable tool even for elderly patients with subacute stroke. LMC training was in fact performed with a high level of active participation, without adverse effects, and contributed to increase the recovery of hand abilities.

Integrated fMRI Preprocessing Framework Using Extended Kalman Filter for Estimation of Slice-Wise Motion

PubMed Central

Pinsard, Basile; Boutin, Arnaud; Doyon, Julien; Benali, Habib

2018-01-01

Functional MRI acquisition is sensitive to subjects' motion that cannot be fully constrained. Therefore, signal corrections have to be applied a posteriori in order to mitigate the complex interactions between changing tissue localization and magnetic fields, gradients and readouts. To circumvent current preprocessing strategies limitations, we developed an integrated method that correct motion and spatial low-frequency intensity fluctuations at the level of each slice in order to better fit the acquisition processes. The registration of single or multiple simultaneously acquired slices is achieved online by an Iterated Extended Kalman Filter, favoring the robust estimation of continuous motion, while an intensity bias field is non-parametrically fitted. The proposed extraction of gray-matter BOLD activity from the acquisition space to an anatomical group template space, taking into account distortions, better preserves fine-scale patterns of activity. Importantly, the proposed unified framework generalizes to high-resolution multi-slice techniques. When tested on simulated and real data the latter shows a reduction of motion explained variance and signal variability when compared to the conventional preprocessing approach. These improvements provide more stable patterns of activity, facilitating investigation of cerebral information representation in healthy and/or clinical populations where motion is known to impact fine-scale data. PMID:29755312

Integrated fMRI Preprocessing Framework Using Extended Kalman Filter for Estimation of Slice-Wise Motion.

PubMed

Pinsard, Basile; Boutin, Arnaud; Doyon, Julien; Benali, Habib

2018-01-01

Functional MRI acquisition is sensitive to subjects' motion that cannot be fully constrained. Therefore, signal corrections have to be applied a posteriori in order to mitigate the complex interactions between changing tissue localization and magnetic fields, gradients and readouts. To circumvent current preprocessing strategies limitations, we developed an integrated method that correct motion and spatial low-frequency intensity fluctuations at the level of each slice in order to better fit the acquisition processes. The registration of single or multiple simultaneously acquired slices is achieved online by an Iterated Extended Kalman Filter, favoring the robust estimation of continuous motion, while an intensity bias field is non-parametrically fitted. The proposed extraction of gray-matter BOLD activity from the acquisition space to an anatomical group template space, taking into account distortions, better preserves fine-scale patterns of activity. Importantly, the proposed unified framework generalizes to high-resolution multi-slice techniques. When tested on simulated and real data the latter shows a reduction of motion explained variance and signal variability when compared to the conventional preprocessing approach. These improvements provide more stable patterns of activity, facilitating investigation of cerebral information representation in healthy and/or clinical populations where motion is known to impact fine-scale data.

Automated video-based assessment of surgical skills for training and evaluation in medical schools.

PubMed

Zia, Aneeq; Sharma, Yachna; Bettadapura, Vinay; Sarin, Eric L; Ploetz, Thomas; Clements, Mark A; Essa, Irfan

2016-09-01

Routine evaluation of basic surgical skills in medical schools requires considerable time and effort from supervising faculty. For each surgical trainee, a supervisor has to observe the trainees in person. Alternatively, supervisors may use training videos, which reduces some of the logistical overhead. All these approaches however are still incredibly time consuming and involve human bias. In this paper, we present an automated system for surgical skills assessment by analyzing video data of surgical activities. We compare different techniques for video-based surgical skill evaluation. We use techniques that capture the motion information at a coarser granularity using symbols or words, extract motion dynamics using textural patterns in a frame kernel matrix, and analyze fine-grained motion information using frequency analysis. We were successfully able to classify surgeons into different skill levels with high accuracy. Our results indicate that fine-grained analysis of motion dynamics via frequency analysis is most effective in capturing the skill relevant information in surgical videos. Our evaluations show that frequency features perform better than motion texture features, which in-turn perform better than symbol-/word-based features. Put succinctly, skill classification accuracy is positively correlated with motion granularity as demonstrated by our results on two challenging video datasets.

Systematic Motion of Fine-scale Jets and Successive Reconnection in Solar Chromospheric Anemone Jet Observed with the Solar Optical Telescope/Hinode

NASA Astrophysics Data System (ADS)

Singh, K. A. P.; Isobe, H.; Nishida, K.; Shibata, K.

2012-11-01

The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A λ-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets (~1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergram images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.

Athletes in Motion: Training for the Olympic Games with Mind and Body: Two Case Studies.

ERIC Educational Resources Information Center

Ungerleider, Steven

Two case studies illustrate the Fine-Tuning Effect and its benefit to participants in athletic competition. The Fine-Tuning Effect is the sharpening of psychological processes that enable physical skills to be expressed in a maximum fashion. Such techniques as muscle relaxation, visual imagery, guided fantasy, autogenic training, and meditation…

Ventral aspect of the visual form pathway is not critical for the perception of biological motion

PubMed Central

Gilaie-Dotan, Sharon; Saygin, Ayse Pinar; Lorenzi, Lauren J.; Rees, Geraint; Behrmann, Marlene

2015-01-01

Identifying the movements of those around us is fundamental for many daily activities, such as recognizing actions, detecting predators, and interacting with others socially. A key question concerns the neurobiological substrates underlying biological motion perception. Although the ventral “form” visual cortex is standardly activated by biologically moving stimuli, whether these activations are functionally critical for biological motion perception or are epiphenomenal remains unknown. To address this question, we examined whether focal damage to regions of the ventral visual cortex, resulting in significant deficits in form perception, adversely affects biological motion perception. Six patients with damage to the ventral cortex were tested with sensitive point-light display paradigms. All patients were able to recognize unmasked point-light displays and their perceptual thresholds were not significantly different from those of three different control groups, one of which comprised brain-damaged patients with spared ventral cortex (n > 50). Importantly, these six patients performed significantly better than patients with damage to regions critical for biological motion perception. To assess the necessary contribution of different regions in the ventral pathway to biological motion perception, we complement the behavioral findings with a fine-grained comparison between the lesion location and extent, and the cortical regions standardly implicated in biological motion processing. This analysis revealed that the ventral aspects of the form pathway (e.g., fusiform regions, ventral extrastriate body area) are not critical for biological motion perception. We hypothesize that the role of these ventral regions is to provide enhanced multiview/posture representations of the moving person rather than to represent biological motion perception per se. PMID:25583504

Evaluating Effectiveness of Modeling Motion System Feedback in the Enhanced Hess Structural Model of the Human Operator

NASA Technical Reports Server (NTRS)

Zaychik, Kirill; Cardullo, Frank; George, Gary; Kelly, Lon C.

2009-01-01

In order to use the Hess Structural Model to predict the need for certain cueing systems, George and Cardullo significantly expanded it by adding motion feedback to the model and incorporating models of the motion system dynamics, motion cueing algorithm and a vestibular system. This paper proposes a methodology to evaluate effectiveness of these innovations by performing a comparison analysis of the model performance with and without the expanded motion feedback. The proposed methodology is composed of two stages. The first stage involves fine-tuning parameters of the original Hess structural model in order to match the actual control behavior recorded during the experiments at NASA Visual Motion Simulator (VMS) facility. The parameter tuning procedure utilizes a new automated parameter identification technique, which was developed at the Man-Machine Systems Lab at SUNY Binghamton. In the second stage of the proposed methodology, an expanded motion feedback is added to the structural model. The resulting performance of the model is then compared to that of the original one. As proposed by Hess, metrics to evaluate the performance of the models include comparison against the crossover models standards imposed on the crossover frequency and phase margin of the overall man-machine system. Preliminary results indicate the advantage of having the model of the motion system and motion cueing incorporated into the model of the human operator. It is also demonstrated that the crossover frequency and the phase margin of the expanded model are well within the limits imposed by the crossover model.

Use of 3D vision for fine robot motion

NASA Technical Reports Server (NTRS)

Lokshin, Anatole; Litwin, Todd

1989-01-01

An integration of 3-D vision systems with robot manipulators will allow robots to operate in a poorly structured environment by visually locating targets and obstacles. However, by using computer vision for objects acquisition makes the problem of overall system calibration even more difficult. Indeed, in a CAD based manipulation a control architecture has to find an accurate mapping between the 3-D Euclidean work space and a robot configuration space (joint angles). If a stereo vision is involved, then one needs to map a pair of 2-D video images directly into the robot configuration space. Neural Network approach aside, a common solution to this problem is to calibrate vision and manipulator independently, and then tie them via common mapping into the task space. In other words, both vision and robot refer to some common Absolute Euclidean Coordinate Frame via their individual mappings. This approach has two major difficulties. First a vision system has to be calibrated over the total work space. And second, the absolute frame, which is usually quite arbitrary, has to be the same with a high degree of precision for both robot and vision subsystem calibrations. The use of computer vision to allow robust fine motion manipulation in a poorly structured world which is currently in progress is described along with the preliminary results and encountered problems.

Ultra-Fine Scale Spatially-Integrated Mapping of Habitat and Occupancy Using Structure-From-Motion.

PubMed

McDowall, Philip; Lynch, Heather J

2017-01-01

Organisms respond to and often simultaneously modify their environment. While these interactions are apparent at the landscape extent, the driving mechanisms often occur at very fine spatial scales. Structure-from-Motion (SfM), a computer vision technique, allows the simultaneous mapping of organisms and fine scale habitat, and will greatly improve our understanding of habitat suitability, ecophysiology, and the bi-directional relationship between geomorphology and habitat use. SfM can be used to create high-resolution (centimeter-scale) three-dimensional (3D) habitat models at low cost. These models can capture the abiotic conditions formed by terrain and simultaneously record the position of individual organisms within that terrain. While coloniality is common in seabird species, we have a poor understanding of the extent to which dense breeding aggregations are driven by fine-scale active aggregation or limited suitable habitat. We demonstrate the use of SfM for fine-scale habitat suitability by reconstructing the locations of nests in a gentoo penguin colony and fitting models that explicitly account for conspecific attraction. The resulting digital elevation models (DEMs) are used as covariates in an inhomogeneous hybrid point process model. We find that gentoo penguin nest site selection is a function of the topography of the landscape, but that nests are far more aggregated than would be expected based on terrain alone, suggesting a strong role of behavioral aggregation in driving coloniality in this species. This integrated mapping of organisms and fine scale habitat will greatly improve our understanding of fine-scale habitat suitability, ecophysiology, and the complex bi-directional relationship between geomorphology and habitat use.

Leap Motion-based virtual reality training for improving motor functional recovery of upper limbs and neural reorganization in subacute stroke patients.

PubMed

Wang, Zun-Rong; Wang, Ping; Xing, Liang; Mei, Li-Ping; Zhao, Jun; Zhang, Tong

2017-11-01

Virtual reality is nowadays used to facilitate motor recovery in stroke patients. Most virtual reality studies have involved chronic stroke patients; however, brain plasticity remains good in acute and subacute patients. Most virtual reality systems are only applicable to the proximal upper limbs (arms) because of the limitations of their capture systems. Nevertheless, the functional recovery of an affected hand is most difficult in the case of hemiparesis rehabilitation after a stroke. The recently developed Leap Motion controller can track the fine movements of both hands and fingers. Therefore, the present study explored the effects of a Leap Motion-based virtual reality system on subacute stroke. Twenty-six subacute stroke patients were assigned to an experimental group that received virtual reality training along with conventional occupational rehabilitation, and a control group that only received conventional rehabilitation. The Wolf motor function test (WMFT) was used to assess the motor function of the affected upper limb; functional magnetic resonance imaging was used to measure the cortical activation. After four weeks of treatment, the motor functions of the affected upper limbs were significantly improved in all the patients, with the improvement in the experimental group being significantly better than in the control group. The action performance time in the WMFT significantly decreased in the experimental group. Furthermore, the activation intensity and the laterality index of the contralateral primary sensorimotor cortex increased in both the experimental and control groups. These results confirmed that Leap Motion-based virtual reality training was a promising and feasible supplementary rehabilitation intervention, could facilitate the recovery of motor functions in subacute stroke patients. The study has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-OCH-12002238).

Leap Motion-based virtual reality training for improving motor functional recovery of upper limbs and neural reorganization in subacute stroke patients

PubMed Central

Wang, Zun-rong; Wang, Ping; Xing, Liang; Mei, Li-ping; Zhao, Jun; Zhang, Tong

2017-01-01

Virtual reality is nowadays used to facilitate motor recovery in stroke patients. Most virtual reality studies have involved chronic stroke patients; however, brain plasticity remains good in acute and subacute patients. Most virtual reality systems are only applicable to the proximal upper limbs (arms) because of the limitations of their capture systems. Nevertheless, the functional recovery of an affected hand is most difficult in the case of hemiparesis rehabilitation after a stroke. The recently developed Leap Motion controller can track the fine movements of both hands and fingers. Therefore, the present study explored the effects of a Leap Motion-based virtual reality system on subacute stroke. Twenty-six subacute stroke patients were assigned to an experimental group that received virtual reality training along with conventional occupational rehabilitation, and a control group that only received conventional rehabilitation. The Wolf motor function test (WMFT) was used to assess the motor function of the affected upper limb; functional magnetic resonance imaging was used to measure the cortical activation. After four weeks of treatment, the motor functions of the affected upper limbs were significantly improved in all the patients, with the improvement in the experimental group being significantly better than in the control group. The action performance time in the WMFT significantly decreased in the experimental group. Furthermore, the activation intensity and the laterality index of the contralateral primary sensorimotor cortex increased in both the experimental and control groups. These results confirmed that Leap Motion-based virtual reality training was a promising and feasible supplementary rehabilitation intervention, could facilitate the recovery of motor functions in subacute stroke patients. The study has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-OCH-12002238). PMID:29239328

Design and evaluation of an optical fine-pointing control system for telescopes utilizing a digital star sensor

NASA Technical Reports Server (NTRS)

Ostroff, A. J.; Romanczyk, K. C.

1973-01-01

One of the most significant problems associated with the development of large orbiting astronomical telescopes is that of maintaining the very precise pointing accuracy required. A proposed solution to this problem utilizes dual-level pointing control. The primary control system maintains the telescope structure attitude stabilized within the field of view to the desired accuracy. In order to demonstrate the feasibility of optically stabilizing the star images to the desired accuracy a regulating system has been designed and evaluated. The control system utilizes a digital star sensor and an optical star image motion compensator, both of which have been developed for this application. These components have been analyzed mathematically, analytical models have been developed, and hardware has been built and tested.

Global velocity constrained cloud motion prediction for short-term solar forecasting

NASA Astrophysics Data System (ADS)

Chen, Yanjun; Li, Wei; Zhang, Chongyang; Hu, Chuanping

2016-09-01

Cloud motion is the primary reason for short-term solar power output fluctuation. In this work, a new cloud motion estimation algorithm using a global velocity constraint is proposed. Compared to the most used Particle Image Velocity (PIV) algorithm, which assumes the homogeneity of motion vectors, the proposed method can capture the accurate motion vector for each cloud block, including both the motional tendency and morphological changes. Specifically, global velocity derived from PIV is first calculated, and then fine-grained cloud motion estimation can be achieved by global velocity based cloud block researching and multi-scale cloud block matching. Experimental results show that the proposed global velocity constrained cloud motion prediction achieves comparable performance to the existing PIV and filtered PIV algorithms, especially in a short prediction horizon.

AstroTech 21. Volume 1: Missions.

DTIC Science & Technology

1993-03-26

and evolution, and the sun and other solar system bodies . It will thus complement die capabilities of other NASA missions, such as HST and SIRTF, and...the line of sight - be nearly perfectly isolated from the motions of the rest of the aircraft. Current Status: Rotational isolation will be...types of bearings or isolators. The telescope’s gross elevation motion will be actuated by a spur gear, 11 3/19/93 and its fine motion by three

Integrated controls-structures design methodology development for a class of flexible spacecraft

NASA Technical Reports Server (NTRS)

Maghami, P. G.; Joshi, S. M.; Walz, J. E.; Armstrong, E. S.

1990-01-01

Future utilization of space will require large space structures in low-Earth and geostationary orbits. Example missions include: Earth observation systems, personal communication systems, space science missions, space processing facilities, etc., requiring large antennas, platforms, and solar arrays. The dimensions of such structures will range from a few meters to possibly hundreds of meters. For reducing the cost of construction, launching, and operating (e.g., energy required for reboosting and control), it will be necessary to make the structure as light as possible. However, reducing structural mass tends to increase the flexibility which would make it more difficult to control with the specified precision in attitude and shape. Therefore, there is a need to develop a methodology for designing space structures which are optimal with respect to both structural design and control design. In the current spacecraft design practice, it is customary to first perform the structural design and then the controller design. However, the structural design and the control design problems are substantially coupled and must be considered concurrently in order to obtain a truly optimal spacecraft design. For example, let C denote the set of the 'control' design variables (e.g., controller gains), and L the set of the 'structural' design variables (e.g., member sizes). If a structural member thickness is changed, the dynamics would change which would then change the control law and the actuator mass. That would, in turn, change the structural model. Thus, the sets C and L depend on each other. Future space structures can be roughly divided into four mission classes. Class 1 missions include flexible spacecraft with no articulated appendages which require fine attitude pointing and vibration suppression (e.g., large space antennas). Class 2 missions consist of flexible spacecraft with articulated multiple payloads, where the requirement is to fine-point the spacecraft and each individual payload while suppressing the elastic motion. Class 3 missions include rapid slewing of spacecraft without appendages, while Class 4 missions include general nonlinear motion of a flexible spacecraft with articulated appendages and robot arms. Class 1 and 2 missions represent linear mathematical modeling and control system design problems (except for actuator and sensor nonlinearities), while Class 3 and 4 missions represent nonlinear problems. The development of an integrated controls/structures design approach for Class 1 missions is addressed. The performance for these missions is usually specified in terms of (1) root mean square (RMS) pointing errors at different locations on the structure, and (2) the rate of decay of the transient response. Both of these performance measures include the contributions of rigid as well as elastic motion.

Design constraints of the LST fine guidance sensor

NASA Technical Reports Server (NTRS)

Wissinger, A. B.

1975-01-01

The LST Fine Guidance Sensor design is shaped by the rate of occurrence of suitable guide stars, the competition for telescope focal plane space with the Science Instruments, and the sensitivity of candidate image motion sensors. The relationship between these parameters is presented, and sensitivity to faint stars is shown to be of prime importance. An interferometric technique of image motion sensing is shown to have improved sensitivity and, therefore, a reduced focal plane area requirement in comparison with other candidate techniques (image-splitting prism and image dissector tube techniques). Another design requirement is speed in acquiring the guide star in order to maximize the time available for science observations. The design constraints are shown parametrically, and modelling results are presented.

Magnetic suspension and pointing system

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Groom, N. J. (Inventor)

1978-01-01

An apparatus is reported for accurate pointing of instruments on a carrier vehicle and for isolation of the instruments from the vehicle's motion disturbances. The apparatus includes two assemblies with connecting interfaces. The first assembly is attached to the carrier vehicle and consists of an azimuth gimbal and an elevation gimbal which provide coarse pointing by allowing two rotations of the instruments relative to the carrier vehicle. The second or vernier pointing assembly is made up of magnetic suspension and fine pointing actuators, roll motor segments, and an instrument mounting plase which provides appropriate magnetic circuits for the actuators and the roll motor segments. The vernier pointing assembly provides attitude fine pointing and roll positioning of the instruments as well as six degree-of-freedom isolation from carrier motion disturbances.

Ultra-Fine Scale Spatially-Integrated Mapping of Habitat and Occupancy Using Structure-From-Motion

PubMed Central

McDowall, Philip; Lynch, Heather J.

2017-01-01

Organisms respond to and often simultaneously modify their environment. While these interactions are apparent at the landscape extent, the driving mechanisms often occur at very fine spatial scales. Structure-from-Motion (SfM), a computer vision technique, allows the simultaneous mapping of organisms and fine scale habitat, and will greatly improve our understanding of habitat suitability, ecophysiology, and the bi-directional relationship between geomorphology and habitat use. SfM can be used to create high-resolution (centimeter-scale) three-dimensional (3D) habitat models at low cost. These models can capture the abiotic conditions formed by terrain and simultaneously record the position of individual organisms within that terrain. While coloniality is common in seabird species, we have a poor understanding of the extent to which dense breeding aggregations are driven by fine-scale active aggregation or limited suitable habitat. We demonstrate the use of SfM for fine-scale habitat suitability by reconstructing the locations of nests in a gentoo penguin colony and fitting models that explicitly account for conspecific attraction. The resulting digital elevation models (DEMs) are used as covariates in an inhomogeneous hybrid point process model. We find that gentoo penguin nest site selection is a function of the topography of the landscape, but that nests are far more aggregated than would be expected based on terrain alone, suggesting a strong role of behavioral aggregation in driving coloniality in this species. This integrated mapping of organisms and fine scale habitat will greatly improve our understanding of fine-scale habitat suitability, ecophysiology, and the complex bi-directional relationship between geomorphology and habitat use. PMID:28076351

A General Tool for Evaluating High-Contrast Coronagraphic Telescope Performance Error Budgets

NASA Technical Reports Server (NTRS)

Marchen, Luis F.; Shaklan, Stuart B.

2009-01-01

This paper describes a general purpose Coronagraph Performance Error Budget (CPEB) tool that we have developed under the NASA Exoplanet Exploration Program. The CPEB automates many of the key steps required to evaluate the scattered starlight contrast in the dark hole of a space-based coronagraph. It operates in 3 steps: first, a CodeV or Zemax prescription is converted into a MACOS optical prescription. Second, a Matlab program calls ray-trace code that generates linear beam-walk and aberration sensitivity matrices for motions of the optical elements and line-of-sight pointing, with and without controlled coarse and fine-steering mirrors. Third, the sensitivity matrices are imported by macros into Excel 2007 where the error budget is created. Once created, the user specifies the quality of each optic from a predefined set of PSDs. The spreadsheet creates a nominal set of thermal and jitter motions and combines them with the sensitivity matrices to generate an error budget for the system. The user can easily modify the motion allocations to perform trade studies.

Automatic Synthesis of Fine-Motion Strategies for Robots.

DTIC Science & Technology

1983-12-01

ADA-A39 532 AUTOMATI CSYNTHESISOF FNE-MOTIONSTRATEGIESFORa R080 S(U) MASSACHUSETTS INS OF TECH CAMBRIDOE ARTIFCIAL INTELLGENCE LAB IOZANO-PEREZ DEC...N00014-82-K-0334 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK Artificial Intelligence Laboratory AREA...provides correct- ness criteria for compliant motion strategies. MASSACHUSETTS INSTITUTE OF TECHNOLOGY ARTIFICIAL INTELLIGENCE LABORATORY A. I. MEMO 759

Fine-resolution repeat topographic surveying of dryland landscapes using UAS-based structure-from-motion photogrammetry: Assessing accuracy and precision against traditional ground-based erosion measurements

USDA-ARS?s Scientific Manuscript database

Structure-from-motion (SfM) photogrammetry from unmanned aircraft system (UAS) imagery is an emerging tool for repeat topographic surveying of dryland erosion. These methods are particularly appealing due to the ability to cover large landscapes compared to field methods and at reduced costs and hig...

Experimental study of trajectory planning and control of a high precision robot manipulator

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Antrazi, Sami S.

1991-01-01

The kinematic and trajectory planning is presented for a 6 DOF end-effector whose design was based on the Stewart Platform mechanism. The end-effector was used as a testbed for studying robotic assembly of NASA hardware with passive compliance. Vector analysis was employed to derive a closed-form solution for the end-effector inverse kinematic transformation. A computationally efficient numerical solution was obtained for the end-effector forward kinematic transformation using Newton-Raphson method. Three trajectory planning schemes, two for fine motion and one for gross motion, were developed for the end-effector. Experiments conducted to evaluate the performance of the trajectory planning schemes showed excellent tracking quality with minimal errors. Current activities focus on implementing the developed trajectory planning schemes on mating and demating space-rated connectors and using the compliant platform to acquire forces/torques applied on the end-effector during the assembly task.

HELICAL MOTIONS OF FINE-STRUCTURE PROMINENCE THREADS OBSERVED BY HINODE AND IRIS

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

Okamoto, Takenori J.; Liu, Wei; Tsuneta, Saku, E-mail: joten.okamoto@nao.ac.jp

Fine-structure dynamics in solar prominences holds critical clues to understanding their physical nature of significant space-weather implications. We report evidence of rotational motions of horizontal helical threads in two active-region prominences observed by the Hinode and/or Interface Region Imaging Spectrograph satellites at high resolution. In the first event, we found transverse motions of brightening threads at speeds up to 55 km s{sup -1} seen in the plane of the sky. Such motions appeared as sinusoidal space–time trajectories with a typical period of ∼390 s, which is consistent with plane-of-sky projections of rotational motions. Phase delays at different locations suggest themore » propagation of twists along the threads at phase speeds of 90–270 km s{sup -1}. At least 15 episodes of such motions occurred in two days, none associated with an eruption. For these episodes, the plane-of-sky speed is linearly correlated with the vertical travel distance, suggestive of a constant angular speed. In the second event, we found Doppler velocities of 30–40 km s{sup -1} in opposite directions in the top and bottom portions of the prominence, comparable to the plane-of-sky speed. The moving threads have about twice broader line widths than stationary threads. These observations, when taken together, provide strong evidence for rotations of helical prominence threads, which were likely driven by unwinding twists triggered by magnetic reconnection between twisted prominence magnetic fields and ambient coronal fields.« less

A simulation of the instrument pointing system for the Astro-1 mission

NASA Technical Reports Server (NTRS)

Whorton, M.; West, M.; Rakoczy, J.

1991-01-01

NASA has recently completed a shuttle-borne stellar ultraviolet astronomy mission known as Astro-1. A three axis instrument pointing system (IPS) was employed to accurately point the science instruments. In order to analyze the pointing control system and verify pointing performance, a simulation of the IPS was developed using the multibody dynamics software TREETOPS. The TREETOPS IPS simulation is capable of accurately modeling the multibody IPS system undergoing large angle, nonlinear motion. The simulation is documented and example cases are presented demonstrating disturbance rejection, fine pointing operations, and multiple target pointing and slewing of the IPS.

Repeated crossing of two concentric spherical thin-shells with charge

NASA Astrophysics Data System (ADS)

Mazharimousavi, S. Habib; Halilsoy, M.

Interaction/collision of two concentric spherical thin-shells of linear fluid resulting in collapse has been considered recently. We show that addition of finely tuned electric charges on the shells apart from the cosmological constant serves to delay the collapse indefinitely, yielding an ever colliding system of two concentric fluid shells. Given the finely tuned charges, this provides an example of a perpetual two-body motion in general relativity.

Improved optical flow motion estimation for digital image stabilization

NASA Astrophysics Data System (ADS)

Lai, Lijun; Xu, Zhiyong; Zhang, Xuyao

2015-11-01

Optical flow is the instantaneous motion vector at each pixel in the image frame at a time instant. The gradient-based approach for optical flow computation can't work well when the video motion is too large. To alleviate such problem, we incorporate this algorithm into a pyramid multi-resolution coarse-to-fine search strategy. Using pyramid strategy to obtain multi-resolution images; Using iterative relationship from the highest level to the lowest level to obtain inter-frames' affine parameters; Subsequence frames compensate back to the first frame to obtain stabilized sequence. The experiment results demonstrate that the promoted method has good performance in global motion estimation.

Fuzzy-Based Hybrid Control Algorithm for the Stabilization of a Tri-Rotor UAV.

PubMed

Ali, Zain Anwar; Wang, Daobo; Aamir, Muhammad

2016-05-09

In this paper, a new and novel mathematical fuzzy hybrid scheme is proposed for the stabilization of a tri-rotor unmanned aerial vehicle (UAV). The fuzzy hybrid scheme consists of a fuzzy logic controller, regulation pole-placement tracking (RST) controller with model reference adaptive control (MRAC), in which adaptive gains of the RST controller are being fine-tuned by a fuzzy logic controller. Brushless direct current (BLDC) motors are installed in the triangular frame of the tri-rotor UAV, which helps maintain control on its motion and different altitude and attitude changes, similar to rotorcrafts. MRAC-based MIT rule is proposed for system stability. Moreover, the proposed hybrid controller with nonlinear flight dynamics is shown in the presence of translational and rotational velocity components. The performance of the proposed algorithm is demonstrated via MATLAB simulations, in which the proposed fuzzy hybrid controller is compared with the existing adaptive RST controller. It shows that our proposed algorithm has better transient performance with zero steady-state error, and fast convergence towards stability.

Effects of coarse grain size distribution and fine particle content on pore fluid pressure and shear behavior in experimental debris flows

NASA Astrophysics Data System (ADS)

Kaitna, Roland; Palucis, Marisa C.; Yohannes, Bereket; Hill, Kimberly M.; Dietrich, William E.

2016-02-01

Debris flows are typically a saturated mixture of poorly sorted particles and interstitial fluid, whose density and flow properties depend strongly on the presence of suspended fine sediment. Recent research suggests that grain size distribution (GSD) influences excess pore pressures (i.e., pressure in excess of predicted hydrostatic pressure), which in turn plays a governing role in debris flow behaviors. We report a series of controlled laboratory experiments in a 4 m diameter vertically rotating drum where the coarse particle size distribution and the content of fine particles were varied independently. We measured basal pore fluid pressures, pore fluid pressure profiles (using novel sensor probes), velocity profiles, and longitudinal profiles of the flow height. Excess pore fluid pressure was significant for mixtures with high fines fraction. Such flows exhibited lower values for their bulk flow resistance (as measured by surface slope of the flow), had damped fluctuations of normalized fluid pressure and normal stress, and had velocity profiles where the shear was concentrated at the base of the flow. These effects were most pronounced in flows with a wide coarse GSD distribution. Sustained excess fluid pressure occurred during flow and after cessation of motion. Various mechanisms may cause dilation and contraction of the flows, and we propose that the sustained excess fluid pressures during flow and once the flow has stopped may arise from hindered particle settling and yield strength of the fluid, resulting in transfer of particle weight to the fluid. Thus, debris flow behavior may be strongly influenced by sustained excess fluid pressures controlled by particle settling rates.

Anomalous permittivity in fine-grain barium titanate

NASA Astrophysics Data System (ADS)

Ostrander, Steven Paul

Fine-grain barium titanate capacitors exhibit anomalously large permittivity. It is often observed that these materials will double or quadruple the room temperature permittivity of a coarse-grain counterpart. However, aside from a general consensus on this permittivity enhancement, the properties of the fine-grain material are poorly understood. This thesis examines the effect of grain size on dielectric properties of a self-consistent set of high density undoped barium titanate capacitors. This set included samples with grain sizes ranging from submicron to ˜20 microns, and with densities generally above 95% of the theoretical. A single batch of well characterized powder was milled, dry-pressed then isostatically-pressed. Compacts were fast-fired, but sintering temperature alone was used to control the grain size. With this approach, the extrinsic influences are minimized within the set of samples, but more importantly, they are normalized between samples. That is, with a single batch of powder and with identical green processing, uniform impurity concentration is expected. The fine-grain capacitors exhibited a room temperature permittivity of ˜5500 and dielectric losses of ˜2%. The Curie-temperature decreased by {˜}5sp°C from that of the coarse-grain material, and the two ferroelectric-ferroelectric phase transition temperatures increased by {˜}10sp°C. The grain size induced permittivity enhancement was only active in the tetragonal and orthorhombic phases. Strong dielectric anomalies were observed in samples with grain size as small as {˜}0.4\\ mum. It is suggested that the strong first-order character observed in the present data is related to control of microstructure and stoichiometry. Grain size effects on conductivity losses, ferroelectric losses, ferroelectric dispersion, Maxwell-Wagner dispersion, and dielectric aging of permittivity and loss were observed. For the fine-grain material, these observations suggest the suppression of domain wall motion below the Curie transition, and the suppression of conductivity above the Curie transition.

A spiral motion piezoelectric micromotor for autofocus and auto zoom in a medical endoscope

NASA Astrophysics Data System (ADS)

Chen, Xi; Chen, Zhijiang; Li, Xiaotian; Shan, Liang; Sun, Wanchen; Wang, Xiguang; Xie, Tianyu; Dong, Shuxiang

2016-02-01

We report a hollow type piezoelectric micromotor made of a PZT ceramic/metal composite cylinder with sizes of only 3.6 mm in diameter and 3.0 mm in length aiming at medical endoscope application. The hollow piezoelectric stator of the micromotor, acting as a nut, can excite E02-mode traveling wave along its circumferential direction, and a hollow rotor with a fine lens inside, acting as a screw, is driven to produce a spiral motion along its axis direction inside the hollow stator via the traveling wave. The features of the developed micromotors are its hollow, fine structure and submicrometer step resolution, ensuring that the optical path passes in a narrow and limited space and that the optical focal length is tuned precisely inside the endoscope, which is meaningful in medical diagnosis.

From Supercomputer Modeling to Highest Mass Resolution in FT-ICR.

PubMed

N Nikolaev, Evgene; N Vladimirov, Gleb; Jertz, Roland; Baykut, Gökhan

2013-01-01

Understanding of behavior of ion ensembles inside FT-ICR cell based on the computer simulation of ion motion gives rise to the new ideas of cell designs. The recently introduced novel FT-ICR cell based on a Penning ion trap with specially shaped excitation and detection electrodes prevents distortion of ion cyclotron motion phases (normally caused by non-ideal electric trapping fields) by averaging the trapping DC electric field during the ion motion in the ICR cell. Detection times of 5 min resulting in resolving power close to 40,000,000 have been reached for reserpine at m/z 609 at a magnetic field of only 7 Tesla. Fine structures of resolved 13Cn isotopic cluster groups could be measured for molecular masses up to 5.7 kDa (insulin) with resolving power of 4,000,000 at 7 Tesla. Based on resolved fine structure patterns atomic compositions can be directly determined using a new developed algorithm for fine structure processing. Mass spectra of proteins and multimers of proteins reaching masses up to 186 kDa (enolase tetramer) could be measured with isotopic resolution. For instance, at 7 Tesla resolving power of 800,000 was achieved for enolase dimer (96 kDa) and 500,000 for molecular masses above 100 kDa. Experimental data indicate that there is practically no limit for the resolving power of this ICR cell except by collisional damping in the ultrahigh vacuum chamber.

Variable mass pendulum behaviour processed by wavelet analysis

NASA Astrophysics Data System (ADS)

Caccamo, M. T.; Magazù, S.

2017-01-01

The present work highlights how, in order to characterize the motion of a variable mass pendulum, wavelet analysis can be an effective tool in furnishing information on the time evolution of the oscillation spectral content. In particular, the wavelet transform is applied to process the motion of a hung funnel that loses fine sand at an exponential rate; it is shown how, in contrast to the Fourier transform which furnishes only an average frequency value for the motion, the wavelet approach makes it possible to perform a joint time-frequency analysis. The work is addressed at undergraduate and graduate students.

Effect of damping on excitability of high-order normal modes. [for a large space telescope spacecraft

NASA Technical Reports Server (NTRS)

Merchant, D. H.; Gates, R. M.; Straayer, J. W.

1975-01-01

The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs.

High-resolution observations of active region moss and its dynamics

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

Morton, R. J.; McLaughlin, J. A., E-mail: richard.morton@northumbria.ac.uk

2014-07-10

The High Resolution Coronal Imager has provided the sharpest view of the EUV corona to date. In this paper, we exploit its impressive resolving power to provide the first analysis of the fine-scale structure of moss in an active region. The data reveal that the moss is made up of a collection of fine threads that have widths with a mean and standard deviation of 440 ± 190 km (FWHM). The brightest moss emission is located at the visible head of the fine-scale structure and the fine structure appears to extend into the lower solar atmosphere. The emission decreases alongmore » the features, implying that the lower sections are most likely dominated by cooler transition region plasma. These threads appear to be the cool, lower legs of the hot loops. In addition, the increased resolution allows for the first direct observation of physical displacements of the moss fine structure in a direction transverse to its central axis. Some of these transverse displacements demonstrate periodic behavior, which we interpret as a signature of kink (Alfvénic) waves. Measurements of the properties of the transverse motions are made and the wave motions have means and standard deviations of 55 ± 37 km for the transverse displacement amplitude, 77 ± 33 s for the period, and 4.7 ± 2.5 km s{sup –1} for the velocity amplitude. The presence of waves in the transition region of hot loops could have important implications for the heating of active regions.« less

Fine Pointing Of The Solar Optical Telescope In The Space Shuttle Environment

NASA Astrophysics Data System (ADS)

Gowrinathan, Sankaran

1987-02-01

Instruments attached to the payload bay of the Space Shuttle require special attention where fine pointing is involved. Fine pointing, for purposes of this discussion, is defined as sub-arc second pointing. Instruments requiring such fine pointing (Solar Optical Telescope and Shuttle Infrared Telescope, for example) will require two stages of pointing (coarse and fine). Coarse pointing will be performed by a gimbal system such as the Instrument Pointing System (IPS). Fine pointing will be provided by image motion compensation (IMC). Most forms of IMC involve adjustable optical elements in the optical system to compensate for fast transient disturbances. This paper describes work performed on the Solar Optical Telescope (SOT) concept design that illustrates IMC as applied to SOT. The fine pointing requirements on SOT dictate use of IMC at about 20 Hz. bandwidth. It will be shown that the need for this high bandwidth is related to shuttle-induced disturbances. Shuttle-induced disturbances are primarily due to two sources; man push-offs and vernier thruster firings. Both disturbance sources have high-frequency content that drive the IMC bandwidth.

Zero-gyro control of the International Ultraviolet Explorer

NASA Technical Reports Server (NTRS)

O'Donnell, James R., Jr.; Hoffman, Henry C.

1993-01-01

The IUE was built for an anticipated lifespan of three years with a goal of five. It has been operating for over 15 years, even though it has had only two working gyros since August 17, 1985, through the use of a two-gyro attitude control system that uses information from IUE's fine sun sensor (FSS) and the two remaining gyros to provide three-axis control. A one-gyro control system that uses an additional axis of information from the FSS has been developed and tested on-orbit. The purpose of this paper is to discuss the work in progress towards the development of a zero-gyro control law for IUE. Motion about the sunline, which cannot be measured by the FSS, is measured and controlled in the zero-gyro system by applying a momentum bias perpendicular to the sunline and measuring the transfer of this momentum between the spacecraft reaction wheels, while the spacecraft is held in the other two axes using position and derived-rate information from the FSS.

Design of motion adjusting system for space camera based on ultrasonic motor

NASA Astrophysics Data System (ADS)

Xu, Kai; Jin, Guang; Gu, Song; Yan, Yong; Sun, Zhiyuan

2011-08-01

Drift angle is a transverse intersection angle of vector of image motion of the space camera. Adjusting the angle could reduce the influence on image quality. Ultrasonic motor (USM) is a new type of actuator using ultrasonic wave stimulated by piezoelectric ceramics. They have many advantages in comparison with conventional electromagnetic motors. In this paper, some improvement was designed for control system of drift adjusting mechanism. Based on ultrasonic motor T-60 was designed the drift adjusting system, which is composed of the drift adjusting mechanical frame, the ultrasonic motor, the driver of Ultrasonic Motor, the photoelectric encoder and the drift adjusting controller. The TMS320F28335 DSP was adopted as the calculation and control processor, photoelectric encoder was used as sensor of position closed loop system and the voltage driving circuit designed as generator of ultrasonic wave. It was built the mathematic model of drive circuit of the ultrasonic motor T-60 using matlab modules. In order to verify the validity of the drift adjusting system, was introduced the source of the disturbance, and made simulation analysis. It designed the control systems of motor drive for drift adjusting system with the improved PID control. The drift angle adjusting system has such advantages as the small space, simple configuration, high position control precision, fine repeatability, self locking property and low powers. It showed that the system could accomplish the mission of drift angle adjusting excellent.

Finalizing the Dtag: implementation and testing of design improvements for reliability and availability

DTIC Science & Technology

2016-10-14

ABSTRACT DTAGs have proven to be a valuable tool for the study of marine mammal acoustics and fine scale motion. The success of the DTAG has resulted in...Underwater Acoustics , Digital Communications 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF a. REPORT b. ABSTRACT c. THIS PAGE ABSTRACT u u u...continuously monitor and improve the tag design.\\ OBJECTIVES Dtags have proven to be a valuable tool for the study of marine mammal acoustics and fine

Microsoft Kinect Sensor Evaluation

NASA Technical Reports Server (NTRS)

Billie, Glennoah

2011-01-01

My summer project evaluates the Kinect game sensor input/output and its suitability to perform as part of a human interface for a spacecraft application. The primary objective is to evaluate, understand, and communicate the Kinect system's ability to sense and track fine (human) position and motion. The project will analyze the performance characteristics and capabilities of this game system hardware and its applicability for gross and fine motion tracking. The software development kit for the Kinect was also investigated and some experimentation has begun to understand its development environment. To better understand the software development of the Kinect game sensor, research in hacking communities has brought a better understanding of the potential for a wide range of personal computer (PC) application development. The project also entails the disassembly of the Kinect game sensor. This analysis would involve disassembling a sensor, photographing it, and identifying components and describing its operation.

On Integral Invariants for Effective 3-D Motion Trajectory Matching and Recognition.

PubMed

Shao, Zhanpeng; Li, Youfu

2016-02-01

Motion trajectories tracked from the motions of human, robots, and moving objects can provide an important clue for motion analysis, classification, and recognition. This paper defines some new integral invariants for a 3-D motion trajectory. Based on two typical kernel functions, we design two integral invariants, the distance and area integral invariants. The area integral invariants are estimated based on the blurred segment of noisy discrete curve to avoid the computation of high-order derivatives. Such integral invariants for a motion trajectory enjoy some desirable properties, such as computational locality, uniqueness of representation, and noise insensitivity. Moreover, our formulation allows the analysis of motion trajectories at a range of scales by varying the scale of kernel function. The features of motion trajectories can thus be perceived at multiscale levels in a coarse-to-fine manner. Finally, we define a distance function to measure the trajectory similarity to find similar trajectories. Through the experiments, we examine the robustness and effectiveness of the proposed integral invariants and find that they can capture the motion cues in trajectory matching and sign recognition satisfactorily.

Fuzzy-Based Hybrid Control Algorithm for the Stabilization of a Tri-Rotor UAV

PubMed Central

Ali, Zain Anwar; Wang, Daobo; Aamir, Muhammad

2016-01-01

In this paper, a new and novel mathematical fuzzy hybrid scheme is proposed for the stabilization of a tri-rotor unmanned aerial vehicle (UAV). The fuzzy hybrid scheme consists of a fuzzy logic controller, regulation pole-placement tracking (RST) controller with model reference adaptive control (MRAC), in which adaptive gains of the RST controller are being fine-tuned by a fuzzy logic controller. Brushless direct current (BLDC) motors are installed in the triangular frame of the tri-rotor UAV, which helps maintain control on its motion and different altitude and attitude changes, similar to rotorcrafts. MRAC-based MIT rule is proposed for system stability. Moreover, the proposed hybrid controller with nonlinear flight dynamics is shown in the presence of translational and rotational velocity components. The performance of the proposed algorithm is demonstrated via MATLAB simulations, in which the proposed fuzzy hybrid controller is compared with the existing adaptive RST controller. It shows that our proposed algorithm has better transient performance with zero steady-state error, and fast convergence towards stability. PMID:27171084

A Sensory-Motor Control Model of Animal Flight Explains Why Bats Fly Differently in Light Versus Dark

PubMed Central

Bar, Nadav S.; Skogestad, Sigurd; Marçal, Jose M.; Ulanovsky, Nachum; Yovel, Yossi

2015-01-01

Animal flight requires fine motor control. However, it is unknown how flying animals rapidly transform noisy sensory information into adequate motor commands. Here we developed a sensorimotor control model that explains vertebrate flight guidance with high fidelity. This simple model accurately reconstructed complex trajectories of bats flying in the dark. The model implies that in order to apply appropriate motor commands, bats have to estimate not only the angle-to-target, as was previously assumed, but also the angular velocity (“proportional-derivative” controller). Next, we conducted experiments in which bats flew in light conditions. When using vision, bats altered their movements, reducing the flight curvature. This change was explained by the model via reduction in sensory noise under vision versus pure echolocation. These results imply a surprising link between sensory noise and movement dynamics. We propose that this sensory-motor link is fundamental to motion control in rapidly moving animals under different sensory conditions, on land, sea, or air. PMID:25629809

Direct Numerical Simulation of a Temporally Evolving Incompressible Plane Wake: Effect of Initial Conditions on Evolution and Topology

NASA Technical Reports Server (NTRS)

Sondergaard, R.; Cantwell, B.; Mansour, N.

1997-01-01

Direct numerical simulations have been used to examine the effect of the initial disturbance field on the development of three-dimensionality and the transition to turbulence in the incompressible plane wake. The simulations were performed using a new numerical method for solving the time-dependent, three-dimensional, incompressible Navier-Stokes equations in flows with one infinite and two periodic directions. The method uses standard Fast Fourier Transforms and is applicable to cases where the vorticity field is compact in the infinite direction. Initial disturbances fields examined were combinations of two-dimensional waves and symmetric pairs of 60 deg oblique waves at the fundamental, subharmonic, and sub-subharmonic wavelengths. The results of these simulations indicate that the presence of 60 deg disturbances at the subharmonic streamwise wavelength results in the development of strong coherent three-dimensional structures. The resulting strong three-dimensional rate-of-strain triggers the growth of intense fine scale motions. Wakes initiated with 60 deg disturbances at the fundamental streamwise wavelength develop weak coherent streamwise structures, and do not develop significant fine scale motions, even at high Reynolds numbers. The wakes which develop strong three-dimensional structures exhibit growth rates on par with experimentally observed turbulent plane wakes. Wakes which develop only weak three-dimensional structures exhibit significantly lower late time growth rates. Preliminary studies of wakes initiated with an oblique fundamental and a two-dimensional subharmonic, which develop asymmetric coherent oblique structures at the subharmonic wavelength, indicate that significant fine scale motions only develop if the resulting oblique structures are above an angle of approximately 45 deg.

Luminous Herbig-Haro objects from a massive protostar: The unique case of HH 80/81

NASA Astrophysics Data System (ADS)

Reipurth, Bo

2017-08-01

Herbig-Haro (HH) objects are the optical manifestations of shock waves excited by outflows from young stars. They represent one of the few classes of spatially extended astronomical objects where both structural changes and proper motions can be measured on time scales of years to decades. HH 80/81 is a pair of HH objects in Sagittarius which are the intrinsically most luminous HH objects known. The driving source of HH 80/81 is the embedded star IRAS 18162-2048, which has a luminosity of 20,000 Lsun and excites a compact HII region, suggesting that it is a newborn massive star. HH objects associated with massive young stars are very rare, only a handful of cases are known, but what makes the HH 80/81 source unique among massive protostars is that it produces a finely collimated bipolar radio jet with extremely high velocity and pointing straight to HH 80/81. We propose to observe the HH 80/81 complex with WFC3 and the following four filters: Halpha 6563, Hbeta 4861, [SII] 6717/31, and [OIII] 5007. First epoch HST images were obtained 22 years ago, which now allows a very precise determination of proper motions. Groundbased optical and radio proper motions are not only uncertain, but actually contradict each other, a controversy that will be resolved by HST. The fine resolution of WFC3 allows a study of both fine structural details and structural changes of the shocks. Finally we will use a sophisticated adaptive grid code to interpret the (de-reddened) line ratios across the shocks.

Catching What We Can't See: Manual Interception of Occluded Fly-Ball Trajectories

PubMed Central

Bosco, Gianfranco; Delle Monache, Sergio; Lacquaniti, Francesco

2012-01-01

Control of interceptive actions may involve fine interplay between feedback-based and predictive mechanisms. These processes rely heavily on target motion information available when the target is visible. However, short-term visual memory signals as well as implicit knowledge about the environment may also contribute to elaborate a predictive representation of the target trajectory, especially when visual feedback is partially unavailable because other objects occlude the visual target. To determine how different processes and information sources are integrated in the control of the interceptive action, we manipulated a computer-generated visual environment representing a baseball game. Twenty-four subjects intercepted fly-ball trajectories by moving a mouse cursor and by indicating the interception with a button press. In two separate sessions, fly-ball trajectories were either fully visible or occluded for 750, 1000 or 1250 ms before ball landing. Natural ball motion was perturbed during the descending trajectory with effects of either weightlessness (0 g) or increased gravity (2 g) at times such that, for occluded trajectories, 500 ms of perturbed motion were visible before ball disappearance. To examine the contribution of previous visual experience with the perturbed trajectories to the interception of invisible targets, the order of visible and occluded sessions was permuted among subjects. Under these experimental conditions, we showed that, with fully visible targets, subjects combined servo-control and predictive strategies. Instead, when intercepting occluded targets, subjects relied mostly on predictive mechanisms based, however, on different type of information depending on previous visual experience. In fact, subjects without prior experience of the perturbed trajectories showed interceptive errors consistent with predictive estimates of the ball trajectory based on a-priori knowledge of gravity. Conversely, the interceptive responses of subjects previously exposed to fully visible trajectories were compatible with the fact that implicit knowledge of the perturbed motion was also taken into account for the extrapolation of occluded trajectories. PMID:23166653

Catching what we can't see: manual interception of occluded fly-ball trajectories.

PubMed

Bosco, Gianfranco; Delle Monache, Sergio; Lacquaniti, Francesco

2012-01-01

Control of interceptive actions may involve fine interplay between feedback-based and predictive mechanisms. These processes rely heavily on target motion information available when the target is visible. However, short-term visual memory signals as well as implicit knowledge about the environment may also contribute to elaborate a predictive representation of the target trajectory, especially when visual feedback is partially unavailable because other objects occlude the visual target. To determine how different processes and information sources are integrated in the control of the interceptive action, we manipulated a computer-generated visual environment representing a baseball game. Twenty-four subjects intercepted fly-ball trajectories by moving a mouse cursor and by indicating the interception with a button press. In two separate sessions, fly-ball trajectories were either fully visible or occluded for 750, 1000 or 1250 ms before ball landing. Natural ball motion was perturbed during the descending trajectory with effects of either weightlessness (0 g) or increased gravity (2 g) at times such that, for occluded trajectories, 500 ms of perturbed motion were visible before ball disappearance. To examine the contribution of previous visual experience with the perturbed trajectories to the interception of invisible targets, the order of visible and occluded sessions was permuted among subjects. Under these experimental conditions, we showed that, with fully visible targets, subjects combined servo-control and predictive strategies. Instead, when intercepting occluded targets, subjects relied mostly on predictive mechanisms based, however, on different type of information depending on previous visual experience. In fact, subjects without prior experience of the perturbed trajectories showed interceptive errors consistent with predictive estimates of the ball trajectory based on a-priori knowledge of gravity. Conversely, the interceptive responses of subjects previously exposed to fully visible trajectories were compatible with the fact that implicit knowledge of the perturbed motion was also taken into account for the extrapolation of occluded trajectories.

Testing fine motor coordination via telehealth: effects of video characteristics on reliability and validity.

PubMed

Hoenig, Helen M; Amis, Kristopher; Edmonds, Carol; Morgan, Michelle S; Landerman, Lawrence; Caves, Kevin

2017-01-01

Background There is limited research about the effects of video quality on the accuracy of assessments of physical function. Methods A repeated measures study design was used to assess reliability and validity of the finger-nose test (FNT) and the finger-tapping test (FTT) carried out with 50 veterans who had impairment in gross and/or fine motor coordination. Videos were scored by expert raters under eight differing conditions, including in-person, high definition video with slow motion review and standard speed videos with varying bit rates and frame rates. Results FTT inter-rater reliability was excellent with slow motion video (ICC 0.98-0.99) and good (ICC 0.59) under the normal speed conditions. Inter-rater reliability for FNT 'attempts' was excellent (ICC 0.97-0.99) for all viewing conditions; for FNT 'misses' it was good to excellent (ICC 0.89) with slow motion review but substantially worse (ICC 0.44) on the normal speed videos. FTT criterion validity (i.e. compared to slow motion review) was excellent (β = 0.94) for the in-person rater and good ( β = 0.77) on normal speed videos. Criterion validity for FNT 'attempts' was excellent under all conditions ( r ≥ 0.97) and for FNT 'misses' it was good to excellent under all conditions ( β = 0.61-0.81). Conclusions In general, the inter-rater reliability and validity of the FNT and FTT assessed via video technology is similar to standard clinical practices, but is enhanced with slow motion review and/or higher bit rate.

New Measurement of the Electron Magnetic Moment and the Fine Structure Constant: A First Application of a One-Electron Quantum Cyclotron

ScienceCinema

Gabrielse, Gerald

2018-05-22

Remarkably, the famous UW measurement of the electron magnetic moment has stood since 1987. With QED theory, this measurement has determined the accepted value of the fine structure constant. This colloquium is about a new Harvard measurement of these fundamental constants. The new measurement has an uncertainty that is about six times smaller, and it shifts the values by 1.7 standard deviations. One electron suspended in a Penning trap is used for the new measurement, like in the old measurement. What is different is that the lowest quantum levels of the spin and cyclotron motion are resolved, and the cyclotron as well as spin frequencies are determined using quantum jump spectroscopy. In addition, a 0.1 mK Penning trap that is also a cylindrical microwave cavity is used to control the radiation field, to suppress spontaneous emission by more than a factor of 100, to control cavity shifts, and to eliminate the blackbody photons that otherwise stimulate excitations from the cyclotron ground state. Finally, great signal-to-noise for one-quantum transitions is obtained using electronic feedback to realize the first one-particle self-excited oscillator. The new methods may also allow a million times improved measurement of the 500 times small antiproton magnetic moment.

Macroscopic self-reorientation of interacting two-dimensional crystals

PubMed Central

Woods, C. R.; Withers, F.; Zhu, M. J.; Cao, Y.; Yu, G.; Kozikov, A.; Ben Shalom, M.; Morozov, S. V.; van Wijk, M. M.; Fasolino, A.; Katsnelson, M. I.; Watanabe, K.; Taniguchi, T.; Geim, A. K.; Mishchenko, A.; Novoselov, K. S.

2016-01-01

Microelectromechanical systems, which can be moved or rotated with nanometre precision, already find applications in such fields as radio-frequency electronics, micro-attenuators, sensors and many others. Especially interesting are those which allow fine control over the motion on the atomic scale because of self-alignment mechanisms and forces acting on the atomic level. Such machines can produce well-controlled movements as a reaction to small changes of the external parameters. Here we demonstrate that, for the system of graphene on hexagonal boron nitride, the interplay between the van der Waals and elastic energies results in graphene mechanically self-rotating towards the hexagonal boron nitride crystallographic directions. Such rotation is macroscopic (for graphene flakes of tens of micrometres the tangential movement can be on hundreds of nanometres) and can be used for reproducible manufacturing of aligned van der Waals heterostructures. PMID:26960435

Effects of Spatial Attention on Motion Discrimination are Greater in the Left than Right Visual Field

PubMed Central

Bosworth, Rain G.; Petrich, Jennifer A.; Dobkins, Karen R.

2012-01-01

In order to investigate differences in the effects of spatial attention between the left visual field (LVF) and the right visual field (RVF), we employed a full/poor attention paradigm using stimuli presented in the LVF vs. RVF. In addition, to investigate differences in the effects of spatial attention between the Dorsal and Ventral processing streams, we obtained motion thresholds (motion coherence thresholds and fine direction discrimination thresholds) and orientation thresholds, respectively. The results of this study showed negligible effects of attention on the orientation task, in either the LVF or RVF. In contrast, for both motion tasks, there was a significant effect of attention in the LVF, but not in the RVF. These data provide psychophysical evidence for greater effects of spatial attention in the LVF/right hemisphere, specifically, for motion processing in the Dorsal stream. PMID:22051893

[Joint correction for motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging].

PubMed

Wu, Wenchuan; Fang, Sheng; Guo, Hua

2014-06-01

Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.

Space telescope optical telescope assembly/scientific instruments. Phase B: Preliminary design and program definition study. Volume 2A(3): Astrometry

NASA Technical Reports Server (NTRS)

1976-01-01

Wide field measurements, namely, measurements of relative angular separations between stars over a relatively wide field for parallax and proper motion determinations, were made with the third fine guidance sensor. Narrow field measurements, i.e., double star measurements, are accomplished primarily with the area photometer or faint object camera at f/96. The wavelength range required can be met by the fine guidance sensor which has a spectral coverage from 3000 to 7500 A. The field of view of the fine guidance sensor also exceeds that required for the wide field astrometric instrument. Requirements require a filter wheel for the wide field astrometer, and so one was incorporated into the design of the fine guidance sensor. The filter wheel probably would contain two neutral density filters to extend the dynamic range of the sensor and three spectral filters for narrowing effective double star magnitude difference.

Network support for turn-taking in multimedia collaboration

NASA Astrophysics Data System (ADS)

Dommel, Hans-Peter; Garcia-Luna-Aceves, Jose J.

1997-01-01

The effectiveness of collaborative multimedia systems depends on the regulation of access to their shared resources, such as continuous media or instruments used concurrently by multiple parties. Existing applications use only simple protocols to mediate such resource contention. Their cooperative rules follow a strict agenda and are largely application-specific. The inherent problem of floor control lacks a systematic methodology. This paper presents a general model on floor control for correct, scalable, fine-grained and fair resource sharing that integrates user interaction with network conditions, and adaptation to various media types. The motion of turn-taking known from psycholinguistics in studies on discourse structure is adapted for this framework. Viewed as a computational analogy to speech communication, online collaboration revolves around dynamically allocated access permissions called floors. The control semantics of floors derives from concurrently control methodology. An explicit specification and verification of a novel distributed Floor Control Protocol are presented. Hosts assume sharing roles that allow for efficient dissemination of control information, agreeing on a floor holder which is granted mutually exclusive access to a resource. Performance analytic aspects of floor control protocols are also briefly discussed.

Deposition and fine particle production during dynamic flow in a dry powder inhaler: a CFD approach.

PubMed

Milenkovic, J; Alexopoulos, A H; Kiparissides, C

2014-01-30

In this work the dynamic flow as well as the particle motion and deposition in a commercial dry powder inhaler, DPI (i.e., Turbuhaler) is described using computational fluid dynamics, CFD. The dynamic flow model presented here is an extension of a steady flow model previously described in Milenkovic et al. (2013). The model integrates CFD simulations for dynamic flow, an Eulerian-fluid/Lagrangian-particle description of particle motion as well as a particle/wall interaction model providing the sticking efficiency of particles colliding with the DPI walls. The dynamic flow is imposed by a time varying outlet pressure and the particle injections into the DPI are assumed to occur instantaneously and follow a prescribed particle size distribution, PSD. The total particle deposition and the production of fine particles in the DPI are determined for different peak inspiratory flow rates, PIFR, flow increase rates, FIR, and particle injection times. The simulation results for particle deposition are found to agree well with available experimental data for different values of PIFR and FIR. The predicted values of fine particle fraction are in agreement with available experimental results when the mean size of the injected PSD is taken to depend on the PIFR. Copyright © 2013 Elsevier B.V. All rights reserved.

Velocity of the high-spin low-spin interface inside the thermal hysteresis loop of a spin-crossover crystal, via photothermal control of the interface motion.

PubMed

Slimani, Ahmed; Varret, François; Boukheddaden, Kamel; Garrot, Damien; Oubouchou, Hassane; Kaizaki, Sumio

2013-02-22

We investigated by optical microscopy the thermal transition of the spin-crossover dinuclear iron(II) compound [(Fe(NCSe)(py)(2))(2)(m-bpypz)]. In a high-quality crystal the high-spin (HS) low-spin (LS) thermal transition took place with a sizable hysteresis, at ~108 K and ~116 K on cooling and heating, respectively, through the growth of a single macroscopic domain with a straight LS and HS interface. The interface orientation was almost constant and its propagation velocity was close to ~6 and 26 μ m s(-1) for the on-cooling and on-heating processes, respectively. We found that the motion of the interface was sensitive to the intensity of the irradiation beam of the microscope, through a photothermal effect. By fine-tuning the intensity we could stop and even reverse the interface motion. This way we stabilized a biphasic state of the crystal, and we followed the spontaneous motion of the interface at different temperatures inside the thermal hysteresis loop. This experiment gives access for the first time to an accurate determination of the equilibrium temperature in the case of thermal hysteresis--which was not accessible by the usual quasistatic investigations. The temperature dependence of the propagation velocity inside the hysteretic interval was revealed to be highly nonlinear, and it was quantitatively reproduced by a dynamical mean-field theory, which made possible an estimate of the macroscopic energy barrier.

Fine finger motor skill training with exoskeleton robotic hand in chronic stroke: stroke rehabilitation.

PubMed

Ockenfeld, Corinna; Tong, Raymond K Y; Susanto, Evan A; Ho, Sze-Kit; Hu, Xiao-ling

2013-06-01

Background and Purpose. Stroke survivors often show a limited recovery in the hand function to perform delicate motions, such as full hand grasping, finger pinching and individual finger movement. The purpose of this study is to describe the implementation of an exoskeleton robotic hand together with fine finger motor skill training on 2 chronic stroke patients. Case Descriptions. Two post-stroke patients participated in a 20-session training program by integrating 10 minutes physical therapy, 20 minutes robotic hand training and 15 minutes functional training tasks with delicate objects(card, pen and coin). These two patients (A and B) had cerebrovascular accident at 6 months and 11 months respectively when enrolled in this study. Outcomes. The results showed that both patients had improvements in Fugl-Meyer assessment (FM), Action Research Arm Test (ARAT). Patients had better isolation of the individual finger flexion and extension based on the reduced muscle co-contraction from the electromyographic(EMG) signals and finger extension force after 20 sessions of training. Discussion. This preliminary study showed that by focusing on the fine finger motor skills together with the exoskeleton robotic hand, it could improve the motor recovery of the upper extremity in the fingers and hand function, which were showed in the ARAT. Future randomized controlled trials are needed to evaluate the clinical effectiveness.

Suitability of functional evaluation embedded in serious game rehabilitation exercises to assess motor development across lifespan.

PubMed

Bonnechère, B; Sholukha, V; Omelina, L; Van Vooren, M; Jansen, B; Van Sint Jan, S

2017-09-01

The aim of this study was to determine if the results of activities performed using specially developed serious games for physical rehabilitation could be used as an indicator of the natural maturation and decline of motor control in healthy participants. Eighty-one participants (19 children (5-15 years old), 40 adults (18-65 years old) and 22 aged subjects (60-88 years old) participated in this study. Motions performed were recorded using the Kinect sensor. Three different exercises embedded in the games were used to assess upper limb, trunk and lower limb control. The trial duration and accuracy, measures of gross motor function and fine motor control, respectively, were computed for each participant. ANOVA tests shows statistically significant differences between the three groups for duration (53±15, 27±10 and 119±30s for children, adults and elderly subjects respectively) and accuracy (87±5, 89±10 and 70±8% for children, adults and elderly subjects respectively). The slopes of the curves that approximated the evolution of the performance over various ages are coherent with previous studies about motor control development and physiological decline. The proposed solution, i.e. serious games rehabilitation exercises coupled to motion analysis, seems to be an interesting tool to assess global motor function. Further studies are needed to study the influence of pathologies on the studied parameters. Copyright © 2017. Published by Elsevier B.V.

Intelligent systems approach for automated identification of individual control behavior of a human operator

NASA Astrophysics Data System (ADS)

Zaychik, Kirill B.

Acceptable results have been obtained using conventional techniques to model the generic human operator's control behavior. However, little research has been done in an attempt to identify an individual based on his/her control behavior. The main hypothesis investigated in this dissertation is that different operators exhibit different control behavior when performing a given control task. Furthermore, inter-person differences are manifested in the amplitude and frequency content of the non-linear component of the control behavior. Two enhancements to the existing models of the human operator, which allow personalization of the modeled control behavior, are presented in this dissertation. One of the proposed enhancements accounts for the "testing" control signals, which are introduced by an operator for more accurate control of the system and/or to adjust his/her control strategy. Such enhancement uses the Artificial Neural Network (ANN), which can be fine-tuned to model the "testing" control behavior of a given individual. The other model enhancement took the form of an equiripple filter (EF), which conditions the power spectrum of the control signal before it is passed through the plant dynamics block. The filter design technique uses Parks-McClellan algorithm, which allows parameterization of the desired levels of power at certain frequencies. A novel automated parameter identification technique (APID) was developed to facilitate the identification process of the parameters of the selected models of the human operator. APID utilizes a Genetic Algorithm (GA) based optimization engine called the Bit-climbing Algorithm (BCA). Proposed model enhancements were validated using the experimental data obtained at three different sources: the Manual Control Laboratory software experiments, Unmanned Aerial Vehicle simulation, and NASA Langley Research Center Visual Motion Simulator studies. Validation analysis involves comparison of the actual and simulated control activity signals. Validation criteria used in this dissertation is based on comparing Power Spectral Densities of the control signals against that of the Precision model of the human operator. This dissertation also addresses the issue of applying the proposed human operator model augmentation to evaluate the effectiveness of the motion feedback when simulating the actual pilot control behavior in a flight simulator. The proposed modeling methodology allows for quantitative assessments and prediction of the need for platform motion, while performing aircraft/pilot simulation studies.

Design and testing of a novel multi-stroke micropositioning system with variable resolutions.

PubMed

Xu, Qingsong

2014-02-01

Multi-stroke stages are demanded in micro-/nanopositioning applications which require smaller and larger motion strokes with fine and coarse resolutions, respectively. This paper presents the conceptual design of a novel multi-stroke, multi-resolution micropositioning stage driven by a single actuator for each working axis. It eliminates the issue of the interference among different drives, which resides in conventional multi-actuation stages. The stage is devised based on a fully compliant variable stiffness mechanism, which exhibits unequal stiffnesses in different strokes. Resistive strain sensors are employed to offer variable position resolutions in the different strokes. To quantify the design of the motion strokes and coarse/fine resolution ratio, analytical models are established. These models are verified through finite-element analysis simulations. A proof-of-concept prototype XY stage is designed, fabricated, and tested to demonstrate the feasibility of the presented ideas. Experimental results of static and dynamic testing validate the effectiveness of the proposed design.

Simulation of Near-Edge X-ray Absorption Fine Structure with Time-Dependent Equation-of-Motion Coupled-Cluster Theory.

PubMed

Nascimento, Daniel R; DePrince, A Eugene

2017-07-06

An explicitly time-dependent (TD) approach to equation-of-motion (EOM) coupled-cluster theory with single and double excitations (CCSD) is implemented for simulating near-edge X-ray absorption fine structure in molecular systems. The TD-EOM-CCSD absorption line shape function is given by the Fourier transform of the CCSD dipole autocorrelation function. We represent this transform by its Padé approximant, which provides converged spectra in much shorter simulation times than are required by the Fourier form. The result is a powerful framework for the blackbox simulation of broadband absorption spectra. K-edge X-ray absorption spectra for carbon, nitrogen, and oxygen in several small molecules are obtained from the real part of the absorption line shape function and are compared with experiment. The computed and experimentally obtained spectra are in good agreement; the mean unsigned error in the predicted peak positions is only 1.2 eV. We also explore the spectral signatures of protonation in these molecules.

Significant Change Spotting for Periodic Human Motion Segmentation of Cleaning Tasks Using Wearable Sensors

PubMed Central

Liu, Kai-Chun; Chan, Chia-Tai

2017-01-01

The proportion of the aging population is rapidly increasing around the world, which will cause stress on society and healthcare systems. In recent years, advances in technology have created new opportunities for automatic activities of daily living (ADL) monitoring to improve the quality of life and provide adequate medical service for the elderly. Such automatic ADL monitoring requires reliable ADL information on a fine-grained level, especially for the status of interaction between body gestures and the environment in the real-world. In this work, we propose a significant change spotting mechanism for periodic human motion segmentation during cleaning task performance. A novel approach is proposed based on the search for a significant change of gestures, which can manage critical technical issues in activity recognition, such as continuous data segmentation, individual variance, and category ambiguity. Three typical machine learning classification algorithms are utilized for the identification of the significant change candidate, including a Support Vector Machine (SVM), k-Nearest Neighbors (kNN), and Naive Bayesian (NB) algorithm. Overall, the proposed approach achieves 96.41% in the F1-score by using the SVM classifier. The results show that the proposed approach can fulfill the requirement of fine-grained human motion segmentation for automatic ADL monitoring. PMID:28106853

The effects of magnetic and mechanical microstructures on the twinning stress in Ni-Mn-Ga

NASA Astrophysics Data System (ADS)

Faran, Eilon; Benichou, Itamar; Givli, Sefi; Shilo, Doron

2015-12-01

The ferromagnetic 10M Ni-Mn-Ga alloy exhibits complex magnetic and mechanical microstructures, which are expected to form barriers for motion of macro twin boundaries. Here, the contributions of both microstructures to the magnitude of the twinning stress property are investigated experimentally. A series of uniaxial loading-unloading curves are taken under different orientation angles of a constant magnetic field. The different 180 ° magnetic domains microstructures that are formed across the twin boundary in each case are visualised using a magneto optical film. Analysis of the different loading curves and the corresponding magnetic microstructures show that the latter does not contribute to the barriers for twin boundary motion. In accordance, the internal resisting stress for twin boundary motion under any magnetic field can be taken as the twinning stress measured in the absence of an external field. In addition, a statistical analysis of the fine features in the loading profiles reveals that the barrier for twinning is associated with a μ m sized characteristic length scale. This length scale corresponds to the typical thickness of micro-twinning laminates that constitute a mechanical microstructure. These findings indicate that the magnitude of the twinning stress in 10M Ni-Mn-Ga is determined by the characteristic fine twinned mechanical microstructure of this alloy.

THE ROLE OF MECHANOBIOLOGY IN TENDON HEALING

PubMed Central

Killian, Megan L.; Cavinatto, Leonardo; Galatz, Leesa M.; Thomopoulos, Stavros

2011-01-01

Mechanical cues affect tendon healing, homeostasis, and development in a variety of settings. Alterations in the mechanical environment are known to result in changes in the expression of extracellular matrix proteins, growth factors, transcription factors, and cytokines that can alter tendon structure and cell viability. Loss of muscle force in utero or in the immediate postnatal period delays tendon and enthesis development. The response of healing tendons to mechanical load varies depending on anatomic location. Flexor tendons require motion to prevent adhesion formation, yet excessive force results in gap formation and subsequent weakening of the repair. Excessive motion in the setting of anterior cruciate ligament reconstruction causes accumulation of macrophages, which are detrimental to tendon graft healing. Complete removal of load is detrimental to rotator cuff healing, yet large forces are also harmful. Controlled loading can enhance healing in most settings; however, a fine balance must be reached between loads that are too low (leading to a catabolic state) and too high (leading to micro-damage). This review will summarize existing knowledge of the mechanobiology of tendon development, homeostasis, and healing. PMID:22244066

Comparison of adaptive optics scanning light ophthalmoscopic fluorescein angiography and offset pinhole imaging

PubMed Central

Chui, Toco Y. P.; Dubow, Michael; Pinhas, Alexander; Shah, Nishit; Gan, Alexander; Weitz, Rishard; Sulai, Yusufu N.; Dubra, Alfredo; Rosen, Richard B.

2014-01-01

Recent advances to the adaptive optics scanning light ophthalmoscope (AOSLO) have enabled finer in vivo assessment of the human retinal microvasculature. AOSLO confocal reflectance imaging has been coupled with oral fluorescein angiography (FA), enabling simultaneous acquisition of structural and perfusion images. AOSLO offset pinhole (OP) imaging combined with motion contrast post-processing techniques, are able to create a similar set of structural and perfusion images without the use of exogenous contrast agent. In this study, we evaluate the similarities and differences of the structural and perfusion images obtained by either method, in healthy control subjects and in patients with retinal vasculopathy including hypertensive retinopathy, diabetic retinopathy, and retinal vein occlusion. Our results show that AOSLO OP motion contrast provides perfusion maps comparable to those obtained with AOSLO FA, while AOSLO OP reflectance images provide additional information such as vessel wall fine structure not as readily visible in AOSLO confocal reflectance images. AOSLO OP offers a non-invasive alternative to AOSLO FA without the need for any exogenous contrast agent. PMID:24761299

Pebble abrasion during fluvial transport: Experimental results and implications for the evolution of the sediment load along rivers

NASA Astrophysics Data System (ADS)

Attal, Mikaël; Lavé, Jérôme

2009-12-01

In actively eroding landscapes, fluvial abrasion modifies the characteristics of the sediment carried by rivers and consequently has a direct impact on the ability of mountain rivers to erode their bedrock and on the characteristics and volume of the sediment exported from upland catchments. In this experimental study, we use a novel flume replicating hydrodynamic conditions prevailing in mountain rivers to investigate the role played by different controlling variables on pebble abrasion during fluvial transport. Lithology controls abrasion rates and processes, with differences in abrasion rates exceeding two orders of magnitude. Attrition as well as breaking and splitting are efficient processes in reducing particle size. Mass loss by attrition increases with particle velocity but is weakly dependent on particle size. Fragment production is enhanced by the use of large particles, high impact velocities and the presence of joints. Based on our experimental results, we extrapolate a preliminary generic relationship between pebble attrition rate and transport stage (τ*/τ*c), where τ* = fluvial Shields stress and τ*c = critical Shields stress for incipient pebble motion. This relationship predicts that attrition rates are independent of transport stage for (τ*/τ*c) ≤ 3 and increase linearly with transport stage beyond this value. We evaluate the extent to which abrasion rates control downstream fining in several different natural settings. A simplified model predicts that the most resistant lithologies control bed load flux and fining ratio and that the concavity of transport-limited river profiles should rarely exceed 0.25 in the absence of deposition and sorting.

A robot arm simulation with a shared memory multiprocessor machine

NASA Technical Reports Server (NTRS)

Kim, Sung-Soo; Chuang, Li-Ping

1989-01-01

A parallel processing scheme for a single chain robot arm is presented for high speed computation on a shared memory multiprocessor. A recursive formulation that is derived from a virtual work form of the d'Alembert equations of motion is utilized for robot arm dynamics. A joint drive system that consists of a motor rotor and gears is included in the arm dynamics model, in order to take into account gyroscopic effects due to the spinning of the rotor. The fine grain parallelism of mechanical and control subsystem models is exploited, based on independent computation associated with bodies, joint drive systems, and controllers. Efficiency and effectiveness of the parallel scheme are demonstrated through simulations of a telerobotic manipulator arm. Two different mechanical subsystem models, i.e., with and without gyroscopic effects, are compared, to show the trade-off between efficiency and accuracy.

Art for the Brain's Sake.

ERIC Educational Resources Information Center

Sylwester, Robert

1998-01-01

From fine-tuning muscular systems to integrating emotion and logic, the arts have important biological value. Motion and emotion are central to the arts and life itself. It is counterproductive to promote high performance standards while displacing skill development with computer technologies and reducing arts programs that move students from…

Composition and temperature dependence of the dielectric, piezoelectric and elastic properties of pure PZT ceramics.

PubMed

Zhuang, Z Q; Haun, M J; Jang, S J; Cross, L E

1989-01-01

Pure (undoped) piezoelectric lead zirconate titanate (PZT) ceramic samples at compositions across the ferroelectric region of the phase diagram were prepared from sol-gel-derived fine powders. Excess lead oxide was included in the PZT powders to obtain dense (95-96% of theoretical density) ceramics with large grain size (>7 mum) and to control the lead stoichiometry. The dielectric, piezoelectric, and elastic properties were measured from 4.2 to 300 K. At very low temperatures, the extrinsic domain wall and thermal defect motions freeze out. The low-temperature dielectric data can be used to determine coefficients in a phenomenological theory. The extrinsic contribution to the properties can then be separated from the single-domain properties derived from the theory.

Development of ultrasonic atomizer and its application to S. I. engines

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

Namiyama, K.; Nakamura, H.; Kokubo, K.

1989-01-01

This paper describes a fuel atomizer developed for S.I. engines based on ultrasonic vibrations. As the spray is characterized by fine droplet size and low penetration, it facilitates fuel movement and the formation of a homogeneous mixture. The spray behavior of this atomizer is easily influenced by ambient air motion. Therefore, the spray is most effectively delivered to the cylinders by precise injection timing. The ultrasonic atomizer disperses a fine spray over a wide flow rate range. A single cylinder engine fitted with the atomizer showed advantages in combustion speed and transient response performance.

Morphological relationships in the chromospheric H-alpha fine structure

NASA Technical Reports Server (NTRS)

Foukal, P.

1971-01-01

A continuous relationship is proposed between the basic elements of the dark fine structure of the quiet and active chromosphere. A progression from chromospheric bushes to fibrils, then to chromospheric threads and active region filaments, and finally to diffuse quiescent filaments, is described. It is shown that the horizontal component of the field on opposite sides of an active region quiescent filament can be in the same direction and closely parallel to the filament axis. Consequently, it is unnecessary to postulate twisted or otherwise complex field configurations to reconcile the support mechanism of filaments with the observed motion along their axis.

The relationship between executive function and fine motor control in young and older adults.

PubMed

Corti, Emily J; Johnson, Andrew R; Riddle, Hayley; Gasson, Natalie; Kane, Robert; Loftus, Andrea M

2017-01-01

The present study examined the relationship between executive function (EF) and fine motor control in young and older healthy adults. Participants completed 3 measures of executive function; a spatial working memory (SWM) task, the Stockings of Cambridge task (planning), and the Intra-Dimensional Extra-Dimensional Set-Shift task (set-shifting). Fine motor control was assessed using 3 subtests of the Purdue Pegboard (unimanual, bimanual, sequencing). For the younger adults, there were no significant correlations between measures of EF and fine motor control. For the older adults, all EFs significantly correlated with all measures of fine motor control. Three separate regressions examined whether planning, SWM and set-shifting independently predicted unimanual, bimanual, and sequencing scores for the older adults. Planning was the primary predictor of performance on all three Purdue subtests. A multiple-groups mediation model examined whether planning predicted fine motor control scores independent of participants' age, suggesting that preservation of planning ability may support fine motor control in older adults. Planning remained a significant predictor of unimanual performance in the older age group, but not bimanual or sequencing performance. The findings are discussed in terms of compensation theory, whereby planning is a key compensatory resource for fine motor control in older adults. Copyright © 2016 Elsevier B.V. All rights reserved.

Reconstruction of noisy and blurred images using blur kernel

NASA Astrophysics Data System (ADS)

Ellappan, Vijayan; Chopra, Vishal

2017-11-01

Blur is a common in so many digital images. Blur can be caused by motion of the camera and scene object. In this work we proposed a new method for deblurring images. This work uses sparse representation to identify the blur kernel. By analyzing the image coordinates Using coarse and fine, we fetch the kernel based image coordinates and according to that observation we get the motion angle of the shaken or blurred image. Then we calculate the length of the motion kernel using radon transformation and Fourier for the length calculation of the image and we use Lucy Richardson algorithm which is also called NON-Blind(NBID) Algorithm for more clean and less noisy image output. All these operation will be performed in MATLAB IDE.

Coupling of Excitons and Discrete Acoustic Phonons in Vibrationally Isolated Quantum Emitters.

PubMed

Werschler, Florian; Hinz, Christopher; Froning, Florian; Gumbsheimer, Pascal; Haase, Johannes; Negele, Carla; de Roo, Tjaard; Mecking, Stefan; Leitenstorfer, Alfred; Seletskiy, Denis V

2016-09-14

The photoluminescence emission by mesoscopic condensed matter is ultimately dictated by the fine-structure splitting of the fundamental exciton into optically allowed and dipole-forbidden states. In epitaxially grown semiconductor quantum dots, nonradiative equilibration between the fine-structure levels is mediated by bulk acoustic phonons, resulting in asymmetric spectral broadening of the excitonic luminescence. In isolated colloidal quantum dots, spatial confinement of the vibrational motion is expected to give rise to an interplay between the quantized electronic and phononic degrees of freedom. In most cases, however, zero-dimensional colloidal nanocrystals are strongly coupled to the substrate such that the charge relaxation processes are still effectively governed by the bulk properties. Here we show that encapsulation of single colloidal CdSe/CdS nanocrystals into individual organic polymer shells allows for systematic vibrational decoupling of the semiconductor nanospheres from the surroundings. In contrast to epitaxially grown quantum dots, simultaneous quantization of both electronic and vibrational degrees of freedom results in a series of strong and narrow acoustic phonon sidebands observed in the photoluminescence. Furthermore, an individual analysis of more than 200 compound particles reveals that enhancement or suppression of the radiative properties of the fundamental exciton is controlled by the interaction between fine-structure states via the discrete vibrational modes. For the first time, pronounced resonances in the scattering rate between the fine-structure states are directly observed, in good agreement with a quantum mechanical model. The unambiguous assignment of mediating acoustic modes to the observed scattering resonances complements the experimental findings. Thus, our results form an attractive basis for future studies on subterahertz quantum opto-mechanics and efficient laser cooling at the nanoscale.

Chaotic behavior of channeling particles.

PubMed

Chen, Ling; Kaloyeros, Alain E.; Wang, Guang-Hou

1994-03-01

Channeling describes the collimated motion of energetic charged particles along the lattice plane or axis in a crystal. The energetic particles are steered through the channels formed by strings of atomic constituents in the lattice. In the case of planar channeling, the motion of a charged particle between the atomic planes can be periodic or quasiperiodic, such as a simple oscillatory motion in the transverse direction. In practice, however, the periodic motion of the channeling particles can be accompanied by an irregular, chaotic behavior. In this paper, the Moliere potential, which is considered as a good analytical approximation for the interaction of channeling particles with the rows of atoms in the lattice, is used to simulate the channeling behavior of positively charged particles in a tungsten (100) crystal plane. By appropriate selection of channeling parameters, such as the projectile energy E(0) and incident angle psi(0), the transition of channeling particles from regular to chaotic motion is demonstrated. It is argued that the fine structures that appear in the angular scan channeling experiments are due to the particles' chaotic motion.

Wrist joint assembly

NASA Technical Reports Server (NTRS)

Kersten, L.; Johnson, J. D. (Inventor)

1978-01-01

A wrist joint assembly is provided for use with a mechanical manipulator arm for finely positioning an end-effector carried by the wrist joint on the terminal end of the manipulator arm. The wrist joint assembly is pivotable about a first axis to produce a yaw motion, a second axis is to produce a pitch motion, and a third axis to produce a roll motion. The wrist joint assembly includes a disk segment affixed to the terminal end of the manipulator arm and a first housing member, a second housing member, and a third housing member. The third housing member and the mechanical end-effector are moved in the yaw, pitch, and roll motion. Drive means are provided for rotating each of the housings about their respective axis which includes a cluster of miniature motors having spur gears carried on the output drive shaft which mesh with a center drive gear affixed on the housing to be rotated.

Science with a selfie stick: Plant biomass estimation using smartphone based ‘Structure From Motion’ photogrammetry

USDA-ARS?s Scientific Manuscript database

Significant advancements in photogrammetric Structure-from-Motion (SfM) software, coupled with improvements in the quality and resolution of smartphone cameras, has made it possible to create ultra-fine resolution three-dimensional models of physical objects using an ordinary smartphone. Here we pre...

Interferometer-Controlled Optical Tweezers Constructed for Nanotechnology and Biotechnology

NASA Technical Reports Server (NTRS)

Decker, Arthur J.

2002-01-01

A new method to control microparticles was developed in-house at the NASA Glenn Research Center in support of the nanotechnology project under NASA's Aerospace Propulsion and Power Base Research Program. A prototype interferometer-controlled optical tweezers was constructed to manipulate scanning probe microscope (SPM) tips. A laser beam passed through a Mach-Zehnder interferometer, and a microscope objective then produced an optical trap from the coaxial beams. The trap levitated and generated the coarse motion of a 10-mm polystyrene sphere used to simulate a SPM tip. The interference between the beams provided fine control of the forces and moments on the sphere. The interferometer included a piezoelectric-scanned mirror to modulate the interference pattern. The 10-mm sphere was observed to oscillate about 1 mm as the mirror and fringe pattern oscillated. The prototype tweezers proved the feasibility of constructing a more sophisticated interferometer tweezers to hold and manipulate SPM tips. The SPM tips are intended to interrogate and manipulate nanostructures. A more powerful laser will be used to generate multiple traps to hold nanostructures and SPM tips. The vibrating mirror in the interferometer will be replaced with a spatial light modulator. The modulator will allow the optical phase distribution in one leg of the interferometer to be programmed independently at 640 by 480 points for detailed control of the forces and moments. The interference patterns will be monitored to measure the motion of the SPM tips. Neuralnetwork technology will provide fast analysis of the interference patterns for diagnostic purposes and for local or remote feedback control of the tips. This effort also requires theoretical and modeling support in the form of scattering calculations for twin coherent beams from nonspherical particles.

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

Singh, K. A. P.; Nishida, K.; Shibata, K.

The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A {lambda}-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets ({approx}1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergrammore » images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.« less

Effectiveness of double fines as a speed control measure in safety corridors.

DOT National Transportation Integrated Search

2002-12-01

The use of elevated traffic fines, and specifically doubling of applicable traffic fines under certain conditions, is widely used in Oregon as a speed control measure. Double fines have applied to safety corridors in Oregon since 1999. Double f...

Laboratory-Scale Internal Wave Apparatus for Studying Copepod Behavior

NASA Astrophysics Data System (ADS)

Jung, S.; Webster, D. R.; Haas, K. A.; Yen, J.

2016-02-01

Internal waves are ubiquitous features in coastal marine environments and have been observed to mediate vertical distributions of zooplankton in situ. Internal waves create fine-scale hydrodynamic cues that copepods and other zooplankton are known to sense, such as fluid density gradients and velocity gradients (quantified as shear deformation rate). The role of copepod behavior in response to cues associated with internal waves is largely unknown. The objective is to provide insight to the bio-physical interaction and the role of biological versus physical forcing in mediating organism distributions. We constructed a laboratory-scale internal wave apparatus to facilitate fine-scale observations of copepod behavior in flows that replicate in situ conditions of internal waves in two-layer stratification. Two cases were chosen with density jump of 1 and 1.5 sigma-t units. Analytical analysis of the two-layer system provided guidance to the target forcing frequency needed to generate a standing internal wave with a single dominate frequency of oscillation. Flow visualization and signal processing of the interface location were used to quantify the wave characteristics. The results show a close match to the target wave parameters. Marine copepod (mixed population of Acartia tonsa, Temora longicornis, and Eurytemora affinis) behavior assays were conducted for three different physical arrangements: (1) no density stratification, (2) stagnant two-layer density stratification, and (3) two-layer density stratification with internal wave motion. Digitized trajectories of copepod swimming behavior indicate that in the control (case 1) the animals showed no preferential motion in terms of direction. In the stagnant density jump treatment (case 2) copepods preferentially moved horizontally, parallel to the density interface. In the internal wave treatment (case 3) copepods demonstrated orbital trajectories near the density interface.

Fine motor control

MedlinePlus

... figure out the child's developmental age. Children develop fine motor skills over time, by practicing and being taught. To have fine motor control, children need: Awareness and planning Coordination ...

Modeling and control of flexible space platforms with articulated payloads

NASA Technical Reports Server (NTRS)

Graves, Philip C.; Joshi, Suresh M.

1989-01-01

The first steps in developing a methodology for spacecraft control-structure interaction (CSI) optimization are identification and classification of anticipated missions, and the development of tractable mathematical models in each mission class. A mathematical model of a generic large flexible space platform (LFSP) with multiple independently pointed rigid payloads is considered. The objective is not to develop a general purpose numerical simulation, but rather to develop an analytically tractable mathematical model of such composite systems. The equations of motion for a single payload case are derived, and are linearized about zero steady-state. The resulting model is then extended to include multiple rigid payloads, yielding the desired analytical form. The mathematical models developed clearly show the internal inertial/elastic couplings, and are therefore suitable for analytical and numerical studies. A simple decentralized control law is proposed for fine pointing the payloads and LFSP attitude control, and simulation results are presented for an example problem. The decentralized controller is shown to be adequate for the example problem chosen, but does not, in general, guarantee stability. A centralized dissipative controller is then proposed, requiring a symmetric form of the composite system equations. Such a controller guarantees robust closed loop stability despite unmodeled elastic dynamics and parameter uncertainties.

Fine structure of striations observed in barium plasma injections in the magnetospheric cleft

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

Simons, D.J.; Eastman, T.E.; Pongratz, M.B.

1976-01-01

In January and November of 1975, the Los Alamos Scientific Laboratory sponsored four high altitude shaped charge barium plasma injections in the magnetospheric cleft region. These experiments were TORDO UNO (January 6), TORDO DOS (January 11), PERIQUITO UNO (November 25), and PERIQUITO DOS (November 28). All four injections took place near 500 km altitude, and optical data were taken from two aircraft and a ground station. The TORDO DOS and the PERIQUITO experiments showed rapid formation of striations (within one minute after injection), and fast horizontal spreading in contrast with TORDO UNO. In PERIQUITO DOS, the debris cloud spread magneticallymore » east-west with a small net northerly motion. TORDO UNO shows very rapid poleward motion, and the remaining two events resulted in magnetically east-west horizontal spreading, with no noticeable poleward motion. Striations observed in the PERIQUITO DOS experiment separate in opposite directions with relative velocities of up to 3 km/sec. These field-aligned structures appear to form in sheets of approximately constant magnetic latitude. Significant spatial variations occur on a scale of less than 200 meters. Spatial frequency power spectra across these striations have been determined at various times. Observations of the debris cloud and the fast barium streak show strong field-aligned coherency of striation fine structure, indicating a field line mapping of transverse electric fields and gradients.« less

Influence of upper limb disability, manual dexterity and fine motor skill on general self-efficacy in institutionalized elderly with osteoarthritis.

PubMed

Pérez-Mármol, Jose Manuel; Ortega-Valdivieso, María Azucena; Cano-Deltell, Enrique Elías; Peralta-Ramírez, María Isabel; García-Ríos, M Carmen; Aguilar-Ferrándiz, María Encarnación

2016-01-01

Descriptive, cross-sectional. The impact of upper limb (UL) disability, dexterity and fine motor skill on self-efficacy in older adults with osteoarthritis (OA) is not well known yet. To evaluate the self-efficacy and its relationship with UL function/disability in institutionalized OA. Institutionalized adults (n = 45) over the age of 65 years with OA were evaluated in a single session, to determine pinch strength, active range of motion of the hand and UL disability and functionality. They were classified as self-efficacious or not based on their general self-efficacy level. The influence on self-efficacy on upper limb function was statistically analyzed using bivariate and multivariate regression analyses. Self-effective older adults showed significantly lower scores in disability and higher scores in pinch strength, dexterity and motion of thumb than those who were classified as non-self-effective. Self-efficacy was associated with pinch strength (p ≤ 0.038), disability (p < 0.001) and dexterity (p ≤ 0.048). Multiple regression analyses showed that disability explained almost 40% of the variability of self-efficacy. Older adults classified as non-self-effective have higher UL disability and less pinch strength, manual dexterity and thumb motion than those who are self-effective, suggesting a relationship between impairment and perceived ability. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Parvocellular Pathway Impairment in Autism Spectrum Disorder: Evidence from Visual Evoked Potentials

ERIC Educational Resources Information Center

Fujita, Takako; Yamasaki, Takao; Kamio, Yoko; Hirose, Shinichi; Tobimatsu, Shozo

2011-01-01

In humans, visual information is processed via parallel channels: the parvocellular (P) pathway analyzes color and form information, whereas the magnocellular (M) stream plays an important role in motion analysis. Individuals with autism spectrum disorder (ASD) often show superior performance in processing fine detail, but impaired performance in…

Kinematics and Dynamics of Motion Control Based on Acceleration Control

NASA Astrophysics Data System (ADS)

Ohishi, Kiyoshi; Ohba, Yuzuru; Katsura, Seiichiro

The first IEEE International Workshop on Advanced Motion Control was held in 1990 pointed out the importance of physical interpretation of motion control. The software servoing technology is now common in machine tools, robotics, and mechatronics. It has been intensively developed for the numerical control (NC) machines. Recently, motion control in unknown environment will be more and more important. Conventional motion control is not always suitable due to the lack of adaptive capability to the environment. A more sophisticated ability in motion control is necessary for compliant contact with environment. Acceleration control is the key technology of motion control in unknown environment. The acceleration control can make a motion system to be a zero control stiffness system without losing the robustness. Furthermore, a realization of multi-degree-of-freedom motion is necessary for future human assistance. A human assistant motion will require various control stiffness corresponding to the task. The review paper focuses on the modal coordinate system to integrate the various control stiffness in the virtual axes. A bilateral teleoperation is a good candidate to consider the future human assistant motion and integration of decentralized systems. Thus the paper reviews and discusses the bilateral teleoperation from the control stiffness and the modal control design points of view.

Multiscale mechanobiology: computational models for integrating molecules to multicellular systems

PubMed Central

Mak, Michael; Kim, Taeyoon

2015-01-01

Mechanical signals exist throughout the biological landscape. Across all scales, these signals, in the form of force, stiffness, and deformations, are generated and processed, resulting in an active mechanobiological circuit that controls many fundamental aspects of life, from protein unfolding and cytoskeletal remodeling to collective cell motions. The multiple scales and complex feedback involved present a challenge for fully understanding the nature of this circuit, particularly in development and disease in which it has been implicated. Computational models that accurately predict and are based on experimental data enable a means to integrate basic principles and explore fine details of mechanosensing and mechanotransduction in and across all levels of biological systems. Here we review recent advances in these models along with supporting and emerging experimental findings. PMID:26019013

Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation

PubMed Central

Ooi, Chinchun; Earhart, Christopher M.; Wilson, Robert J.; Wang, Shan X.

2014-01-01

NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells’ magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells. This method utilizes a cross-correlation algorithm to analyze the cells’ motion in a simple fluidic channel to obtain their magnetophoretic velocity, and is effective even when the magnetic moments of cells are small. This rapid characterization is proven useful in optimizing our microfabricated magnetic sifter procedures for magnetic cell capture. PMID:24771946

77 FR 24985 - Importer of Controlled Substances; Notice of Registration; ISP Freetown Fine Chemicals

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-26

... Registration; ISP Freetown Fine Chemicals By Notice dated October 8, 2010, and published in the Federal Register on October 20, 2010, 75 FR 64743, ISP Freetown Fine Chemicals, 238 South Main Street, Assonet... that the registration of ISP Freetown Fine Chemicals to import the basic class of controlled substance...

78 FR 69134 - Manufacturer of Controlled Substances; Notice of Registration: AMPAC Fine Chemicals, LLC.

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-18

...; Notice of Registration: AMPAC Fine Chemicals, LLC. By Notice dated July 23, 2013, and published in the Federal Register on July 31, 2013, 78 FR 46372, AMPAC Fine Chemicals, LLC., Highway 50 and Hazel Avenue... AMPAC Fine Chemicals, LLC., to manufacture the listed basic classes of controlled substances is...

77 FR 64142 - Importer of Controlled Substances, Notice of Registration, ISP Freetown Fine Chemicals

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-18

... Registration, ISP Freetown Fine Chemicals By Notice dated July 2, 2012, and published in the Federal Register on July 11, 2012, 77 FR 40910, ISP Freetown Fine Chemicals, 238 South Main Street, Assonet... that the registration of ISP Freetown Fine Chemicals to import the basic class of controlled substance...

77 FR 24988 - Manufacturer of Controlled Substances; Notice of Registration; ISP Freetown Fine Chemicals

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-26

...; Notice of Registration; ISP Freetown Fine Chemicals By Notice dated October 8, 2010, and published in the Federal Register on October 20, 2010, 75 FR 64746, ISP Freetown Fine Chemicals, 238 South Main Street... Fine Chemicals, to manufacture the listed basic classes of controlled substances is consistent with the...

Stability and Interaction of Coherent Structure in Supersonic Reactive Wakes

NASA Technical Reports Server (NTRS)

Menon, Suresh

1983-01-01

A theoretical formulation and analysis is presented for a study of the stability and interaction of coherent structure in reacting free shear layers. The physical problem under investigation is a premixed hydrogen-oxygen reacting shear layer in the wake of a thin flat plate. The coherent structure is modeled as a periodic disturbance and its stability is determined by the application of linearized hydrodynamic stability theory which results in a generalized eigenvalue problem for reactive flows. Detailed stability analysis of the reactive wake for neutral, symmetrical and antisymmetrical disturbance is presented. Reactive stability criteria is shown to be quite different from classical non-reactive stability. The interaction between the mean flow, coherent structure and fine-scale turbulence is theoretically formulated using the von-Kaman integral technique. Both time-averaging and conditional phase averaging are necessary to separate the three types of motion. The resulting integro-differential equations can then be solved subject to initial conditions with appropriate shape functions. In the laminar flow transition region of interest, the spatial interaction between the mean motion and coherent structure is calculated for both non-reactive and reactive conditions and compared with experimental data wherever available. The fine-scale turbulent motion determined by the application of integral analysis to the fluctuation equations. Since at present this turbulence model is still untested, turbulence is modeled in the interaction problem by a simple algebraic eddy viscosity model. The applicability of the integral turbulence model formulated here is studied parametrically by integrating these equations for the simple case of self-similar mean motion with assumed shape functions. The effect of the motion of the coherent structure is studied and very good agreement is obtained with previous experimental and theoretical works for non-reactive flow. For the reactive case, lack of experimental data made direct comparison difficult. It was determined that the growth rate of the disturbance amplitude is lower for reactive case. The results indicate that the reactive flow stability is in qualitative agreement with experimental observation.

Influence of grid control and object detection on radiation exposure and image quality using mobile C-arms - first results.

PubMed

Gosch, D; Ratzmer, A; Berauer, P; Kahn, T

2007-09-01

The objective of this study was to examine the extent to which the image quality on mobile C-arms can be improved by an innovative exposure rate control system (grid control). In addition, the possible dose reduction in the pulsed fluoroscopy mode using 25 pulses/sec produced by automatic adjustment of the pulse rate through motion detection was to be determined. As opposed to conventional exposure rate control systems, which use a measuring circle in the center of the field of view, grid control is based on a fine mesh of square cells which are overlaid on the entire fluoroscopic image. The system uses only those cells for exposure control that are covered by the object to be visualized. This is intended to ensure optimally exposed images, regardless of the size, shape and position of the object to be visualized. The system also automatically detects any motion of the object. If a pulse rate of 25 pulses/sec is selected and no changes in the image are observed, the pulse rate used for pulsed fluoroscopy is gradually reduced. This may decrease the radiation exposure. The influence of grid control on image quality was examined using an anthropomorphic phantom. The dose reduction achieved with the help of object detection was determined by evaluating the examination data of 146 patients from 5 different countries. The image of the static phantom made with grid control was always optimally exposed, regardless of the position of the object to be visualized. The average dose reduction when using 25 pulses/sec resulting from object detection and automatic down-pulsing was 21 %, and the maximum dose reduction was 60 %. Grid control facilitates C-arm operation, since optimum image exposure can be obtained independently of object positioning. Object detection may lead to a reduction in radiation exposure for the patient and operating staff.

A coupled ALE-AMR method for shock hydrodynamics

DOE PAGES

Waltz, J.; Bakosi, J.

2018-03-05

We present a numerical method combining adaptive mesh refinement (AMR) with arbitrary Lagrangian-Eulerian (ALE) mesh motion for the simulation of shock hydrodynamics on unstructured grids. The primary goal of the coupled method is to use AMR to reduce numerical error in ALE simulations at reduced computational expense relative to uniform fine mesh calculations, in the same manner that AMR has been used in Eulerian simulations. We also identify deficiencies with ALE methods that AMR is able to mitigate, and discuss the unique coupling challenges. The coupled method is demonstrated using three-dimensional unstructured meshes of up to O(10 7) tetrahedral cells.more » Convergence of ALE-AMR solutions towards both uniform fine mesh ALE results and analytic solutions is demonstrated. Speed-ups of 5-10× for a given level of error are observed relative to uniform fine mesh calculations.« less

A coupled ALE-AMR method for shock hydrodynamics

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

Waltz, J.; Bakosi, J.

We present a numerical method combining adaptive mesh refinement (AMR) with arbitrary Lagrangian-Eulerian (ALE) mesh motion for the simulation of shock hydrodynamics on unstructured grids. The primary goal of the coupled method is to use AMR to reduce numerical error in ALE simulations at reduced computational expense relative to uniform fine mesh calculations, in the same manner that AMR has been used in Eulerian simulations. We also identify deficiencies with ALE methods that AMR is able to mitigate, and discuss the unique coupling challenges. The coupled method is demonstrated using three-dimensional unstructured meshes of up to O(10 7) tetrahedral cells.more » Convergence of ALE-AMR solutions towards both uniform fine mesh ALE results and analytic solutions is demonstrated. Speed-ups of 5-10× for a given level of error are observed relative to uniform fine mesh calculations.« less

Detecting agency from the biological motion of veridical vs animated agents

PubMed Central

Kelley, William M.; Heatherton, Todd F.; Macrae, C. Neil

2007-01-01

The ability to detect agency is fundamental for understanding the social world. Underlying this capacity are neural circuits that respond to patterns of intentional biological motion in the superior temporal sulcus and temporoparietal junction. Here we show that the brain's blood oxygenation level dependent (BOLD) response to such motion is modulated by the representation of the actor. Dynamic social interactions were portrayed by either live-action agents or computer-animated agents, enacting the exact same patterns of biological motion. Using an event-related design, we found that the BOLD response associated with the perception and interpretation of agency was greater when identical physical movements were performed by real rather than animated agents. This finding has important implications for previous work on biological motion that has relied upon computer-animated stimuli and demonstrates that the neural substrates of social perception are finely tuned toward real-world agents. In addition, the response in lateral temporal areas was observed in the absence of instructions to make mental inferences, thus demonstrating the spontaneous implementation of the intentional stance. PMID:18985141

Straight-line climbing flight aerodynamics of a fruit bat

NASA Astrophysics Data System (ADS)

Viswanath, K.; Nagendra, K.; Cotter, J.; Frauenthal, M.; Tafti, D. K.

2014-02-01

From flight data obtained on a fruit bat, Cynopterus brachyotis, a kinematic model for straight-line flapping motion is extracted and analyzed in a computational fluid dynamics (CFD) framework to gain insight into the complexity of bat flight. The intricate functional mechanics and architecture of the bat wings set it apart from other vertebrate flight. The extracted kinematic model is simulated for a range of Reynolds numbers, to observe the effect these phenomena have on the unsteady transient mechanisms of the flow produced by the flapping wings. The Strouhal number calculated from the data is high indicating that the oscillatory motion dominates the flow physics. From the obtained data, the bat exhibits fine control of its mechanics by actively varying wing camber, wing area, torsional rotation of the wing, forward and backward translational sweep of the wing, and wing conformation to dictate the fluid dynamics. As is common in flapping flight, the primary force generation is through the attached unsteady vortices on the wing surface. The bat through varying the wing camber and the wing area modulates this force output. The power requirement for the kinematics is analyzed and correlated with the aerodynamic performance.

Application of tumbling melt granulation (TMG) method to prepare controlled-release fine granules.

PubMed

Maejima, T; Kubo, M; Osawa, T; Nakajima, K; Kobayashi, M

1998-03-01

The tumbling melt granulation (TMG) method was applied to prepare controlled-release fine granules of diltiazem hydrochloride (DH). The entire process, from the preparation of the cores by the adherence of DH to the sucrose crystal to the subsequent coating of the controlled-release layer, was performed without using any solvent. A mixture of meltable material, talc, and ethylcellulose was used for the controlled-release layer and controlled-release fine granules approximately 400 microns in diameter were obtained with excellent producibility. The dissolution rate of DH from these fine granules was similar to that of a once-a-day dosage form obtained in the market; further, the dependency of the dissolution profile on pH of the media was less. Thus, it was concluded that this TMG method was very useful for preparing not only controlled-release beads of granule size (usually 500 to 1400 microns) but also fine granules.

A situated reasoning architecture for space-based repair and replace tasks

NASA Technical Reports Server (NTRS)

Bloom, Ben; Mcgrath, Debra; Sanborn, Jim

1989-01-01

Space-based robots need low level control for collision detection and avoidance, short-term load management, fine-grained motion, and other physical tasks. In addition, higher level control is required to focus strategic decision making as missions are assigned and carried out. Reasoning and control must be responsive to ongoing changes in the environment. Research aimed at bridging the gap between high level artificial intelligence (AI) planning techniques and task-level robot programming for telerobotic systems is described. Situated reasoning is incorporated into AI and Robotics systems in order to coordinate a robot's activity within its environment. An integrated system under development in a component maintenance domain is described. It is geared towards replacing worn and/or failed Orbital Replacement Units (ORUs) designed for use aboard NASA's Space Station Freedom based on the collection of components available at a given time. High level control reasons in component space in order to maximize the number operational component-cells over time, while the task-level controls sensors and effectors, detects collisions, and carries out pick and place tasks in physical space. Situated reasoning is used throughout the system to cope with component failures, imperfect information, and unexpected events.

Neck Proprioception Shapes Body Orientation and Perception of Motion

PubMed Central

Pettorossi, Vito Enrico; Schieppati, Marco

2014-01-01

This review article deals with some effects of neck muscle proprioception on human balance, gait trajectory, subjective straight-ahead (SSA), and self-motion perception. These effects are easily observed during neck muscle vibration, a strong stimulus for the spindle primary afferent fibers. We first remind the early findings on human balance, gait trajectory, SSA, induced by limb, and neck muscle vibration. Then, more recent findings on self-motion perception of vestibular origin are described. The use of a vestibular asymmetric yaw-rotation stimulus for emphasizing the proprioceptive modulation of motion perception from the neck is mentioned. In addition, an attempt has been made to conjointly discuss the effects of unilateral neck proprioception on motion perception, SSA, and walking trajectory. Neck vibration also induces persistent aftereffects on the SSA and on self-motion perception of vestibular origin. These perceptive effects depend on intensity, duration, side of the conditioning vibratory stimulation, and on muscle status. These effects can be maintained for hours when prolonged high-frequency vibration is superimposed on muscle contraction. Overall, this brief outline emphasizes the contribution of neck muscle inflow to the construction and fine-tuning of perception of body orientation and motion. Furthermore, it indicates that tonic neck-proprioceptive input may induce persistent influences on the subject’s mental representation of space. These plastic changes might adapt motion sensitiveness to lasting or permanent head positional or motor changes. PMID:25414660

Neck proprioception shapes body orientation and perception of motion.

PubMed

Pettorossi, Vito Enrico; Schieppati, Marco

2014-01-01

This review article deals with some effects of neck muscle proprioception on human balance, gait trajectory, subjective straight-ahead (SSA), and self-motion perception. These effects are easily observed during neck muscle vibration, a strong stimulus for the spindle primary afferent fibers. We first remind the early findings on human balance, gait trajectory, SSA, induced by limb, and neck muscle vibration. Then, more recent findings on self-motion perception of vestibular origin are described. The use of a vestibular asymmetric yaw-rotation stimulus for emphasizing the proprioceptive modulation of motion perception from the neck is mentioned. In addition, an attempt has been made to conjointly discuss the effects of unilateral neck proprioception on motion perception, SSA, and walking trajectory. Neck vibration also induces persistent aftereffects on the SSA and on self-motion perception of vestibular origin. These perceptive effects depend on intensity, duration, side of the conditioning vibratory stimulation, and on muscle status. These effects can be maintained for hours when prolonged high-frequency vibration is superimposed on muscle contraction. Overall, this brief outline emphasizes the contribution of neck muscle inflow to the construction and fine-tuning of perception of body orientation and motion. Furthermore, it indicates that tonic neck-proprioceptive input may induce persistent influences on the subject's mental representation of space. These plastic changes might adapt motion sensitiveness to lasting or permanent head positional or motor changes.

The Development of Novel, High-Flux, Heat Transfer Cells for Thermal Control in Microgravity

NASA Technical Reports Server (NTRS)

Smith, Marc K.; Glezer, Ari

1996-01-01

In order to meet the future needs of thermal management and control in space applications such as the Space Lab, new heat-transfer technology capable of much larger heat fluxes must be developed. To this end, we describe complementary numerical and experimental investigations into the fundamental fluid mechanics and heat-transfer processes involved in a radically new, self contained, heat transfer cell for microgravity applications. In contrast to conventional heat pipes, the heat transfer in this cell is based on a forced droplet evaporation process using a fine spray. The spray is produced by a novel fluidic technology recently developed at Georgia Tech. This technology is based on a vibration induced droplet atomization process. In this technique, a liquid droplet is placed on a flexible membrane and is vibrated normal to itself. When the proper drop size is attained, the droplet resonates with the surface motion of the membrane and almost immediately bursts into a shower of very fine secondary droplets. The small droplets travel to the opposite end of the cell where they impact a heated surface and are evaporated. The vapor returns to the cold end of the cell and condenses to form the large droplets that are fragmented to form the spray. Preliminary estimates show that a heat transfer cell based on this technology would have a heat-flux capacity that is an order of magnitude higher than those of current heat pipes designs used in microgravity applications.

Five-dimensional motion compensation for respiratory and cardiac motion with cone-beam CT of the thorax region

NASA Astrophysics Data System (ADS)

Sauppe, Sebastian; Hahn, Andreas; Brehm, Marcus; Paysan, Pascal; Seghers, Dieter; Kachelrieß, Marc

2016-03-01

We propose an adapted method of our previously published five-dimensional (5D) motion compensation (MoCo) algorithm1, developed for micro-CT imaging of small animals, to provide for the first time motion artifact-free 5D cone-beam CT (CBCT) images from a conventional flat detector-based CBCT scan of clinical patients. Image quality of retrospectively respiratory- and cardiac-gated volumes from flat detector CBCT scans is deteriorated by severe sparse projection artifacts. These artifacts further complicate motion estimation, as it is required for MoCo image reconstruction. For high quality 5D CBCT images at the same x-ray dose and the same number of projections as todays 3D CBCT we developed a double MoCo approach based on motion vector fields (MVFs) for respiratory and cardiac motion. In a first step our already published four-dimensional (4D) artifact-specific cyclic motion-compensation (acMoCo) approach is applied to compensate for the respiratory patient motion. With this information a cyclic phase-gated deformable heart registration algorithm is applied to the respiratory motion-compensated 4D CBCT data, thus resulting in cardiac MVFs. We apply these MVFs on double-gated images and thereby respiratory and cardiac motion-compensated 5D CBCT images are obtained. Our 5D MoCo approach processing patient data acquired with the TrueBeam 4D CBCT system (Varian Medical Systems). Our double MoCo approach turned out to be very efficient and removed nearly all streak artifacts due to making use of 100% of the projection data for each reconstructed frame. The 5D MoCo patient data show fine details and no motion blurring, even in regions close to the heart where motion is fastest.

Modeling and analysis of propulsion in the multiflagellated micoorganism Giardia lamblia

NASA Astrophysics Data System (ADS)

Lenaghan, Scott C.; Chen, Jun; Zhang, Mingjun

2013-07-01

The goal of this work was to analyze the propulsion of multiflagellated microorganisms, and to draw insight to the underlying physics and biology of the movement. Giardia lamblia was chosen as the model organism due to its unique ability to mechanically attach to various surfaces, its rapid movement, and its fine control over steering and navigation. In this work, a mechanics model was utilized to study the mechanics and propulsive contribution of the ventral and anterior flagella in Giardia. It was discovered that energy is supplied mainly at the proximal portion of these flagella, supporting the hypothesis that a decreasing adenosine triphosphate (ATP) gradient along the length of the flagella would not affect the motion observed. Similarly, the elasticity of the flagella allows the energy input at the proximal portion to be transferred to the distal portion, where the majority of thrust is generated. Specifically, we found that the ventral flagella are the driving force for planar propulsion and turning, while the anterior flagella are used for steering and control.

Turning behaviour depends on frictional damping in the fruit fly Drosophila.

PubMed

Hesselberg, Thomas; Lehmann, Fritz-Olaf

2007-12-01

Turning behaviour in the fruit fly Drosophila depends on several factors including not only feedback from sensory organs and muscular control of wing motion, but also the mass moments of inertia and the frictional damping coefficient of the rotating body. In the present study we evaluate the significance of body friction for yaw turning and thus the limits of visually mediated flight control in Drosophila, by scoring tethered flies flying in a flight simulator on their ability to visually compensate a bias on a moving object and a visual background panorama at different simulated frictional dampings. We estimated the fly's natural damping coefficient from a numerical aerodynamic model based on both friction on the body and the flapping wings during saccadic turning. The model predicts a coefficient of 54 x 10(-12) Nm s, which is more than 100-times larger than the value estimated from a previous study on the body alone. Our estimate suggests that friction plays a larger role for yaw turning in Drosophila than moments of inertia. The simulator experiments showed that visual performance of the fruit fly collapses near the physical conditions estimated for freely flying animals, which is consistent with the suggested role of the halteres for flight stabilization. However, kinematic analyses indicate that the measured loss of flight control might be due predominantly to the limited fine control in the fly's steering muscles below a threshold of 1-2 degrees stroke amplitude, rather than resulting from the limits of visual motion detection by the fly's compound eyes. We discuss the impact of these results and suggest that the elevated frictional coefficient permits freely flying fruit flies to passively terminate rotational body movements without producing counter-torque during the second half of the saccadic turning manoeuvre.

Imaging synthetic aperture radar

DOEpatents

Burns, Bryan L.; Cordaro, J. Thomas

1997-01-01

A linear-FM SAR imaging radar method and apparatus to produce a real-time image by first arranging the returned signals into a plurality of subaperture arrays, the columns of each subaperture array having samples of dechirped baseband pulses, and further including a processing of each subaperture array to obtain coarse-resolution in azimuth, then fine-resolution in range, and lastly, to combine the processed subapertures to obtain the final fine-resolution in azimuth. Greater efficiency is achieved because both the transmitted signal and a local oscillator signal mixed with the returned signal can be varied on a pulse-to-pulse basis as a function of radar motion. Moreover, a novel circuit can adjust the sampling location and the A/D sample rate of the combined dechirped baseband signal which greatly reduces processing time and hardware. The processing steps include implementing a window function, stabilizing either a central reference point and/or all other points of a subaperture with respect to doppler frequency and/or range as a function of radar motion, sorting and compressing the signals using a standard fourier transforms. The stabilization of each processing part is accomplished with vector multiplication using waveforms generated as a function of radar motion wherein these waveforms may be synthesized in integrated circuits. Stabilization of range migration as a function of doppler frequency by simple vector multiplication is a particularly useful feature of the invention; as is stabilization of azimuth migration by correcting for spatially varying phase errors prior to the application of an autofocus process.

The final word. OSHA's final ruling offers firm deadlines for infection control.

PubMed

West, K

1992-03-01

Departments that have put off program development while waiting for the final ruling to be published have a lot of work to do. Many departments have been cited and fined by OSHA in the past year for failure to begin infection-control programs or provide hepatitis-B vaccines to personnel. Under the new budget, OSHA was granted permission to up its fine structure sevenfold--thus, a small fine is $7,000, and the highest fine for a single violation is $70,000. Fines can have a greater impact on a department's budget than implementation of the program over time. A key point to remember is that a strong infection-control program will reduce exposure follow-up costs and worker-compensation claims. Infection control is a win-win situation.

Modeling a space-variant cortical representation for apparent motion.

PubMed

Wurbs, Jeremy; Mingolla, Ennio; Yazdanbakhsh, Arash

2013-08-06

Receptive field sizes of neurons in early primate visual areas increase with eccentricity, as does temporal processing speed. The fovea is evidently specialized for slow, fine movements while the periphery is suited for fast, coarse movements. In either the fovea or periphery discrete flashes can produce motion percepts. Grossberg and Rudd (1989) used traveling Gaussian activity profiles to model long-range apparent motion percepts. We propose a neural model constrained by physiological data to explain how signals from retinal ganglion cells to V1 affect the perception of motion as a function of eccentricity. Our model incorporates cortical magnification, receptive field overlap and scatter, and spatial and temporal response characteristics of retinal ganglion cells for cortical processing of motion. Consistent with the finding of Baker and Braddick (1985), in our model the maximum flash distance that is perceived as an apparent motion (Dmax) increases linearly as a function of eccentricity. Baker and Braddick (1985) made qualitative predictions about the functional significance of both stimulus and visual system parameters that constrain motion perception, such as an increase in the range of detectable motions as a function of eccentricity and the likely role of higher visual processes in determining Dmax. We generate corresponding quantitative predictions for those functional dependencies for individual aspects of motion processing. Simulation results indicate that the early visual pathway can explain the qualitative linear increase of Dmax data without reliance on extrastriate areas, but that those higher visual areas may serve as a modulatory influence on the exact Dmax increase.

On the fine-structure constant in a plasma model of the fluctuating vacuum substratum

NASA Technical Reports Server (NTRS)

Cragin, B. L.

1986-01-01

The existence of an intimate connection between the quivering motion of electrons and positrons (Zitterbewegung), predicted by the Dirac equation, and the zero-point fluctuations of the vacuum is suggested. The nature of the proposed connection is discussed quantitatively, and an approximate self-consistency relation is derived, supplying a purely mathematical expression that relates the dimensionless coupling strengths (fine-structure constants) alpha sub e and alpha sub g of electromagnetism and gravity. These considerations provide a tentative explanation for the heretofore puzzling number 1/alpha sub e of about 137.036 and suggest that attempts to unify gravity with the electroweak and strong interactions will ultimately prove successful.

Hubble Space Telescope Reduced-Gyro Control Law Design, Implementation, and On-Orbit Performance

NASA Technical Reports Server (NTRS)

Clapp, Brian R.; Ramsey, Patrick R.; Wirzburger, John H.; Smith, Daniel C.; VanArsadall, John C.

2008-01-01

Following gyro failures in April 2001 and April 2003, HST Pointing Control System engineers designed reduced-gyro control laws to extend the spacecraft science mission. The Two-Gyro Science (TGS) and One-Gyro Science (OGS) control laws were designed and implemented using magnetometers, star trackers, and Fine Guidance Sensors in succession to control vehicle rate about the missing gyro axes. Both TGS and OGS have demonstrated on-orbit pointing stability of 7 milli-arcseconds or less, which depends upon the guide star magnitude used by the Fine Guidance Sensor. This paper describes the design, implementation, and on-orbit performance of the TGS and OGS control law fine-pointing modes using Fixed Head Star Trackers and Fine Guidance Sensors, after successfully achieving coarse-pointing control using magnetometers.

Proceedings from the 2nd International Symposium on Formation Flying Missions and Technologies

NASA Technical Reports Server (NTRS)

2004-01-01

Topics discussed include: The Stellar Imager (SI) "Vision Mission"; First Formation Flying Demonstration Mission Including on Flight Nulling; Formation Flying X-ray Telescope in L2 Orbit; SPECS: The Kilometer-baseline Far-IR Interferometer in NASA's Space Science Roadmap Presentation; A Tight Formation for Along-track SAR Interferometry; Realization of the Solar Power Satellite using the Formation Flying Solar Reflector; SIMBOL-X : Formation Flying for High-Energy Astrophysics; High Precision Optical Metrology for DARWIN; Close Formation Flight of Micro-Satellites for SAR Interferometry; Station-Keeping Requirements for Astronomical Imaging with Constellations of Free-Flying Collectors; Closed-Loop Control of Formation Flying Satellites; Formation Control for the MAXIM Mission; Precision Formation Keeping at L2 Using the Autonomous Formation Flying Sensor; Robust Control of Multiple Spacecraft Formation Flying; Virtual Rigid Body (VRB) Satellite Formation Control: Stable Mode-Switching and Cross-Coupling; Electromagnetic Formation Flight (EMFF) System Design, Mission Capabilities, and Testbed Development; Navigation Algorithms for Formation Flying Missions; Use of Formation Flying Small Satellites Incorporating OISL's in a Tandem Cluster Mission; Semimajor Axis Estimation Strategies; Relative Attitude Determination of Earth Orbiting Formations Using GPS Receivers; Analysis of Formation Flying in Eccentric Orbits Using Linearized Equations of Relative Motion; Conservative Analytical Collision Probabilities for Orbital Formation Flying; Equations of Motion and Stability of Two Spacecraft in Formation at the Earth/Moon Triangular Libration Points; Formations Near the Libration Points: Design Strategies Using Natural and Non-Natural Ares; An Overview of the Formation and Attitude Control System for the Terrestrial Planet Finder Formation Flying Interferometer; GVE-Based Dynamics and Control for Formation Flying Spacecraft; GNC System Design for a New Concept of X-Ray Distributed Telescope; GNC System for the Deployment and Fine Control of the DARWIN Free-Flying Interferometer; Formation Algorithm and Simulation Testbed; and PLATFORM: A Formation Flying, RvD and Robotic Validation Test-bench.

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

Zhang, X; Sisniega, A; Zbijewski, W

Purpose: Visualization and quantification of coronary artery calcification and atherosclerotic plaque benefits from coronary artery motion (CAM) artifact elimination. This work applies a rigid linear motion model to a Volume of Interest (VoI) for estimating motion estimation and compensation of image degradation in Coronary Computed Tomography Angiography (CCTA). Methods: In both simulation and testbench experiments, translational CAM was generated by displacement of the imaging object (i.e. simulated coronary artery and explanted human heart) by ∼8 mm, approximating the motion of a main coronary branch. Rotation was assumed to be negligible. A motion degraded region containing a calcification was selected asmore » the VoI. Local residual motion was assumed to be rigid and linear over the acquisition window, simulating motion observed during diastasis. The (negative) magnitude of the image gradient of the reconstructed VoI was chosen as the motion estimation objective and was minimized with Covariance Matrix Adaptation Evolution Strategy (CMAES). Results: Reconstruction incorporated the estimated CAM yielded signification recovery of fine calcification structures as well as reduced motion artifacts within the selected local region. The compensated reconstruction was further evaluated using two image similarity metrics, the structural similarity index (SSIM) and Root Mean Square Error (RMSE). At the calcification site, the compensated data achieved a 3% increase in SSIM and a 91.2% decrease in RMSE in comparison with the uncompensated reconstruction. Conclusion: Results demonstrate the feasibility of our image-based motion estimation method exploiting a local rigid linear model for CAM compensation. The method shows promising preliminary results for the application of such estimation in CCTA. Further work will involve motion estimation of complex motion corrupted patient data acquired from clinical CT scanner.« less

Transitional analysis of organic thin color filter layers in displays during baking process using multi-speckle diffusing wave spectroscopy

NASA Astrophysics Data System (ADS)

Park, Baek Sung; Hyung, Kyung Hee; Oh, Gwi Jeong; Jung, Hyun Wook

2018-02-01

The color filter (CF) is one of the key components for improving the performance of TV displays such as liquid crystal display (LCD) and white organic light emitting diodes (WOLED). The profile defects like undercut during the fine fabrication processes for CF layers are inevitably generated through the UV exposure and development processes, however, these can be controlled through the baking process. In order to resolve the profile defects of CF layers, in this study, the real-time dynamic changes of CF layers are monitored during the baking process by changing components such as polymeric binder and acrylate. The motion of pigment particles in CF layers during baking is quantitatively interpreted using multi-speckle diffusing wave spectroscopy (MSDWS), in terms of the autocorrelation function and the characteristic time of α-relaxation.

The chaotic interaction of two walkers

NASA Astrophysics Data System (ADS)

Tadrist, Loic; Samara, Naresh; Schlagheck, Peter; Gilet, Tristan

2016-11-01

A droplet bouncing on a vertically vibrated bath may be propelled horizontally by the Faraday waves that it generates at each rebound. This association of a wave and a particle is called a walker. Ten years ago, Yves Couder and co-workers noted that the dynamical encounter of two walkers may lead to either scattered trajectories or orbital motion. In this work, we investigate the interaction of two walkers more systematically. The walkers are launched towards each other with finely controlled initial conditions. Output trajectories are classified in four types: scattering, orbiting, wandering and complex. The interaction appears stochastic: the same set of initial parameters (to the measurement accuracy) can produce different outputs. Our analysis of the underlying chaos provides new insights on the stochastic nature of this experiment. This work is supported by the ARC Quandrops of the Wallonia-Brussels Federation.

Global rotation of mechanical metamaterials induced by their internal deformation

NASA Astrophysics Data System (ADS)

Dudek, K. K.; Gatt, R.; Mizzi, L.; Dudek, M. R.; Attard, D.; Grima, J. N.

2017-09-01

In this work, we propose the concept that a device based on mechanical metamaterials can be used to induce and control its own rotational motion as a result of internal deformations due to the conversion of translational degrees of freedom into rotational ones. The application of a linear force on the structural units of the system may be fine-tuned in order to obtain a desired type of rotation. In particular, we show, how it is possible to maximise the extent of rotation of the system through the alteration of the geometry of the system. We also show how a device based on this concept can be connected to an external body in order to rotate it which result may potentially prove to be very important in the case of applications such as telescopes employed in space.

Nanoscale Engineering of Designer Cellulosomes.

PubMed

Gunnoo, Melissabye; Cazade, Pierre-André; Galera-Prat, Albert; Nash, Michael A; Czjzek, Mirjam; Cieplak, Marek; Alvarez, Beatriz; Aguilar, Marina; Karpol, Alon; Gaub, Hermann; Carrión-Vázquez, Mariano; Bayer, Edward A; Thompson, Damien

2016-07-01

Biocatalysts showcase the upper limit obtainable for high-speed molecular processing and transformation. Efforts to engineer functionality in synthetic nanostructured materials are guided by the increasing knowledge of evolving architectures, which enable controlled molecular motion and precise molecular recognition. The cellulosome is a biological nanomachine, which, as a fundamental component of the plant-digestion machinery from bacterial cells, has a key potential role in the successful development of environmentally-friendly processes to produce biofuels and fine chemicals from the breakdown of biomass waste. Here, the progress toward so-called "designer cellulosomes", which provide an elegant alternative to enzyme cocktails for lignocellulose breakdown, is reviewed. Particular attention is paid to rational design via computational modeling coupled with nanoscale characterization and engineering tools. Remaining challenges and potential routes to industrial application are put forward. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Body Fineness Ratio as a Predictor of Maximum Prolonged-Swimming Speed in Coral Reef Fishes

PubMed Central

Walker, Jeffrey A.; Alfaro, Michael E.; Noble, Mae M.; Fulton, Christopher J.

2013-01-01

The ability to sustain high swimming speeds is believed to be an important factor affecting resource acquisition in fishes. While we have gained insights into how fin morphology and motion influences swimming performance in coral reef fishes, the role of other traits, such as body shape, remains poorly understood. We explore the ability of two mechanistic models of the causal relationship between body fineness ratio and endurance swimming-performance to predict maximum prolonged-swimming speed (Umax) among 84 fish species from the Great Barrier Reef, Australia. A drag model, based on semi-empirical data on the drag of rigid, submerged bodies of revolution, was applied to species that employ pectoral-fin propulsion with a rigid body at U max. An alternative model, based on the results of computer simulations of optimal shape in self-propelled undulating bodies, was applied to the species that swim by body-caudal-fin propulsion at Umax. For pectoral-fin swimmers, Umax increased with fineness, and the rate of increase decreased with fineness, as predicted by the drag model. While the mechanistic and statistical models of the relationship between fineness and Umax were very similar, the mechanistic (and statistical) model explained only a small fraction of the variance in Umax. For body-caudal-fin swimmers, we found a non-linear relationship between fineness and Umax, which was largely negative over most of the range of fineness. This pattern fails to support either predictions from the computational models or standard functional interpretations of body shape variation in fishes. Our results suggest that the widespread hypothesis that a more optimal fineness increases endurance-swimming performance via reduced drag should be limited to fishes that swim with rigid bodies. PMID:24204575

Search of massive star formation with COMICS

NASA Astrophysics Data System (ADS)

Okamoto, Yoshiko K.

2004-04-01

Mid-infrared observations is useful for studies of massive star formation. Especially COMICS offers powerful tools: imaging survey of the circumstellar structures of forming massive stars such as massive disks and cavity structures, mass estimate from spectroscopy of fine structure lines, and high dispersion spectroscopy to census gas motion around formed stars. COMICS will open the next generation infrared studies of massive star formation.

Semi-active compressor valve

DOEpatents

Brun, Klaus; Gernentz, Ryan S.

2010-07-27

A method and system for fine-tuning the motion of suction or discharge valves associated with cylinders of a reciprocating gas compressor, such as the large compressors used for natural gas transmission. The valve's primary driving force is conventional, but the valve also uses an electromagnetic coil to sense position of the plate (or other plugging element) and to provide an opposing force prior to impact.

Rulemaking To Amend Dates in Federal Implementation Plans Addressing Interstate Transport of Ozone and Fine Particulate Matter (79 FR 71663)

EPA Pesticide Factsheets

EPA amends the Code of Federal Regulations to reflect compliance deadlines for CSAPR as revised by the action of the U.S. Court of Appeals for the D.C. Circuit granting the EPA’s motion to lift the previous stay of CSAPR and delay its deadlines by 3 years.

The accuracy of dynamic attitude propagation

NASA Technical Reports Server (NTRS)

Harvie, E.; Chu, D.; Woodard, M.

1990-01-01

Propagating attitude by integrating Euler's equation for rigid body motion has long been suggested for the Earth Radiation Budget Satellite (ERBS) but until now has not been implemented. Because of limited Sun visibility, propagation is necessary for yaw determination. With the deterioration of the gyros, dynamic propagation has become more attractive. Angular rates are derived from integrating Euler's equation with a stepsize of 1 second, using torques computed from telemetered control system data. The environmental torque model was quite basic. It included gravity gradient and unshadowed aerodynamic torques. Knowledge of control torques is critical to the accuracy of dynamic modeling. Due to their coarseness and sparsity, control actuator telemetry were smoothed before integration. The dynamic model was incorporated into existing ERBS attitude determination software. Modeled rates were then used for attitude propagation in the standard ERBS fine-attitude algorithm. In spite of the simplicity of the approach, the dynamically propagated attitude matched the attitude propagated with good gyros well for roll and yaw but diverged up to 3 degrees for pitch because of the very low resolution in pitch momentum wheel telemetry. When control anomalies significantly perturb the nominal attitude, the effect of telemetry granularity is reduced and the dynamically propagated attitudes are accurate on all three axes.

Validation results of specifications for motion control interoperability

NASA Astrophysics Data System (ADS)

Szabo, Sandor; Proctor, Frederick M.

1997-01-01

The National Institute of Standards and Technology (NIST) is participating in the Department of Energy Technologies Enabling Agile Manufacturing (TEAM) program to establish interface standards for machine tool, robot, and coordinate measuring machine controllers. At NIST, the focus is to validate potential application programming interfaces (APIs) that make it possible to exchange machine controller components with a minimal impact on the rest of the system. This validation is taking place in the enhanced machine controller (EMC) consortium and is in cooperation with users and vendors of motion control equipment. An area of interest is motion control, including closed-loop control of individual axes and coordinated path planning. Initial tests of the motion control APIs are complete. The APIs were implemented on two commercial motion control boards that run on two different machine tools. The results for a baseline set of APIs look promising, but several issues were raised. These include resolving differing approaches in how motions are programmed and defining a standard measurement of performance for motion control. This paper starts with a summary of the process used in developing a set of specifications for motion control interoperability. Next, the EMC architecture and its classification of motion control APIs into two classes, Servo Control and Trajectory Planning, are reviewed. Selected APIs are presented to explain the basic functionality and some of the major issues involved in porting the APIs to other motion controllers. The paper concludes with a summary of the main issues and ways to continue the standards process.

A novel diamond micro-/nano-machining process for the generation of hierarchical micro-/nano-structures

NASA Astrophysics Data System (ADS)

Zhu, Zhiwei; To, Suet; Ehmann, Kornel F.; Xiao, Gaobo; Zhu, Wule

2016-03-01

A new mechanical micro-/nano-machining process that combines rotary spatial vibrations (RSV) of a diamond tool and the servo motions of the workpiece is proposed and applied for the generation of multi-tier hierarchical micro-/nano-structures. In the proposed micro-/nano-machining system, the servo motion, as the primary cutting motion generated by a slow-tool-servo, is adopted for the fine generation of the primary surfaces with complex shapes. The RSV, as the tertiary cutting operation, is superimposed on the secondary fundamental rotary cutting motion to construct secondary nano-structures on the primary surface. Since the RSV system generally works at much higher frequencies and motion resolution than the primary and secondary motions, it leads to an inherent hierarchical cutting architecture. To investigate the machining performance, complex micro-/nano-structures were generated and explored by both numerical simulations and actual cutting tests. Rotary vibrations of the diamond tool at a constant rotational distance offer an inherent constant cutting velocity, leading to the ability for the generation of homogeneous micro-/nano-structures with fixed amplitudes and frequencies of the vibrations, even over large-scale surfaces. Furthermore, by deliberately combining the non-resonant three-axial vibrations and the servo motion, the generation of a variety of micro-/nano-structures with complex shapes and with flexibly tunable feature sizes can be achieved.

A combined system for measuring animal motion activities.

PubMed

Young, M S; Young, C W; Li, Y C

2000-01-31

In this study, we have developed a combined animal motion activity measurement system that combines an infrared light matrix subsystem with an ultrasonic phase shift subsystem for animal activity measurement. Accordingly, in conjunction with an IBM PC/AT compatible personal computer, the combined system has the advantages of both infrared and ultrasonic subsystems. That is, it can at once measure and directly analyze detailed changes in animal activity ranging from locomotion to tremor. The main advantages of this combined system are that it features real time data acquisition with the option of animated real time or recorded display/playback of the animal's motion. Additionally, under the multi-task operating condition of IBM PC, it can acquire and process behavior using both IR and ultrasound systems simultaneously. Traditional systems have had to make separate runs for gross and fine movement recording. This combined system can be profitably employed for normative behavioral activity studies and for neurological and pharmacological research.

40 CFR 52.131 - Control Strategy and regulations: Fine Particle Matter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.131 Section 52.131 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Strategy and regulations: Fine Particle Matter. (a) Determination of Attainment: Effective February 6, 2013...

40 CFR 52.247 - Control Strategy and regulations: Fine Particle Matter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.247 Section 52.247 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Strategy and regulations: Fine Particle Matter. (a) Determination of Attainment: Effective February 8, 2013...

40 CFR 52.247 - Control Strategy and regulations: Fine Particle Matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.247 Section 52.247 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Strategy and regulations: Fine Particle Matter. (a) Determination of Attainment: Effective February 8, 2013...

40 CFR 52.131 - Control Strategy and regulations: Fine Particle Matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.131 Section 52.131 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Strategy and regulations: Fine Particle Matter. (a) Determination of Attainment: Effective February 6, 2013...

Effects of Practical Life Materials on Kindergartners' Fine Motor Skills.

ERIC Educational Resources Information Center

Rule, Audrey C.; Stewart, Roger A.

2002-01-01

A pretest-posttest control group design was used to measure the effect of practical life materials (e.g., tweezers, tongs, spoons) on kindergarten children's fine motor skill development. Experimental and control group teachers reported equal amounts of fine motor activity in their classrooms; however, significant interaction effects were found…

Realtime motion planning for a mobile robot in an unknown environment using a neurofuzzy based approach

NASA Astrophysics Data System (ADS)

Zheng, Taixiong

2005-12-01

A neuro-fuzzy network based approach for robot motion in an unknown environment was proposed. In order to control the robot motion in an unknown environment, the behavior of the robot was classified into moving to the goal and avoiding obstacles. Then, according to the dynamics of the robot and the behavior character of the robot in an unknown environment, fuzzy control rules were introduced to control the robot motion. At last, a 6-layer neuro-fuzzy network was designed to merge from what the robot sensed to robot motion control. After being trained, the network may be used for robot motion control. Simulation results show that the proposed approach is effective for robot motion control in unknown environment.

Guaranteeing Isochronous Control of Networked Motion Control Systems Using Phase Offset Adjustment

PubMed Central

Kim, Ikhwan; Kim, Taehyoun

2015-01-01

Guaranteeing isochronous transfer of control commands is an essential function for networked motion control systems. The adoption of real-time Ethernet (RTE) technologies may be profitable in guaranteeing deterministic transfer of control messages. However, unpredictable behavior of software in the motion controller often results in unexpectedly large deviation in control message transmission intervals, and thus leads to imprecise motion. This paper presents a simple and efficient heuristic to guarantee the end-to-end isochronous control with very small jitter. The key idea of our approach is to adjust the phase offset of control message transmission time in the motion controller by investigating the behavior of motion control task. In realizing the idea, we performed a pre-runtime analysis to determine a safe and reliable phase offset and applied the phase offset to the runtime code of motion controller by customizing an open-source based integrated development environment (IDE). We also constructed an EtherCAT-based motion control system testbed and performed extensive experiments on the testbed to verify the effectiveness of our approach. The experimental results show that our heuristic is highly effective even for low-end embedded controller implemented in open-source software components under various configurations of control period and the number of motor drives. PMID:26076407

The effect of amblyopia on fine motor skills in children.

PubMed

Webber, Ann L; Wood, Joanne M; Gole, Glen A; Brown, Brian

2008-02-01

In an investigation of the functional impact of amblyopia in children, the fine motor skills of amblyopes and age-matched control subjects were compared. The influence of visual factors that might predict any decrement in fine motor skills was also explored. Vision and fine motor skills were tested in a group of children (n = 82; mean age, 8.2 +/- 1.7 [SD] years) with amblyopia of different causes (infantile esotropia, n = 17; acquired strabismus, n = 28; anisometropia, n = 15; mixed, n = 13; and deprivation n = 9), and age-matched control children (n = 37; age 8.3 +/- 1.3 years). Visual motor control (VMC) and upper limb speed and dexterity (ULSD) items of the Bruininks-Oseretsky Test of Motor Proficiency were assessed, and logMAR visual acuity (VA) and Randot stereopsis were measured. Multiple regression models were used to identify the visual determinants of fine motor skills performance. Amblyopes performed significantly poorer than control subjects on 9 of 16 fine motor skills subitems and for the overall age-standardized scores for both VMC and ULSD items (P < 0.05). The effects were most evident on timed tasks. The etiology of amblyopia and level of binocular function significantly affected fine motor skill performance on both items; however, when examined in a multiple regression model that took into account the intercorrelation between visual characteristics, poorer fine motor skills performance was associated with strabismus (F(1,75) = 5.428; P = 0.022), but not with the level of binocular function, refractive error, or visual acuity in either eye. Fine motor skills were reduced in children with amblyopia, particularly those with strabismus, compared with control subjects. The deficits in motor performance were greatest on manual dexterity tasks requiring speed and accuracy.

14 CFR 29.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Motion and effect of cockpit controls. 29... Accommodations § 29.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 27.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Motion and effect of cockpit controls. 27... Accommodations § 27.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 29.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Motion and effect of cockpit controls. 29... Accommodations § 29.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 29.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Motion and effect of cockpit controls. 29... Accommodations § 29.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 27.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Motion and effect of cockpit controls. 27... Accommodations § 27.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 27.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Motion and effect of cockpit controls. 27... Accommodations § 27.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 29.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Motion and effect of cockpit controls. 29... Accommodations § 29.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 27.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Motion and effect of cockpit controls. 27... Accommodations § 27.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 29.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Motion and effect of cockpit controls. 29... Accommodations § 29.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

14 CFR 27.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Motion and effect of cockpit controls. 27... Accommodations § 27.779 Motion and effect of cockpit controls. Cockpit controls must be designed so that they... collective pitch control, must operate with a sense of motion which corresponds to the effect on the...

Julius Edgar Lilienfeld Prize Talk: Measuring the Electron Magnetic Moment and the Fine Structure Constant

NASA Astrophysics Data System (ADS)

Gabrielse, Gerald

2011-05-01

The electron magnetic moment in Bohr magnetons has been measured to a precision of 3 parts in 1013. This measurement, with quantum electrodynamics (AED) theory, provides the most precise value of the fine structure constant. This measurement, with a value of the fine structure from other measurements, also tests QED and sets a limit on the internal structure of the electron. A one-electron quantum cyclotron is at the heart of the measurement -- an electron suspended in a magnetic field and cooled enough that its lowest cyclotron and spin quantum states can be deduced with quantum nondemolition (QND) measurements. A cylindrical Penning trap cavity inhibits spontaneous emission and feedback methods make the electron excite and sustain its own motion for detection. A new apparatus is being commissioned in pursuit of more precise measurements. Adapted methods are promising for observing a proton spin flip, which should make it possible to compare the antiproton and proton magnetic moments a million times more accurately than is currently possible.

Adaptation of fine roots to annual fertilization and irrigation in a 13-year-old Pinus pinaster stand.

PubMed

Bakker, M R; Jolicoeur, E; Trichet, P; Augusto, L; Plassard, C; Guinberteau, J; Loustau, D

2009-02-01

Effects of fertilization and irrigation on fine roots and fungal hyphae were studied in 13-year-old maritime pine (Pinus pinaster Aït. in Soland), 7 years after the initiation of the treatments. The fertilization trials consisted of a phosphorus treatment, a complete fertilizer treatment (N, P, K, Ca and Mg), and an unfertilized treatment (control). Fertilizers were applied annually and were adjusted according to foliar target values. Two irrigation regimes (no irrigation and irrigation of a set amount each day) were applied from May to October. Root samples to depths of 120 cm were collected in summer of 2005, and the biomass of small roots (diameter 2-20 mm) and fine roots (diameter

Contrast gain control in first- and second-order motion perception.

PubMed

Lu, Z L; Sperling, G

1996-12-01

A novel pedestal-plus-test paradigm is used to determine the nonlinear gain-control properties of the first-order (luminance) and the second-order (texture-contrast) motion systems, that is, how these systems' responses to motion stimuli are reduced by pedestals and other masking stimuli. Motion-direction thresholds were measured for test stimuli consisting of drifting luminance and texture-contrast-modulation stimuli superimposed on pedestals of various amplitudes. (A pedestal is a static sine-wave grating of the same type and same spatial frequency as the moving test grating.) It was found that first-order motion-direction thresholds are unaffected by small pedestals, but at pedestal contrasts above 1-2% (5-10 x pedestal threshold), motion thresholds increase proportionally to pedestal amplitude (a Weber law). For first-order stimuli, pedestal masking is specific to the spatial frequency of the test. On the other hand, motion-direction thresholds for texture-contrast stimuli are independent of pedestal amplitude (no gain control whatever) throughout the accessible pedestal amplitude range (from 0 to 40%). However, when baseline carrier contrast increases (with constant pedestal modulation amplitude), motion thresholds increase, showing that gain control in second-order motion is determined not by the modulator (as in first-order motion) but by the carrier. Note that baseline contrast of the carrier is inherently independent of spatial frequency of the modulator. The drastically different gain-control properties of the two motion systems and prior observations of motion masking and motion saturation are all encompassed in a functional theory. The stimulus inputs to both first- and second-order motion process are normalized by feedforward, shunting gain control. The different properties arise because the modulator is used to control the first-order gain and the carrier is used to control the second-order gain.

Motion-mode energy method for vehicle dynamics analysis and control

NASA Astrophysics Data System (ADS)

Zhang, Nong; Wang, Lifu; Du, Haiping

2014-01-01

Vehicle motion and vibration control is a fundamental motivation for the development of advanced vehicle suspension systems. In a vehicle-fixed coordinate system, the relative motions of the vehicle between body and wheel can be classified into several dynamic stages based on energy intensity, and can be decomposed into sets of uncoupled motion-modes according to modal parameters. Vehicle motions are coupled, but motion-modes are orthogonal. By detecting and controlling the predominating vehicle motion-mode, the system cost and energy consumption of active suspensions could be reduced. A motion-mode energy method (MEM) is presented in this paper to quantify the energy contribution of each motion-mode to vehicle dynamics in real time. The control of motion-modes is prioritised according to the level of motion-mode energy. Simulation results on a 10 degree-of-freedom nonlinear full-car model with the magic-formula tyre model illustrate the effectiveness of the proposed MEM. The contribution of each motion-mode to the vehicle's dynamic behaviour is analysed under different excitation inputs from road irregularities, directional manoeuvres and braking. With the identified dominant motion-mode, novel cost-effective suspension systems, such as active reconfigurable hydraulically interconnected suspension, can possibly be used to control full-car motions with reduced energy consumption. Finally, discussion, conclusions and suggestions for future work are provided.

Effects of Motion Cues on the Training of Multi-Axis Manual Control Skills

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Mobertz, Xander R. I.

2017-01-01

The study described in this paper investigated the effects of two different hexapod motion configurations on the training and transfer of training of a simultaneous roll and pitch control task. Pilots were divided between two groups which trained either under a baseline hexapod motion condition, with motion typically provided by current training simulators, or an optimized hexapod motion condition, with increased fidelity of the motion cues most relevant for the task. All pilots transferred to the same full-motion condition, representing motion experienced in flight. A cybernetic approach was used that gave insights into the development of pilots use of visual and motion cues over the course of training and after transfer. Based on the current results, neither of the hexapod motion conditions can unambiguously be chosen as providing the best motion for training and transfer of training of the used multi-axis control task. However, the optimized hexapod motion condition did allow pilots to generate less visual lead, control with higher gains, and have better disturbance-rejection performance at the end of the training session compared to the baseline hexapod motion condition. Significant adaptations in control behavior still occurred in the transfer phase under the full-motion condition for both groups. Pilots behaved less linearly compared to previous single-axis control-task experiments; however, this did not result in smaller motion or learning effects. Motion and learning effects were more pronounced in pitch compared to roll. Finally, valuable lessons were learned that allow us to improve the adopted approach for future transfer-of-training studies.

A Simple Force-Motion Relation for Migrating Cells Revealed by Multipole Analysis of Traction Stress

PubMed Central

Tanimoto, Hirokazu; Sano, Masaki

2014-01-01

For biophysical understanding of cell motility, the relationship between mechanical force and cell migration must be uncovered, but it remains elusive. Since cells migrate at small scale in dissipative circumstances, the inertia force is negligible and all forces should cancel out. This implies that one must quantify the spatial pattern of the force instead of just the summation to elucidate the force-motion relation. Here, we introduced multipole analysis to quantify the traction stress dynamics of migrating cells. We measured the traction stress of Dictyostelium discoideum cells and investigated the lowest two moments, the force dipole and quadrupole moments, which reflect rotational and front-rear asymmetries of the stress field. We derived a simple force-motion relation in which cells migrate along the force dipole axis with a direction determined by the force quadrupole. Furthermore, as a complementary approach, we also investigated fine structures in the stress field that show front-rear asymmetric kinetics consistent with the multipole analysis. The tight force-motion relation enables us to predict cell migration only from the traction stress patterns. PMID:24411233

Automatic generation of endocardial surface meshes with 1-to-1 correspondence from cine-MR images

NASA Astrophysics Data System (ADS)

Su, Yi; Teo, S.-K.; Lim, C. W.; Zhong, L.; Tan, R. S.

2015-03-01

In this work, we develop an automatic method to generate a set of 4D 1-to-1 corresponding surface meshes of the left ventricle (LV) endocardial surface which are motion registered over the whole cardiac cycle. These 4D meshes have 1- to-1 point correspondence over the entire set, and is suitable for advanced computational processing, such as shape analysis, motion analysis and finite element modelling. The inputs to the method are the set of 3D LV endocardial surface meshes of the different frames/phases of the cardiac cycle. Each of these meshes is reconstructed independently from border-delineated MR images and they have no correspondence in terms of number of vertices/points and mesh connectivity. To generate point correspondence, the first frame of the LV mesh model is used as a template to be matched to the shape of the meshes in the subsequent phases. There are two stages in the mesh correspondence process: (1) a coarse matching phase, and (2) a fine matching phase. In the coarse matching phase, an initial rough matching between the template and the target is achieved using a radial basis function (RBF) morphing process. The feature points on the template and target meshes are automatically identified using a 16-segment nomenclature of the LV. In the fine matching phase, a progressive mesh projection process is used to conform the rough estimate to fit the exact shape of the target. In addition, an optimization-based smoothing process is used to achieve superior mesh quality and continuous point motion.

AN INTRIGUING CHROMOSPHERIC JET OBSERVED BY HINODE: FINE STRUCTURE KINEMATICS AND EVIDENCE OF UNWINDING TWISTS

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

Liu Wei; Berger, Thomas E.; Title, Alan M.

2009-12-10

We report a chromospheric jet lasting for more than 1 hr observed by the Hinode Solar Optical Telescope in unprecedented detail. The ejection occurred in three episodes separated by 12-14 minutes, with the amount and velocity of material decreasing with time. The upward velocities range from 438 to 33 km s{sup -1}, while the downward velocities of the material falling back have smaller values (mean: -56km s{sup -1}) and a narrower distribution (standard deviation: 14km s{sup -1}). The average acceleration inferred from parabolic spacetime tracks is 141 m s{sup -2}, a fraction of the solar gravitational acceleration. The jet consistsmore » of fine threads (0.''5-2'' wide), which exhibit coherent, oscillatory transverse motions perpendicular to the jet axis and about a common equilibrium position. These motions propagate upward along the jet, with the maximum phase speed of 744+-11 km s{sup -1}at the leading front of the jet. The transverse oscillation velocities range from 151 to 26 km s{sup -1}, amplitudes from 6.0 to 1.9 Mm, and periods from 250 to 536 s. The oscillations slow down with time and cease when the material starts to fall back. The falling material travels along almost straight lines in the original direction of ascent, showing no transverse motions. These observations are consistent with the scenario that the jet involves untwisting helical threads, which rotate about the axis of a single large cylinder and shed magnetic helicity into the upper atmosphere.« less

New dimensions in surgical training: immersive virtual reality laparoscopic simulation exhilarates surgical staff.

PubMed

Huber, Tobias; Paschold, Markus; Hansen, Christian; Wunderling, Tom; Lang, Hauke; Kneist, Werner

2017-11-01

Virtual reality (VR) and head mount displays (HMDs) have been advanced for multimedia and information technologies but have scarcely been used in surgical training. Motion sickness and individual psychological changes have been associated with VR. The goal was to observe first experiences and performance scores using a new combined highly immersive virtual reality (IVR) laparoscopy setup. During the study, 10 members of the surgical department performed three tasks (fine dissection, peg transfer, and cholecystectomy) on a VR simulator. We then combined a VR HMD with the VR laparoscopic simulator and displayed the simulation on a 360° video of a laparoscopic operation to create an IVR laparoscopic simulation. The tasks were then repeated. Validated questionnaires on immersion and motion sickness were used for the study. Participants' times for fine dissection were significantly longer during the IVR session (regular: 86.51 s [62.57 s; 119.62 s] vs. IVR: 112.35 s [82.08 s; 179.40 s]; p = 0.022). The cholecystectomy task had higher error rates during IVR. Motion sickness did not occur at any time for any participant. Participants experienced a high level of exhilaration, rarely thought about others in the room, and had a high impression of presence in the generated IVR world. This is the first clinical and technical feasibility study using the full IVR laparoscopy setup combined with the latest laparoscopic simulator in a 360° surrounding. Participants were exhilarated by the high level of immersion. The setup enables a completely new generation of surgical training.

Honoring the life and legacy of Václav Havel by directing the House of Representatives Fine Arts Board to provide for the display of a bust of Václav Havel in the United States Capitol.

THOMAS, 113th Congress

Rep. Royce, Edward R. [R-CA-39

2014-03-06

House - 03/11/2014 On motion to suspend the rules and agree to the resolution Agreed to by voice vote. (All Actions) Tracker: This bill has the status Agreed to in HouseHere are the steps for Status of Legislation:

Integrating optical finger motion tracking with surface touch events.

PubMed

MacRitchie, Jennifer; McPherson, Andrew P

2015-01-01

This paper presents a method of integrating two contrasting sensor systems for studying human interaction with a mechanical system, using piano performance as the case study. Piano technique requires both precise small-scale motion of fingers on the key surfaces and planned large-scale movement of the hands and arms. Where studies of performance often focus on one of these scales in isolation, this paper investigates the relationship between them. Two sensor systems were installed on an acoustic grand piano: a monocular high-speed camera tracking the position of painted markers on the hands, and capacitive touch sensors attach to the key surfaces which measure the location of finger-key contacts. This paper highlights a method of fusing the data from these systems, including temporal and spatial alignment, segmentation into notes and automatic fingering annotation. Three case studies demonstrate the utility of the multi-sensor data: analysis of finger flexion or extension based on touch and camera marker location, timing analysis of finger-key contact preceding and following key presses, and characterization of individual finger movements in the transitions between successive key presses. Piano performance is the focus of this paper, but the sensor method could equally apply to other fine motor control scenarios, with applications to human-computer interaction.

Integrating optical finger motion tracking with surface touch events

PubMed Central

MacRitchie, Jennifer; McPherson, Andrew P.

2015-01-01

This paper presents a method of integrating two contrasting sensor systems for studying human interaction with a mechanical system, using piano performance as the case study. Piano technique requires both precise small-scale motion of fingers on the key surfaces and planned large-scale movement of the hands and arms. Where studies of performance often focus on one of these scales in isolation, this paper investigates the relationship between them. Two sensor systems were installed on an acoustic grand piano: a monocular high-speed camera tracking the position of painted markers on the hands, and capacitive touch sensors attach to the key surfaces which measure the location of finger-key contacts. This paper highlights a method of fusing the data from these systems, including temporal and spatial alignment, segmentation into notes and automatic fingering annotation. Three case studies demonstrate the utility of the multi-sensor data: analysis of finger flexion or extension based on touch and camera marker location, timing analysis of finger-key contact preceding and following key presses, and characterization of individual finger movements in the transitions between successive key presses. Piano performance is the focus of this paper, but the sensor method could equally apply to other fine motor control scenarios, with applications to human-computer interaction. PMID:26082732

An Action-Based Fine-Grained Access Control Mechanism for Structured Documents and Its Application

PubMed Central

Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo

2014-01-01

This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical. PMID:25136651

An action-based fine-grained access control mechanism for structured documents and its application.

PubMed

Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo

2014-01-01

This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical.

Relationship between postural control and fine motor skills in preterm infants at 6 and 12 months adjusted age.

PubMed

Wang, Tien-Ni; Howe, Tsu-Hsin; Hinojosa, Jim; Weinberg, Sharon L

2011-01-01

We examined the relationship between postural control and fine motor skills of preterm infants at 6 and 12 mo adjusted age. The Alberta Infant Motor Scale was used to measure postural control, and the Peabody Developmental Motor Scales II was used to measure fine motor skills. The data analyzed were taken from 105 medical records from a preterm infant follow-up clinic at an urban academic medical center in south Taiwan. Using multiple regression analyses, we found that the development of postural control is related to the development of fine motor skills, especially in the group of preterm infants with delayed postural control. This finding supports the theoretical assumption of proximal-distal development used by many occupational therapists to guide intervention. Further research is suggested to corroborate findings.

An analysis of the Hubble Space Telescope fine guidance sensor fine lock mode

NASA Technical Reports Server (NTRS)

Taff, L. G.

1991-01-01

There are two guiding modes of the Hubble Space Telescope (HST) used for the acquisition of astronomical data by one of its six scientific instruments. The more precise one is called Fine Lock. Command and control problems in the onboard electronics has limited Fine Lock to brighter stars, V less than 13.0 mag, instead of fulfilling its goal of V = 14.5 mag. Consequently, the less precise guiding mode of Coarse Track (approximately 40 milli-arc seconds) has to be used fairly frequently. Indeed, almost half of the scientific observations to have been made with the HST will be compromised. The only realistic or extensive simulations of the Fine Lock guidance mode are reported. The theoretical analysis underlying the Monte Carlo experiments and the numerical computations clearly show both that the control electronics are severely under-engineered and how to adjust the various control parameters to successfully extend Fine Lock guiding performance back to V = 14.0 mag and sometimes beyond.

Electromagnetic liquid pistons for capillarity-based pumping

NASA Astrophysics Data System (ADS)

Malouin, Bernard; Olles, Joseph; Cheng, Lili; Hirsa, Amir; Vogel, Michael

2011-11-01

Two adjoining ferrofluid droplets can behave as an electronically-controlled oscillator or switch by an appropriate balance of magnetic, capillary, and inertial forces. Their motion can be exploited to displace a surrounding liquid, forming electromagnetic liquid pistons. Such ferrofluid pistons can pump a precise volume of liquid via finely tunable amplitudes or resonant frequencies with no solid moving parts. Here we demonstrate the use of these liquid pistons in capillarity-dominated systems for variable focal distance liquid lenses with nearly perfect spherical interfaces. These liquid/liquid lenses feature many promising qualities not previously realized together in a liquid lens, including large apertures, immunity to evaporation, invariance to orientation relative to gravity, and low driving voltages. The dynamics of these liquid pistons is examined, with experimental measurements showing good agreement with a spherical cap model. A centimeter-scale lens was shown to respond in excess of 30 Hz, with resonant frequencies over 1 kHz predicted for scaled down systems.

The Annular Suspension and Pointing (ASP) system for space experiments and predicted pointing accuracies

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Joshi, S. M.

1975-01-01

An annular suspension and pointing system consisting of pointing assemblies for coarse and vernier pointing is described. The first assembly is attached to a carrier spacecraft (e.g., the space shuttle) and consists of an azimuth gimbal and an elevation gimbal which provide 'coarse' pointing. The second or vernier pointing assembly is made up of magnetic actuators of suspension and fine pointing, roll motor segments, and an instrument or experiment mounting plate around which is attached a continuous annular rim similar to that used in the annular momentum control device. The rim provides appropriate magnetic circuits for the actuators and the roll motor segments for any instrument roll position. The results of a study to determine the pointing accuracy of the system in the presence of crew motion disturbances are presented. Typical 3 sigma worst-case errors are found to be of the order of 0.001 arc-second.

Fine motor skills in children with rolandic epilepsy.

PubMed

Ayaz, Muhammed; Kara, Bülent; Soylu, Nusret; Ayaz, Ayşe Burcu

2013-11-01

This study aimed to evaluate fine motor skills in children with rolandic epilepsy (RE). The research included 44 children diagnosed with typical RE and 44 controls matched in terms of age, gender, and level of education. Fine motor skills were evaluated with the Purdue Pegboard Test, and intelligence was measured with the Wechsler Intelligence Scale for Children. After controlling for the effect of intelligence on fine motor skills, the results showed that the children with RE did not perform as well as the controls in the PPT dominant hand, both hands, and assembly subtests. Epileptic focus, treatment status, type of antiepileptic treatment, age at the time of the first seizure, time since the last seizure, and total number of seizures did not affect motor skills. Rolandic epilepsy negatively affected fine motor skills regardless of the children's level of intelligence. © 2013.

Improved Analysis of Nanopore Sequence Data and Scanning Nanopore Techniques

NASA Astrophysics Data System (ADS)

Szalay, Tamas

The field of nanopore research has been driven by the need to inexpensively and rapidly sequence DNA. In order to help realize this goal, this thesis describes the PoreSeq algorithm that identifies and corrects errors in real-world nanopore sequencing data and improves the accuracy of de novo genome assembly with increasing coverage depth. The approach relies on modeling the possible sources of uncertainty that occur as DNA advances through the nanopore and then using this model to find the sequence that best explains multiple reads of the same region of DNA. PoreSeq increases nanopore sequencing read accuracy of M13 bacteriophage DNA from 85% to 99% at 100X coverage. We also use the algorithm to assemble E. coli with 30X coverage and the lambda genome at a range of coverages from 3X to 50X. Additionally, we classify sequence variants at an order of magnitude lower coverage than is possible with existing methods. This thesis also reports preliminary progress towards controlling the motion of DNA using two nanopores instead of one. The speed at which the DNA travels through the nanopore needs to be carefully controlled to facilitate the detection of individual bases. A second nanopore in close proximity to the first could be used to slow or stop the motion of the DNA in order to enable a more accurate readout. The fabrication process for a new pyramidal nanopore geometry was developed in order to facilitate the positioning of the nanopores. This thesis demonstrates that two of them can be placed close enough to interact with a single molecule of DNA, which is a prerequisite for being able to use the driving force of the pores to exert fine control over the motion of the DNA. Another strategy for reading the DNA is to trap it completely with one pore and to move the second nanopore instead. To that end, this thesis also shows that a single strand of immobilized DNA can be captured in a scanning nanopore and examined for a full hour, with data from many scans at many different voltages obtained in order to detect a bound protein placed partway along the molecule.

Effects of False Tilt Cues on the Training of Manual Roll Control Skills

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Popovici, Alexandru; Zavala, Melinda A.

2015-01-01

This paper describes a transfer-of-training study performed in the NASA Ames Vertica lMotion Simulator. The purpose of the study was to investigate the effect of false tilt cues on training and transfer of training of manual roll control skills. Of specific interest were the skills needed to control unstable roll dynamics of a mid-size transport aircraft close to the stall point. Nineteen general aviation pilots trained on a roll control task with one of three motion conditions: no motion, roll motion only, or reduced coordinated roll motion. All pilots transferred to full coordinated roll motion in the transfer session. A novel multimodal pilot model identification technique was successfully applied to characterize how pilots' use of visual and motion cues changed over the course of training and after transfer. Pilots who trained with uncoordinated roll motion had significantly higher performance during training and after transfer, even though they experienced the false tilt cues. Furthermore, pilot control behavior significantly changed during the two sessions, as indicated by increasing visual and motion gains, and decreasing lead time constants. Pilots training without motion showed higher learning rates after transfer to the full coordinated roll motion case.

Spatial filtering precedes motion detection.

PubMed

Morgan, M J

1992-01-23

When we perceive motion on a television or cinema screen, there must be some process that allows us to track moving objects over time: if not, the result would be a conflicting mass of motion signals in all directions. A possible mechanism, suggested by studies of motion displacement in spatially random patterns, is that low-level motion detectors have a limited spatial range, which ensures that they tend to be stimulated over time by the same object. This model predicts that the direction of displacement of random patterns cannot be detected reliably above a critical absolute displacement value (Dmax) that is independent of the size or density of elements in the display. It has been inferred that Dmax is a measure of the size of motion detectors in the visual pathway. Other studies, however, have shown that Dmax increases with element size, in which case the most likely interpretation is that Dmax depends on the probability of false matches between pattern elements following a displacement. These conflicting accounts are reconciled here by showing that Dmax is indeed determined by the spacing between the elements in the pattern, but only after fine detail has been removed by a physiological prefiltering stage: the filter required to explain the data has a similar size to the receptive field of neurons in the primate magnocellular pathway. The model explains why Dmax can be increased by removing high spatial frequencies from random patterns, and simplifies our view of early motion detection.

Towards breaking the spatial resolution barriers: An optical flow and super-resolution approach for sea ice motion estimation

NASA Astrophysics Data System (ADS)

Petrou, Zisis I.; Xian, Yang; Tian, YingLi

2018-04-01

Estimation of sea ice motion at fine scales is important for a number of regional and local level applications, including modeling of sea ice distribution, ocean-atmosphere and climate dynamics, as well as safe navigation and sea operations. In this study, we propose an optical flow and super-resolution approach to accurately estimate motion from remote sensing images at a higher spatial resolution than the original data. First, an external example learning-based super-resolution method is applied on the original images to generate higher resolution versions. Then, an optical flow approach is applied on the higher resolution images, identifying sparse correspondences and interpolating them to extract a dense motion vector field with continuous values and subpixel accuracies. Our proposed approach is successfully evaluated on passive microwave, optical, and Synthetic Aperture Radar data, proving appropriate for multi-sensor applications and different spatial resolutions. The approach estimates motion with similar or higher accuracy than the original data, while increasing the spatial resolution of up to eight times. In addition, the adopted optical flow component outperforms a state-of-the-art pattern matching method. Overall, the proposed approach results in accurate motion vectors with unprecedented spatial resolutions of up to 1.5 km for passive microwave data covering the entire Arctic and 20 m for radar data, and proves promising for numerous scientific and operational applications.

Development of fine-leaved Festuca grass populations identified genetic resources having potential for improved forage production and wildfire control in the western United States

USDA-ARS?s Scientific Manuscript database

Drought and heat tolerant fine-leaved fescue (Festuca ssp.) grasses have potential as components in rangeland greenstrips for wildfire control in semi-arid climates. However, such fine-leaved grasses have been difficult to identify because of specific adaptations, lack of late maturity, and often p...

Asthma-Related Outcomes in Patients Initiating Extrafine Ciclesonide or Fine-Particle Inhaled Corticosteroids

PubMed Central

Postma, Dirkje S.; Dekhuijzen, Richard; van der Molen, Thys; Martin, Richard J.; van Aalderen, Wim; Roche, Nicolas; Guilbert, Theresa W.; Israel, Elliot; van Eickels, Daniela; Khalid, Javaria Mona; Herings, Ron M.C.; Overbeek, Jetty A.; Miglio, Cristiana; Thomas, Victoria; Hutton, Catherine; Hillyer, Elizabeth V.

2017-01-01

Purpose Extrafine-particle inhaled corticosteroids (ICS) have greater small airway deposition than standard fine-particle ICS. We sought to compare asthma-related outcomes after patients initiated extrafine-particle ciclesonide or fine-particle ICS (fluticasone propionate or non-extrafine beclomethasone). Methods This historical, matched cohort study included patients aged 12-60 years prescribed their first ICS as ciclesonide or fine-particle ICS. The 2 cohorts were matched 1:1 for key demographic and clinical characteristics over the baseline year. Co-primary endpoints were 1-year severe exacerbation rates, risk-domain asthma control, and overall asthma control; secondary endpoints included therapy change. Results Each cohort included 1,244 patients (median age 45 years; 65% women). Patients in the ciclesonide cohort were comparable to those in the fine-particle ICS cohort apart from higher baseline prevalence of hospitalization, gastroesophageal reflux disease, and rhinitis. Median (interquartile range) prescribed doses of ciclesonide and fine-particle ICS were 160 (160-160) µg/day and 500 (250-500) µg/day, respectively (P<0.001). During the outcome year, patients prescribed ciclesonide experienced lower severe exacerbation rates (adjusted rate ratio [95% CI], 0.69 [0.53-0.89]), and higher odds of risk-domain asthma control (adjusted odds ratio [95% CI], 1.62 [1.27-2.06]) and of overall asthma control (2.08 [1.68-2.57]) than those prescribed fine-particle ICS. The odds of therapy change were 0.70 (0.59-0.83) with ciclesonide. Conclusions In this matched cohort analysis, we observed that initiation of ICS with ciclesonide was associated with better 1-year asthma outcomes and fewer changes to therapy, despite data suggesting more difficult-to-control asthma. The median prescribed dose of ciclesonide was one-third that of fine-particle ICS. PMID:28102056

Open architecture CMM motion controller

NASA Astrophysics Data System (ADS)

Chang, David; Spence, Allan D.; Bigg, Steve; Heslip, Joe; Peterson, John

2001-12-01

Although initially the only Coordinate Measuring Machine (CMM) sensor available was a touch trigger probe, technological advances in sensors and computing have greatly increased the variety of available inspection sensors. Non-contact laser digitizers and analog scanning touch probes require very well tuned CMM motion control, as well as an extensible, open architecture interface. This paper describes the implementation of a retrofit CMM motion controller designed for open architecture interface to a variety of sensors. The controller is based on an Intel Pentium microcomputer and a Servo To Go motion interface electronics card. Motor amplifiers, safety, and additional interface electronics are housed in a separate enclosure. Host Signal Processing (HSP) is used for the motion control algorithm. Compared to the usual host plus DSP architecture, single CPU HSP simplifies integration with the various sensors, and implementation of software geometric error compensation. Motion control tuning is accomplished using a remote computer via 100BaseTX Ethernet. A Graphical User Interface (GUI) is used to enter geometric error compensation data, and to optimize the motion control tuning parameters. It is shown that this architecture achieves the required real time motion control response, yet is much easier to extend to additional sensors.

Control of chemical dynamics by lasers: theoretical considerations.

PubMed

Kondorskiy, Alexey; Nanbu, Shinkoh; Teranishi, Yoshiaki; Nakamura, Hiroki

2010-06-03

Theoretical ideas are proposed for laser control of chemical dynamics. There are the following three elementary processes in chemical dynamics: (i) motion of the wave packet on a single adiabatic potential energy surface, (ii) excitation/de-excitation or pump/dump of wave packet, and (iii) nonadiabatic transitions at conical intersections of potential energy surfaces. A variety of chemical dynamics can be controlled, if we can control these three elementary processes as we desire. For (i) we have formulated the semiclassical guided optimal control theory, which can be applied to multidimensional real systems. The quadratic or periodic frequency chirping method can achieve process (ii) with high efficiency close to 100%. Concerning process (iii) mentioned above, the directed momentum method, in which a predetermined momentum vector is given to the initial wave packet, makes it possible to enhance the desired transitions at conical intersections. In addition to these three processes, the intriguing phenomenon of complete reflection in the nonadiabatic-tunneling-type of potential curve crossing can also be used to control a certain class of chemical dynamics. The basic ideas and theoretical formulations are provided for the above-mentioned processes. To demonstrate the effectiveness of these controlling methods, numerical examples are shown by taking the following processes: (a) vibrational photoisomerization of HCN, (b) selective and complete excitation of the fine structure levels of K and Cs atoms, (c) photoconversion of cyclohexadiene to hexatriene, and (d) photodissociation of OHCl to O + HCl.

The effect of autogenic training and biofeedback on motion sickness tolerance.

PubMed

Jozsvai, E E; Pigeau, R A

1996-10-01

Motion sickness is characterized by symptoms of vomiting, drowsiness, fatigue and idiosyncratic changes in autonomic nervous system (ANS) responses such as heart rate (HR) and skin temperature (ST). Previous studies found that symptoms of motion sickness are controllable through self-regulation of ANS responses and the best method to teach such control is autogenic-feedback (biofeedback) training. Recent experiments indicated that biofeedback training is ineffective in reducing symptoms of motion sickness or in increasing tolerance to motion. If biofeedback facilitates learning of ANS self-regulation then autogenic training with true feedback (TFB) should lead to better control over ANS responses and better motion tolerance than autogenic training with false feedback (FFB). If there is a relationship between ANS self-regulation and coping with motion stress, a significant correlation should be found between amounts of control over ANS responses and measures of motion tolerance and/or symptoms of motion sickness. There were 3 groups of 6 subjects exposed for 6 weeks to weekly sessions of Coriolis stimulation to induce motion sickness. Between the first and second Coriolis sessions, subjects in the experimental groups received five episodes of autogenic training with either true (group TFB) or false (group FFB) feedback on their HR and ST. The control group (CTL) received no treatment. Subjects learned to control their HR and ST independent of whether they received true or false feedback. Learned control of ST and HR was not related to severity of motion sickness or subject's ability to withstand Coriolis stimulation following treatment. A lack of significant correlation between these variables suggested that subjects were not able to apply their skills of ANS self-regulation in the motion environment, and/ or such skills had little value in reducing symptoms of motion sickness or enhancing their ability to withstand rotations.

Changes in fine-root production, phenology and spatial distribution in response to N application in irrigated sweet cherry trees.

PubMed

Artacho, Pamela; Bonomelli, Claudia

2016-05-01

Factors regulating fine-root growth are poorly understood, particularly in fruit tree species. In this context, the effects of N addition on the temporal and spatial distribution of fine-root growth and on the fine-root turnover were assessed in irrigated sweet cherry trees. The influence of other exogenous and endogenous factors was also examined. The rhizotron technique was used to measure the length-based fine-root growth in trees fertilized at two N rates (0 and 60 kg ha(-1)), and the above-ground growth, leaf net assimilation, and air and soil variables were simultaneously monitored. N fertilization exerted a basal effect throughout the season, changing the magnitude, temporal patterns and spatial distribution of fine-root production and mortality. Specifically, N addition enhanced the total fine-root production by increasing rates and extending the production period. On average, N-fertilized trees had a length-based production that was 110-180% higher than in control trees, depending on growing season. Mortality was proportional to production, but turnover rates were inconsistently affected. Root production and mortality was homogeneously distributed in the soil profile of N-fertilized trees while control trees had 70-80% of the total fine-root production and mortality concentrated below 50 cm depth. Root mortality rates were associated with soil temperature and water content. In contrast, root production rates were primarily under endogenous control, specifically through source-sink relationships, which in turn were affected by N supply through changes in leaf photosynthetic level. Therefore, exogenous and endogenous factors interacted to control the fine-root dynamics of irrigated sweet cherry trees. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Changes in fine-root production, phenology and spatial distribution in response to N application in irrigated sweet cherry trees

PubMed Central

Artacho, Pamela; Bonomelli, Claudia

2016-01-01

Factors regulating fine-root growth are poorly understood, particularly in fruit tree species. In this context, the effects of N addition on the temporal and spatial distribution of fine-root growth and on the fine-root turnover were assessed in irrigated sweet cherry trees. The influence of other exogenous and endogenous factors was also examined. The rhizotron technique was used to measure the length-based fine-root growth in trees fertilized at two N rates (0 and 60 kg ha−1), and the above-ground growth, leaf net assimilation, and air and soil variables were simultaneously monitored. N fertilization exerted a basal effect throughout the season, changing the magnitude, temporal patterns and spatial distribution of fine-root production and mortality. Specifically, N addition enhanced the total fine-root production by increasing rates and extending the production period. On average, N-fertilized trees had a length-based production that was 110–180% higher than in control trees, depending on growing season. Mortality was proportional to production, but turnover rates were inconsistently affected. Root production and mortality was homogeneously distributed in the soil profile of N-fertilized trees while control trees had 70–80% of the total fine-root production and mortality concentrated below 50 cm depth. Root mortality rates were associated with soil temperature and water content. In contrast, root production rates were primarily under endogenous control, specifically through source–sink relationships, which in turn were affected by N supply through changes in leaf photosynthetic level. Therefore, exogenous and endogenous factors interacted to control the fine-root dynamics of irrigated sweet cherry trees. PMID:26888890

Fractional Diffusion, Low Exponent Lévy Stable Laws, and 'Slow Motion' Denoising of Helium Ion Microscope Nanoscale Imagery.

PubMed

Carasso, Alfred S; Vladár, András E

2012-01-01

Helium ion microscopes (HIM) are capable of acquiring images with better than 1 nm resolution, and HIM images are particularly rich in morphological surface details. However, such images are generally quite noisy. A major challenge is to denoise these images while preserving delicate surface information. This paper presents a powerful slow motion denoising technique, based on solving linear fractional diffusion equations forward in time. The method is easily implemented computationally, using fast Fourier transform (FFT) algorithms. When applied to actual HIM images, the method is found to reproduce the essential surface morphology of the sample with high fidelity. In contrast, such highly sophisticated methodologies as Curvelet Transform denoising, and Total Variation denoising using split Bregman iterations, are found to eliminate vital fine scale information, along with the noise. Image Lipschitz exponents are a useful image metrology tool for quantifying the fine structure content in an image. In this paper, this tool is applied to rank order the above three distinct denoising approaches, in terms of their texture preserving properties. In several denoising experiments on actual HIM images, it was found that fractional diffusion smoothing performed noticeably better than split Bregman TV, which in turn, performed slightly better than Curvelet denoising.

The dynamics and control of large flexible asymmetric spacecraft

NASA Astrophysics Data System (ADS)

Humphries, T. T.

1991-02-01

This thesis develops the equations of motion for a large flexible asymmetric Earth observation satellite and finds the characteristics of its motion under the influence of control forces. The mathematical model of the structure is produced using analytical methods. The equations of motion are formed using an expanded momentum technique which accounts for translational motion of the spacecraft hub and employs orthogonality relations between appendage and vehicle modes. The controllability and observability conditions of the full spacecraft motions using force and torque actuators are defined. A three axis reaction wheel control system is implemented for both slewing the spacecraft and controlling its resulting motions. From minor slew results it is shown that the lowest frequency elastic mode of the spacecraft is more important than higher frequency modes, when considering the effects of elastic motion on instrument pointing from the hub. Minor slews of the spacecraft configurations considered produce elastic deflections resulting in rotational attitude motions large enough to contravene pointing accuracy requirements of instruments aboard the spacecraft hub. Active vibration damping is required to reduce these hub motions to acceptable bounds in sufficiently small time. A comparison between hub mounted collocated and hub/appendage mounted non-collocated control systems verifies that provided the non-collocated system is stable, it can more effectively damp elastic modes whilst maintaining adequate damping of rigid modes. Analysis undertaken shows that the reaction wheel controller could be replaced by a thruster control system which decouples the modes of the spacecraft motion, enabling them to be individually damped.

SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell

PubMed Central

González-Partida, José-Tomás; Almorox-González, Pablo; Burgos-García, Mateo; Dorta-Naranjo, Blas-Pablo

2008-01-01

This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad Politécnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar. PMID:27879884

SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell.

PubMed

González-Partida, José-Tomás; Almorox-González, Pablo; Burgos-Garcia, Mateo; Dorta-Naranjo, Blas-Pablo

2008-05-23

This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad Politécnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar.

Controllable rotational inversion in nanostructures with dual chirality.

PubMed

Dai, Lu; Zhu, Ka-Di; Shen, Wenzhong; Huang, Xiaojiang; Zhang, Li; Goriely, Alain

2018-04-05

Chiral structures play an important role in natural sciences due to their great variety and potential applications. A perversion connecting two helices with opposite chirality creates a dual-chirality helical structure. In this paper, we develop a novel model to explore quantitatively the mechanical behavior of normal, binormal and transversely isotropic helical structures with dual chirality and apply these ideas to known nanostructures. It is found that both direction and amplitude of rotation can be finely controlled by designing the cross-sectional shape. A peculiar rotational inversion of overwinding followed by unwinding, observed in some gourd and cucumber tendril perversions, not only exists in transversely isotropic dual-chirality helical nanobelts, but also in the binormal/normal ones when the cross-sectional aspect ratio is close to 1. Beyond this rotational inversion region, the binormal and normal dual-chirality helical nanobelts exhibit a fixed directional rotation of unwinding and overwinding, respectively. Moreover, in the binormal case, the rotation of these helical nanobelts is nearly linear, which is promising as a possible design for linear-to-rotary motion converters. The present work suggests new designs for nanoscale devices.

The research of the coupled orbital-attitude controlled motion of celestial body in the neighborhood of the collinear libration point L1

NASA Astrophysics Data System (ADS)

Shmyrov, A.; Shmyrov, V.; Shymanchuk, D.

2017-10-01

This article considers the motion of a celestial body within the restricted three-body problem of the Sun-Earth system. The equations of controlled coupled attitude-orbit motion in the neighborhood of collinear libration point L1 are investigated. The translational orbital motion of a celestial body is described using Hill's equations of circular restricted three-body problem of the Sun-Earth system. Rotational orbital motion is described using Euler's dynamic equations and quaternion kinematic equation. We investigate the problem of stability of celestial body rotational orbital motion in relative equilibrium positions and stabilization of celestial body rotational orbital motion with proposed control laws in the neighborhood of collinear libration point L1. To study stabilization problem, Lyapunov function is constructed in the form of the sum of the kinetic energy and special "kinematic function" of the Rodriguez-Hamiltonian parameters. Numerical modeling of the controlled rotational motion of a celestial body at libration point L1 is carried out. The numerical characteristics of the control parameters and rotational motion are given.

The Vestibular System and Human Dynamic Space Orientation

NASA Technical Reports Server (NTRS)

Meiry, J. L.

1966-01-01

The motion sensors of the vestibular system are studied to determine their role in human dynamic space orientation and manual vehicle control. The investigation yielded control models for the sensors, descriptions of the subsystems for eye stabilization, and demonstrations of the effects of motion cues on closed loop manual control. Experiments on the abilities of subjects to perceive a variety of linear motions provided data on the dynamic characteristics of the otoliths, the linear motion sensors. Angular acceleration threshold measurements supplemented knowledge of the semicircular canals, the angular motion sensors. Mathematical models are presented to describe the known control characteristics of the vestibular sensors, relating subjective perception of motion to objective motion of a vehicle. The vestibular system, the neck rotation proprioceptors and the visual system form part of the control system which maintains the eye stationary relative to a target or a reference. The contribution of each of these systems was identified through experiments involving head and body rotations about a vertical axis. Compensatory eye movements in response to neck rotation were demonstrated and their dynamic characteristics described by a lag-lead model. The eye motions attributable to neck rotations and vestibular stimulation obey superposition when both systems are active. Human operator compensatory tracking is investigated in simple vehicle orientation control system with stable and unstable controlled elements. Control of vehicle orientation to a reference is simulated in three modes: visual, motion and combined. Motion cues sensed by the vestibular system through tactile sensation enable the operator to generate more lead compensation than in fixed base simulation with only visual input. The tracking performance of the human in an unstable control system near the limits of controllability is shown to depend heavily upon the rate information provided by the vestibular sensors.

Fine pointing control for free-space optical communication

NASA Technical Reports Server (NTRS)

Portillo, A. A.; Ortiz, G. G.; Racho, C.

2000-01-01

Free-Space Optical Communications requires precise, stable laser pointing to maintain operating conditions. This paper also describes the software and hardware implementation of Fine Pointing Control based on the Optical Communications Demonstrator architecture.

Interferometric estimation of ice sheet motion and topography

NASA Technical Reports Server (NTRS)

Joughlin, Ian; Kwok, Ron; Fahnestock, Mark; Winebrenner, Dale; Tulaczyk, Slawek; Gogenini, Prasad

1997-01-01

With ERS-1/2 satellite radar interferometry, it is possible to make measurements of glacier motion with high accuracy and fine spatial resolution. Interferometric techniques were applied to map velocity and topography for several outlet glaciers in Greenland. For the Humboldt and Petermann glaciers, data from several adjacent tracks were combined to make a wide-area map that includes the enhanced flow regions of both glaciers. The discharge flux of the Petermann glacier upstream of the grounding line was estimated, thereby establishing the potential use of ERS-1/2 interferometric data for monitoring ice-sheet discharge. Interferograms collected along a single track are sensitive to only one component of motion. By utilizing data from ascending and descending passes and by making a surface-parallel flow assumption, it is possible to measure the full three-dimensional vector flow field. The application of this technique for an area on the Ryder glacier is demonstrated. Finally, ERS-1/2 interferograms were used to observe a mini-surge on the Ryder glacier that occurred in autumn of 1995.

Radio Frequencies Emitted by Mobile Granular Materials: A Basis for Remote Sensing of Sand and Dust Activity on Mars and Earth

NASA Technical Reports Server (NTRS)

Marshall, J.; Farrell, W.; Houser, G.; Bratton, C.

1999-01-01

In recent laboratory experiments, measurements were made of microsecond radio-wave (RF) bursts emitted by grains of sand as they energetically circulated in a closed, electrically ungrounded chamber. The bursts appeared to result from nanoscale electrical discharging from grain surfaces. Both the magnitude and wave form of the RF pulses varied with the type of material undergoing motion. The release of RF from electrical discharging is a well-known phenomenon, but it is generally measured on much larger energy scales (e.g., in association with lightning or electrical motors). This phenomenon might be used to detect, on planetary surfaces, the motion and composition of sand moving over dunes, the turbulent motion of fine particles in dust storms, highly-energetic grain and rock collisions in volcanic eruptions, and frictional grinding of granular materials in dry debris flows, landslides, and avalanches. The occurrence of these discharges has been predicted from theoretical considerations Additional information is contained in the original.

Synthesis of a controller for stabilizing the motion of a rigid body about a fixed point

NASA Astrophysics Data System (ADS)

Zabolotnov, Yu. M.; Lobanov, A. A.

2017-05-01

A method for the approximate design of an optimal controller for stabilizing the motion of a rigid body about a fixed point is considered. It is assumed that rigid body motion is nearly the motion in the classical Lagrange case. The method is based on the common use of the Bellman dynamic programming principle and the averagingmethod. The latter is used to solve theHamilton-Jacobi-Bellman equation approximately, which permits synthesizing the controller. The proposed method for controller design can be used in many problems close to the problem of motion of the Lagrange top (the motion of a rigid body in the atmosphere, the motion of a rigid body fastened to a cable in deployment of the orbital cable system, etc.).

Development of the fine-particle agglomerator

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

Feldman, P.; Balasic, P.

1999-07-01

This paper presents the current status of the commercial development of a new technology to more efficiently control fine particulate emissions. The technology is based on an invention by Environmental Elements Corporation (EEC) which utilizes laminar flow to promote contact of fine submicron particles with larger particles to form agglomerates prior to their removal in a conventional particulate control device, such as an ESP. As agglomerates the particles are easily captured in the control device, whereas a substantial amount would pass through if allowed to remain as fine particles. EEC has developed the laminar-flow agglomerator technology through the laboratory proof-of-conceptmore » stage, which was funded by a DOE SBIR grant, to pilot-scale and full-scale demonstrations.« less

Model Predictive Control Based Motion Drive Algorithm for a Driving Simulator

NASA Astrophysics Data System (ADS)

Rehmatullah, Faizan

In this research, we develop a model predictive control based motion drive algorithm for the driving simulator at Toronto Rehabilitation Institute. Motion drive algorithms exploit the limitations of the human vestibular system to formulate a perception of motion within the constrained workspace of a simulator. In the absence of visual cues, the human perception system is unable to distinguish between acceleration and the force of gravity. The motion drive algorithm determines control inputs to displace the simulator platform, and by using the resulting inertial forces and angular rates, creates the perception of motion. By using model predictive control, we can optimize the use of simulator workspace for every maneuver while simulating the vehicle perception. With the ability to handle nonlinear constraints, the model predictive control allows us to incorporate workspace limitations.

Vestibular models for design and evaluation of flight simulator motion

NASA Technical Reports Server (NTRS)

Bussolari, S. R.; Sullivan, R. B.; Young, L. R.

1986-01-01

The use of spatial orientation models in the design and evaluation of control systems for motion-base flight simulators is investigated experimentally. The development of a high-fidelity motion drive controller using an optimal control approach based on human vestibular models is described. The formulation and implementation of the optimal washout system are discussed. The effectiveness of the motion washout system was evaluated by studying the response of six motion washout systems to the NASA/AMES Vertical Motion Simulator for a single dash-quick-stop maneuver. The effects of the motion washout system on pilot performance and simulator acceptability are examined. The data reveal that human spatial orientation models are useful for the design and evaluation of flight simulator motion fidelity.

Do motion controllers make action video games less sedentary? A randomized experiment.

PubMed

Lyons, Elizabeth J; Tate, Deborah F; Ward, Dianne S; Ribisl, Kurt M; Bowling, J Michael; Kalyanaraman, Sriram

2012-01-01

Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal · kg(-1) · hr(-1)) produced 0.10 kcal · kg(-1) · hr(-1) (95% confidence interval 0.03 to 0.17) greater energy expenditure than traditional control (0.86 [0.17] kcal · kg(-1) · hr(-1), P = .048). All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior.

Do Motion Controllers Make Action Video Games Less Sedentary? A Randomized Experiment

PubMed Central

Lyons, Elizabeth J.; Tate, Deborah F.; Ward, Dianne S.; Ribisl, Kurt M.; Bowling, J. Michael; Kalyanaraman, Sriram

2012-01-01

Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal · kg−1 · hr−1) produced 0.10 kcal · kg−1 · hr−1 (95% confidence interval 0.03 to 0.17) greater energy expenditure than traditional control (0.86 [0.17] kcal · kg−1 · hr−1, P = .048). All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior. PMID:22028959

Acoustic bubble: Controlled and selective micropropulsion and chemical waveform generator

NASA Astrophysics Data System (ADS)

Ahmed, Daniel

The physics governing swimming at the microscale---where viscous forces dominate over inertial---is distinctly different than that at the macroscale. Devices capable of finely controlled swimming at the microscale could enable bold ideas such as targeted drug delivery, non-invasive microsurgery, and precise materials assembly. Progress has already been made towards such artificial microswimmers using several means of actuation: chemical reactions and applied magnetic, electric or acoustic fields. However, the prevailing goal of selective actuation of a single microswimmer from within a group, the first step towards collaborative, guided action by a group of swimmers, has so far not been achieved. Here I present a new class of microswimmer that accomplishes for the first time selective actuation (Chapter 1). The swimmer design eschews the commonly-held design paradigm that microswimmers must use non-reciprocal motion to achieve propulsion; instead, the swimmer is propelled by oscillatory motion of an air bubble trapped within the swimmer's polymer body. This oscillatory motion is driven by a low-power biocompatible acoustic field to the ambient liquid, with meaningful swimmer propulsion occurring only at resonance frequencies of the bubble. This acoustically-powered microswimmer performs controllable rapid translational and rotational motion even in highly viscous liquid. By using a group of swimmers each with a different bubble size (and thus different resonance frequencies) selective actuation of a single swimmer from among the group can be readily achieved. Cellular response to chemical microenvironments depends on the spatiotemporal characteristics of the stimulus, which is central to many biological processes including gene expression, cell migration, differentiation, apoptosis, and intercellular signaling. To date, studies have been limited to digital (or step) chemical stimulation with little control over the temporal counterparts. Microfluidic approaches have offered a higher level of sophistication in terms of liquid manipulation, however, due to low Reynolds number associated with these methods, precise temporal manipulation has remained a challenge. Furthermore, varying the sample concentration rapidly and controllably, an important task for a plethora of chemical and biological studies, has proven to be extremely difficult. Here I demonstrate (Chapter 3) a novel approach for generating chemical waveforms that permits continuous modulation of the signal characteristics including the shape, frequency, amplitude (sample concentration), and duty cycle, with frequencies reaching up to 30 Hz. Furthermore, using multiple bubbles of different sizes in a single microchannel, we show fast switching between multiple distinct stimuli, wherein the waveform of each stimulus is independently controlled. Using our device, we characterized the frequency-dependent activation and internalization of the -adrenergic receptor (beta2-AR), a prototypic G-protein coupled receptors (GPCRs) due to epinephrine. We determined that beta2-AR internalization due to epinephrine occurs on timescales between 100 ms and 5sec. The chemical waveform generation and switching method presented herein is expected to be useful for understanding the dynamics of fast biomolecular processes.

Generation and characterization of field-emitting surface dielectric barrier discharges in liquids

NASA Astrophysics Data System (ADS)

Kawamura, Tomohisa; Kanno, Moriyuki; Stauss, Sven; Kuribara, Koichi; Pai, David Z.; Ito, Tsuyohito; Terashima, Kazuo

2018-01-01

Field-emitting surface dielectric barrier discharges (FESDBDs), previously generated in CO2 from high pressures up to supercritical conditions using 10 kHz ac excitation, were investigated in non-aqueous liquid CO2 and liquid silicone oil. In both liquids, the maximum amount of negative charge Q-deposited as a function of the applied voltage amplitude was consistent with the Fowler-Nordheim equation, which demonstrated the presence of field emission. Furthermore, purely continuum optical emission spectra attributable to electron-neutral bremsstrahlung were confirmed. The fact that these characteristics were identical to those in high-pressure CO2 reported from previous research shows that FESDBDs can be generated independently of the medium type and that they are low-power (on the order of 10 mW) discharges. To investigate the charging function of FESDBDs, the motion of fine particles suspended above the FESDBDs was studied by high-speed imaging. It revealed that the speed of fine particles affected by the FESDBDs depends on the particle size, the FESDBDs' function being to charge fine particles.

Behavioral methods of alleviating motion sickness: effectiveness of controlled breathing and a music audiotape.

PubMed

Yen Pik Sang, Fleur D; Billar, Jessica P; Golding, John F; Gresty, Michael A

2003-01-01

Behavioral countermeasures for motion sickness would be advantageous because of the side effects of antiemetic drugs, but few alternative treatments are available. The objective of this study was to compare the effectiveness of controlling breathing and listening to a music audiotape designed to reduce motion sickness symptoms, on increasing tolerance to motion-induced nausea. Twenty-four healthy subjects were exposed to nauseogenic Coriolis stimulation on a rotating turntable under three conditions: whilst focusing on controlling breathing; listening to a music audiotape; or without intervention (control). The three conditions were performed by each subject according to a replicated factorial design at 1-week intervals at the same time of day. Ratings of motion sickness were obtained every 30 seconds. Once a level of mild nausea was reached subjects commenced controlling breathing or listened to the music audiotape. Motion was stopped after the onset of moderate nausea. Mean (+/- SD) motion exposure time in minutes tolerated before the onset of moderate nausea was significantly longer (p <.01) for controlling breathing (10.7 +/- 5.6 min) and longer (p <.01) for music (10.4 +/- 5.6 min) compared with control (9.2 +/- 5.9 min). Both controlling breathing and the music audiotape provided significant protection against motion sickness and with similar effectiveness. These nonpharmacologic countermeasures are only half as effective as standard doses of anti-motion sickness drugs, such as oral scopolamine; however, they are easy to implement and free of side effects.

A proportional control scheme for high density force myography.

PubMed

Belyea, Alexander T; Englehart, Kevin B; Scheme, Erik J

2018-08-01

Force myography (FMG) has been shown to be a potentially higher accuracy alternative to electromyography for pattern recognition based prosthetic control. Classification accuracy, however, is just one factor that affects the usability of a control system. Others, like the ability to start and stop, to coordinate dynamic movements, and to control the velocity of the device through some proportional control scheme can be of equal importance. To impart effective fine control using FMG-based pattern recognition, it is important that a method of controlling the velocity of each motion be developed. In this work force myography data were collected from 14 able bodied participants and one amputee participant as they performed a set of wrist and hand motions. The offline proportional control performance of a standard mean signal amplitude approach and a proposed regression-based alternative was compared. The impact of providing feedback during training, as well as the use of constrained or unconstrained hand and wrist contractions, were also evaluated. It is shown that the commonly used mean of rectified channel amplitudes approach commonly employed with electromyography does not translate to force myography. The proposed class-based regression proportional control approach is shown significantly outperform this standard approach (ρ  <  0.001), yielding a R 2 correlation coefficients of 0.837 and 0.830 for constrained and unconstrained forearm contractions, respectively for able bodied participants. No significant difference (ρ  =  0.693) was found in R 2 performance when feedback was provided during training or not. The amputee subject achieved a classification accuracy of 83.4%  ±  3.47% demonstrating the ability to distinguish contractions well with FMG. In proportional control the amputee participant achieved an R 2 of of 0.375 for regression based proportional control during unconstrained contractions. This is lower than the unconstrained case for able-bodied subjects for this particular amputee, possibly due to difficultly in visualizing contraction level modulation without feedback. This may be remedied in the use of a prosthetic limb that would provide real-time feedback in the form of device speed. A novel class-specific regression-based approach is proposed for multi-class control is described and shown to provide an effective means of providing FMG-based proportional control.

A simple force-motion relation for migrating cells revealed by multipole analysis of traction stress.

PubMed

Tanimoto, Hirokazu; Sano, Masaki

2014-01-07

For biophysical understanding of cell motility, the relationship between mechanical force and cell migration must be uncovered, but it remains elusive. Since cells migrate at small scale in dissipative circumstances, the inertia force is negligible and all forces should cancel out. This implies that one must quantify the spatial pattern of the force instead of just the summation to elucidate the force-motion relation. Here, we introduced multipole analysis to quantify the traction stress dynamics of migrating cells. We measured the traction stress of Dictyostelium discoideum cells and investigated the lowest two moments, the force dipole and quadrupole moments, which reflect rotational and front-rear asymmetries of the stress field. We derived a simple force-motion relation in which cells migrate along the force dipole axis with a direction determined by the force quadrupole. Furthermore, as a complementary approach, we also investigated fine structures in the stress field that show front-rear asymmetric kinetics consistent with the multipole analysis. The tight force-motion relation enables us to predict cell migration only from the traction stress patterns. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Contrast and assimilation in motion perception and smooth pursuit eye movements.

PubMed

Spering, Miriam; Gegenfurtner, Karl R

2007-09-01

The analysis of visual motion serves many different functions ranging from object motion perception to the control of self-motion. The perception of visual motion and the oculomotor tracking of a moving object are known to be closely related and are assumed to be controlled by shared brain areas. We compared perceived velocity and the velocity of smooth pursuit eye movements in human observers in a paradigm that required the segmentation of target object motion from context motion. In each trial, a pursuit target and a visual context were independently perturbed simultaneously to briefly increase or decrease in speed. Observers had to accurately track the target and estimate target speed during the perturbation interval. Here we show that the same motion signals are processed in fundamentally different ways for perception and steady-state smooth pursuit eye movements. For the computation of perceived velocity, motion of the context was subtracted from target motion (motion contrast), whereas pursuit velocity was determined by the motion average (motion assimilation). We conclude that the human motion system uses these computations to optimally accomplish different functions: image segmentation for object motion perception and velocity estimation for the control of smooth pursuit eye movements.

Task-oriented training with computer gaming in people with rheumatoid arthritisor osteoarthritis of the hand: study protocol of a randomized controlled pilot trial.

PubMed

Srikesavan, Cynthia Swarnalatha; Shay, Barbara; Robinson, David B; Szturm, Tony

2013-03-09

Significant restriction in the ability to participate in home, work and community life results from pain, fatigue, joint damage, stiffness and reduced joint range of motion and muscle strength in people with rheumatoid arthritis or osteoarthritis of the hand. With modest evidence on the therapeutic effectiveness of conventional hand exercises, a task-oriented training program via real life object manipulations has been developed for people with arthritis. An innovative, computer-based gaming platform that allows a broad range of common objects to be seamlessly transformed into therapeutic input devices through instrumentation with a motion-sense mouse has also been designed. Personalized objects are selected to target specific training goals such as graded finger mobility, strength, endurance or fine/gross dexterous functions. The movements and object manipulation tasks that replicate common situations in everyday living will then be used to control and play any computer game, making practice challenging and engaging. The ongoing study is a 6-week, single-center, parallel-group, equally allocated and assessor-blinded pilot randomized controlled trial. Thirty people with rheumatoid arthritis or osteoarthritis affecting the hand will be randomized to receive either conventional hand exercises or the task-oriented training. The purpose is to determine a preliminary estimation of therapeutic effectiveness and feasibility of the task-oriented training program. Performance based and self-reported hand function, and exercise compliance are the study outcomes. Changes in outcomes (pre to post intervention) within each group will be assessed by paired Student t test or Wilcoxon signed-rank test and between groups (control versus experimental) post intervention using unpaired Student t test or Mann-Whitney U test. The study findings will inform decisions on the feasibility, safety and completion rate and will also provide preliminary data on the treatment effects of the task-oriented training compared with conventional hand exercises in people with rheumatoid arthritis or osteoarthritis of the hand. ClinicalTrials.gov: NCT01635582.

Initial Considerations of a Dust Dispenser for Injecting Tungsten Particles in Space

DTIC Science & Technology

2014-09-26

INTRODUCTION We began to learn how to work with tungsten particles as fine as corn starch , which must be ejected as individual particles. Several designs...purchased a quantity of tungsten carbide spheres, with diameters in our desired range, because of their shape and improved resistance to oxidation... resistance . When ignoring air resistance the only force acting on the particle after it leaves the dispenser is gravity. The particle motion can be

A Generalized-Compliant-Motion Primitive

NASA Technical Reports Server (NTRS)

Backes, Paul G.

1993-01-01

Computer program bridges gap between planning and execution of compliant robotic motions developed and installed in control system of telerobot. Called "generalized-compliant-motion primitive," one of several task-execution-primitive computer programs, which receives commands from higher-level task-planning programs and executes commands by generating required trajectories and applying appropriate control laws. Program comprises four parts corresponding to nominal motion, compliant motion, ending motion, and monitoring. Written in C language.

An optimal control strategy for two-dimensional motion camouflage with non-holonimic constraints.

PubMed

Rañó, Iñaki

2012-07-01

Motion camouflage is a stealth behaviour observed both in hover-flies and in dragonflies. Existing controllers for mimicking motion camouflage generate this behaviour on an empirical basis or without considering the kinematic motion restrictions present in animal trajectories. This study summarises our formal contributions to solve the generation of motion camouflage as a non-linear optimal control problem. The dynamics of the system capture the kinematic restrictions to motion of the agents, while the performance index ensures camouflage trajectories. An extensive set of simulations support the technique, and a novel analysis of the obtained trajectories contributes to our understanding of possible mechanisms to obtain sensor based motion camouflage, for instance, in mobile robots.

Metabolic control of respiratory levels in coenzyme Q biosynthesis-deficient Escherichia coli strains leading to fine-tune aerobic lactate fermentation.

PubMed

Wu, Hui; Bennett, George N; San, Ka-Yiu

2015-08-01

A novel strategy to finely control the electron transfer chain (ETC) activity of Escherichia coli was established. In this study, the fine-tuning of the ubiquinone biosynthesis pathway was applied to further controlling ETC function in coenzyme Q8 biosynthesis-deficient E. coli strains, HW108 and HW109, which contain mutations in ubiE and ubiG, respectively. A competing pathway on the intermediate substrates of the Q8 synthesis pathway, catalyzed by diphosphate:4-hydroxybenzoate geranyltransferase (PGT-1) of Lithospermum erythrorhizon, was introduced into these mutant strains. A nearly theoretical yield of lactate production can be achieved under fully aerobic conditions via an in vivo, genetically fine-tunable means to further control the activity of the ETC of the Q8 biosynthesis-deficient E. coli strains. © 2015 Wiley Periodicals, Inc.

Fine spatiotemporal activity in contracting myometrium revealed by motion-corrected calcium imaging.

PubMed

Loftus, Fiona C; Shmygol, Anatoly; Richardson, Magnus J E

2014-10-15

Successful childbirth depends on the occurrence of precisely coordinated uterine contractions during labour. Calcium indicator fluorescence imaging is one of the main techniques for investigating the mechanisms governing this physiological process and its pathologies. The effective spatiotemporal resolution of calcium signals is, however, limited by the motion of contracting tissue: structures of interest in the order of microns can move over a hundred times their width during a contraction. The simultaneous changes in local intensity and tissue configuration make motion tracking a non-trivial problem in image analysis and confound many of the standard techniques. This paper presents a method that tracks local motion throughout the tissue and allows for the almost complete removal of motion artefacts. This provides a stabilized calcium signal down to a pixel resolution, which, for the data examined, is in the order of a few microns. As a byproduct of image stabilization, a complete kinematic description of the contraction-relaxation cycle is also obtained. This contains novel information about the mechanical response of the tissue, such as the identification of a characteristic length scale, in the order of 40-50 μm, below which tissue motion is homogeneous. Applied to our data, we illustrate that the method allows for analyses of calcium dynamics in contracting myometrium in unprecedented spatiotemporal detail. Additionally, we use the kinematics of tissue motion to compare calcium signals at the subcellular level and local contractile motion. The computer code used is provided in a freely modifiable form and has potential applicability to in vivo calcium imaging of neural tissue, as well as other smooth muscle tissue. © 2014 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Fine spatiotemporal activity in contracting myometrium revealed by motion-corrected calcium imaging

PubMed Central

Loftus, Fiona C; Shmygol, Anatoly; Richardson, Magnus J E

2014-01-01

Successful childbirth depends on the occurrence of precisely coordinated uterine contractions during labour. Calcium indicator fluorescence imaging is one of the main techniques for investigating the mechanisms governing this physiological process and its pathologies. The effective spatiotemporal resolution of calcium signals is, however, limited by the motion of contracting tissue: structures of interest in the order of microns can move over a hundred times their width during a contraction. The simultaneous changes in local intensity and tissue configuration make motion tracking a non-trivial problem in image analysis and confound many of the standard techniques. This paper presents a method that tracks local motion throughout the tissue and allows for the almost complete removal of motion artefacts. This provides a stabilized calcium signal down to a pixel resolution, which, for the data examined, is in the order of a few microns. As a byproduct of image stabilization, a complete kinematic description of the contraction–relaxation cycle is also obtained. This contains novel information about the mechanical response of the tissue, such as the identification of a characteristic length scale, in the order of 40–50 μm, below which tissue motion is homogeneous. Applied to our data, we illustrate that the method allows for analyses of calcium dynamics in contracting myometrium in unprecedented spatiotemporal detail. Additionally, we use the kinematics of tissue motion to compare calcium signals at the subcellular level and local contractile motion. The computer code used is provided in a freely modifiable form and has potential applicability to in vivo calcium imaging of neural tissue, as well as other smooth muscle tissue. PMID:25085893

14 CFR 25.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... Rudder Right pedal forward for nose right. (2) Secondary. Controls Motion and effect Flaps (or auxiliary lift devices) Forward for flaps up; rearward for flaps down. Trim tabs (or equivalent) Rotate to... and auxiliary controls: (1) Powerplant. Controls Motion and effect Power or thrust Forward to increase...

14 CFR 25.779 - Motion and effect of cockpit controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... Rudder Right pedal forward for nose right. (2) Secondary. Controls Motion and effect Flaps (or auxiliary lift devices) Forward for flaps up; rearward for flaps down. Trim tabs (or equivalent) Rotate to... and auxiliary controls: (1) Powerplant. Controls Motion and effect Power or thrust Forward to increase...

Maximum Principle for General Controlled Systems Driven by Fractional Brownian Motions

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

Han Yuecai; Hu Yaozhong; Song Jian, E-mail: jsong2@math.rutgers.edu

2013-04-15

We obtain a maximum principle for stochastic control problem of general controlled stochastic differential systems driven by fractional Brownian motions (of Hurst parameter H>1/2). This maximum principle specifies a system of equations that the optimal control must satisfy (necessary condition for the optimal control). This system of equations consists of a backward stochastic differential equation driven by both fractional Brownian motions and the corresponding underlying standard Brownian motions. In addition to this backward equation, the maximum principle also involves the Malliavin derivatives. Our approach is to use conditioning and Malliavin calculus. To arrive at our maximum principle we need tomore » develop some new results of stochastic analysis of the controlled systems driven by fractional Brownian motions via fractional calculus. Our approach of conditioning and Malliavin calculus is also applied to classical system driven by standard Brownian motions while the controller has only partial information. As a straightforward consequence, the classical maximum principle is also deduced in this more natural and simpler way.« less

77 FR 55505 - Manufacturer of Controlled Substances; Notice of Registration; AMPAC Fine Chemicals LLC

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-10

...; Notice of Registration; AMPAC Fine Chemicals LLC By Notice dated May 11, 2012, and published in the Federal Register on May 21, 2012, 77 FR 30026, AMPAC Fine Chemicals LLC., Highway 50 and Hazel Avenue.... 823(a) and determined that the registration of AMPAC Fine Chemicals LLC., to manufacture the listed...

3D landslide motion from a UAV-derived time-series of morphological attributes

NASA Astrophysics Data System (ADS)

Valasia Peppa, Maria; Mills, Jon Philip; Moore, Philip; Miller, Pauline; Chambers, Jon

2017-04-01

Landslides are recognised as dynamic and significantly hazardous phenomena. Time-series observations can improve the understanding of a landslide's complex behaviour and aid assessment of its geometry and kinematics. Conventional quantification of landslide motion involves the installation of survey markers into the ground at discrete locations and periodic observations over time. However, such surveying is labour intensive, provides limited spatial resolution, is occasionally hazardous for steep terrain, or even impossible for inaccessible mountainous areas. The emergence of mini unmanned aerial vehicles (UAVs) equipped with off-the-shelf compact cameras, alongside the structure-from-motion (SfM) photogrammetric pipeline and modern pixel-based matching approaches, has expedited the automatic generation of high resolution digital elevation models (DEMs). Moreover, cross-correlation functions applied to finely co-registered consecutive orthomosaics and/or DEMs have been widely used to determine the displacement of moving features in an automated way, resulting in high spatial resolution motion vectors. This research focuses on estimating the 3D displacement field of an active slow moving earth-slide earth-flow landslide located in Lias mudrocks of North Yorkshire, UK, with the ultimate aim of assessing landslide deformation patterns. The landslide extends approximately 290 m E-W and 230 m N-S, with an average slope of 12˚ and 50 m elevation difference from N-S. Cross-correlation functions were applied to an eighteen-month duration, UAV-derived, time-series of morphological attributes in order to determine motion vectors for subsequent landslide analysis. A self-calibrating bundle adjustment was firstly incorporated into the SfM pipeline and utilised to process imagery acquired using a Panasonic Lumix DMC-LX5 compact camera from a mini fixed-wing Quest 300 UAV, with 2 m wingspan and maximum 5 kg payload. Data from six field campaigns were used to generate a DEM time-series at 6 cm spatial resolution. DEMs were georeferenced into a common reference frame using control information from surveyed ground control points. The accuracy of the co-registration was estimated from planimetric and vertical RMS errors at independent checkpoints as 4 cm and 3 cm respectively. Afterwards, various morphological attributes, including shaded relief, curvature and openness were calculated from the UAV-derived DEMs. These attributes are indicative of the local structures of discernible geomorphological features (e.g. scarps, ridges, cracks, etc.), the motion of which can be monitored using the cross-correlation algorithm. Multiple experiments were conducted to test the performance of the cross-correlation function implemented on successive epochs. Two benchmark datasets were used for validation of the cross-correlation results: a) the motion vectors generated from the surveyed 3D position of installed markers; b) the calculated displacements of features, manually tracked from successive UAV-derived orthomosaics. Both benchmark datasets detected a maximum planimetric displacement of approximately 1 m at the foot of the landslide, with a dominant N-S orientation, between December 2014 and May 2016. Preliminary cross-correlation results illustrated a similar planimetric motion in both magnitude and orientation, however user intervention was required to filter spurious displacement vectors.

Vertical-angle control system in the LLMC

NASA Astrophysics Data System (ADS)

Li, Binhua; Yang, Lei; Tie, Qiongxian; Mao, Wei

2000-10-01

A control system of the vertical angle transmission used in the Lower Latitude Meridian Circle (LLMC) is described in this paper. The transmission system can change the zenith distance of the tube quickly and precisely. It works in three modes: fast motion, slow motion and lock mode. The fast motion mode and the slow motion mode are that the tube of the instrument is driven by a fast motion stepper motor and a slow motion one separately. The lock mode is running for lock mechanism that is driven by a lock stepper motor. These three motors are controlled together by a single chip microcontroller, which is controlled in turn by a host personal computer. The slow motion mechanism and its rotational step angle are fully discussed because the mechanism is not used before. Then the hardware structure of this control system based on a microcontroller is described. Control process of the system is introduced during a normal observation, which is divided into eleven steps. All the steps are programmed in our control software in C++ and/or in ASM. The C++ control program is set up in the host PC, while the ASM control program is in the microcontroller system. Structures and functions of these rprograms are presented. Some details and skills for programming are discussed in the paper too.

Planning and executing motions for multibody systems in free-fall. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Cameron, Jonathan M.

1991-01-01

The purpose of this research is to develop an end-to-end system that can be applied to a multibody system in free-fall to analyze its possible motions, save those motions in a database, and design a controller that can execute those motions. A goal is for the process to be highly automated and involve little human intervention. Ideally, the output of the system would be data and algorithms that could be put in ROM to control the multibody system in free-fall. The research applies to more than just robots in space. It applies to any multibody system in free-fall. Mathematical techniques from nonlinear control theory were used to study the nature of the system dynamics and its possible motions. Optimization techniques were applied to plan motions. Image compression techniques were proposed to compress the precomputed motion data for storage. A linearized controller was derived to control the system while it executes preplanned trajectories.

Ceramic transactions - Materials processing and design: Grain-boundary-controlled properties of fine ceramics II. Volume 44

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

Niihara, Koichi; Ishizaki, Kozo; Isotani, Mitsuo

This volume contains selected papers presented at a workshop by the Japan Fine Ceramics Center, `Materials Processing and Design Through Better Control of Grain Boundaries: Emphasizing Fine Ceramics II,` which was held March 17-19, 1994, in Koda-cho, Aichi, Japan. The focus of the workshop was the application of grain boundary phenomena to materials processing and design. The topics covered included electronic materials, evaluation methods, structural materials, and interfaces. Also included is an illuminating overview of the current status of work on grain boundary assisted materials processing and design, particularly for fine ceramics. The volume`s chapter titles are: Electron Microscopy, Evaluation,more » Grain Boundary Control and Design, Functional Ceramics, Composite Materials, Synthesis and Sintering, and Mechanical Properties.« less

Effects of Different Heave Motion Components on Pilot Pitch Control Behavior

NASA Technical Reports Server (NTRS)

Zaal, Petrus M. T.; Zavala, Melinda A.

2016-01-01

The study described in this paper had two objectives. The first objective was to investigate if a different weighting of heave motion components decomposed at the center of gravity, allowing for a higher fidelity of individual components, would result in pilot manual pitch control behavior and performance closer to that observed with full aircraft motion. The second objective was to investigate if decomposing the heave components at the aircraft's instantaneous center of rotation rather than at the center of gravity could result in additional improvements in heave motion fidelity. Twenty-one general aviation pilots performed a pitch attitude control task in an experiment conducted on the Vertical Motion Simulator at NASA Ames under different hexapod motion conditions. The large motion capability of the Vertical Motion Simulator also allowed for a full aircraft motion condition, which served as a baseline. The controlled dynamics were of a transport category aircraft trimmed close to the stall point. When the ratio of center of gravity pitch heave to center of gravity heave increased in the hexapod motion conditions, pilot manual control behavior and performance became increasingly more similar to what is observed with full aircraft motion. Pilot visual and motion gains significantly increased, while the visual lead time constant decreased. The pilot visual and motion time delays remained approximately constant and decreased, respectively. The neuromuscular damping and frequency both decreased, with their values more similar to what is observed with real aircraft motion when there was an equal weighting of the heave of the center of gravity and heave due to rotations about the center of gravity. In terms of open- loop performance, the disturbance and target crossover frequency increased and decreased, respectively, and their corresponding phase margins remained constant and increased, respectively. The decomposition point of the heave components only had limited effects on pilot manual control behavior and performance.

SAR imaging - Seeing the unseen

NASA Technical Reports Server (NTRS)

Kobrick, M.

1982-01-01

The functional abilities and operations of synthetic aperture radar (SAR) are described. SAR employs long wavelength radio waves in bursts, imaging a target by 'listening' to the small frequency changes that result from the Doppler shift due to the relative motion of the imaging craft and the motions of the target. The time delay of the signal return allows a determination of the location of the target, leading to the build up of a two-dimensional image. The uses of both Doppler shifts and time delay enable detailed imagery which is independent of distance. The synthetic aperture part of the name of SAR derives from the beaming of multiple pulses, which result in a picture that is effectively the same as using a large antenna. Mechanisms contributing to the fineness of SAR images are outlined.

Global motion perception is associated with motor function in 2-year-old children.

PubMed

Thompson, Benjamin; McKinlay, Christopher J D; Chakraborty, Arijit; Anstice, Nicola S; Jacobs, Robert J; Paudel, Nabin; Yu, Tzu-Ying; Ansell, Judith M; Wouldes, Trecia A; Harding, Jane E

2017-09-29

The dorsal visual processing stream that includes V1, motion sensitive area V5 and the posterior parietal lobe, supports visually guided motor function. Two recent studies have reported associations between global motion perception, a behavioural measure of processing in V5, and motor function in pre-school and school aged children. This indicates a relationship between visual and motor development and also supports the use of global motion perception to assess overall dorsal stream function in studies of human neurodevelopment. We investigated whether associations between vision and motor function were present at 2 years of age, a substantially earlier stage of development. The Bayley III test of Infant and Toddler Development and measures of vision including visual acuity (Cardiff Acuity Cards), stereopsis (Lang stereotest) and global motion perception were attempted in 404 2-year-old children (±4 weeks). Global motion perception (quantified as a motion coherence threshold) was assessed by observing optokinetic nystagmus in response to random dot kinematograms of varying coherence. Linear regression revealed that global motion perception was modestly, but statistically significantly associated with Bayley III composite motor (r 2 =0.06, P<0.001, n=375) and gross motor scores (r 2 =0.06, p<0.001, n=375). The associations remained significant when language score was included in the regression model. In addition, when language score was included in the model, stereopsis was significantly associated with composite motor and fine motor scores, but unaided visual acuity was not statistically significantly associated with any of the motor scores. These results demonstrate that global motion perception and binocular vision are associated with motor function at an early stage of development. Global motion perception can be used as a partial measure of dorsal stream function from early childhood. Copyright © 2017 Elsevier B.V. All rights reserved.

The influence of ship motion of manual control skills

NASA Technical Reports Server (NTRS)

Mcleod, P.; Poulton, C.; Duross, H.; Lewis, W.

1981-01-01

The effects of ship motion on a range of typical manual control skills were examined on the Warren Spring ship motion simulator driven in heave, pitch, and roll by signals taken from the frigate HMS Avenger at 13 m/s (25 knots) into a force 4 wind. The motion produced a vertical r.m.s. acceleration of 0.024g, mostly between 0.1 and 0.3 Hz, with comparatively little pitch or roll. A task involving unsupported arm movements was seriously affected by the motion; a pursuit tracking task showed a reliable decrement although it was still performed reasonably well (pressure and free moving tracking controls were affected equally by the motion); a digit keying task requiring ballistic hand movements was unaffected. There was no evidence that these effects were caused by sea sickness. The differing response to motion of the different tasks, from virtual destruction to no effect, suggests that a major benefit could come from an attempt to design the man/control interface onboard ship around motion resistant tasks.

Control system and method for payload control in mobile platform cranes

DOEpatents

Robinett, III, Rush D.; Groom, Kenneth N.; Feddema, John T.; Parker, Gordon G.

2002-01-01

A crane control system and method provides a way to generate crane commands responsive to a desired payload motion to achieve substantially pendulation-free actual payload motion. The control system and method apply a motion compensator to maintain a payload in a defined payload configuration relative to an inertial coordinate frame. The control system and method can further comprise a pendulation damper controller to reduce an amount of pendulation between a sensed payload configuration and the defined payload configuration. The control system and method can further comprise a command shaping filter to filter out a residual payload pendulation frequency from the desired payload motion.

Singular orientations and faceted motion of dislocations in body-centered cubic crystals.

PubMed

Kang, Keonwook; Bulatov, Vasily V; Cai, Wei

2012-09-18

Dislocation mobility is a fundamental material property that controls strength and ductility of crystals. An important measure of dislocation mobility is its Peierls stress, i.e., the minimal stress required to move a dislocation at zero temperature. Here we report that, in the body-centered cubic metal tantalum, the Peierls stress as a function of dislocation orientation exhibits fine structure with several singular orientations of high Peierls stress-stress spikes-surrounded by vicinal plateau regions. While the classical Peierls-Nabarro model captures the high Peierls stress of singular orientations, an extension that allows dislocations to bend is necessary to account for the plateau regions. Our results clarify the notion of dislocation kinks as meaningful only for orientations within the plateau regions vicinal to the Peierls stress spikes. These observations lead us to propose a Read-Shockley type classification of dislocation orientations into three distinct classes-special, vicinal, and general-with respect to their Peierls stress and motion mechanisms. We predict that dislocation loops expanding under stress at sufficiently low temperatures, should develop well defined facets corresponding to two special orientations of highest Peierls stress, the screw and the M111 orientations, both moving by kink mechanism. We propose that both the screw and the M111 dislocations are jointly responsible for the yield behavior of BCC metals at low temperatures.

Characterization and control of self-motions in redundant manipulators

NASA Technical Reports Server (NTRS)

Burdick, J.; Seraji, Homayoun

1989-01-01

The presence of redundant degrees of freedom in a manipulator structure leads to a physical phenomenon known as a self-motion, which is a continuous motion of the manipulator joints that leaves the end-effector motionless. In the first part of the paper, a global manifold mapping reformulation of manipulator kinematics is reviewed, and the inverse kinematic solution for redundant manipulators is developed in terms of self-motion manifolds. Global characterizations of the self-motion manifolds in terms of their number, geometry, homotopy class, and null space are reviewed using examples. Much previous work in redundant manipulator control has been concerned with the redundancy resolution problem, in which methods are developed to determine, or resolve, the motion of the joints in order to achieve end-effector trajectory control while optimizing additional objective functions. Redundancy resolution problems can be equivalently posed as the control of self-motions. Alternatives for redundancy resolution are briefly discussed.

Illusory visual motion stimulus elicits postural sway in migraine patients

PubMed Central

Imaizumi, Shu; Honma, Motoyasu; Hibino, Haruo; Koyama, Shinichi

2015-01-01

Although the perception of visual motion modulates postural control, it is unknown whether illusory visual motion elicits postural sway. The present study examined the effect of illusory motion on postural sway in patients with migraine, who tend to be sensitive to it. We measured postural sway for both migraine patients and controls while they viewed static visual stimuli with and without illusory motion. The participants’ postural sway was measured when they closed their eyes either immediately after (Experiment 1), or 30 s after (Experiment 2), viewing the stimuli. The patients swayed more than the controls when they closed their eyes immediately after viewing the illusory motion (Experiment 1), and they swayed less than the controls when they closed their eyes 30 s after viewing it (Experiment 2). These results suggest that static visual stimuli with illusory motion can induce postural sway that may last for at least 30 s in patients with migraine. PMID:25972832

Brain-machine interfacing control of whole-body humanoid motion

PubMed Central

Bouyarmane, Karim; Vaillant, Joris; Sugimoto, Norikazu; Keith, François; Furukawa, Jun-ichiro; Morimoto, Jun

2014-01-01

We propose to tackle in this paper the problem of controlling whole-body humanoid robot behavior through non-invasive brain-machine interfacing (BMI), motivated by the perspective of mapping human motor control strategies to human-like mechanical avatar. Our solution is based on the adequate reduction of the controllable dimensionality of a high-DOF humanoid motion in line with the state-of-the-art possibilities of non-invasive BMI technologies, leaving the complement subspace part of the motion to be planned and executed by an autonomous humanoid whole-body motion planning and control framework. The results are shown in full physics-based simulation of a 36-degree-of-freedom humanoid motion controlled by a user through EEG-extracted brain signals generated with motor imagery task. PMID:25140134

The use of vestibular models for design and evaluation of flight simulator motion

NASA Technical Reports Server (NTRS)

Bussolari, Steven R.; Young, Laurence R.; Lee, Alfred T.

1989-01-01

Quantitative models for the dynamics of the human vestibular system are applied to the design and evaluation of flight simulator platform motion. An optimal simulator motion control algorithm is generated to minimize the vector difference between perceived spatial orientation estimated in flight and in simulation. The motion controller has been implemented on the Vertical Motion Simulator at NASA Ames Research Center and evaluated experimentally through measurement of pilot performance and subjective rating during VTOL aircraft simulation. In general, pilot performance in a longitudinal tracking task (formation flight) did not appear to be sensitive to variations in platform motion condition as long as motion was present. However, pilot assessment of motion fidelity by means of a rating scale designed for this purpose, were sensitive to motion controller design. Platform motion generated with the optimal motion controller was found to be generally equivalent to that generated by conventional linear crossfeed washout. The vestibular models are used to evaluate the motion fidelity of transport category aircraft (Boeing 727) simulation in a pilot performance and simulator acceptability study at the Man-Vehicle Systems Research Facility at NASA Ames Research Center. Eighteen airline pilots, currently flying B-727, were given a series of flight scenarios in the simulator under various conditions of simulator motion. The scenarios were chosen to reflect the flight maneuvers that these pilots might expect to be given during a routine pilot proficiency check. Pilot performance and subjective rating of simulator fidelity was relatively insensitive to the motion condition, despite large differences in the amplitude of motion provided. This lack of sensitivity may be explained by means of the vestibular models, which predict little difference in the modeled motion sensations of the pilots when different motion conditions are imposed.

Analysis of achievable disturbance attenuation in a precision magnetically-suspended motion control system

NASA Technical Reports Server (NTRS)

Kuzin, Alexander V.; Holmes, Michael L.; Behrouzjou, Roxana; Trumper, David L.

1994-01-01

The results of the analysis of the achievable disturbance attenuation to get an Angstrom motion control resolution and macroscopic travel in a precision magnetically-suspended motion control system are presented in this paper. Noise sources in the transducers, electronics, and mechanical vibrations are used to develop the control design.

Minimum-variance Brownian motion control of an optically trapped probe.

PubMed

Huang, Yanan; Zhang, Zhipeng; Menq, Chia-Hsiang

2009-10-20

This paper presents a theoretical and experimental investigation of the Brownian motion control of an optically trapped probe. The Langevin equation is employed to describe the motion of the probe experiencing random thermal force and optical trapping force. Since active feedback control is applied to suppress the probe's Brownian motion, actuator dynamics and measurement delay are included in the equation. The equation of motion is simplified to a first-order linear differential equation and transformed to a discrete model for the purpose of controller design and data analysis. The derived model is experimentally verified by comparing the model prediction to the measured response of a 1.87 microm trapped probe subject to proportional control. It is then employed to design the optimal controller that minimizes the variance of the probe's Brownian motion. Theoretical analysis is derived to evaluate the control performance of a specific optical trap. Both experiment and simulation are used to validate the design as well as theoretical analysis, and to illustrate the performance envelope of the active control. Moreover, adaptive minimum variance control is implemented to maintain the optimal performance in the case in which the system is time varying when operating the actively controlled optical trap in a complex environment.

78 FR 5500 - Manufacturer of Controlled Substances; Notice of Registration; Ampac Fine Chemicals, LLC

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

...; Notice of Registration; Ampac Fine Chemicals, LLC By Notice dated September 20, 2012, and published in the Federal Register on October 2, 2012, 77 FR 60145, AMPAC Fine Chemicals, LLC, Highway 50 and Hazel... considered the factors in 21 U.S.C. 823(a), and determined that the registration of AMPAC Fine Chemicals, LLC...

Optimal Control of Stochastic Systems Driven by Fractional Brownian Motions

DTIC Science & Technology

2014-10-09

problems for stochastic partial differential equations driven by fractional Brownian motions are explicitly solved. For the control of a continuous time...linear systems with Brownian motion or a discrete time linear system with a white Gaussian noise and costs 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND...Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 stochastic optimal control, fractional Brownian motion , stochastic

Model-based control strategies for systems with constraints of the program type

NASA Astrophysics Data System (ADS)

Jarzębowska, Elżbieta

2006-08-01

The paper presents a model-based tracking control strategy for constrained mechanical systems. Constraints we consider can be material and non-material ones referred to as program constraints. The program constraint equations represent tasks put upon system motions and they can be differential equations of orders higher than one or two, and be non-integrable. The tracking control strategy relies upon two dynamic models: a reference model, which is a dynamic model of a system with arbitrary order differential constraints and a dynamic control model. The reference model serves as a motion planner, which generates inputs to the dynamic control model. It is based upon a generalized program motion equations (GPME) method. The method enables to combine material and program constraints and merge them both into the motion equations. Lagrange's equations with multipliers are the peculiar case of the GPME, since they can be applied to systems with constraints of first orders. Our tracking strategy referred to as a model reference program motion tracking control strategy enables tracking of any program motion predefined by the program constraints. It extends the "trajectory tracking" to the "program motion tracking". We also demonstrate that our tracking strategy can be extended to a hybrid program motion/force tracking.

Deep learning-based fine-grained car make/model classification for visual surveillance

NASA Astrophysics Data System (ADS)

Gundogdu, Erhan; Parıldı, Enes Sinan; Solmaz, Berkan; Yücesoy, Veysel; Koç, Aykut

2017-10-01

Fine-grained object recognition is a potential computer vision problem that has been recently addressed by utilizing deep Convolutional Neural Networks (CNNs). Nevertheless, the main disadvantage of classification methods relying on deep CNN models is the need for considerably large amount of data. In addition, there exists relatively less amount of annotated data for a real world application, such as the recognition of car models in a traffic surveillance system. To this end, we mainly concentrate on the classification of fine-grained car make and/or models for visual scenarios by the help of two different domains. First, a large-scale dataset including approximately 900K images is constructed from a website which includes fine-grained car models. According to their labels, a state-of-the-art CNN model is trained on the constructed dataset. The second domain that is dealt with is the set of images collected from a camera integrated to a traffic surveillance system. These images, which are over 260K, are gathered by a special license plate detection method on top of a motion detection algorithm. An appropriately selected size of the image is cropped from the region of interest provided by the detected license plate location. These sets of images and their provided labels for more than 30 classes are employed to fine-tune the CNN model which is already trained on the large scale dataset described above. To fine-tune the network, the last two fully-connected layers are randomly initialized and the remaining layers are fine-tuned in the second dataset. In this work, the transfer of a learned model on a large dataset to a smaller one has been successfully performed by utilizing both the limited annotated data of the traffic field and a large scale dataset with available annotations. Our experimental results both in the validation dataset and the real field show that the proposed methodology performs favorably against the training of the CNN model from scratch.

Motion and Balance. Physical Science in Action[TM]. Schlessinger Science Library. [Videotape].

ERIC Educational Resources Information Center

2000

Motion allows things to get done, to communicate and to travel. But is motion controlled? Students will learn about the universal laws that apply to motion, the forces that cause it and how it is related to balance. They will also discover why motion occurs when forces are out of control and learn more about this interesting concept by viewing…

Integration Method of Emphatic Motions and Adverbial Expressions with Scalar Parameters for Robotic Motion Coaching System

NASA Astrophysics Data System (ADS)

Okuno, Keisuke; Inamura, Tetsunari

A robotic coaching system can improve humans' learning performance of motions by intelligent usage of emphatic motions and adverbial expressions according to user reactions. In robotics, however, method to control both the motions and the expressions and how to bind them had not been adequately discussed from an engineering point of view. In this paper, we propose a method for controlling and binding emphatic motions and adverbial expressions by using two scalar parameters in a phase space. In the phase space, variety of motion patterns and verbal expressions are connected and can be expressed as static points. We show the feasibility of the proposing method through experiments of actual sport coaching tasks for beginners. From the results of participants' improvements in motion learning, we confirmed the feasibility of the methods to control and bind emphatic motions and adverbial expressions, as well as confirmed contribution of the emphatic motions and positive correlation of adverbial expressions for participants' improvements in motion learning. Based on the results, we introduce a hypothesis that individually optimized method for binding adverbial expression is required.

Designing, producing, and constructing fine-graded hot mix asphalt on Illinois roadways.

DOT National Transportation Integrated Search

2015-04-01

Fine-graded (F-G) asphalt concrete mixtures are composed of an aggregate structure in which the fine fraction controls the : load-carrying capacity of the mix. Other states have reported benefits in using F-G mixtures, including improved compaction, ...

On the Feedback Phenomenon of an Impinging Jet

DTIC Science & Technology

1979-09-01

the double-structured nature of turbulent flows: time dependent quasi- ordered large scale structures, and fine-scale random structures. Numerous ...downstream and upstream waves d Nozzle diameter f Frequency (Hz) Gf Normalized power si.c ,ur’ of i G ,(f) Normalized cr,- tr bee -en i(t) and J(t) I ,j xiv...1975) suggested that these quasi- ordered structures are deterministic, in the sense that they have a characteristic shape, size and convection motion

Finalizing the DTAG: Implementation and Testing of Design Improvements for Reliability and Availability

DTIC Science & Technology

2015-09-30

acoustics and fine scale motion. The success of the Dtag has resulted in an increased demand for the instrument from researchers both within the...sensor blocks sound when the animal is close to the surface. The polyethylene shell was eliminated in the Dtag-3 design to improve acoustic ...into 3 main sub-assemblies (Figure 5): 1) foam sub-assembly, 2) sensor sub-assembly, and 3) Electronics sub-assembly. This separation enables rapid

[Implementation of control system and software design for limbs rehabilitation training based on PCI-1240].

PubMed

Zhu, Wenchao; Xu, Xiulin; Hu, Xiufang; An, Meijun

2017-06-01

This article presents the design of a motion control system for seated lower-limb rehabilitation training. The system is composed of lower limb exoskeleton, motor drive circuit, program of motion control, and so forth. The power of lower limbs joints is provided by six motors. The PCI-1240 motion control card is used as the core. This study achieved repetitive rotation training and gait trajectory training of lower limbs joints, of which the velocity, angle and time can be accurately controlled and adjusted. The experimental results showed that the motion control system can meet the requirement of repetitive rehabilitation training for patients with lower limb dysfunction. This article provides a new method to the research of motion control system in rehabilitation training, which can promote industrial automation technique to be used for health care, and conducive to the further study of the rehabilitation robot.

Control of joint motion simulators for biomechanical research

NASA Technical Reports Server (NTRS)

Colbaugh, R.; Glass, K.

1992-01-01

The authors present a hierarchical adaptive algorithm for controlling upper extremity human joint motion simulators. A joint motion simulator is a computer-controlled, electromechanical system which permits the application of forces to the tendons of a human cadaver specimen in such a way that the cadaver joint under study achieves a desired motion in a physiologic manner. The proposed control scheme does not require knowledge of the cadaver specimen dynamic model, and solves on-line the indeterminate problem which arises because human joints typically possess more actuators than degrees of freedom. Computer simulation results are given for an elbow/forearm system and wrist/hand system under hierarchical control. The results demonstrate that any desired normal joint motion can be accurately tracked with the proposed algorithm. These simulation results indicate that the controller resolved the indeterminate problem redundancy in a physiologic manner, and show that the control scheme was robust to parameter uncertainty and to sensor noise.

An open architecture motion controller

NASA Technical Reports Server (NTRS)

Rossol, Lothar

1994-01-01

Nomad, an open architecture motion controller, is described. It is formed by a combination of TMOS, C-WORKS, and other utilities. Nomad software runs in a UNIX environment and provides for sensor-controlled robotic motions, with user replaceable kinematics. It can also be tailored for highly specialized applications. Open controllers such as Nomad should have a major impact on the robotics industry.

Detector motion method to increase spatial resolution in photon-counting detectors

NASA Astrophysics Data System (ADS)

Lee, Daehee; Park, Kyeongjin; Lim, Kyung Taek; Cho, Gyuseong

2017-03-01

Medical imaging requires high spatial resolution of an image to identify fine lesions. Photon-counting detectors in medical imaging have recently been rapidly replacing energy-integrating detectors due to the former`s high spatial resolution, high efficiency and low noise. Spatial resolution in a photon counting image is determined by the pixel size. Therefore, the smaller the pixel size, the higher the spatial resolution that can be obtained in an image. However, detector redesigning is required to reduce pixel size, and an expensive fine process is required to integrate a signal processing unit with reduced pixel size. Furthermore, as the pixel size decreases, charge sharing severely deteriorates spatial resolution. To increase spatial resolution, we propose a detector motion method using a large pixel detector that is less affected by charge sharing. To verify the proposed method, we utilized a UNO-XRI photon-counting detector (1-mm CdTe, Timepix chip) at the maximum X-ray tube voltage of 80 kVp. A similar spatial resolution of a 55- μm-pixel image was achieved by application of the proposed method to a 110- μm-pixel detector with a higher signal-to-noise ratio. The proposed method could be a way to increase spatial resolution without a pixel redesign when pixels severely suffer from charge sharing as pixel size is reduced.

Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

PubMed

Rosenblatt, Steven David; Crane, Benjamin Thomas

2015-01-01

A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37) participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s) at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001) and rotation (p<0.001), and arrows (p = 0.02). For the visual motion stimuli, inertial motion perception was shifted in the direction consistent with the visual stimulus. Arrows had a small effect on self-motion perception driven by a minority of subjects. There was no significant effect of illusory motion on self-motion perception for either translation or rotation (p>0.1 for both). Thus, although a true moving visual field can induce self-motion, results of this study show that illusory motion does not.

Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft.

PubMed

Wang, Xingjian; Liao, Rui; Shi, Cun; Wang, Shaoping

2017-10-25

Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA.

Composite synchronization of three eccentric rotors driven by induction motors in a vibrating system

NASA Astrophysics Data System (ADS)

Kong, Xiangxi; Chen, Changzheng; Wen, Bangchun

2018-03-01

This paper addresses the problem of composite synchronization of three eccentric rotors (ERs) driven by induction motors in a vibrating system. The composite synchronous motion of three ERs is composed of the controlled synchronous motion of two ERs and the self-synchronous motion of the third ER. Combining an adaptive sliding mode control (ASMC) algorithm with a modified master-slave control structure, the controllers are designed to implement controlled synchronous motion of two ERs with zero phase difference. Based on Lyapunov stability theorem and Barbalat's lemma, the stability of the designed controllers is verified. On basis of controlled synchronization of two ERs, self-synchronization of the third ER is introduced to implement composite synchronous motion of three ERs. The feasibility of the proposed composite synchronization method is analyzed by numerical method. The effects of motor and structure parameters on composite synchronous motion are discussed. Experiments on a vibrating test bench driven by three ERs are operated to validate the effectiveness of the proposed composite synchronization method, including a comparison with self-synchronization method.

Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft

PubMed Central

Liao, Rui; Shi, Cun; Wang, Shaoping

2017-01-01

Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA. PMID:29068392

OCILOW-Wheeled Platform Controls Executable Set

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

Jansen, John F.

2005-11-30

The OCILOW Controls Executable Set is the complete set of machine executable instructions to control the motion of wheeled platforms that incorporate Off-Centered In-Line Omni-directional Wheels (OCILOW). The controls utilize command signals for the desired motion of the platform (X, Y and Theta) and calculate and control the steering and rolling motion required of each OCILOW wheels to achieve the desired translational and rotational platform motion. The controls utilize signals from the wheel steering and rolling resolvers, and from three load cells located at each wheels, to coordinate the motion of all wheels, while respecting their non-holonomic constraints (i.e., keepingmore » internal stresses and slippage due to possible errors, uneven floors, bumps, misalignment, etc. bounded). The OCILOW Controls Executable Set, which is copyrighted here, is an embodiment of the generic OCILOW algorithms (patented separately) developed specifically for controls of the Proof-of-Principle-Transporter (POP-T) system that has been developed to demonstrate the overall OCILOW controls feasibility and capabilities.« less

Flying Qualities Design Requirements for Sidestick Controllers

DTIC Science & Technology

1979-10-01

Harper vs wc - Fine Tracking 111 56. Cooper-Harper vs wc - Fine Tracking 111 57. Cooper-Harper ve wc - Landing 112 58. Cooper-Harper vs wc - Lending 112...c - Fine Tracking 119 62. Preference Rating vs wc - Fine Tracking 119 64. Preference Rating vs wc - Landing 120 65. Preference Rating vs w(c...a "fast airplane" to make up for the filtering effect of his arm and the stick. In fine tracking with a center stick the pilot will rest his arm

Visual motion integration for perception and pursuit

NASA Technical Reports Server (NTRS)

Stone, L. S.; Beutter, B. R.; Lorenceau, J.

2000-01-01

To examine the relationship between visual motion processing for perception and pursuit, we measured the pursuit eye-movement and perceptual responses to the same complex-motion stimuli. We show that humans can both perceive and pursue the motion of line-figure objects, even when partial occlusion makes the resulting image motion vastly different from the underlying object motion. Our results show that both perception and pursuit can perform largely accurate motion integration, i.e. the selective combination of local motion signals across the visual field to derive global object motion. Furthermore, because we manipulated perceived motion while keeping image motion identical, the observed parallel changes in perception and pursuit show that the motion signals driving steady-state pursuit and perception are linked. These findings disprove current pursuit models whose control strategy is to minimize retinal image motion, and suggest a new framework for the interplay between visual cortex and cerebellum in visuomotor control.

Complex motion of a vehicle through a series of signals controlled by power-law phase

NASA Astrophysics Data System (ADS)

Nagatani, Takashi

2017-07-01

We study the dynamic motion of a vehicle moving through the series of traffic signals controlled by the position-dependent phase of power law. All signals are controlled by both cycle time and position-dependent phase. The dynamic model of the vehicular motion is described in terms of the nonlinear map. The vehicular motion varies in a complex manner by varying cycle time for various values of the power of the position-dependent phase. The vehicle displays the periodic motion with a long cycle for the integer power of the phase, while the vehicular motion exhibits the very complex behavior for the non-integer power of the phase.

Dynamics and control of tethered antennas/reflectors in orbit

NASA Astrophysics Data System (ADS)

Liu, Liangdong; Bainum, Peter M.

The system linear equations for the motion of a tethered shallow spherical shell in orbit with its symmetry axis nominally following the local vertical are developed. The shell roll, yaw, tether out-of-plane swing motion and elastic vibrations are decoupled from the shell and tether in-plane pitch motions and elastic vibrations. The neutral gravity stability conditions for the special case of a constant length rigid tether are given for in-plane motion and out-of-plant motion. It is proved that the in-plane motion of the system could be asymptotically stable based on Rupp's tension control law, for a variable length tether. However, the system simulation results indicate that the transient responses can be improved significantly, especially for the damping of the tether and shell pitch motion, by an optimal feedback control law for the rigid variable length tether model. It is also seen that the system could be unstable when the effect of tether flexibility is included if the control gains are not chosen carefully. The transient responses for three different tension control laws are compared during typical station keeping operations.

Critical Technology Assessment: Fine Grain, High Density Graphite

DTIC Science & Technology

2010-04-01

Control Classification Number ( ECCN ) 1C107.a on the Commerce Control List (CCL). The parameters of 1C107.a stem from controls established by the Missile...Technology Control Regime (MTCR). In this assessment, BIS specifically examined: • The application of ECCN 1C107.a and related licensing...export licensing process for fine grain, high density graphite controlled by ECCN 1C107.a, especially to China, requires more license conditions and

Knowledge-Based Motion Control of AN Intelligent Mobile Autonomous System

NASA Astrophysics Data System (ADS)

Isik, Can

An Intelligent Mobile Autonomous System (IMAS), which is equipped with vision and low level sensors to cope with unknown obstacles, is modeled as a hierarchy of path planning and motion control. This dissertation concentrates on the lower level of this hierarchy (Pilot) with a knowledge-based controller. The basis of a theory of knowledge-based controllers is established, using the example of the Pilot level motion control of IMAS. In this context, the knowledge-based controller with a linguistic world concept is shown to be adequate for the minimum time control of an autonomous mobile robot motion. The Pilot level motion control of IMAS is approached in the framework of production systems. The three major components of the knowledge-based control that are included here are the hierarchies of the database, the rule base and the rule evaluator. The database, which is the representation of the state of the world, is organized as a semantic network, using a concept of minimal admissible vocabulary. The hierarchy of rule base is derived from the analytical formulation of minimum-time control of IMAS motion. The procedure introduced for rule derivation, which is called analytical model verbalization, utilizes the concept of causalities to describe the system behavior. A realistic analytical system model is developed and the minimum-time motion control in an obstacle strewn environment is decomposed to a hierarchy of motion planning and control. The conditions for the validity of the hierarchical problem decomposition are established, and the consistency of operation is maintained by detecting the long term conflicting decisions of the levels of the hierarchy. The imprecision in the world description is modeled using the theory of fuzzy sets. The method developed for the choice of the rule that prescribes the minimum-time motion control among the redundant set of applicable rules is explained and the usage of fuzzy set operators is justified. Also included in the dissertation are the description of the computer simulation of Pilot within the hierarchy of IMAS control and the simulated experiments that demonstrate the theoretical work.

An Improved Framework for Confound Regression and Filtering for Control of Motion Artifact in the Preprocessing of Resting-State Functional Connectivity Data

PubMed Central

Satterthwaite, Theodore D.; Elliott, Mark A.; Gerraty, Raphael T.; Ruparel, Kosha; Loughead, James; Calkins, Monica E.; Eickhoff, Simon B.; Hakonarson, Hakon; Gur, Ruben C.; Gur, Raquel E.; Wolf, Daniel H.

2013-01-01

Several recent reports in large, independent samples have demonstrated the influence of motion artifact on resting-state functional connectivity MRI (rsfc-MRI). Standard rsfc-MRI preprocessing typically includes regression of confounding signals and band-pass filtering. However, substantial heterogeneity exists in how these techniques are implemented across studies, and no prior study has examined the effect of differing approaches for the control of motion-induced artifacts. To better understand how in-scanner head motion affects rsfc-MRI data, we describe the spatial, temporal, and spectral characteristics of motion artifacts in a sample of 348 adolescents. Analyses utilize a novel approach for describing head motion on a voxelwise basis. Next, we systematically evaluate the efficacy of a range of confound regression and filtering techniques for the control of motion-induced artifacts. Results reveal that the effectiveness of preprocessing procedures on the control of motion is heterogeneous, and that improved preprocessing provides a substantial benefit beyond typical procedures. These results demonstrate that the effect of motion on rsfc-MRI can be substantially attenuated through improved preprocessing procedures, but not completely removed. PMID:22926292

KALI - An environment for the programming and control of cooperative manipulators

NASA Technical Reports Server (NTRS)

Hayward, Vincent; Hayati, Samad

1988-01-01

A design description is given of a controller for cooperative robots. The background and motivation for multiple arm control are discussed. A set of programming primitives which permit a programmer to specify cooperative tasks are described. Motion primitives specify asynchronous motions, master/slave motions, and cooperative motions. In the context of cooperative robots, trajectory generation issues are discussed and the authors' implementation briefly described. The relations between programming and control in the case of multiple robots are examined. The allocation of various tasks among a multiprocessor computer is described.

Optimization of motion control laws for tether crawler or elevator systems

NASA Technical Reports Server (NTRS)

Swenson, Frank R.; Von Tiesenhausen, Georg

1988-01-01

Based on the proposal of a motion control law by Lorenzini (1987), a method is developed for optimizing motion control laws for tether crawler or elevator systems in terms of the performance measures of travel time, the smoothness of acceleration and deceleration, and the maximum values of velocity and acceleration. The Lorenzini motion control law, based on powers of the hyperbolic tangent function, is modified by the addition of a constant-velocity section, and this modified function is then optimized by parameter selections to minimize the peak acceleration value for a selected travel time or to minimize travel time for the selected peak values of velocity and acceleration. It is shown that the addition of a constant-velocity segment permits further optimization of the motion control law performance.

Research and development of a control system for multi axis cooperative motion based on PMAC

NASA Astrophysics Data System (ADS)

Guo, Xiao-xiao; Dong, Deng-feng; Zhou, Wei-hu

2017-10-01

Based on Programmable Multi-axes Controller (PMAC), a design of a multi axis motion control system for the simulator of spatial targets' dynamic optical properties is proposed. According to analysis the properties of spatial targets' simulator motion control system, using IPC as the main control layer, TurboPMAC2 as the control layer to meet coordinated motion control, data acquisition and analog output. A simulator using 5 servomotors which is connected with speed reducers to drive the output axis was implemented to simulate the motion of both the sun and the space target. Based on PMAC using PID and a notch filter algorithm, negative feedback, the speed and acceleration feed forward algorithm to satisfy the axis' requirements of the good stability and high precision at low speeds. In the actual system, it shows that the velocity precision is higher than 0.04 s ° and the precision of repetitive positioning is better than 0.006° when each axis is at a low-speed. Besides, the system achieves the control function of multi axis coordinated motion. The design provides an important technical support for detecting spatial targets, also promoting the theoretical research.

System training and assessment in simultaneous proportional myoelectric prosthesis control

PubMed Central

2014-01-01

Background Pattern recognition control of prosthetic hands take inputs from one or more myoelectric sensors and controls one or more degrees of freedom. However, most systems created allow only sequential control of one motion class at a time. Additionally, only recently have researchers demonstrated proportional myoelectric control in such systems, an option that is believed to make fine control easier for the user. Recent developments suggest improved reliability if the user follows a so-called prosthesis guided training (PGT) scheme. Methods In this study, a system for simultaneous proportional myoelectric control has been developed for a hand prosthesis with two motor functions (hand open/close, and wrist pro-/supination). The prosthesis has been used with a prosthesis socket equivalent designed for normally-limbed subjects. An extended version of PGT was developed for use with proportional control. The control system’s performance was tested for two subjects in the Clothespin Relocation Task and the Southampton Hand Assessment Procedure (SHAP). Simultaneous proportional control was compared with three other control strategies implemented on the same prosthesis: mutex proportional control (the same system but with simultaneous control disabled), mutex on-off control, and a more traditional, sequential proportional control system with co-contractions for state switching. Results The practical tests indicate that the simultaneous proportional control strategy and the two mutex-based pattern recognition strategies performed equally well, and superiorly to the more traditional sequential strategy according to the chosen outcome measures. Conclusions This is the first simultaneous proportional myoelectric control system demonstrated on a prosthesis affixed to the forearm of a subject. The study illustrates that PGT is a promising system training method for proportional control. Due to the limited number of subjects in this study, no definite conclusions can be drawn. PMID:24775602

Insects modify their behaviour depending on the feedback sensor used when walking on a trackball in virtual reality.

PubMed

Taylor, Gavin J; Paulk, Angelique C; Pearson, Thomas W J; Moore, Richard J D; Stacey, Jacqui A; Ball, David; van Swinderen, Bruno; Srinivasan, Mandyam V

2015-10-01

When using virtual-reality paradigms to study animal behaviour, careful attention must be paid to how the animal's actions are detected. This is particularly relevant in closed-loop experiments where the animal interacts with a stimulus. Many different sensor types have been used to measure aspects of behaviour, and although some sensors may be more accurate than others, few studies have examined whether, and how, such differences affect an animal's behaviour in a closed-loop experiment. To investigate this issue, we conducted experiments with tethered honeybees walking on an air-supported trackball and fixating a visual object in closed-loop. Bees walked faster and along straighter paths when the motion of the trackball was measured in the classical fashion - using optical motion sensors repurposed from computer mice - than when measured more accurately using a computer vision algorithm called 'FicTrac'. When computer mouse sensors were used to measure bees' behaviour, the bees modified their behaviour and achieved improved control of the stimulus. This behavioural change appears to be a response to a systematic error in the computer mouse sensor that reduces the sensitivity of this sensor system under certain conditions. Although the large perceived inertia and mass of the trackball relative to the honeybee is a limitation of tethered walking paradigms, observing differences depending on the sensor system used to measure bee behaviour was not expected. This study suggests that bees are capable of fine-tuning their motor control to improve the outcome of the task they are performing. Further, our findings show that caution is required when designing virtual-reality experiments, as animals can potentially respond to the artificial scenario in unexpected and unintended ways. © 2015. Published by The Company of Biologists Ltd.

A dual-armed free flyer

NASA Technical Reports Server (NTRS)

Beck, D.; Das, B.; Dickson, C.; Douglas, B.; Long, L.; Middour, K.; Reid, S.; Uber, J.; Walsh, G.; Wang, L.

1989-01-01

This summary presents the main conclusions and results of the design studies conducted by a group of 13 students at the University of Maryland. The students, all participants in the spring 1989 course ENEE418 in the Electrical Engineering Department, met weekly in a two-hour class to discuss and evaluate design alternatives. The main problem considered was the design and control of a planar testbed simulating a free-flying space robot for applications in satellite servicing. This project grew out of the 1988 class where a dual-armed free flyer (DAFF) was designed and partially built. This year, a group of six students continued the development of the DAFF, achieving computer-controlled motion of the DAFF's arms. All fabrication and testing of the DAFF is being conducted in the Intelligent Servosystems Laboratory at the University of Maryland. While the work related to the design and development of the DAFF is the main subject of the report, it should be noted that other students in the ENEE418 class have investigated additional issues related to manipulation in space. For example, one group studied a new parallel linkage based manipulator for fine motion applications such as in assembly operations in space. They investigated the mechanism's kinematics, its reachable workspace, and precision of applying forces and torques. In yet another project, a student set out to measure and map the friction characteristics of the actuators used in the Modular Dextrous Hand, which has been recently developed in the Intelligent Servosystems Laboratory. The results are expected to help compensate for this friction, which is a highly nonlinear disturbance and presents significant problems in high-precision, low-speed operations. This summary continues with the discussion of the results obtained by the group of students who have been working on developing the DAFF testbed.

Lateral control system design for VTOL landing on a DD963 in high sea states. M.S. Thesis

NASA Technical Reports Server (NTRS)

Bodson, M.

1982-01-01

The problem of designing lateral control systems for the safe landing of VTOL aircraft on small ships is addressed. A ship model is derived. The issues of estimation and prediction of ship motions are discussed, using optimal linear linear estimation techniques. The roll motion is the most important of the lateral motions, and it is found that it can be predicted for up to 10 seconds in perfect conditions. The automatic landing of the VTOL aircraft is considered, and a lateral controller, defined as a ship motion tracker, is designed, using optimal control techniqes. The tradeoffs between the tracking errors and the control authority are obtained. The important couplings between the lateral motions and controls are demonstrated, and it is shown that the adverse couplings between the sway and the roll motion at the landing pad are significant constraints in the tracking of the lateral ship motions. The robustness of the control system, including the optimal estimator, is studied, using the singular values analysis. Through a robustification procedure, a robust control system is obtained, and the usefulness of the singular values to define stability margins that take into account general types of unstructured modelling errors is demonstrated. The minimal destabilizing perturbations indicated by the singular values analysis are interpreted and related to the multivariable Nyquist diagrams.

Active Control of Solar Array Dynamics During Spacecraft Maneuvers

NASA Technical Reports Server (NTRS)

Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

2016-01-01

Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

Neck motion, motor control, pain and disability: A longitudinal study of associations in neck pain patients in physiotherapy treatment.

PubMed

Meisingset, Ingebrigt; Stensdotter, Ann-Katrin; Woodhouse, Astrid; Vasseljen, Ottar

2016-04-01

Neck pain is associated with several alterations in neck motion and motor control, but most of the findings are based on cross-sectional studies. The aim of this study was to investigate associations between changes in neck motion and motor control, and changes in neck pain and disability in physiotherapy patients during a course of treatment. Prospective cohort study. Subjects with non-specific neck pain (n = 71) participated in this study. Neck flexibility, joint position error (JPE), head steadiness, trajectory movement control and postural sway were recorded before commencement of physiotherapy (baseline), at 2 weeks, and at 2 months. Numerical Rating Scale and Neck Disability Index were used to measure neck pain and disability at the day of testing. To analyze within subjects effects in neck motion and motor control, neck pain, and disability over time we used fixed effects linear regression analysis. Changes in neck motion and motor control occurred primarily within 2 weeks. Reduction in neck pain was associated with increased cervical range of motion in flexion-/extension and increased postural sway when standing with eyes open. Decreased neck disability was associated with some variables for neck flexibility and trajectory movement control. Cervical range of motion in flexion-/extension was the only variable associated with changes in both neck pain and neck disability. This study shows that few of the variables for neck motion and motor control were associated with changes neck pain and disability over a course of 2 months with physiotherapy treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

USGS Publications Warehouse

Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

2014-01-01

Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

Strong confinement-induced engineering of the g factor and lifetime of conduction electron spins in Ge quantum wells

PubMed Central

Giorgioni, Anna; Paleari, Stefano; Cecchi, Stefano; Vitiello, Elisa; Grilli, Emanuele; Isella, Giovanni; Jantsch, Wolfgang; Fanciulli, Marco; Pezzoli, Fabio

2016-01-01

Control of electron spin coherence via external fields is fundamental in spintronics. Its implementation demands a host material that accommodates the desirable but contrasting requirements of spin robustness against relaxation mechanisms and sizeable coupling between spin and orbital motion of the carriers. Here, we focus on Ge, which is a prominent candidate for shuttling spin quantum bits into the mainstream Si electronics. So far, however, the intrinsic spin-dependent phenomena of free electrons in conventional Ge/Si heterojunctions have proved to be elusive because of epitaxy constraints and an unfavourable band alignment. We overcome these fundamental limitations by investigating a two-dimensional electron gas in quantum wells of pure Ge grown on Si. These epitaxial systems demonstrate exceptionally long spin lifetimes. In particular, by fine-tuning quantum confinement we demonstrate that the electron Landé g factor can be engineered in our CMOS-compatible architecture over a range previously inaccessible for Si spintronics. PMID:28000670

Two-dimensional nanowires on homoepitaxial interfaces: Atomic-scale mechanism of breakdown and disintegration

NASA Astrophysics Data System (ADS)

Michailov, Michail; Ranguelov, Bogdan

2018-03-01

We present a model for hole-mediated spontaneous breakdown of ahomoepitaxial two-dimensional (2D) flat nanowire based exclusively on random, thermally-activated motion of atoms. The model suggests a consecutive three-step mechanism driving the rupture and complete disintegration of the nanowire on a crystalline surface. The breakdown scenario includes: (i) local narrowing of a part of the stripe to a monatomic chain, (ii) formation of a recoverable single vacancy or a 2D vacancy cluster that causes temporary nanowire rupture, (iii) formation of a non-recoverable 2D hole leading to permanent nanowire breakdown. These successive events in the temporal evolution of the nanowire morphology bring the nanowire stripe into an irreversible unstable state, leading to a dramatic change in its peculiar physical properties and conductivity. The atomistic simulations also reveal a strong increase of the nanowire lifetime with an enlargement of its width and open up a way for a fine atomic-scale control of the nanowire lifetime and structural, morphological and thermodynamic stability.

Extreme-UV scanning wafer and reticle stages

DOEpatents

Williams, Mark E.

2002-01-01

A stage for precise positioning of a chuck in three orthogonal linear axes and in three orthogonal rotation axes that includes first and second subassemblies. The a first subassembly includes (i) a monolithic mirror that supports the chuck wherein the monolithic mirror has at least two polished orthogonal faces for interferometric determination of the X, Y, and .THETA.z positions; (ii) a plurality of electromagnetic actuators that control fine positioning in all six axes and coarse positioning in one axis; (iii) a position sensor for measuring the vertical Z position of the monolithic mirror; and (iv) a Lorentz actuator, that includes magnet array, for effecting motion in the Y axis. The a second subassembly comprising a stepping axis beam over which the first subassembly is suspended, wherein the stepping axis beam includes a drive coil array for the Lorentz actuator. T the stage can also include a cable stage subassembly that is positioned a fixed distance away from the monolithic mirror and/or a mechanical zero reference for the first subassembly.

Incorporating both physical and kinetic limitations in quantifying dissolved oxygen flux to aquatic sediments

USGS Publications Warehouse

O'Connor, B.L.; Hondzo, Miki; Harvey, J.W.

2009-01-01

Traditionally, dissolved oxygen (DO) fluxes have been calculated using the thin-film theory with DO microstructure data in systems characterized by fine sediments and low velocities. However, recent experimental evidence of fluctuating DO concentrations near the sediment-water interface suggests that turbulence and coherent motions control the mass transfer, and the surface renewal theory gives a more mechanistic model for quantifying fluxes. Both models involve quantifying the mass transfer coefficient (k) and the relevant concentration difference (??C). This study compared several empirical models for quantifying k based on both thin-film and surface renewal theories, as well as presents a new method for quantifying ??C (dynamic approach) that is consistent with the observed DO concentration fluctuations near the interface. Data were used from a series of flume experiments that includes both physical and kinetic uptake limitations of the flux. Results indicated that methods for quantifying k and ??C using the surface renewal theory better estimated the DO flux across a range of fluid-flow conditions. ?? 2009 ASCE.

Investigation of human-robot interface performance in household environments

NASA Astrophysics Data System (ADS)

Cremer, Sven; Mirza, Fahad; Tuladhar, Yathartha; Alonzo, Rommel; Hingeley, Anthony; Popa, Dan O.

2016-05-01

Today, assistive robots are being introduced into human environments at an increasing rate. Human environments are highly cluttered and dynamic, making it difficult to foresee all necessary capabilities and pre-program all desirable future skills of the robot. One approach to increase robot performance is semi-autonomous operation, allowing users to intervene and guide the robot through difficult tasks. To this end, robots need intuitive Human-Machine Interfaces (HMIs) that support fine motion control without overwhelming the operator. In this study we evaluate the performance of several interfaces that balance autonomy and teleoperation of a mobile manipulator for accomplishing several household tasks. Our proposed HMI framework includes teleoperation devices such as a tablet, as well as physical interfaces in the form of piezoresistive pressure sensor arrays. Mobile manipulation experiments were performed with a sensorized KUKA youBot, an omnidirectional platform with a 5 degrees of freedom (DOF) arm. The pick and place tasks involved navigation and manipulation of objects in household environments. Performance metrics included time for task completion and position accuracy.

Piezoelectric translator. A simple and inexpensive device to move microelectrodes and micropipettes small distances rapidly.

PubMed

Lederer, W J

1983-09-01

A device is described that is capable of rapidly moving microelectrodes and micropipettes over distances up to 15 mu. This piezoelectric transLator uses the diaphragm from virtually any available piezoelectric buzzer in combination with simple physical support and drive electronics. All of the necessary details for the construction of this small device are presented. Each finished unit is about 2 cm long with a diameter of 2 cm and can be readily adapted to existing manipulators. The translator has been found useful in aiding the independent penetration by one or more microelectrodes of single cells or of more complicated multicellular preparations (including those that lie behind a connective tissue layer). This new device offers fine control of microelectrode motion that cannot be obtained by the other methods used to aid microelectrode and micropipette penetration of cell membranes (e.g. capacitance overcompensation--"ringing in"' or "tickling"--or tapping the manipulator base). Finally, the device described in this paper is extremely simple and inexpensive to build.

Impaired Perception of Biological Motion in Parkinson’s Disease

PubMed Central

Jaywant, Abhishek; Shiffrar, Maggie; Roy, Serge; Cronin-Golomb, Alice

2016-01-01

Objective We examined biological motion perception in Parkinson’s disease (PD). Biological motion perception is related to one’s own motor function and depends on the integrity of brain areas affected in PD, including posterior superior temporal sulcus. If deficits in biological motion perception exist, they may be specific to perceiving natural/fast walking patterns that individuals with PD can no longer perform, and may correlate with disease-related motor dysfunction. Method 26 non-demented individuals with PD and 24 control participants viewed videos of point-light walkers and scrambled versions that served as foils, and indicated whether each video depicted a human walking. Point-light walkers varied by gait type (natural, parkinsonian) and speed (0.5, 1.0, 1.5 m/s). Participants also completed control tasks (object motion, coherent motion perception), a contrast sensitivity assessment, and a walking assessment. Results The PD group demonstrated significantly less sensitivity to biological motion than the control group (p<.001, Cohen’s d=1.22), regardless of stimulus gait type or speed, with a less substantial deficit in object motion perception (p=.02, Cohen’s d=.68). There was no group difference in coherent motion perception. Although individuals with PD had slower walking speed and shorter stride length than control participants, gait parameters did not correlate with biological motion perception. Contrast sensitivity and coherent motion perception also did not correlate with biological motion perception. Conclusion PD leads to a deficit in perceiving biological motion, which is independent of gait dysfunction and low-level vision changes, and may therefore arise from difficulty perceptually integrating form and motion cues in posterior superior temporal sulcus. PMID:26949927

Multimodal Pilot Behavior in Multi-Axis Tracking Tasks with Time-Varying Motion Cueing Gains

NASA Technical Reports Server (NTRS)

Zaal, P. M. T; Pool, D. M.

2014-01-01

In a large number of motion-base simulators, adaptive motion filters are utilized to maximize the use of the available motion envelope of the motion system. However, not much is known about how the time-varying characteristics of such adaptive filters affect pilots when performing manual aircraft control. This paper presents the results of a study investigating the effects of time-varying motion filter gains on pilot control behavior and performance. An experiment was performed in a motion-base simulator where participants performed a simultaneous roll and pitch tracking task, while the roll and/or pitch motion filter gains changed over time. Results indicate that performance increases over time with increasing motion gains. This increase is a result of a time-varying adaptation of pilots' equalization dynamics, characterized by increased visual and motion response gains and decreased visual lead time constants. Opposite trends are found for decreasing motion filter gains. Even though the trends in both controlled axes are found to be largely the same, effects are less significant in roll. In addition, results indicate minor cross-coupling effects between pitch and roll, where a cueing variation in one axis affects the behavior adopted in the other axis.

Dominant-limb range-of-motion and humeral-retrotorsion adaptation in collegiate baseball and softball position players.

PubMed

Hibberd, Elizabeth E; Oyama, Sakiko; Tatman, Justin; Myers, Joseph B

2014-01-01

Biomechanically, the motions used by baseball and softball pitchers differ greatly; however, the throwing motions of position players in both sports are strikingly similar. Although the adaptations to the dominant limb from overhead throwing have been well documented in baseball athletes, these adaptations have not been clearly identified in softball players. This information is important in order to develop and implement injury-prevention programs specific to decreasing the risk of upper extremity injury in softball athletes. To compare range-of-motion and humeral-retrotorsion characteristics of collegiate baseball and softball position players and of baseball and softball players to sex-matched controls. Cross-sectional study. Research laboratories and athletic training rooms at the University of North Carolina at Chapel Hill. Fifty-three collegiate baseball players, 35 collegiate softball players, 25 male controls (nonoverhead athletes), and 19 female controls (nonoverhead athletes). Range of motion and humeral retrotorsion were measured using a digital inclinometer and diagnostic ultrasound. Glenohumeral internal-rotation deficit, external-rotation gain, total glenohumeral range of motion, and humeral retrotorsion. Baseball players had greater glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference than softball players and male controls. There were no differences between glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference in softball players and female controls. Few differences were evident between softball players and female control participants, although range-of-motion and humeral-retrotorsion adaptations were significantly different than baseball players. The throwing motions are similar between softball and baseball, but the athletes adapt to the demands of the sport differently; thus, stretching/strengthening programs designed for baseball may not be the most effective programs for softball athletes.

Dominant-Limb Range-of-Motion and Humeral-Retrotorsion Adaptation in Collegiate Baseball and Softball Position Players

PubMed Central

Hibberd, Elizabeth E.; Oyama, Sakiko; Tatman, Justin; Myers, Joseph B.

2014-01-01

Context: Biomechanically, the motions used by baseball and softball pitchers differ greatly; however, the throwing motions of position players in both sports are strikingly similar. Although the adaptations to the dominant limb from overhead throwing have been well documented in baseball athletes, these adaptations have not been clearly identified in softball players. This information is important in order to develop and implement injury-prevention programs specific to decreasing the risk of upper extremity injury in softball athletes. Objective: To compare range-of-motion and humeral-retrotorsion characteristics of collegiate baseball and softball position players and of baseball and softball players to sex-matched controls. Design: Cross-sectional study. Setting: Research laboratories and athletic training rooms at the University of North Carolina at Chapel Hill. Patients or Other Participants: Fifty-three collegiate baseball players, 35 collegiate softball players, 25 male controls (nonoverhead athletes), and 19 female controls (nonoverhead athletes). Intervention(s): Range of motion and humeral retrotorsion were measured using a digital inclinometer and diagnostic ultrasound. Main Outcome Measure(s): Glenohumeral internal-rotation deficit, external-rotation gain, total glenohumeral range of motion, and humeral retrotorsion. Results: Baseball players had greater glenohumeral internal-rotation deficit, total–range-of-motion, and humeral-retrotorsion difference than softball players and male controls. There were no differences between glenohumeral internal-rotation deficit, total–range-of-motion, and humeral-retrotorsion difference in softball players and female controls. Conclusions: Few differences were evident between softball players and female control participants, although range-of-motion and humeral-retrotorsion adaptations were significantly different than baseball players. The throwing motions are similar between softball and baseball, but the athletes adapt to the demands of the sport differently; thus, stretching/strengthening programs designed for baseball may not be the most effective programs for softball athletes. PMID:25098655

Effect of Ablation of Area Postrema on Frequency and Latency of Motion Sickness-Induced Emesis in the Squirrel Monkey

NASA Technical Reports Server (NTRS)

Brizzee, K. R.; Ordy, J. M.; Mehler, W. R.

1980-01-01

Twelve young adult squirrel monkeys of the Bolivian subspecies were subjected to continuous counter-clockwise horizontal rotary motion at 25 rpm, together with a sinusoidal vertical excursion of 6 in. every 2 sec (0.5 Hz). Each animal was exposed to this motion regimen for a period of 60 min once each week for three consecutive weeks. Following the third weekly motion test bilateral ablation of the Area Postrema (AP) was performed in eight of the animals by thermal cautery. Two control animals were sham-operated after the third motion test while two additional controls were given the motion tests as noted above but were not operated. The four controls were considered as a single group for statistical analyses of results of the motion tests. After a recovery period of 30 to 40 days, and at a comparable interval in the non-operated controls, each animal was again tested for motion sensitivity for three consecutive weeks. The brains of all of the animals were then fixed by left ventriculal cardiac perfusion with Bouin's fluid and processed for histological evaluation of the bilateral AP ablation in comparison with the control brains. Five of the AP-ablated animals postoperatively were completely refractory to the motion stimuli, two exhibited a decreased number of emetic responses, and one exhibited the same number of responses before and after the AP lesions. The controls exhibited no significant difference in emetic sensitivity on the second series of three weekly tests than on the first series. The results of this investigation appear to be in agreement with the observations of Wang and Chinn in the dog indicating that the integrity of the AP (CTZ) is essential to the emetic response to motion.

An Open-Access Educational Tool for Teaching Motion Dynamics in Multi-Axis Servomotor Control

ERIC Educational Resources Information Center

Rivera-Guillen, J. R.; de Jesus Rangel-Magdaleno, J.; de Jesus Romero-Troncoso, R.; Osornio-Rios, R. A.; Guevara-Gonzalez, R. G.

2012-01-01

Servomotors are widely used in computerized numerically controlled (CNC) machines, hence motion control is a major topic covered in undergraduate/graduate engineering courses. Despite the fact that several syllabi include the motion dynamics topic in their courses, there are neither suitable tools available for designing and simulating multi-axis…

Automatic Learning of Fine Operating Rules for Online Power System Security Control.

PubMed

Sun, Hongbin; Zhao, Feng; Wang, Hao; Wang, Kang; Jiang, Weiyong; Guo, Qinglai; Zhang, Boming; Wehenkel, Louis

2016-08-01

Fine operating rules for security control and an automatic system for their online discovery were developed to adapt to the development of smart grids. The automatic system uses the real-time system state to determine critical flowgates, and then a continuation power flow-based security analysis is used to compute the initial transfer capability of critical flowgates. Next, the system applies the Monte Carlo simulations to expected short-term operating condition changes, feature selection, and a linear least squares fitting of the fine operating rules. The proposed system was validated both on an academic test system and on a provincial power system in China. The results indicated that the derived rules provide accuracy and good interpretability and are suitable for real-time power system security control. The use of high-performance computing systems enables these fine operating rules to be refreshed online every 15 min.

The role of inattention and hyperactivity/impulsivity in the fine motor coordination in children with ADHD.

PubMed

Fenollar-Cortés, Javier; Gallego-Martínez, Ana; Fuentes, Luis J

2017-10-01

Deficits in fine motor coordination have been suggested to be associated with Attention-Deficit/Hyperactivity Disorder (ADHD). However, despite the negative impact of poor fine motor skills on academic achievement, researchers have paid little attention to this problem. The aim of this study was to explore the relationship between ADHD dimensions and fine motor performance. Participants were 43 children with a diagnosis of ADHD aged between 7 and 14 years (M=9.61; 81% male) and 42 typically developing (TP) children in the same age range (M=10.76; 75.2% male). Children with ADHD performed worse than TP on all tasks (δ Fine_motor_tasks, -0.19 to -0.44). After controlling for age and ADHD-HY (hyperactivity/impulsivity), higher scores on ADHD-IN (inattentiveness) predicted a larger number of mistakes among all psychomotricity tasks and conditions (β 0.39-0.58, ps<0.05). The ADHD group showed poorer fine motor performance than controls across all fine motor coordination tasks. However, lower performance (more mistakes), was related to the inattention dimension but not to the hyperactivity/impulsivity dimensions. Authors recommend including training and enhancement of the fine motor skills for more comprehensive ADHD treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

A programmable display layer for virtual reality system architectures.

PubMed

Smit, Ferdi Alexander; van Liere, Robert; Froehlich, Bernd

2010-01-01

Display systems typically operate at a minimum rate of 60 Hz. However, existing VR-architectures generally produce application updates at a lower rate. Consequently, the display is not updated by the application every display frame. This causes a number of undesirable perceptual artifacts. We describe an architecture that provides a programmable display layer (PDL) in order to generate updated display frames. This replaces the default display behavior of repeating application frames until an update is available. We will show three benefits of the architecture typical to VR. First, smooth motion is provided by generating intermediate display frames by per-pixel depth-image warping using 3D motion fields. Smooth motion eliminates various perceptual artifacts due to judder. Second, we implement fine-grained latency reduction at the display frame level using a synchronized prediction of simulation objects and the viewpoint. This improves the average quality and consistency of latency reduction. Third, a crosstalk reduction algorithm for consecutive display frames is implemented, which improves the quality of stereoscopic images. To evaluate the architecture, we compare image quality and latency to that of a classic level-of-detail approach.

Synchronizing MIDI and wireless EEG measurements during natural piano performance.

PubMed

Zamm, Anna; Palmer, Caroline; Bauer, Anna-Katharina R; Bleichner, Martin G; Demos, Alexander P; Debener, Stefan

2017-07-08

Although music performance has been widely studied in the behavioural sciences, less work has addressed the underlying neural mechanisms, perhaps due to technical difficulties in acquiring high-quality neural data during tasks requiring natural motion. The advent of wireless electroencephalography (EEG) presents a solution to this problem by allowing for neural measurement with minimal motion artefacts. In the current study, we provide the first validation of a mobile wireless EEG system for capturing the neural dynamics associated with piano performance. First, we propose a novel method for synchronously recording music performance and wireless mobile EEG. Second, we provide results of several timing tests that characterize the timing accuracy of our system. Finally, we report EEG time domain and frequency domain results from N=40 pianists demonstrating that wireless EEG data capture the unique temporal signatures of musicians' performances with fine-grained precision and accuracy. Taken together, we demonstrate that mobile wireless EEG can be used to measure the neural dynamics of piano performance with minimal motion constraints. This opens many new possibilities for investigating the brain mechanisms underlying music performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Improvement of vertical stabilization on KSTAR

NASA Astrophysics Data System (ADS)

Mueller, D.; Bak, J. G.; Boyer, M. D.; Eideitis, N.; Hahn, S. H.; Humphreys, D. A.; Kim, H. S.; Jeon, Y. M.; Lanctot, M.; Walker, M. L.

2017-10-01

The successful control of strongly shaped plasmas on the Korea Superconducting Tokamak Advanced Research (KSTAR) device requires active feedback of fast motion of the plasma vertical position by the use of internal normal conducting coils (IVC). This has required new electronics to supply relative flux loop differences, for zp, and voltage loop differences, for dzp/dt, as well as a novel technique (Zfast) to use a high-pass filter, typically 1 Hz, on the error in the signal in the feedback loop. Use of Zfast avoids the potential contention encountered when the internal coil attempts to perform control of the plasma shape which should be controlled by the slower and more powerful superconducting coils. A common problem of this contention is saturation of the IVC and loss of fast vertical control. This is eliminated by proper use of the Zfast. A Ziegler-Nichols relay feedback system was used to fine tune the required feedback gains. The selection of the magnetic sensors, filter time constants, control gains and of the Zfast control strategy which allowed vertically stable operation at a plasma elongation, kappa. of up to 2.16 at li = 1.15 and Betap = 2.4 will be discussed which is beyond the design reference of KSTAR of kappa = 2.0 at li = 1.2 and Betap = 1.9. Work Supported by U.S.D.O.E. Contract No. DE-AC02-09CH11466 and DE-SC0010685 and the KSTAR project.

The Inertia Coefficients of an Airship in a Frictionless Fluid

NASA Technical Reports Server (NTRS)

Bateman, H.

1979-01-01

The apparent inertia of an airship hull is examined. The exact solution of the aerodynamical problem is studied for hulls of various shapes with special attention given to the case of an ellipsoidal hull. So that the results for the ellipsoidal hull may be readily adapted to other cases, they are expressed in terms of the area and perimeter of the largest cross section perpendicular to the direction of motion by means of a formula involving a coefficient kappa which varies only slowly when the shape of the hull is changed, being 0.637 for a circular or elliptic disk, 0.5 for a sphere, and about 0.25 for a spheroid of fineness ratio. The case of rotation of an airship hull is investigated and a coefficient is defined with the same advantages as the corresponding coefficient for rectilinear motion.

Magnetic suspension and pointing system. [on a carrier vehicle

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Groom, N. J. (Inventor)

1979-01-01

Apparatus for providing accurate pointing of instruments on a carrier vehicle and for providing isolation of the instruments from the vehicle's motion disturbances is presented. The apparatus includes two assemblies, with connecting interfaces, each assembly having a separate function. The first assembly is attached to the carrier vehicle and consists of an azimuth gimbal and an elevation gimbal which provide coarse pointing of the instruments by allowing two rotations of the instruments relative to the carrier vehicle. The second or vernier pointing assembly is made up of magnetic suspension and fine pointing actuators, roll motor segments, and an instrument mounting plate around which a continuous annular rim is attached which provides appropriate magnetic circuits for the actuators and the roll motor segments. The vernier pointing assembly provides six degree-of-freedom isolation from carrier motion disturbances.

REVIEWS OF TOPICAL PROBLEMS: Periodic weather and climate variations

NASA Astrophysics Data System (ADS)

Ivanov, Vladimir V.

2002-07-01

Variations in meteorological parameters are largely due to periodic processes and can be forecast for several years. Many such processes are related to astronomical factors such as the gravitational influences of the Moon and the Sun, and the modulation of solar irradiance by lunar and planetary motion. The Moon, Jupiter, and Venus have the strongest effect. These influences produce lines in the spectra of meteorological variations, which are combinations of the harmonics of the frequencies of revolution of the planets, the Earth, and the Moon around the Sun with the harmonics of the lunar revolution around the Earth. Due to frequency differences between the orbital and radial motions, fine spectral features of three types appear: line splitting, line-profile complications due to radial oscillations, and additional lines due to the combination of radial-oscillation frequencies with perturbation harmonics.

SU-E-P-25: Evaluation of Motion in Pancreas SBRT Treatment Deliveries

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

Xiong, L; Halvorsen, P

2015-06-15

Purpose: Stereotactic Body Radiation Therapy (SBRT) procedures for pancreatic cancer present a challenge in motion management because the target is directly adjacent to critical structures and the target is subject to significant respiratory motion. Gated treatment is usually planned with a tight (few mm) PTV margin. The positioning and setup relies on on-board-imaging (OBI) of internal fiducials. This study evaluates the corrections for inter- and intra-fractional target motion as evidenced by the OBI. Methods: 20 patients with gated pancreas SBRT treatment were setup with KV imaging guidance before and during each treatment. The couch position was fine-tuned to align withmore » the internal fiducials for each patient. The data for 148 intra- and 111 inter-fractional couch movements were captured and analyzed. Results: The mean ± standard deviation of couch shifts for the initial daily setup is 4.9±4.1 mm for couch vertical, 5.3±4.6 mm for couch longitudinal, and 3.7±4.0 mm for couch lateral. The mean ± standard deviation of intra-treatment adjustments are 1.1±1.6, 2.5±3.8, and 1.1±1.8 mm for couch vertical, longitudinal and lateral. The probability of intra-fractional motion in the three orthogonal directions with magnitude no more than 2 mm, 3 mm and 5 mm is 55%, 68% and 84% respectively. Conclusion: The intra-treatment target motion for pancreas SBRT patients indicates that a PTV margin of 5mm may be necessary.« less

Dynamic Measurement of Extra Long Stroke Cylinder in the Pneumatic System

NASA Astrophysics Data System (ADS)

Chang, Ho; Lan, Chou-wei; Chen, Liang-Chia

2006-10-01

This paper sets up the measure and control system of the dynamic characteristics of the extra long stroke cylinder. In the different types of the control conditions (e.g. different control law, operating pressure and direct control valves), using the measure and control system to measure the relation between the pressure and the velocity of the motion of the long stroke cylinder and to observe the stick slip phenomenon of the motion of the long stroke cylinder. In the innovate measurement system, two pressure sensors are set on the long stroke cylinder to measure the difference of the pressure between the inlet and the exhaust of the long stroke cylinder. In additions, a draw line encoder is set on the system to measure the position and the velocity of the motion of the long stroke cylinder. The measuring data of the measure system is transferred to the computer via A/D interface card and counter card, and Home-made program of Haptic Interface Device is used to control the system, saving the data of the motion of the long stroke cylinder. The system uses different types of direction control valve to control the motion of the long stroke cylinder and compares the difference of the motion of the long stroke cylinder. The results show that the motion of the cylinder that pauses in the middle of the cylinder stroke and causes the stick slip phenomenon is more violent than the stick slip phenomenon in other position. When the length of the pause time reaches the some range, the acceleration of the motion of the cylinder will be rised substantially. This paper not only focuses on the testing method of the dynamic characteristics of the motion of the long stroke cylinder, but also includes the analysis of the dynamic characteristics of the motion of the long stroke cylinder. It provides the data of the dynamic characteristics of the motion of the long stroke cylinder to improve and design the pneumatic system of the long stroke cylinder.

Motion and force control of multiple robotic manipulators

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz-Delgado, Kenneth

1992-01-01

This paper addresses the motion and force control problem of multiple robot arms manipulating a cooperatively held object. A general control paradigm is introduced which decouples the motion and force control problems. For motion control, different control strategies are constructed based on the variables used as the control input in the controller design. There are three natural choices; acceleration of a generalized coordinate, arm tip force vectors, and the joint torques. The first two choices require full model information but produce simple models for the control design problem. The last choice results in a class of relatively model independent control laws by exploiting the Hamiltonian structure of the open loop system. The motion control only determines the joint torque to within a manifold, due to the multiple-arm kinematic constraint. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, an optimization can be performed to best allocate the desired and effector control force to the joint actuators. The other possibility is to control the internal force about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

High-Resolution Multi-Shot Spiral Diffusion Tensor Imaging with Inherent Correction of Motion-Induced Phase Errors

PubMed Central

Truong, Trong-Kha; Guidon, Arnaud

2014-01-01

Purpose To develop and compare three novel reconstruction methods designed to inherently correct for motion-induced phase errors in multi-shot spiral diffusion tensor imaging (DTI) without requiring a variable-density spiral trajectory or a navigator echo. Theory and Methods The first method simply averages magnitude images reconstructed with sensitivity encoding (SENSE) from each shot, whereas the second and third methods rely on SENSE to estimate the motion-induced phase error for each shot, and subsequently use either a direct phase subtraction or an iterative conjugate gradient (CG) algorithm, respectively, to correct for the resulting artifacts. Numerical simulations and in vivo experiments on healthy volunteers were performed to assess the performance of these methods. Results The first two methods suffer from a low signal-to-noise ratio (SNR) or from residual artifacts in the reconstructed diffusion-weighted images and fractional anisotropy maps. In contrast, the third method provides high-quality, high-resolution DTI results, revealing fine anatomical details such as a radial diffusion anisotropy in cortical gray matter. Conclusion The proposed SENSE+CG method can inherently and effectively correct for phase errors, signal loss, and aliasing artifacts caused by both rigid and nonrigid motion in multi-shot spiral DTI, without increasing the scan time or reducing the SNR. PMID:23450457

SLIPPING MAGNETIC RECONNECTION TRIGGERING A SOLAR ERUPTION OF A TRIANGLE-SHAPED FLAG FLUX ROPE

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

Li, Ting; Zhang, Jun, E-mail: liting@nao.cas.cn, E-mail: zjun@nao.cas.cn

2014-08-10

We report the first simultaneous activities of the slipping motion of flare loops and a slipping eruption of a flux rope in 131 Å and 94 Å channels on 2014 February 2. The east hook-like flare ribbon propagated with a slipping motion at a speed of about 50 km s{sup –1}, which lasted about 40 minutes and extended by more than 100 Mm, but the west flare ribbon moved in the opposite direction with a speed of 30 km s{sup –1}. At the later phase of flare activity, there was a well developed ''bi-fan'' system of flare loops. The east footpoints ofmore » the flux rope showed an apparent slipping motion along the hook of the ribbon. Simultaneously, the fine structures of the flux rope rose up rapidly at a speed of 130 km s{sup –1}, much faster than that of the whole flux rope. We infer that the east footpoints of the flux rope are successively heated by a slipping magnetic reconnection during the flare, which results in the apparent slippage of the flux rope. The slipping motion delineates a ''triangle-shaped flag surface'' of the flux rope, implying that the topology of a flux rope is more complex than anticipated.« less

Accurate respiration measurement using DC-coupled continuous-wave radar sensor for motion-adaptive cancer radiotherapy.

PubMed

Gu, Changzhan; Li, Ruijiang; Zhang, Hualiang; Fung, Albert Y C; Torres, Carlos; Jiang, Steve B; Li, Changzhi

2012-11-01

Accurate respiration measurement is crucial in motion-adaptive cancer radiotherapy. Conventional methods for respiration measurement are undesirable because they are either invasive to the patient or do not have sufficient accuracy. In addition, measurement of external respiration signal based on conventional approaches requires close patient contact to the physical device which often causes patient discomfort and undesirable motion during radiation dose delivery. In this paper, a dc-coupled continuous-wave radar sensor was presented to provide a noncontact and noninvasive approach for respiration measurement. The radar sensor was designed with dc-coupled adaptive tuning architectures that include RF coarse-tuning and baseband fine-tuning, which allows the radar sensor to precisely measure movement with stationary moment and always work with the maximum dynamic range. The accuracy of respiration measurement with the proposed radar sensor was experimentally evaluated using a physical phantom, human subject, and moving plate in a radiotherapy environment. It was shown that respiration measurement with radar sensor while the radiation beam is on is feasible and the measurement has a submillimeter accuracy when compared with a commercial respiration monitoring system which requires patient contact. The proposed radar sensor provides accurate, noninvasive, and noncontact respiration measurement and therefore has a great potential in motion-adaptive radiotherapy.

Sled Control and Safety System

NASA Technical Reports Server (NTRS)

Forrest, L. J.

1982-01-01

Computerized system for controlling motion of linear-track accelerator applied to other automated equipment, such as numerically-controlled machine tools and robot manipulators on assembly lines. System controls motions of sled with sine-wave signal created digitally by microprocessor. Dynamic parameters of sled motion are monitored so sled may be stopped safely if malfunction occurs. Sled is capable of sinusoidal accelerations up to 0.5 g with 125-kg load.

The IBM HeadTracking Pointer: improvements in vision-based pointer control.

PubMed

Kjeldsen, Rick

2008-07-01

Vision-based head trackers have been around for some years and are even beginning to be commercialized, but problems remain with respect to usability. Users without the ability to use traditional pointing devices--the intended audience of such systems--have no alternative if the automatic bootstrapping process fails. There is room for improvement in face tracking, and the pointer movement dynamics do not support accurate and efficient pointing. This paper describes the IBM HeadTracking Pointer, a system which attempts to directly address some of these issues. Head gestures are used to provide the end user a greater level of autonomous control over the system. A novel face-tracking algorithm reduces drift under variable lighting conditions, allowing the use of absolute, rather than relative, pointer positioning. Most importantly, the pointer dynamics have been designed to take into account the constraints of head-based pointing, with a non-linear gain which allows stability in fine pointer movement, high speed on long transitions and adjustability to support users with different movement dynamics. User studies have identified some difficulties with training the system and some characteristics of the pointer motion that take time to get used to, but also good user feedback and very promising performance results.

The MICROSCOPE experiment, ready for the in-orbit test of the equivalence principle

NASA Astrophysics Data System (ADS)

Touboul, P.; Métris, G.; Lebat, V.; Robert, A.

2012-09-01

Deviations from standard general relativity are being intensively tested in various aspects. The MICROSCOPE space mission, which has recently been approved to be launched in 2016, aims at testing the universality of free fall with an accuracy better than 10-15. The instrument has been developed and most of the sub-systems have been tested to the level required for the detection of accelerations lower than one tenth of a femto-g. Two concentric test masses are electrostatically levitated inside the same silica structure and controlled on the same trajectory at better than 0.1 Å. Any dissymmetry in the measured electrostatic pressures shall be analysed with respect to the Earth's gravity field. The nearly 300 kg heavy dedicated satellite is defined to provide a very steady environment to the experiment and a fine control of its attitude and of its drag-free motion along the orbit. Both the evaluations of the performance of the instrument and the satellite demonstrate the expected test accuracy. The detailed description of the experiment and the major driving parameters of the instrument, the satellite and the data processing are provided in this paper.

Impaired Comprehension of Speed Verbs in Parkinson's Disease.

PubMed

Speed, Laura J; van Dam, Wessel O; Hirath, Priyantha; Vigliocco, Gabriella; Desai, Rutvik H

2017-05-01

A wealth of studies provide evidence for action simulation during language comprehension. Recent research suggests such action simulations might be sensitive to fine-grained information, such as speed. Here, we present a crucial test for action simulation of speed in language by assessing speed comprehension in patients with Parkinson's disease (PD). Based on the patients' motor deficits, we hypothesized that the speed of motion described in language would modulate their performance in semantic tasks. Specifically, they would have more difficulty processing language about relatively fast speed than language about slow speed. We conducted a semantic similarity judgment task on fast and slow action verbs in patients with PD and age-matched healthy controls. Participants had to decide which of two verbs most closely matched a target word. Compared to controls, PD patients were slower making judgments about fast action verbs, but not for judgments about slow action verbs, suggesting impairment in processing language about fast action. Moreover, this impairment was specific to verbs describing fast action performed with the hand. Problems moving quickly lead to difficulties comprehending language about moving quickly. This study provides evidence that speed is an important part of action representations. (JINS, 2017, 23, 412-420).

MEASUREMENT AND CONTROL OF FOULING IN FINE PORE DIFFUSER SYSTEMS

EPA Science Inventory

The purpose of the study was two-fold: First, to define the efficiency of various methods of cleaning fine pore diffusers and, second, to develop a methodology that could be used to evaluate the efficiency of the cleaning techniques. Dirty fine pore domes from the North Texas Mu...

Maximum efficiency of the collisional Penrose process

NASA Astrophysics Data System (ADS)

Zaslavskii, O. B.

2016-09-01

We consider the collision of two particles that move in the equatorial plane near a general stationary rotating axially symmetric extremal black hole. One of the particles is critical (with fine-tuned parameters) and moves in the outward direction. The second particle (usual, not fine-tuned) comes from infinity. We examine the efficiency η of the collisional Penrose process. There are two relevant cases here: a particle falling into a black hole after collision (i) is heavy or (ii) has a finite mass. We show that the maximum of η in case (ii) is less than or equal to that in case (i). It is argued that for superheavy particles, the bound applies to nonequatorial motion as well. As an example, we analyze collision in the Kerr-Newman background. When the bound is the same for processes (i) and (ii), η =3 for this metric. For the Kerr black hole, recent results in the literature are reproduced.

Fine-scale characteristics of interplanetary sector

NASA Technical Reports Server (NTRS)

Behannon, K. W.; Neubauer, F. M.; Barnstoff, H.

1980-01-01

The structure of the interplanetary sector boundaries observed by Helios 1 within sector transition regions was studied. Such regions consist of intermediate (nonspiral) average field orientations in some cases, as well as a number of large angle directional discontinuities (DD's) on the fine scale (time scales 1 hour). Such DD's are found to be more similar to tangential than rotational discontinuities, to be oriented on average more nearly perpendicular than parallel to the ecliptic plane to be accompanied usually by a large dip ( 80%) in B and, with a most probable thickness of 3 x 10 to the 4th power km, significantly thicker previously studied. It is hypothesized that the observed structures represent multiple traversals of the global heliospheric current sheet due to local fluctuations in the position of the sheet. There is evidence that such fluctuations are sometimes produced by wavelike motions or surface corrugations of scale length 0.05 - 0.1 AU superimposed on the large scale structure.

Fine refinement of solid state structure of racemic form of phospho-tyrosine employing NMR Crystallography approach.

PubMed

Paluch, Piotr; Pawlak, Tomasz; Oszajca, Marcin; Lasocha, Wieslaw; Potrzebowski, Marek J

2015-02-01

We present step by step facets important in NMR Crystallography strategy employing O-phospho-dl-tyrosine as model sample. The significance of three major techniques being components of this approach: solid state NMR (SS NMR), X-ray diffraction of powdered sample (PXRD) and theoretical calculations (Gauge Invariant Projector Augmented Wave; GIPAW) is discussed. Each experimental technique provides different set of structural constraints. From the PXRD measurement the size of the unit cell, space group and roughly refined molecular structure are established. SS NMR provides information about content of crystallographic asymmetric unit, local geometry, molecular motion in the crystal lattice and hydrogen bonding pattern. GIPAW calculations are employed for validation of quality of elucidation and fine refinement of structure. Crystal and molecular structure of O-phospho-dl-tyrosine solved by NMR Crystallography is deposited at Cambridge Crystallographic Data Center under number CCDC 1005924. Copyright © 2014 Elsevier Inc. All rights reserved.

Orbital and angular motion construction for low thrust interplanetary flight

NASA Astrophysics Data System (ADS)

Yelnikov, R. V.; Mashtakov, Y. V.; Ovchinnikov, M. Yu.; Tkachev, S. S.

2016-11-01

Low thrust interplanetary flight is considered. Firstly, the fuel-optimal control is found. Then the angular motion is synthesized. This motion provides the thruster tracking of the required by optimal control direction. And, finally, reaction wheel control law for tracking this angular motion is proposed and implemented. The numerical example is given and total operation time for thrusters is found. Disturbances from solar pressure, thrust eccentricity, inaccuracy of reaction wheels installation and errors of inertia tensor are taken into account.

Impaired visual recognition of biological motion in schizophrenia.

PubMed

Kim, Jejoong; Doop, Mikisha L; Blake, Randolph; Park, Sohee

2005-09-15

Motion perception deficits have been suggested to be an important feature of schizophrenia but the behavioral consequences of such deficits are unknown. Biological motion refers to the movements generated by living beings. The human visual system rapidly and effortlessly detects and extracts socially relevant information from biological motion. A deficit in biological motion perception may have significant consequences for detecting and interpreting social information. Schizophrenia patients and matched healthy controls were tested on two visual tasks: recognition of human activity portrayed in point-light animations (biological motion task) and a perceptual control task involving detection of a grouped figure against the background noise (global-form task). Both tasks required detection of a global form against background noise but only the biological motion task required the extraction of motion-related information. Schizophrenia patients performed as well as the controls in the global-form task, but were significantly impaired on the biological motion task. In addition, deficits in biological motion perception correlated with impaired social functioning as measured by the Zigler social competence scale [Zigler, E., Levine, J. (1981). Premorbid competence in schizophrenia: what is being measured? Journal of Consulting and Clinical Psychology, 49, 96-105.]. The deficit in biological motion processing, which may be related to the previously documented deficit in global motion processing, could contribute to abnormal social functioning in schizophrenia.

Separation and recovery of fine particles from waste circuit boards using an inflatable tapered diameter separation bed.

PubMed

Duan, Chenlong; Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

2014-01-01

Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (-0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5-0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25-0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (-0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.

A Programmable System for Motion Control

NASA Technical Reports Server (NTRS)

Nowlin, Brent C.

2003-01-01

The need for improved flow measurements in the flow path of aeronautics testing facilities has led the NASA Glenn Research Center to develop a new motion control system. The new system is programmable, offering a flexibility unheard of in previous systems. The motion control system is PLC-based, which leads to highly accurate positioning ability, as well as reliability. The user interface is a software-based HMI package, which also adds flexibility to the overall system. The system also has the ability to create and execute motion profiles. This paper discusses the system's operation, control implementation, and experiences.

Influence of Head Motion on the Accuracy of 3D Reconstruction with Cone-Beam CT: Landmark Identification Errors in Maxillofacial Surface Model.

PubMed

Lee, Kyung-Min; Song, Jin-Myoung; Cho, Jin-Hyoung; Hwang, Hyeon-Shik

2016-01-01

The purpose of this study was to investigate the influence of head motion on the accuracy of three-dimensional (3D) reconstruction with cone-beam computed tomography (CBCT) scan. Fifteen dry skulls were incorporated into a motion controller which simulated four types of head motion during CBCT scan: 2 horizontal rotations (to the right/to the left) and 2 vertical rotations (upward/downward). Each movement was triggered to occur at the start of the scan for 1 second by remote control. Four maxillofacial surface models with head motion and one control surface model without motion were obtained for each skull. Nine landmarks were identified on the five maxillofacial surface models for each skull, and landmark identification errors were compared between the control model and each of the models with head motion. Rendered surface models with head motion were similar to the control model in appearance; however, the landmark identification errors showed larger values in models with head motion than in the control. In particular, the Porion in the horizontal rotation models presented statistically significant differences (P < .05). Statistically significant difference in the errors between the right and left side landmark was present in the left side rotation which was opposite direction to the scanner rotation (P < .05). Patient movement during CBCT scan might cause landmark identification errors on the 3D surface model in relation to the direction of the scanner rotation. Clinicians should take this into consideration to prevent patient movement during CBCT scan, particularly horizontal movement.

A Longitudinal Study of the Six Degrees of Freedom Cervical Spine Range of Motion During Dynamic Flexion/Extension and Rotation After Single-Level Anterior Arthrodesis

PubMed Central

Anderst, William J.; West, Tyler; Donaldson, William F; Lee, Joon Y.; Kang, James D.

2016-01-01

Study Design A longitudinal study using biplane radiography to measure in vivo intervertebral range of motion (ROM) during dynamic flexion/extension and rotation. Objective To longitudinally compare intervertebral maximal ROM and midrange motion in asymptomatic control subjects and single-level arthrodesis patients. Summary of Background Data In vitro studies consistently report that adjacent segment maximal ROM increases superior and inferior to cervical arthrodesis. Previous in vivo results have been conflicting, indicating that maximal ROM may or may not increase superior and/or inferior to the arthrodesis. There are no previous reports of midrange motion in arthrodesis patients and similar-aged controls. Methods Eight single-level (C5/C6) anterior arthrodesis patients (tested 7±1 months and 28±6 months post-surgery) and six asymptomatic control subjects (tested twice, 58±6 months apart) performed dynamic full ROM flexion/extension and axial rotation while biplane radiographs were collected at 30 images/s. A previously validated tracking process determined three-dimensional vertebral position from each pair of radiographs with sub-millimeter accuracy. The intervertebral maximal ROM and midrange motion in flexion/extension, rotation, lateral bending, and anterior-posterior translation were compared between test dates and between groups. Results Adjacent segment maximal ROM did not increase over time during flexion/extension or rotation movements. Adjacent segment maximal rotational ROM was not significantly greater in arthrodesis patients than in corresponding motion segments of similar-aged controls. C4/C5 adjacent segment rotation during the midrange of head motion and maximal anterior-posterior translation were significantly greater in arthrodesis patients than in the corresponding motion segment in controls on the second test date. Conclusions C5/C6 arthrodesis appears to significantly affect midrange, but not end-range, adjacent segment motions. The effects of arthrodesis on adjacent segment motion may be best evaluated by longitudinal studies that compare maximal and midrange adjacent segment motion to corresponding motion segments of similar-aged controls to determine if the adjacent segment motion is truly excessive. PMID:27831986

Longitudinal Study of the Six Degrees of Freedom Cervical Spine Range of Motion During Dynamic Flexion, Extension, and Rotation After Single-level Anterior Arthrodesis.

PubMed

Anderst, William J; West, Tyler; Donaldson, William F; Lee, Joon Y; Kang, James D

2016-11-15

A longitudinal study using biplane radiography to measure in vivo intervertebral range of motion (ROM) during dynamic flexion/extension, and rotation. To longitudinally compare intervertebral maximal ROM and midrange motion in asymptomatic control subjects and single-level arthrodesis patients. In vitro studies consistently report that adjacent segment maximal ROM increases superior and inferior to cervical arthrodesis. Previous in vivo results have been conflicting, indicating that maximal ROM may or may not increase superior and/or inferior to the arthrodesis. There are no previous reports of midrange motion in arthrodesis patients and similar-aged controls. Eight single-level (C5/C6) anterior arthrodesis patients (tested 7 ± 1 months and 28 ± 6 months postsurgery) and six asymptomatic control subjects (tested twice, 58 ± 6 months apart) performed dynamic full ROM flexion/extension and axial rotation whereas biplane radiographs were collected at 30 images per second. A previously validated tracking process determined three-dimensional vertebral position from each pair of radiographs with submillimeter accuracy. The intervertebral maximal ROM and midrange motion in flexion/extension, rotation, lateral bending, and anterior-posterior translation were compared between test dates and between groups. Adjacent segment maximal ROM did not increase over time during flexion/extension, or rotation movements. Adjacent segment maximal rotational ROM was not significantly greater in arthrodesis patients than in corresponding motion segments of similar-aged controls. C4/C5 adjacent segment rotation during the midrange of head motion and maximal anterior-posterior translation were significantly greater in arthrodesis patients than in the corresponding motion segment in controls on the second test date. C5/C6 arthrodesis appears to significantly affect midrange, but not end-range, adjacent segment motions. The effects of arthrodesis on adjacent segment motion may be best evaluated by longitudinal studies that compare maximal and midrange adjacent segment motion to corresponding motion segments of similar-aged controls to determine if the adjacent segment motion is truly excessive. 3.

Deficient motion-defined and texture-defined figure-ground segregation in amblyopic children.

PubMed

Wang, Jane; Ho, Cindy S; Giaschi, Deborah E

2007-01-01

Motion-defined form deficits in the fellow eye and the amblyopic eye of children with amblyopia implicate possible direction-selective motion processing or static figure-ground segregation deficits. Deficient motion-defined form perception in the fellow eye of amblyopic children may not be fully accounted for by a general motion processing deficit. This study investigates the contribution of figure-ground segregation deficits to the motion-defined form perception deficits in amblyopia. Performances of 6 amblyopic children (5 anisometropic, 1 anisostrabismic) and 32 control children with normal vision were assessed on motion-defined form, texture-defined form, and global motion tasks. Performance on motion-defined and texture-defined form tasks was significantly worse in amblyopic children than in control children. Performance on global motion tasks was not significantly different between the 2 groups. Faulty figure-ground segregation mechanisms are likely responsible for the observed motion-defined form perception deficits in amblyopia.

Fine root respiration in mature eastern white pine (Pinus strobus) in situ: the importance of CO2 in controlled environments.

Treesearch

Barton D. Clinton; James M. Vose

1999-01-01

Clinton and Vose measured seasonal fine root respiration rate in situ while controlling chamber temperature and [CO2]. Atmospheric and [CO2] ([CO2]a) and measured soil [CO2] ([CO2]s) were alternately delivered...

Development of fine-leaved Festuca grass for forage and wildfire control in the Great Basin

USDA-ARS?s Scientific Manuscript database

Drought and heat tolerant fine-leaved fescue (Festuca ssp.) grasses have potential as components in rangeland greenstrips for wildfire control in semi-arid climates, although such grasses have not been evaluated under rangeland conditions. Therefore, 64 geographically diverse Festuca accessions of ...

Knee motion variability in patients with knee osteoarthritis: the effect of self-reported instability

PubMed Central

Gustafson, Jonathan A.; Robinson, Megan E.; Fitzgerald, G. Kelley; Tashman, Scott; Farrokhi, Shawn

2015-01-01

Background Knee osteoarthritis has been previously associated with a stereotypical knee-stiffening gait pattern and reduced knee joint motion variability due to increased antagonist muscle co-contractions and smaller utilized arc of motion during gait. However, episodic self-reported instability may be a sign of excessive motion variability for a large subgroup of patients with knee osteoarthritis. The objective of this work was to evaluate the differences in knee joint motion variability during gait in patients with knee osteoarthritis with and without self-reported instability compared to a control group of older adults with asymptomatic knees. Methods Forty-three subjects, 8 with knee osteoarthritis but no reports of instability (stable), 11 with knee osteoarthritis and self-reported instability (unstable), and 24 without knee osteoarthritis or instability (control) underwent Dynamic Stereo X-ray analysis during a decline gait task on a treadmill. Knee motion variability was assessed using parametric phase plots during the loading response phase of decline gait. Findings The stable group demonstrated decreased sagittal-plane motion variability compared to the control group (p=0.04), while the unstable group demonstrated increased sagittal-plane motion variability compared to the control (p=0.003) and stable groups (p<0.001). The unstable group also demonstrated increased anterior-posterior joint contact point motion variability for the medial tibiofemoral compartment compared to the control (p=0.03) and stable groups (p=0.03). Interpretation The finding of decreased knee motion variability in patients with knee osteoarthritis without self-reported instability supports previous research. However, presence of self-reported instability is associated with increased knee motion variability in patients with knee osteoarthritis and warrants further investigation. PMID:25796536

Smart Braid Feedback for the Closed-Loop Control of Soft Robotic Systems.

PubMed

Felt, Wyatt; Chin, Khai Yi; Remy, C David

2017-09-01

This article experimentally investigates the potential of using flexible, inductance-based contraction sensors in the closed-loop motion control of soft robots. Accurate motion control remains a highly challenging task for soft robotic systems. Precise models of the actuation dynamics and environmental interactions are often unavailable. This renders open-loop control impossible, while closed-loop control suffers from a lack of suitable feedback. Conventional motion sensors, such as linear or rotary encoders, are difficult to adapt to robots that lack discrete mechanical joints. The rigid nature of these sensors runs contrary to the aspirational benefits of soft systems. As truly soft sensor solutions are still in their infancy, motion control of soft robots has so far relied on laboratory-based sensing systems such as motion capture, electromagnetic (EM) tracking, or Fiber Bragg Gratings. In this article, we used embedded flexible sensors known as Smart Braids to sense the contraction of McKibben muscles through changes in inductance. We evaluated closed-loop control on two systems: a revolute joint and a planar, one degree of freedom continuum manipulator. In the revolute joint, our proposed controller compensated for elasticity in the actuator connections. The Smart Braid feedback allowed motion control with a steady-state root-mean-square (RMS) error of [1.5]°. In the continuum manipulator, Smart Braid feedback enabled tracking of the desired tip angle with a steady-state RMS error of [1.25]°. This work demonstrates that Smart Braid sensors can provide accurate position feedback in closed-loop motion control suitable for field applications of soft robotic systems.

Magnetic Actuation of Biological Systems

NASA Astrophysics Data System (ADS)

Lauback, Stephanie D.

Central to the advancement of many biomedical and nanotechnology capabilities is the capacity to precisely control the motion of micro and nanostructures. These applications range from single molecule experiments to cell isolation and separation, to drug delivery and nanomachine manipulation. This dissertation focuses on actuation of biological micro- and nano-entities through the use of weak external magnetic fields, superparamagnetic beads, and ferromagnetic thin films. The magnetic platform presents an excellent method for actuation of biological systems due to its ability to directly control the motion of an array of micro and nanostructures in real-time with calibrated picoNewton forces. The energy landscape of two ferromagnetic thin film patterns (disks and zigzag wires) is experimentally explored and compared to corresponding theoretical models to quantify the applied forces and trajectories of superparamagnetic beads due to the magnetic traps. A magnetic method to directly actuate DNA nanomachines in real-time with nanometer resolution and sub-second response times using micromagnetic control was implemented through the use of stiff DNA micro-levers which bridged the large length scale mismatch between the micro-actuator and the nanomachine. Compared to current alternative methods which are limited in the actuation speeds and the number of reconfiguration states of DNA constructs, this magnetic approach enables fast actuation (˜ milliseconds) and reconfigurable conformations achieved through a continuous range of finely tuned steps. The system was initially tested through actuation of the stiff arm tethered to the surface, and two prototype DNA nanomachines (rotor and hinge) were successfully actuated using the stiff mechanical lever. These results open new possibilities in the development of functional robotic systems at the molecular scale. In exploiting the use of DNA stiff levers, a new technique was also developed to investigate the emergence of the magnetization of individual superparamagnetic beads as a function of the applied field. Last, since proteins are frequently used for surface adhesion in assembling biomedical devices, preliminary tests were implemented to dynamically pattern proteins on a substrate using transformed E. coli that are magnetically labeled.

Optimal early active mobilisation protocol after extensor tendon repairs in zones V and VI: A systematic review of literature.

PubMed

Collocott, Shirley Jf; Kelly, Edel; Ellis, Richard F

2018-03-01

Early mobilisation protocols after repair of extensor tendons in zone V and VI provide better outcomes than immobilisation protocols. This systematic review investigated different early active mobilisation protocols used after extensor tendon repair in zone V and VI. The purpose was to determine whether any one early active mobilisation protocol provides superior results. An extensive literature search was conducted to identify articles investigating the outcomes of early active mobilisation protocols after extensor tendon repair in zone V and VI. Databases searched were AMED, Embase, Medline, Cochrane and CINAHL. Studies were included if they involved participants with extensor tendon repairs in zone V and VI in digits 2-5 and described a post-operative rehabilitation protocol which allowed early active metacarpophalangeal joint extension. Study designs included were randomised controlled trials, observational studies, cohort studies and case series. The Structured Effectiveness Quality Evaluation Scale was used to evaluate the methodological quality of the included studies. Twelve articles met the inclusion criteria. Two types of early active mobilisation protocols were identified: controlled active motion protocols and relative motion extension splinting protocols. Articles describing relative motion extension splinting protocols were more recent but of lower methodological quality than those describing controlled active motion protocols. Participants treated with controlled active motion and relative motion extension splinting protocols had similar range of motion outcomes, but those in relative motion extension splinting groups returned to work earlier. The evidence reviewed suggested that relative motion extension splinting protocols may allow an earlier return to function than controlled active motion protocols without a greater risk of complication.

Task specific grip force control in writer's cramp.

PubMed

Schneider, A S; Fürholzer, W; Marquardt, C; Hermsdörfer, J

2014-04-01

Writer's cramp is defined as a task specific focal dystonia generating hypertonic muscle co-contractions during handwriting resulting in impaired writing performance and exaggerated finger force. However, little is known about the generalisation of grip force across tasks others than writing. The aim of the study was to directly compare regulation of grip forces during handwriting with force regulation in other fine-motor tasks in patients and control subjects. Handwriting, lifting and cyclic movements of a grasped object were investigated in 21 patients and 14 controls. The applied forces were registered in all three tasks and compared between groups and tasks. In addition, task-specific measures of fine-motor skill were assessed. As expected, patients generated exaggerated forces during handwriting compared to control subjects. However there were no statistically significant group differences during lifting and cyclic movements. The control group revealed a generalisation of grip forces across manual tasks whereas in patients there was no such correlation. We conclude that increased finger forces during handwriting are a task-specific phenomenon that does not necessarily generalise to other fine-motor tasks. Force control of patients with writer's cramp in handwriting and other fine-motor tasks is characterised by individualised control strategies. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Effectiveness and cost-effectiveness of fining non-attendance at public hospitals: a randomised controlled trial from Danish outpatient clinics.

PubMed

Blæhr, Emely Ek; Væggemose, Ulla; Søgaard, Rikke

2018-04-13

Fines have been proposed as means for reducing non-attendance in healthcare. The empirical evidence of the effect of fines is however limited. The objective of this study is to investigate the effectiveness and cost-effectiveness of fining non-attendance at outpatient clinics. 1:1 randomised controlled trial of appointments for an outpatient clinic, posted to Danish addresses, between 1 May 2015 and 30 November 2015. Only first appointment for users was included. Healthcare professionals and investigators were masked. A fine of DKK250 (€34) was issued for non-attendance. Users were informed about the fine in case of non-attendance by the appointment letter, and were able to reschedule or cancel until the appointment. A central administration office administered the fine system. The main outcome measures were non-attendance of non-cancelled appointments, fine policy administration costs, net of productivity consequences and probability of fining non-attendance being cost-effective over no fining for a range of hypothetical values of reduced non-attendance. All of the 6746 appointments included were analysed. Of the 3333 appointments randomised to the fine policy, 130 (5%) of non-cancelled appointments were unattended, and of the 3413 appointments randomised to no-fine policy, 131 (5%) were unattended. The cost per appointment of non-attendance was estimated at DKK 56 (SE 5) in the fine group and DKK47 (SE 4) in the no-fine group, leading to a non-statistically significant difference of DKK10 (95% CI -9 to 22) per appointment attributable to the fine policy. The probability of cost-effectiveness remained around 50%, irrespective of increased values of reduced non-attendance or various alternative assumptions used for sensitivity analyses. At a baseline level of around 5%, fining non-attendance does not seem to further reduce non-attendance. Future studies should focus on other means for reduction of non-attendance such as nudging or negative reinforcement. ISRCTN61925912. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effectiveness and cost-effectiveness of fining non-attendance at public hospitals: a randomised controlled trial from Danish outpatient clinics

PubMed Central

Væggemose, Ulla; Søgaard, Rikke

2018-01-01

Objectives Fines have been proposed as means for reducing non-attendance in healthcare. The empirical evidence of the effect of fines is however limited. The objective of this study is to investigate the effectiveness and cost-effectiveness of fining non-attendance at outpatient clinics. Design, participants and setting 1:1 randomised controlled trial of appointments for an outpatient clinic, posted to Danish addresses, between 1 May 2015 and 30 November 2015. Only first appointment for users was included. Healthcare professionals and investigators were masked. Intervention A fine of DKK250 (€34) was issued for non-attendance. Users were informed about the fine in case of non-attendance by the appointment letter, and were able to reschedule or cancel until the appointment. A central administration office administered the fine system. Main outcome measures The main outcome measures were non-attendance of non-cancelled appointments, fine policy administration costs, net of productivity consequences and probability of fining non-attendance being cost-effective over no fining for a range of hypothetical values of reduced non-attendance. Results All of the 6746 appointments included were analysed. Of the 3333 appointments randomised to the fine policy, 130 (5%) of non-cancelled appointments were unattended, and of the 3413 appointments randomised to no-fine policy, 131 (5%) were unattended. The cost per appointment of non-attendance was estimated at DKK 56 (SE 5) in the fine group and DKK47 (SE 4) in the no-fine group, leading to a non-statistically significant difference of DKK10 (95% CI –9 to 22) per appointment attributable to the fine policy. The probability of cost-effectiveness remained around 50%, irrespective of increased values of reduced non-attendance or various alternative assumptions used for sensitivity analyses. Conclusions At a baseline level of around 5%, fining non-attendance does not seem to further reduce non-attendance. Future studies should focus on other means for reduction of non-attendance such as nudging or negative reinforcement. Trial registration number ISRCTN61925912. PMID:29654019

Tuning the Slide-Roll Motion Mode of Carbon Nanotubes via Hydroxyl Groups

NASA Astrophysics Data System (ADS)

Li, Rui; Wang, Shiwei; Peng, Qing

2018-05-01

Controlling the motion of carbon nanotubes is critical in manipulating nanodevices, including nanorobots. Herein, we investigate the motion behavior of SWCNT (10,10) on Si substrate utilizing molecular dynamics simulations. We show that hydroxyl groups have sensitive effect on the carbon nanotube's motion mode. When the hydroxyl groups' ratio on carbon nanotube and silicon substrate surfaces is larger than 10 and 20%, respectively, the motion of carbon nanotube transforms from sliding to rolling. When the hydroxyl groups' ratio is smaller, the slide or roll mode can be controlled by the speed of carbon nanotube, which is ultimately determined by the competition between the interface potential energy and kinetic energy. The change of motion mode holds true for different carbon nanotubes with hydroxyl groups. The chirality has little effect on the motion behavior, as opposed to the diameter, attributed to the hydroxyl groups' ratio. Our study suggests a new route to control the motion behavior of carbon nanotube via hydroxyl groups.

Tuning the Slide-Roll Motion Mode of Carbon Nanotubes via Hydroxyl Groups.

PubMed

Li, Rui; Wang, Shiwei; Peng, Qing

2018-05-08

Controlling the motion of carbon nanotubes is critical in manipulating nanodevices, including nanorobots. Herein, we investigate the motion behavior of SWCNT (10,10) on Si substrate utilizing molecular dynamics simulations. We show that hydroxyl groups have sensitive effect on the carbon nanotube's motion mode. When the hydroxyl groups' ratio on carbon nanotube and silicon substrate surfaces is larger than 10 and 20%, respectively, the motion of carbon nanotube transforms from sliding to rolling. When the hydroxyl groups' ratio is smaller, the slide or roll mode can be controlled by the speed of carbon nanotube, which is ultimately determined by the competition between the interface potential energy and kinetic energy. The change of motion mode holds true for different carbon nanotubes with hydroxyl groups. The chirality has little effect on the motion behavior, as opposed to the diameter, attributed to the hydroxyl groups' ratio. Our study suggests a new route to control the motion behavior of carbon nanotube via hydroxyl groups.

M-Mode Ultrasound Reveals Earlier Gluteus Minimus Activity in Individuals With Chronic Hip Pain During a Step-down Task.

PubMed

Dieterich, Angela V; Deshon, Louise; Strauss, Geoffrey R; McKay, Jan; Pickard, Christine M

2016-04-01

Controlled laboratory study. The hip abductor muscles are important hip joint stabilizers. Hip joint pain may alter muscle recruitment. Motion-mode (M-mode) ultrasound enables noninvasive measurements of the onset of deep and superficial muscle motion, which is associated with activation onset. To compare (1) the onset of superficial and deep gluteus medius and gluteus minimus muscle motion relative to the instant of peak ground reaction force and (2) the level of swing-phase muscle motion during step-down between subjects with chronic hip pain and controls using M-mode ultrasound. Thirty-five subjects with anterior, nontraumatic hip pain for more than 6 months (mean ± SD age, 54 ± 9 years) and 35 controls (age, 57 ± 7 years) were scanned on the lateral hip of the leading leg during frontal step-down onto a force platform using M-mode ultrasound. Computerized motion detection with the Teager-Kaiser energy operator was applied on the gluteus minimus and the deep and superficial gluteus medius to determine the time lag between muscle motion onset and instant of peak ground reaction force and the level of gluteus minimus motion during the swing phase. Time lags and motion levels were averaged per subject, and t tests were used to determine between-group differences. In participants with hip pain, gluteus minimus motion onset was 103 milliseconds earlier (P = .002) and superficial gluteus medius motion was 70 milliseconds earlier (P = .047) than those in healthy control participants. The level of gluteus minimus swing-phase motion was higher with pain (P = .006). Increased gluteus minimus motion during the swing phase and earlier gluteus minimus and superficial gluteus medius motion in individuals with hip pain suggest an overall increase of muscle activity, possibly a protective behavior.

Differences in kinematic control of ankle joint motions in people with chronic ankle instability.

PubMed

Kipp, Kristof; Palmieri-Smith, Riann M

2013-06-01

People with chronic ankle instability display different ankle joint motions compared to healthy people. The purpose of this study was to investigate the strategies used to control ankle joint motions between a group of people with chronic ankle instability and a group of healthy, matched controls. Kinematic data were collected from 11 people with chronic ankle instability and 11 matched control subjects as they performed a single-leg land-and-cut maneuver. Three-dimensional ankle joint angles were calculated from 100 ms before, to 200 ms after landing. Kinematic control of the three rotational ankle joint degrees of freedom was investigated by simultaneously examining the three-dimensional co-variation of plantarflexion/dorsiflexion, toe-in/toe-out rotation, and inversion/eversion motions with principal component analysis. Group differences in the variance proportions of the first two principal components indicated that the angular co-variation between ankle joint motions was more linear in the control group, but more planar in the chronic ankle instability group. Frontal and transverse plane motions, in particular, contributed to the group differences in the linearity and planarity of angular co-variation. People with chronic ankle instability use a different kinematic control strategy to coordinate ankle joint motions during a single-leg landing task. Compared to the healthy group, the chronic ankle instability group's control strategy appeared to be more complex and involved joint-specific contributions that would tend to predispose this group to recurring episodes of instability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of a force-reflecting robotic platform for cardiac catheter navigation.

PubMed

Park, Jun Woo; Choi, Jaesoon; Pak, Hui-Nam; Song, Seung Joon; Lee, Jung Chan; Park, Yongdoo; Shin, Seung Min; Sun, Kyung

2010-11-01

Electrophysiological catheters are used for both diagnostics and clinical intervention. To facilitate more accurate and precise catheter navigation, robotic cardiac catheter navigation systems have been developed and commercialized. The authors have developed a novel force-reflecting robotic catheter navigation system. The system is a network-based master-slave configuration having a 3-degree of freedom robotic manipulator for operation with a conventional cardiac ablation catheter. The master manipulator implements a haptic user interface device with force feedback using a force or torque signal either measured with a sensor or estimated from the motor current signal in the slave manipulator. The slave manipulator is a robotic motion control platform on which the cardiac ablation catheter is mounted. The catheter motions-forward and backward movements, rolling, and catheter tip bending-are controlled by electromechanical actuators located in the slave manipulator. The control software runs on a real-time operating system-based workstation and implements the master/slave motion synchronization control of the robot system. The master/slave motion synchronization response was assessed with step, sinusoidal, and arbitrarily varying motion commands, and showed satisfactory performance with insignificant steady-state motion error. The current system successfully implemented the motion control function and will undergo safety and performance evaluation by means of animal experiments. Further studies on the force feedback control algorithm and on an active motion catheter with an embedded actuation mechanism are underway. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Detection of visual events along the apparent motion trace in patients with paranoid schizophrenia.

PubMed

Sanders, Lia Lira Olivier; Muckli, Lars; de Millas, Walter; Lautenschlager, Marion; Heinz, Andreas; Kathmann, Norbert; Sterzer, Philipp

2012-07-30

Dysfunctional prediction in sensory processing has been suggested as a possible causal mechanism in the development of delusions in patients with schizophrenia. Previous studies in healthy subjects have shown that while the perception of apparent motion can mask visual events along the illusory motion trace, such motion masking is reduced when events are spatio-temporally compatible with the illusion, and, therefore, predictable. Here we tested the hypothesis that this specific detection advantage for predictable target stimuli on the apparent motion trace is reduced in patients with paranoid schizophrenia. Our data show that, although target detection along the illusory motion trace is generally impaired, both patients and healthy control participants detect predictable targets more often than unpredictable targets. Patients had a stronger motion masking effect when compared to controls. However, patients showed the same advantage in the detection of predictable targets as healthy control subjects. Our findings reveal stronger motion masking but intact prediction of visual events along the apparent motion trace in patients with paranoid schizophrenia and suggest that the sensory prediction mechanism underlying apparent motion is not impaired in paranoid schizophrenia. Copyright © 2012. Published by Elsevier Ireland Ltd.

Content and structure of knowledge base used for virtual control of android arm motion in specified environment

NASA Astrophysics Data System (ADS)

Pritykin, F. N.; Nebritov, V. I.

2018-01-01

The paper presents the configuration of knowledge base necessary for intelligent control of android arm mechanism motion with different positions of certain forbidden regions taken into account. The present structure of the knowledge base characterizes the past experience of arm motion synthesis in the vector of velocities with due regard for the known obstacles. This structure also specifies its intrinsic properties. Knowledge base generation is based on the study of the arm mechanism instantaneous states implementations. Computational experiments connected with the virtual control of android arm motion with known forbidden regions using the developed knowledge base are introduced. Using the developed knowledge base to control virtually the arm motion reduces the time of test assignments calculation. The results of the research can be used in developing control systems of autonomous android robots in the known in advance environment.

Oil Motion Control by an Extra Pinning Structure in Electro-Fluidic Display.

PubMed

Dou, Yingying; Tang, Biao; Groenewold, Jan; Li, Fahong; Yue, Qiao; Zhou, Rui; Li, Hui; Shui, Lingling; Henzen, Alex; Zhou, Guofu

2018-04-06

Oil motion control is the key for the optical performance of electro-fluidic displays (EFD). In this paper, we introduced an extra pinning structure (EPS) into the EFD pixel to control the oil motion inside for the first time. The pinning structure canbe fabricated together with the pixel wall by a one-step lithography process. The effect of the relative location of the EPS in pixels on the oil motion was studied by a series of optoelectronic measurements. EPS showed good control of oil rupture position. The properly located EPS effectively guided the oil contraction direction, significantly accelerated switching on process, and suppressed oil overflow, without declining in aperture ratio. An asymmetrically designed EPS off the diagonal is recommended. This study provides a novel and facile way for oil motion control within an EFD pixel in both direction and timescale.

2D and 3D registration methods for dual-energy contrast-enhanced digital breast tomosynthesis

NASA Astrophysics Data System (ADS)

Lau, Kristen C.; Roth, Susan; Maidment, Andrew D. A.

2014-03-01

Contrast-enhanced digital breast tomosynthesis (CE-DBT) uses an iodinated contrast agent to image the threedimensional breast vasculature. The University of Pennsylvania is conducting a CE-DBT clinical study in patients with known breast cancers. The breast is compressed continuously and imaged at four time points (1 pre-contrast; 3 postcontrast). A hybrid subtraction scheme is proposed. First, dual-energy (DE) images are obtained by a weighted logarithmic subtraction of the high-energy and low-energy image pairs. Then, post-contrast DE images are subtracted from the pre-contrast DE image. This hybrid temporal subtraction of DE images is performed to analyze iodine uptake, but suffers from motion artifacts. Employing image registration further helps to correct for motion, enhancing the evaluation of vascular kinetics. Registration using ANTS (Advanced Normalization Tools) is performed in an iterative manner. Mutual information optimization first corrects large-scale motions. Normalized cross-correlation optimization then iteratively corrects fine-scale misalignment. Two methods have been evaluated: a 2D method using a slice-by-slice approach, and a 3D method using a volumetric approach to account for out-of-plane breast motion. Our results demonstrate that iterative registration qualitatively improves with each iteration (five iterations total). Motion artifacts near the edge of the breast are corrected effectively and structures within the breast (e.g. blood vessels, surgical clip) are better visualized. Statistical and clinical evaluations of registration accuracy in the CE-DBT images are ongoing.

Neural network-based motion control of an underactuated wheeled inverted pendulum model.

PubMed

Yang, Chenguang; Li, Zhijun; Cui, Rongxin; Xu, Bugong

2014-11-01

In this paper, automatic motion control is investigated for one of wheeled inverted pendulum (WIP) models, which have been widely applied for modeling of a large range of two wheeled modern vehicles. First, the underactuated WIP model is decomposed into a fully actuated second order subsystem Σa consisting of planar movement of vehicle forward and yaw angular motions, and a nonactuated first order subsystem Σb of pendulum motion. Due to the unknown dynamics of subsystem Σa and the universal approximation ability of neural network (NN), an adaptive NN scheme has been employed for motion control of subsystem Σa . The model reference approach has been used whereas the reference model is optimized by the finite time linear quadratic regulation technique. The pendulum motion in the passive subsystem Σb is indirectly controlled using the dynamic coupling with planar forward motion of subsystem Σa , such that satisfactory tracking of a set pendulum tilt angle can be guaranteed. Rigours theoretic analysis has been established, and simulation studies have been performed to demonstrate the developed method.

Inertial Sensor-Based Touch and Shake Metaphor for Expressive Control of 3D Virtual Avatars

PubMed Central

Patil, Shashidhar; Chintalapalli, Harinadha Reddy; Kim, Dubeom; Chai, Youngho

2015-01-01

In this paper, we present an inertial sensor-based touch and shake metaphor for expressive control of a 3D virtual avatar in a virtual environment. An intuitive six degrees-of-freedom wireless inertial motion sensor is used as a gesture and motion control input device with a sensor fusion algorithm. The algorithm enables user hand motions to be tracked in 3D space via magnetic, angular rate, and gravity sensors. A quaternion-based complementary filter is implemented to reduce noise and drift. An algorithm based on dynamic time-warping is developed for efficient recognition of dynamic hand gestures with real-time automatic hand gesture segmentation. Our approach enables the recognition of gestures and estimates gesture variations for continuous interaction. We demonstrate the gesture expressivity using an interactive flexible gesture mapping interface for authoring and controlling a 3D virtual avatar and its motion by tracking user dynamic hand gestures. This synthesizes stylistic variations in a 3D virtual avatar, producing motions that are not present in the motion database using hand gesture sequences from a single inertial motion sensor. PMID:26094629

On the Motions of an Oscillating System Under the Influence of Flip-Flop Controls

NASA Technical Reports Server (NTRS)

Fluegge-Lotz, I.; Klotter, K.

1949-01-01

So-called flip-flop controls (also called "on-off-course controls") are frequently preferred to continuous controls because of their simple construction. Thus they are used also for the steering control of airplanes. Such a body possesses-even if one thinks, for instance, only of the symmetric longitudinal motion - three degrees of freedom so that a study of its motions under the influence of an intermittent control is at least lengthy. Thus, it is suggested that an investigation of the basic effect of such a control first be made on a system with one degree of freedom. Furthermore, we limit ourselves in the resent report to the investigation of an "ideal" control where the control surface immediately obeys the command given by the "steering control function". Thus the oscillation properties of the control surface and the defects in linkage, sensing element, and mixing device are, at first, neglected. As long as the deviations from the "ideal" control may be neglected in practice, also the motion of the control surface takes place at the heat of the motion of the principal system. The aim of our investigation is to obtain a survey of the influence of the system and control coefficients on the damping behavior which is to be attained.

Development of Skylab experiment T-013 crew/vehicle disturbances

NASA Technical Reports Server (NTRS)

Conway, B. A.; Woolley, C. T.; Kurzhals, P. R.; Reynolds, R. B.

1972-01-01

A Skylab experiment to determine the characteristics and effects of crew-motion disturbances was developed. The experiment will correlate data from histories of specified astronaut body motions, the disturbance forces and torques produced by these motions, and the resultant spacecraft control system response to the disturbances. Primary application of crew-motion disturbance data will be to the sizing and design of future manned spacecraft control and stabilization systems. The development of the crew/vehicle disturbances experiment is described, and a mathematical model of human body motion which may be used for analysis of a variety of man-motion activities is derived.

Effect of percentage baghouse fines on the amount and type of anti-stripping agent required to control moisture sensitivity : final report.

DOT National Transportation Integrated Search

2003-06-30

This study investigated the effect of moisture and amount of baghouse fines on AC mixes. Two : types of baghouse fines, each with a different gradation, were used in varying concentrations to prepare : laboratory samples. The binder used was PG64-22 ...

Helping Preschoolers Prepare for Writing: Developing Fine Motor Skills

ERIC Educational Resources Information Center

Huffman, J. Michelle; Fortenberry, Callie

2011-01-01

Early childhood is the most intensive period for the development of physical skills. Writing progress depends largely on the development of fine motor skills involving small muscle movements of the hand. Young children need to participate in a variety of developmentally appropriate activities intentionally designed to promote fine motor control.…

Explorations in Aeolian Ecology: Radar and Visual Studies of the Aerofauna during the Convection and Precipitation/electrification (cape) Experiment.

NASA Astrophysics Data System (ADS)

Russell, Robert William

I studied the ecology of aerial insects and birds (the "aerofauna") during the Convection and Precipitation/Electrification (CaPE) Experiment in Florida during the summer of 1991. Visual observations were coordinated with simultaneous measurements of atmospheric motions, permitting novel explorations of: (1) patterns and processes in the distribution of "aerial plankton" (i.e., small, weakly flying insects that drift with boundary-layer winds); (2) the feeding ecology of "aerial planktivores" (i.e., predators that feed on aerial plankton); and (3) the flight tactics of soaring birds. Sensitive Doppler radars regularly detected fine lines of enhanced reflectivity in boundary-layer convergence zones. These "fine lines" were attributable to dense concentrations of aerial plankton entrained by the convergent airflow. Insect densities were inferred to be about an order of magnitude higher inside convergence zones then elsewhere. Anecdotal observations suggested that large quantities of aerial plankton entrained in convergence zones were sometimes "scrubbed" from the boundary layer by precipitation. Radar images clearly depicted the rapid aeolian transport of aerial plankton across the landscape, but also showed that densities of aerial plankton became concentrated along coastlines when winds blew toward the sea. In contrast, airspace over the adjacent ocean remained largely free of radar echoes under all wind conditions. The coastal concentrations, together with the absence of overwater echoes, indicate that the organisms comprising the aerial plankton respond behaviorally to coastlines to avoid being blown out to sea. Several species of aerial insectivorous predators commonly exploited boundary-layer fine lines as food resources. Chimney swifts (Chaetura pelagica), barn swallows (Hirundo rustica), and wandering gliders (Pantala flavescens) showed significant responses to fine lines. Details of these responses differed, but this variation clearly reflected species-specific behavioral constraints and life-history characteristics. Vertical airflows were predictably enhanced in convergence lines, and soaring birds, which require ascending air to employ their preferred mode of flight, appeared to use these lines as aerial corridors for cross-country travel. Theoretical analyses showed that convergence lines can be profitably exploited under a wide variety of circumstances. The results presented here indicate that sensitive Doppler radars capable of detecting clear-air motions offer tremendous potential as research platforms for future studies of the "aerofauna.".

Local position control: A new concept for control of manipulators

NASA Technical Reports Server (NTRS)

Kelly, Frederick A.

1988-01-01

Resolved motion rate control is currently one of the most frequently used methods of manipulator control. It is currently used in the Space Shuttle remote manipulator system (RMS) and in prosthetic devices. Position control is predominately used in locating the end-effector of an industrial manipulator along a path with prescribed timing. In industrial applications, resolved motion rate control is inappropriate since position error accumulates. This is due to velocity being the control variable. In some applications this property is an advantage rather than a disadvantage. It may be more important for motion to end as soon as the input command is removed rather than reduce the position error to zero. Local position control is a new concept for manipulator control which retains the important properties of resolved motion rate control, but reduces the drift. Local position control can be considered to be a generalization of resolved position and resolved rate control. It places both control schemes on a common mathematical basis.

Multimodal Perception and Multicriterion Control of Nested Systems. 1; Coordination of Postural Control and Vehicular Control

NASA Technical Reports Server (NTRS)

Riccio, Gary E.; McDonald, P. Vernon

1998-01-01

The purpose of this report is to identify the essential characteristics of goal-directed whole-body motion. The report is organized into three major sections (Sections 2, 3, and 4). Section 2 reviews general themes from ecological psychology and control-systems engineering that are relevant to the perception and control of whole-body motion. These themes provide an organizational framework for analyzing the complex and interrelated phenomena that are the defining characteristics of whole-body motion. Section 3 of this report applies the organization framework from the first section to the problem of perception and control of aircraft motion. This is a familiar problem in control-systems engineering and ecological psychology. Section 4 examines an essential but generally neglected aspect of vehicular control: coordination of postural control and vehicular control. To facilitate presentation of this new idea, postural control and its coordination with vehicular control are analyzed in terms of conceptual categories that are familiar in the analysis of vehicular control.

List-mode reconstruction for the Biograph mCT with physics modeling and event-by-event motion correction

NASA Astrophysics Data System (ADS)

Jin, Xiao; Chan, Chung; Mulnix, Tim; Panin, Vladimir; Casey, Michael E.; Liu, Chi; Carson, Richard E.

2013-08-01

Whole-body PET/CT scanners are important clinical and research tools to study tracer distribution throughout the body. In whole-body studies, respiratory motion results in image artifacts. We have previously demonstrated for brain imaging that, when provided with accurate motion data, event-by-event correction has better accuracy than frame-based methods. Therefore, the goal of this work was to develop a list-mode reconstruction with novel physics modeling for the Siemens Biograph mCT with event-by-event motion correction, based on the MOLAR platform (Motion-compensation OSEM List-mode Algorithm for Resolution-Recovery Reconstruction). Application of MOLAR for the mCT required two algorithmic developments. First, in routine studies, the mCT collects list-mode data in 32 bit packets, where averaging of lines-of-response (LORs) by axial span and angular mashing reduced the number of LORs so that 32 bits are sufficient to address all sinogram bins. This degrades spatial resolution. In this work, we proposed a probabilistic LOR (pLOR) position technique that addresses axial and transaxial LOR grouping in 32 bit data. Second, two simplified approaches for 3D time-of-flight (TOF) scatter estimation were developed to accelerate the computationally intensive calculation without compromising accuracy. The proposed list-mode reconstruction algorithm was compared to the manufacturer's point spread function + TOF (PSF+TOF) algorithm. Phantom, animal, and human studies demonstrated that MOLAR with pLOR gives slightly faster contrast recovery than the PSF+TOF algorithm that uses the average 32 bit LOR sinogram positioning. Moving phantom and a whole-body human study suggested that event-by-event motion correction reduces image blurring caused by respiratory motion. We conclude that list-mode reconstruction with pLOR positioning provides a platform to generate high quality images for the mCT, and to recover fine structures in whole-body PET scans through event-by-event motion correction.

List-mode Reconstruction for the Biograph mCT with Physics Modeling and Event-by-Event Motion Correction

PubMed Central

Jin, Xiao; Chan, Chung; Mulnix, Tim; Panin, Vladimir; Casey, Michael E.; Liu, Chi; Carson, Richard E.

2013-01-01

Whole-body PET/CT scanners are important clinical and research tools to study tracer distribution throughout the body. In whole-body studies, respiratory motion results in image artifacts. We have previously demonstrated for brain imaging that, when provided accurate motion data, event-by-event correction has better accuracy than frame-based methods. Therefore, the goal of this work was to develop a list-mode reconstruction with novel physics modeling for the Siemens Biograph mCT with event-by-event motion correction, based on the MOLAR platform (Motion-compensation OSEM List-mode Algorithm for Resolution-Recovery Reconstruction). Application of MOLAR for the mCT required two algorithmic developments. First, in routine studies, the mCT collects list-mode data in 32-bit packets, where averaging of lines of response (LORs) by axial span and angular mashing reduced the number of LORs so that 32 bits are sufficient to address all sinogram bins. This degrades spatial resolution. In this work, we proposed a probabilistic assignment of LOR positions (pLOR) that addresses axial and transaxial LOR grouping in 32-bit data. Second, two simplified approaches for 3D TOF scatter estimation were developed to accelerate the computationally intensive calculation without compromising accuracy. The proposed list-mode reconstruction algorithm was compared to the manufacturer's point spread function + time-of-flight (PSF+TOF) algorithm. Phantom, animal, and human studies demonstrated that MOLAR with pLOR gives slightly faster contrast recovery than the PSF+TOF algorithm that uses the average 32-bit LOR sinogram positioning. Moving phantom and a whole-body human study suggested that event-by-event motion correction reduces image blurring caused by respiratory motion. We conclude that list-mode reconstruction with pLOR positioning provides a platform to generate high quality images for the mCT, and to recover fine structures in whole-body PET scans through event-by-event motion correction. PMID:23892635

Observing Mode Attitude Controller for the Lunar Reconnaissance Orbiter

NASA Technical Reports Server (NTRS)

Calhourn, Philip C.; Garrick, Joseph C.

2007-01-01

The Lunar Reconnaissance Orbiter (LRO) mission is the first of a series of lunar robotic spacecraft scheduled for launch in Fall 2008. LRO will spend at least one year in a low altitude polar orbit around the Moon, collecting lunar environment science and mapping data to enable future human exploration. The LRO employs a 3-axis stabilized attitude control system (ACS) whose primary control mode, the "Observing mode", provides Lunar Nadir, off-Nadir, and Inertial fine pointing for the science data collection and instrument calibration. The controller combines the capability of fine pointing with that of on-demand large angle full-sky attitude reorientation into a single ACS mode, providing simplicity of spacecraft operation as well as maximum flexibility for science data collection. A conventional suite of ACS components is employed in this mode to meet the pointing and control objectives. This paper describes the design and analysis of the primary LRO fine pointing and attitude re-orientation controller function, known as the "Observing mode" of the ACS subsystem. The control design utilizes quaternion feedback, augmented with a unique algorithm that ensures accurate Nadir tracking during large angle yaw maneuvers in the presence of high system momentum and/or maneuver rates. Results of system stability analysis and Monte Carlo simulations demonstrate that the observing mode controller can meet fine pointing and maneuver performance requirements.

Language Acquisition and Categorical Perception with Particular Reference to /r/ and /1/.

ERIC Educational Resources Information Center

Perecman, Ellen; Kellar, Lucia A.

1983-01-01

Examines the relationship between the development of fine motor control for articulation and the development of fine motor control in other muscle systems. Discusses whether the late appearance of /r/ and /1/ is due to the fact that their articulation requires finer motor coordination than other classes of sounds. (EKN)

The Influence of Motion Cues on Driver-Vehicle Performance in a Simulator

NASA Technical Reports Server (NTRS)

Repa, B. S.; Leucht, P. M.; Wierwille, W. W.

1981-01-01

Four different motion base configurations were studied on driving simulator. Differently responding vehicles were simulated on each motion configurations and the effects of the vehicle characteristics on driver vehicle system performance, driver control activity, and driver opinion ratings of vehicle performance during driving are compared for different motion configurations. Data show that: (1)) the effects of changes in vehicle characteristics on the different objective and subjective measures of driver vehicle performance are not disguised by the lack of physical motion; (2) fixed base simulator can be used to draw inferences despite the lack of motion; (3) the presence of motion tends to reduce path keeping errors and driver control activity; (4) roll and yaw motions are recommended because of their marked influence on driver vehicle performance (5) the importance of motion increases as the driving maneuvers become more extreme.

Dual-Arm Generalized Compliant Motion With Shared Control

NASA Technical Reports Server (NTRS)

Backes, Paul G.

1994-01-01

Dual-Arm Generalized Compliant Motion (DAGCM) primitive computer program implementing improved unified control scheme for two manipulator arms cooperating in task in which both grasp same object. Provides capabilities for autonomous, teleoperation, and shared control of two robot arms. Unifies cooperative dual-arm control with multi-sensor-based task control and makes complete task-control capability available to higher-level task-planning computer system via large set of input parameters used to describe desired force and position trajectories followed by manipulator arms. Some concepts discussed in "A Generalized-Compliant-Motion Primitive" (NPO-18134).

Intermediate Cognitive Phenotypes in Bipolar Disorder

PubMed Central

Langenecker, Scott A.; Saunders, Erika F.H.; Kade, Allison M.; Ransom, Michael T.; McInnis, Melvin G.

2013-01-01

Background Intermediate cognitive phenotypes (ICPs) are measurable and quantifiable states that may be objectively assessed in a standardized method, and can be integrated into association studies, including genetic, biochemical, clinical, and imaging based correlates. The present study used neuropsychological measures as ICPs, with factor scores in executive functioning, attention, memory, fine motor function, and emotion processing, similar to prior work in schizophrenia. Methods Healthy control subjects (HC, n=34) and euthymic (E, n=66), depressed (D, n=43), or hypomanic/mixed (HM, n=13) patients with bipolar disorder (BD) were assessed with neuropsychological tests. These were from eight domains consistent with previous literature; auditory memory, visual memory, processing speed with interference resolution, verbal fluency and processing speed, conceptual reasoning and set-shifting, inhibitory control, emotion processing, and fine motor dexterity. Results Of the eight factor scores, the HC group outperformed the E group in three (Processing Speed with Interference Resolution, Visual Memory, Fine Motor Dexterity), the D group in seven (all except Inhibitory Control), and the HM group in four (Inhibitory Control, Processing Speed with Interference Resolution, Fine Motor Dexterity, and Auditory Memory). Limitations The HM group was relatively small, thus effects of this phase of illness may have been underestimated. Effects of medication could not be fully controlled without a randomized, double-blind, placebo-controlled study. Conclusions Use of the factor scores can assist in determining ICPs for BD and related disorders, and may provide more specific targets for development of new treatments. We highlight strong ICPs (Processing Speed with Interference Resolution, Visual Memory, Fine Motor Dexterity) for further study, consistent with the existing literature. PMID:19800130

Effects of inhaled fine dust on lung tissue changes and antibody response induced by spores of opportunistic fungi in goats.

PubMed

Purdy, Charles W; Layton, Robert C; Straus, David C; Ayers, J R

2008-04-01

To investigate the effects of sterile fine dust aerosol inhalation on antibody responses and lung tissue changes induced by Mucor ramosissimus or Trichoderma viride spores following intratracheal inoculation in goats. 36 weanling Boer-Spanish goats. 6 goats were allocated to each of 2 M ramosissimus-inoculated groups, 2 T viride-inoculated groups, and 2 control (tent or pen) groups. One of each pair of sporetreated groups and the tent control group were exposed 7 times to sterilized fine feedyard dust (mean+/-SD particle diameter, <7.72+/-0.69 microm) for 4 hours in a specially constructed tent. Goats in the 4 fungal treatment groups were inoculated intratracheally 5 times with a fungal spore preparation (30 mL), whereas tent control goats were intratracheally inoculated with physiologic saline (0.9% NaCl) solution (30 mL). Pen control goats were not inoculated or exposed to dust. Goats received an IV challenge with equine RBCs to assess antibody responses to foreign antigens. Postmortem examinations were performed at study completion (day 68) to evaluate lung tissue lesions. 5 of 7 deaths occurred between days 18 and 45 and were attributed to fine dust exposures prior to fungal treatments. Fine dust inhalation induced similar lung lesions and precipitating antibodies among spore-treated goats. Following spore inoculations, dust-exposed goats had significantly more spores per gram of consolidated lung tissue than did their nonexposed counterparts. Fine dust inhalation appeared to decrease the ability of goats to successfully clear fungal spores from the lungs following intratracheal inoculation.

The 3D Human Motion Control Through Refined Video Gesture Annotation

NASA Astrophysics Data System (ADS)

Jin, Yohan; Suk, Myunghoon; Prabhakaran, B.

In the beginning of computer and video game industry, simple game controllers consisting of buttons and joysticks were employed, but recently game consoles are replacing joystick buttons with novel interfaces such as the remote controllers with motion sensing technology on the Nintendo Wii [1] Especially video-based human computer interaction (HCI) technique has been applied to games, and the representative game is 'Eyetoy' on the Sony PlayStation 2. Video-based HCI technique has great benefit to release players from the intractable game controller. Moreover, in order to communicate between humans and computers, video-based HCI is very crucial since it is intuitive, easy to get, and inexpensive. On the one hand, extracting semantic low-level features from video human motion data is still a major challenge. The level of accuracy is really dependent on each subject's characteristic and environmental noises. Of late, people have been using 3D motion-capture data for visualizing real human motions in 3D space (e.g, 'Tiger Woods' in EA Sports, 'Angelina Jolie' in Bear-Wolf movie) and analyzing motions for specific performance (e.g, 'golf swing' and 'walking'). 3D motion-capture system ('VICON') generates a matrix for each motion clip. Here, a column is corresponding to a human's sub-body part and row represents time frames of data capture. Thus, we can extract sub-body part's motion only by selecting specific columns. Different from low-level feature values of video human motion, 3D human motion-capture data matrix are not pixel values, but is closer to human level of semantics.

Final Report: CNC Micromachines LDRD No.10793

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

JOKIEL JR., BERNHARD; BENAVIDES, GILBERT L.; BIEG, LOTHAR F.

2003-04-01

The three-year LDRD ''CNC Micromachines'' was successfully completed at the end of FY02. The project had four major breakthroughs in spatial motion control in MEMS: (1) A unified method for designing scalable planar and spatial on-chip motion control systems was developed. The method relies on the use of parallel kinematic mechanisms (PKMs) that when properly designed provide different types of motion on-chip without the need for post-fabrication assembly, (2) A new type of actuator was developed--the linear stepping track drive (LSTD) that provides open loop linear position control that is scalable in displacement, output force and step size. Several versionsmore » of this actuator were designed, fabricated and successfully tested. (3) Different versions of XYZ translation only and PTT motion stages were designed, successfully fabricated and successfully tested demonstrating absolutely that on-chip spatial motion control systems are not only possible, but are a reality. (4) Control algorithms, software and infrastructure based on MATLAB were created and successfully implemented to drive the XYZ and PTT motion platforms in a controlled manner. The control software is capable of reading an M/G code machine tool language file, decode the instructions and correctly calculate and apply position and velocity trajectories to the motion devices linear drive inputs to position the device platform along the trajectory as specified by the input file. A full and detailed account of design methodology, theory and experimental results (failures and successes) is provided.« less

Analysis and decoupling control of a permanent magnet spherical actuator.

PubMed

Zhang, Liang; Chen, Weihai; Liu, Jingmeng; Wu, Xingming

2013-12-01

This paper presents the analysis and decoupling control of a spherical actuator, which is capable of performing three degree-of-freedom motion in one joint. The proposed actuator consists of a rotor with multiple PM (Permanent Magnet) poles in a circle and a stator with circumferential coils in three layers. Based on this actuator design, a decoupling control approach is developed. Unlike existing control methods that each coil is responsible for both the spinning and tilting motion, the proposed control strategy specifies the function of each coil. Specifically, the spinning motion is governed by the middle layer coils with a step control approach; while the tilting motion is regulated by upper and lower coils with a computed torque control method. Experiments have been conducted on the prototype to verify the validity of the design procedure, and the experimental results demonstrate the effectiveness of the analysis and control strategy.

Motion and force control for multiple cooperative manipulators

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz, Kenneth

1989-01-01

The motion and force control of multiple robot arms manipulating a commonly held object is addressed. A general control paradigm that decouples the motion and force control problems is introduced. For motion control, there are three natural choices: (1) joint torques, (2) arm-tip force vectors, and (3) the acceleration of a generalized coordinate. Choice (1) allows a class of relatively model-independent control laws by exploiting the Hamiltonian structure of the open-loop system; (2) and (3) require the full model information but produce simpler problems. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, the allocation of the desired end-effector control force to the joint actuators can be optimized; otherwise the internal force can be controlled about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

Slewing maneuvers and vibration control of space structures by feedforward/feedback moment-gyro controls

NASA Technical Reports Server (NTRS)

Yang, Li-Farn; Mikulas, Martin M., Jr.; Park, K. C.; Su, Renjeng

1993-01-01

This paper presents a moment-gyro control approach to the maneuver and vibration suppression of a flexible truss arm undergoing a constant slewing motion. The overall slewing motion is triggered by a feedforward input, and a companion feedback controller is employed to augment the feedforward input and subsequently to control vibrations. The feedforward input for the given motion requirement is determined from the combined CMG (Control Momentum Gyro) devices and the desired rigid-body motion. The rigid-body dynamic model has enabled us to identify the attendant CMG momentum saturation constraints. The task for vibration control is carried out in two stages; first in the search of a suitable CMG placement along the beam span for various slewing maneuvers, and subsequently in the development of Liapunov-based control algorithms for CMG spin-stabilization. Both analytical and numerical results are presented to show the effectiveness of the present approach.

Time evolution of fine structures in the solar chromosphere.

NASA Astrophysics Data System (ADS)

Tsiropoula, G.; Alissandrakis, C. E.; Schmieder, B.

1994-10-01

We have studied the temporal evolution of two quiet chromospheric regions, one with a typical rosette and another with chains of mottles at the junction of three supergranules. The observations were obtained during 15 minutes with the Multichannel Subtractive Double Pass spectrograph (MSDP) operating in Hα at the Pic du Midi Observatory. We derived intensity maps and Doppler shift velocities at different wavelengths along the Hα profile over a two dimensional field of view. The observed contrast profiles were matched with theoretical contrast profiles using Beckers' cloud model for a more accurate determination of the line of sight velocity. A statistical analysis with cross correlation functions showed that the fine structures were stable in intensity over the observation period (15 min), but the line of sight velocity showed important changes within a few minutes. A detailed analysis of the velocities along the axes of dark mottles showed that the predominant pattern of bulk motion is that of downflow at their footpoints and alternating phases of upflow and downflow at their tops. This motion is consistent with Pikel'ner's model for spicules, which attributes this pattern to the reconnection of opposite magnetic filed lines. This picture is also consistent with the velocity reversals with time observed in spicules and may be associated to the systematic downflows observed in the transition region. Doppler shift velocities in dark mottles are too low compared to those derived with the cloud model; the latter are comparable to those reported for spicules, strengthening the view that these structures are identical.

Real-time physics-based 3D biped character animation using an inverted pendulum model.

PubMed

Tsai, Yao-Yang; Lin, Wen-Chieh; Cheng, Kuangyou B; Lee, Jehee; Lee, Tong-Yee

2010-01-01

We present a physics-based approach to generate 3D biped character animation that can react to dynamical environments in real time. Our approach utilizes an inverted pendulum model to online adjust the desired motion trajectory from the input motion capture data. This online adjustment produces a physically plausible motion trajectory adapted to dynamic environments, which is then used as the desired motion for the motion controllers to track in dynamics simulation. Rather than using Proportional-Derivative controllers whose parameters usually cannot be easily set, our motion tracking adopts a velocity-driven method which computes joint torques based on the desired joint angular velocities. Physically correct full-body motion of the 3D character is computed in dynamics simulation using the computed torques and dynamical model of the character. Our experiments demonstrate that tracking motion capture data with real-time response animation can be achieved easily. In addition, physically plausible motion style editing, automatic motion transition, and motion adaptation to different limb sizes can also be generated without difficulty.

Structured Kernel Subspace Learning for Autonomous Robot Navigation.

PubMed

Kim, Eunwoo; Choi, Sungjoon; Oh, Songhwai

2018-02-14

This paper considers two important problems for autonomous robot navigation in a dynamic environment, where the goal is to predict pedestrian motion and control a robot with the prediction for safe navigation. While there are several methods for predicting the motion of a pedestrian and controlling a robot to avoid incoming pedestrians, it is still difficult to safely navigate in a dynamic environment due to challenges, such as the varying quality and complexity of training data with unwanted noises. This paper addresses these challenges simultaneously by proposing a robust kernel subspace learning algorithm based on the recent advances in nuclear-norm and l 1 -norm minimization. We model the motion of a pedestrian and the robot controller using Gaussian processes. The proposed method efficiently approximates a kernel matrix used in Gaussian process regression by learning low-rank structured matrix (with symmetric positive semi-definiteness) to find an orthogonal basis, which eliminates the effects of erroneous and inconsistent data. Based on structured kernel subspace learning, we propose a robust motion model and motion controller for safe navigation in dynamic environments. We evaluate the proposed robust kernel learning in various tasks, including regression, motion prediction, and motion control problems, and demonstrate that the proposed learning-based systems are robust against outliers and outperform existing regression and navigation methods.

Head motion parameters in fMRI differ between patients with mild cognitive impairment and Alzheimer disease versus elderly control subjects.

PubMed

Haller, Sven; Monsch, Andreas U; Richiardi, Jonas; Barkhof, Frederik; Kressig, Reto W; Radue, Ernst W

2014-11-01

Motion artifacts are a well-known and frequent limitation during neuroimaging workup of cognitive decline. While head motion typically deteriorates image quality, we test the hypothesis that head motion differs systematically between healthy controls (HC), amnestic mild cognitive impairment (aMCI) and Alzheimer disease (AD) and consequently might contain diagnostic information. This prospective study was approved by the local ethics committee and includes 28 HC (age 71.0 ± 6.9 years, 18 females), 15 aMCI (age 67.7 ± 10.9 years, 9 females) and 20 AD (age 73.4 ± 6.8 years, 10 females). Functional magnetic resonance imaging (fMRI) at 3T included a 9 min echo-planar imaging sequence with 180 repetitions. Cumulative average head rotation and translation was estimated based on standard fMRI preprocessing and compared between groups using receiver operating characteristic statistics. Global cumulative head rotation discriminated aMCI from controls [p < 0.01, area under curve (AUC) 0.74] and AD from controls (p < 0.01, AUC 0.73). The ratio of rotation z versus y discriminated AD from controls (p < 0.05, AUC 0.71) and AD from aMCI (p < 0.05, AUC of 0.75). Head motion systematically differs between aMCI/AD and controls. Since motion is not random but convoluted with diagnosis, the higher amount of motion in aMCI and AD as compared to controls might be a potential confounding factor for fMRI group comparisons. Additionally, head motion not only deteriorates image quality, yet also contains useful discriminatory information and is available for free as a "side product" of fMRI data preprocessing.

Relationships between fine root dynamics and nitrogen availability in Michigan northern hardwood forests

Treesearch

A. J. Burton; K. S. Pregitzer; R. L. Hendrick

2000-01-01

Minirhizotrons were used to observe fine root (≤1 mm) production, mortality, and longevity over 2 years in four sugar-maple-dominated northern hardwood forests located along a latitudinal temperature gradient. The sites also differed in N availability, allowing us to assess the relative influences of soil temperature and N availability in controlling fine...

Resolved motion rate and resolved acceleration servo-control of wheeled mobile robots

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

Muir, P.F.; Neuman, C.P.; Carnegie-Mellon Univ., Pittsburgh, PA

1989-01-01

Accurate motion control of wheeled mobile robots (WMRs) is required for their application to autonomous, semi-autonomous and teleoperated tasks. The similarities between WMRs and stationary manipulators suggest that current, successful, model-based manipulator control algorithms may be applied to WMRs. Special characteristics of WMRs including higher-pairs, closed-chains, friction and unactuated and unsensed joints require innovative modeling methodologies. The WMR modeling challenge has been recently overcome, thus enabling the application of manipulator control algorithms to WMRs. This realization lays the foundation for significant technology transfer from manipulator control to WMR control. We apply two Cartesian-space manipulator control algorithms: resolved motion rate (kinematics-based)more » and resolved acceleration (dynamics-based) control to WMR servo-control. We evaluate simulation studies of two exemplary WMRs: Uranus (a three degree-of-freedom WMR constructed at Carnegie Mellon University), and Bicsun-Bicas (a two degree-of-freedom WMR being constructed at Sandia National Laboratories) under the control of these algorithms. Although resolved motion rate servo-control is adequate for the control of Uranus, resolved acceleration servo-control is required for the control of the mechanically simpler Bicsun-Bicas because it exhibits more dynamic coupling and nonlinearities. Successful accurate motion control of these WMRs in simulation is driving current experimental research studies. 18 refs., 7 figs., 5 tabs.« less

Fatal Wounds by "Manja" to a Motorbike Rider in Motion.

PubMed

Borkar, Jaydeo Laxman; Tumram, Nilesh Keshav; Ambade, Vipul Namdeorao; Dixit, Pradeep Gangadhar

2015-07-01

"Kite fights" are quite popular throughout Asia. Most kite variations, including the fighter kites of India, Pakistan, and Japan, are small, flat, roughly diamond-shaped kites composed of paper, with a tapered bamboo spine and a balanced bow. They are flown with the help of a "Manja," which is a thread made of cotton or nylon, and coated with fine glass powder using glue and other chemical adhesives to cut down opponent's kite string. The nylon "Manja" is particularly more dangerous, as it not only cuts down opponent's kite string but also causes bodily injuries to humans, which may be at times fatal. The pattern of injuries by Manja is underreported in literature. In the present case, the deceased had encountered fatal injuries by "Manja" while riding on his motorbike. This case discusses the pattern of injuries caused by Manja when the victims are in motion on their two-wheelers. © 2015 American Academy of Forensic Sciences.

A zero phase adaptive fuzzy Kalman filter for physiological tremor suppression in robotically assisted minimally invasive surgery.

PubMed

Sang, Hongqiang; Yang, Chenghao; Liu, Fen; Yun, Jintian; Jin, Guoguang; Chen, Fa

2016-12-01

Hand physiological tremor of surgeons can cause vibration at the surgical instrument tip, which may make it difficult for the surgeon to perform fine manipulations of tissue, needles, and sutures. A zero phase adaptive fuzzy Kalman filter (ZPAFKF) is proposed to suppress hand tremor and vibration of a robotic surgical system. The involuntary motion can be reduced by adding a compensating signal that has the same magnitude and frequency but opposite phase with the tremor signal. Simulations and experiments using different filters were performed. Results show that the proposed filter can avoid the loss of useful motion information and time delay, and better suppress minor and varying tremor. The ZPAFKF can provide less error, preferred accuracy, better tremor estimation, and more desirable compensation performance, to suppress hand tremor and decrease vibration at the surgical instrument tip. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Running SW4 On New Commodity Technology Systems (CTS-1) Platform

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

Rodgers, Arthur J.; Petersson, N. Anders; Pitarka, Arben

We have recently been running earthquake ground motion simulations with SW4 on the new capacity computing systems, called the Commodity Technology Systems - 1 (CTS-1) at Lawrence Livermore National Laboratory (LLNL). SW4 is a fourth order time domain finite difference code developed by LLNL and distributed by the Computational Infrastructure for Geodynamics (CIG). SW4 simulates seismic wave propagation in complex three-dimensional Earth models including anelasticity and surface topography. We are modeling near-fault earthquake strong ground motions for the purposes of evaluating the response of engineered structures, such as nuclear power plants and other critical infrastructure. Engineering analysis of structures requiresmore » the inclusion of high frequencies which can cause damage, but are often difficult to include in simulations because of the need for large memory to model fine grid spacing on large domains.« less

Dark energy from the motions of neutrinos

NASA Astrophysics Data System (ADS)

Simpson, Fergus; Jimenez, Raul; Pena-Garay, Carlos; Verde, Licia

2018-06-01

Ordinarily, a scalar field may only play the role of dark energy if it possesses a potential that is either extraordinarily flat or extremely fine-tuned. Here we demonstrate that these restrictions are lifted when the scalar field undergoes persistent energy exchange with another fluid. In this scenario, the field is prevented from reversing its direction of motion, and instead may come to rest while displaced from the local minimum of its potential. Therefore almost any scalar potential is capable of initiating a prolonged phase of cosmic acceleration. If the rate of energy transfer is modulated via a derivative coupling, the field undergoes a rapid process of freezing, after which the field's equation of state mimicks that of a cosmological constant. We present a physically motivated realisation in the form of a neutrino-majoron coupling, which avoids the dynamical instabilities associated with mass-varying neutrino models. Finally we discuss possible means by which this model could be experimentally verified.

Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks

PubMed Central

Yu, Haiyang; Wu, Zhihai; Wang, Shuqin; Wang, Yunpeng; Ma, Xiaolei

2017-01-01

Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs), for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs) and long short-term memory (LSTM) neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction. PMID:28672867

Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks.

PubMed

Yu, Haiyang; Wu, Zhihai; Wang, Shuqin; Wang, Yunpeng; Ma, Xiaolei

2017-06-26

Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs), for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs) and long short-term memory (LSTM) neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction.

Inferential modeling and predictive feedback control in real-time motion compensation using the treatment couch during radiotherapy

NASA Astrophysics Data System (ADS)

Qiu, Peng; D'Souza, Warren D.; McAvoy, Thomas J.; Liu, K. J. Ray

2007-09-01

Tumor motion induced by respiration presents a challenge to the reliable delivery of conformal radiation treatments. Real-time motion compensation represents the technologically most challenging clinical solution but has the potential to overcome the limitations of existing methods. The performance of a real-time couch-based motion compensation system is mainly dependent on two aspects: the ability to infer the internal anatomical position and the performance of the feedback control system. In this paper, we propose two novel methods for the two aspects respectively, and then combine the proposed methods into one system. To accurately estimate the internal tumor position, we present partial-least squares (PLS) regression to predict the position of the diaphragm using skin-based motion surrogates. Four radio-opaque markers were placed on the abdomen of patients who underwent fluoroscopic imaging of the diaphragm. The coordinates of the markers served as input variables and the position of the diaphragm served as the output variable. PLS resulted in lower prediction errors compared with standard multiple linear regression (MLR). The performance of the feedback control system depends on the system dynamics and dead time (delay between the initiation and execution of the control action). While the dynamics of the system can be inverted in a feedback control system, the dead time cannot be inverted. To overcome the dead time of the system, we propose a predictive feedback control system by incorporating forward prediction using least-mean-square (LMS) and recursive least square (RLS) filtering into the couch-based control system. Motion data were obtained using a skin-based marker. The proposed predictive feedback control system was benchmarked against pure feedback control (no forward prediction) and resulted in a significant performance gain. Finally, we combined the PLS inference model and the predictive feedback control to evaluate the overall performance of the feedback control system. Our results show that, with the tumor motion unknown but inferred by skin-based markers through the PLS model, the predictive feedback control system was able to effectively compensate intra-fraction motion.

Fine motor skills predict performance in the Jebsen Taylor Hand Function Test after stroke.

PubMed

Allgöwer, Kathrin; Hermsdörfer, Joachim

2017-10-01

To determine factors characterizing the differences in fine motor performance between stroke patients and controls. To confirm the relevance of the factors by analyzing their predictive power with regard to the Jebsen Taylor Hand Function Test (JTHFT), a common clinical test of fine motor control. Twenty-two people with slight paresis in an early chronic phase following stroke and twenty-two healthy controls were examined. Performance on the JTHFT, Nine-Hole Peg Test and 2-point discrimination was evaluated. To analyze object manipulation skills, grip forces and temporal measures were examined during (1) lifting actions with variations of weight and surface (2) cyclic movements (3) predictive/reactive catching tasks. Three other aspects of force control included (4) visuomotor tracking (5) fast force changes and (6) grip strength. Based on 9 parameters which significantly distinguished fine motor performance in the two groups, we identified three principal components (factors): grip force scaling, motor coordination and speed of movement. The three factors are shown to predict JTHFT scores via linear regression (R 2 =0.687, p<0.001). We revealed a factor structure behind fine motor impairments following stroke and showed that it explains JTHFT results to a large extend. This result can serve as a basis for improving diagnostics and enabling more targeted therapy. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Tongue Motion Patterns in Post-Glossectomy and Typical Speakers: A Principal Components Analysis

PubMed Central

Stone, Maureen; Langguth, Julie M.; Woo, Jonghye; Chen, Hegang; Prince, Jerry L.

2015-01-01

Purpose In this study, the authors examined changes in tongue motion caused by glossectomy surgery. A speech task that involved subtle changes in tongue-tip positioning (the motion from /i/ to /s/) was measured. The hypothesis was that patients would have limited motion on the tumor (resected) side and would compensate with greater motion on the nontumor side in order to elevate the tongue tip and blade for /s/. Method Velocity fields were extracted from tagged magnetic resonance images in the left, middle, and right tongue of 3 patients and 10 controls. Principal components (PCs) analysis quantified motion differences and distinguished between the subject groups. Results PCs 1 and 2 represented variance in (a) size and independence of the tongue tip, and (b) direction of motion of the tip, body, or both. Patients and controls were correctly separated by a small number of PCs. Conclusions Motion of the tumor slice was different between patients and controls, but the nontumor side of the patients’ tongues did not show excessive or adaptive motion. Both groups contained apical and laminal /s/ users, and 1 patient created apical /s/ in a highly unusual manner. PMID:24023377

Correction And Use Of Jitter In Television Images

NASA Technical Reports Server (NTRS)

Diner, Daniel B.; Fender, Derek H.; Fender, Antony R. H.

1989-01-01

Proposed system stabilizes jittering television image and/or measures jitter to extract information on motions of objects in image. Alternative version, system controls lateral motion on camera to generate stereoscopic views to measure distances to objects. In another version, motion of camera controlled to keep object in view. Heart of system is digital image-data processor called "jitter-miser", which includes frame buffer and logic circuits to correct for jitter in image. Signals from motion sensors on camera sent to logic circuits and processed into corrections for motion along and across line of sight.

Being in the zone: physiological markers of togetherness in joint improvisation

PubMed Central

Noy, Lior; Levit-Binun, Nava; Golland, Yulia

2015-01-01

Performers improvising together describe special moments of ‘being in the zone’ – periods of high performance, synchrony, and enhanced sense of togetherness. Existing evidence suggests a possible route for attaining togetherness – interpersonal synchrony, the fine-grained sensory-motor coordination that promotes social connectedness. Here, we investigated the physiological characteristics of togetherness using a practice from theater and dance, the mirror game. Pairs of expert improvisers jointly improvised synchronized linear motion, while their motion tracks and cardiovascular activity were continuously monitored. Players also provided dynamic ratings of togetherness while watching video recordings of their games. We identified periods of togetherness using kinematic and subjective markers and assessed their physiological characteristics. The kinematic and the subjective measures of togetherness showed some agreement, with more extensive game periods being marked by the subjective than the kinematic one. Game rounds with high rates of togetherness were characterized by increased players’ cardiovascular activity, increased correlation of players’ heart rates (HRs), and increased motion intensity. By comparing motion segments with similar motion intensity, we showed that moments of togetherness in the mirror game were marked by increased players’ HRs, regardless of motion intensity. This pattern was robust for the subjectively defined periods of togetherness, while showing a marginal effect for the kinematically defined togetherness. Building upon similar findings in flow research we suggest that the observed increase of players’ HRs during togetherness periods in the mirror game might indicate the enhanced engagement and enjoyment reported by performers going into ‘the zone.’ The suggested approach, combining temporal measurements of kinematic, physiological and subjective responses, demonstrates how the dynamics of spontaneously emerging dyadic states can be studied empirically. PMID:25999832

Being in the zone: physiological markers of togetherness in joint improvisation.

PubMed

Noy, Lior; Levit-Binun, Nava; Golland, Yulia

2015-01-01

Performers improvising together describe special moments of 'being in the zone' - periods of high performance, synchrony, and enhanced sense of togetherness. Existing evidence suggests a possible route for attaining togetherness - interpersonal synchrony, the fine-grained sensory-motor coordination that promotes social connectedness. Here, we investigated the physiological characteristics of togetherness using a practice from theater and dance, the mirror game. Pairs of expert improvisers jointly improvised synchronized linear motion, while their motion tracks and cardiovascular activity were continuously monitored. Players also provided dynamic ratings of togetherness while watching video recordings of their games. We identified periods of togetherness using kinematic and subjective markers and assessed their physiological characteristics. The kinematic and the subjective measures of togetherness showed some agreement, with more extensive game periods being marked by the subjective than the kinematic one. Game rounds with high rates of togetherness were characterized by increased players' cardiovascular activity, increased correlation of players' heart rates (HRs), and increased motion intensity. By comparing motion segments with similar motion intensity, we showed that moments of togetherness in the mirror game were marked by increased players' HRs, regardless of motion intensity. This pattern was robust for the subjectively defined periods of togetherness, while showing a marginal effect for the kinematically defined togetherness. Building upon similar findings in flow research we suggest that the observed increase of players' HRs during togetherness periods in the mirror game might indicate the enhanced engagement and enjoyment reported by performers going into 'the zone.' The suggested approach, combining temporal measurements of kinematic, physiological and subjective responses, demonstrates how the dynamics of spontaneously emerging dyadic states can be studied empirically.

Self-Motion and the Shaping of Sensory Signals

PubMed Central

Jenks, Robert A.; Vaziri, Ashkan; Boloori, Ali-Reza

2010-01-01

Sensory systems must form stable representations of the external environment in the presence of self-induced variations in sensory signals. It is also possible that the variations themselves may provide useful information about self-motion relative to the external environment. Rats have been shown to be capable of fine texture discrimination and object localization based on palpation by facial vibrissae, or whiskers, alone. During behavior, the facial vibrissae brush against objects and undergo deflection patterns that are influenced both by the surface features of the objects and by the animal's own motion. The extent to which behavioral variability shapes the sensory inputs to this pathway is unknown. Using high-resolution, high-speed videography of unconstrained rats running on a linear track, we measured several behavioral variables including running speed, distance to the track wall, and head angle, as well as the proximal vibrissa deflections while the distal portions of the vibrissae were in contact with periodic gratings. The measured deflections, which serve as the sensory input to this pathway, were strongly modulated both by the properties of the gratings and the trial-to-trial variations in head-motion and locomotion. Using presumed internal knowledge of locomotion and head-rotation, gratings were classified using short-duration trials (<150 ms) from high-frequency vibrissa motion, and the continuous trajectory of the animal's own motion through the track was decoded from the low frequency content. Together, these results suggest that rats have simultaneous access to low- and high-frequency information about their environment, which has been shown to be parsed into different processing streams that are likely important for accurate object localization and texture coding. PMID:20164407

The MPI Emotional Body Expressions Database for Narrative Scenarios

PubMed Central

Volkova, Ekaterina; de la Rosa, Stephan; Bülthoff, Heinrich H.; Mohler, Betty

2014-01-01

Emotion expression in human-human interaction takes place via various types of information, including body motion. Research on the perceptual-cognitive mechanisms underlying the processing of natural emotional body language can benefit greatly from datasets of natural emotional body expressions that facilitate stimulus manipulation and analysis. The existing databases have so far focused on few emotion categories which display predominantly prototypical, exaggerated emotion expressions. Moreover, many of these databases consist of video recordings which limit the ability to manipulate and analyse the physical properties of these stimuli. We present a new database consisting of a large set (over 1400) of natural emotional body expressions typical of monologues. To achieve close-to-natural emotional body expressions, amateur actors were narrating coherent stories while their body movements were recorded with motion capture technology. The resulting 3-dimensional motion data recorded at a high frame rate (120 frames per second) provides fine-grained information about body movements and allows the manipulation of movement on a body joint basis. For each expression it gives the positions and orientations in space of 23 body joints for every frame. We report the results of physical motion properties analysis and of an emotion categorisation study. The reactions of observers from the emotion categorisation study are included in the database. Moreover, we recorded the intended emotion expression for each motion sequence from the actor to allow for investigations regarding the link between intended and perceived emotions. The motion sequences along with the accompanying information are made available in a searchable MPI Emotional Body Expression Database. We hope that this database will enable researchers to study expression and perception of naturally occurring emotional body expressions in greater depth. PMID:25461382

Carbon nanotube growth density control

NASA Technical Reports Server (NTRS)

Delzeit, Lance D. (Inventor); Schipper, John F. (Inventor)

2010-01-01

Method and system for combined coarse scale control and fine scale control of growth density of a carbon nanotube (CNT) array on a substrate, using a selected electrical field adjacent to a substrate surface for coarse scale density control (by one or more orders of magnitude) and a selected CNT growth temperature range for fine scale density control (by multiplicative factors of less than an order of magnitude) of CNT growth density. Two spaced apart regions on a substrate may have different CNT growth densities and/or may use different feed gases for CNT growth.

A Methodology for Evaluating the Hygroscopic Behavior of Wood in Adaptive Building Skins using Motion Grammar

NASA Astrophysics Data System (ADS)

El-Dabaa, Rana; Abdelmohsen, Sherif

2018-05-01

The challenge in designing kinetic architecture lies in the lack of applying computational design and human computer interaction to successfully design intelligent and interactive interfaces. The use of ‘programmable materials’ as specifically fabricated composite materials that afford motion upon stimulation is promising for low-cost low-tech systems for kinetic facades in buildings. Despite efforts to develop working prototypes, there has been no clear methodological framework for understanding and controlling the behavior of programmable materials or for using them for such purposes. This paper introduces a methodology for evaluating the motion acquired from programmed material – resulting from the hygroscopic behavior of wood – through ‘motion grammar’. Motion grammar typically allows for the explanation of desired motion control in a computationally tractable method. The paper analyzed and evaluated motion parameters related to the hygroscopic properties and behavior of wood, and introduce a framework for tracking and controlling wood as a programmable material for kinetic architecture.

Effectiveness of a 10-week tier-1 response to intervention program in improving fine motor and visual-motor skills in general education kindergarten students.

PubMed

Ohl, Alisha M; Graze, Hollie; Weber, Karen; Kenny, Sabrina; Salvatore, Christie; Wagreich, Sarah

2013-01-01

This study examined the efficacy of a 10-wk Tier 1 Response to Intervention (RtI) program developed in collaboration with classroom teachers to improve the fine motor and visual-motor skills of general education kindergarten students. We recruited 113 students in six elementary schools. Two general education kindergarten classrooms at each school participated in the study. Classrooms were randomly assigned to the intervention and control groups. Fine motor skills, pencil grip, and visual-motor integration were measured at the beginning of the school year and after the 10-wk intervention. The intervention group demonstrated a statistically significant increase in fine motor and visual-motor skills, whereas the control group demonstrated a slight decline in both areas. Neither group demonstrated a change in pencil grip. This study provides preliminary evidence that a Tier 1 RtI program can improve fine motor and visual-motor skills in kindergarten students. Copyright © 2013 by the American Occupational Therapy Association, Inc.

Visual imaging capacity and imagery control in Fine Arts students.

PubMed

Pérez-Fabello, Maria José; Campos, Alfredo; Gómez-Juncal, Rocío

2007-06-01

This study investigated relationships between visual imaging abilities (imaging capacity and imagery control) and academic performance in 146 Fine Arts students (31 men, 115 women). Mean age was 22.3 yr. (SD= 1.9; range 20-26 yr.). All of the participants who volunteered for the experiment regularly attended classes and were first, second, or third year students. For evaluation of imaging abilities, the Spanish versions of the Gordon Test of Visual Imagery Control, the Vividness of Visual Imagery Questionnaire, the Verbalizer-Visualizer Questionnaire, and Betts' Questionnaire Upon Mental Imagery were used. Academic performance was assessed in four areas, Drawing, Painting, Sculpture, and Complementary Subjects, over a three-year period. The results indicate that imagery control was associated with academic performance in Fine Arts. These findings are discussed in the context of previous studies, and new lines of research are proposed.

Motion control of multi-actuator hydraulic systems for mobile machineries: Recent advancements and future trends

NASA Astrophysics Data System (ADS)

Xu, Bing; Cheng, Min

2018-06-01

This paper presents a survey of recent advancements and upcoming trends in motion control technologies employed in designing multi-actuator hydraulic systems for mobile machineries. Hydraulic systems have been extensively used in mobile machineries due to their superior power density and robustness. However, motion control technologies of multi-actuator hydraulic systems have faced increasing challenges due to stringent emission regulations. In this study, an overview of the evolution of existing throttling control technologies is presented, including open-center and load sensing controls. Recent advancements in energy-saving hydraulic technologies, such as individual metering, displacement, and hybrid controls, are briefly summarized. The impact of energy-saving hydraulic technologies on dynamic performance and control solutions are also discussed. Then, the advanced operation methods of multi-actuator mobile machineries are reviewed, including coordinated and haptic controls. Finally, challenges and opportunities of advanced motion control technologies are presented by providing an overall consideration of energy efficiency, controllability, cost, reliability, and other aspects.

Steering microtubule shuttle transport with dynamically controlled magnetic fields

DOE PAGES

Mahajan, K. D.; Ruan, G.; Dorcéna, C. J.; ...

2016-03-23

Nanoscale control of matter is critical to the design of integrated nanosystems. Here, we describe a method to dynamically control directionality of microtubule (MT) motion using programmable magnetic fields. MTs are combined with magnetic quantum dots (i.e., MagDots) that are manipulated by external magnetic fields provided by magnetic nanowires. MT shuttles thus undergo both ATP-driven and externally-directed motion with a fluorescence component that permits simultaneous visualization of shuttle motion. This technology is used to alter the trajectory of MTs in motion and to pin MT motion. Ultimately, such an approach could be used to evaluate the MT-kinesin transport system andmore » could serve as the basis for improved lab-on-a-chip technologies based on MT transport.« less

A cable-driven wrist robotic rehabilitator using a novel torque-field controller for human motion training.

PubMed

Chen, Weihai; Cui, Xiang; Zhang, Jianbin; Wang, Jianhua

2015-06-01

Rehabilitation technologies have great potentials in assisted motion training for stroke patients. Considering that wrist motion plays an important role in arm dexterous manipulation of activities of daily living, this paper focuses on developing a cable-driven wrist robotic rehabilitator (CDWRR) for motion training or assistance to subjects with motor disabilities. The CDWRR utilizes the wrist skeletal joints and arm segments as the supporting structure and takes advantage of cable-driven parallel design to build the system, which brings the properties of flexibility, low-cost, and low-weight. The controller of the CDWRR is designed typically based on a virtual torque-field, which is to plan "assist-as-needed" torques for the spherical motion of wrist responding to the orientation deviation in wrist motion training. The torque-field controller can be customized to different levels of rehabilitation training requirements by tuning the field parameters. Additionally, a rapidly convergent parameter self-identification algorithm is developed to obtain the uncertain parameters automatically for the floating wearable structure of the CDWRR. Finally, experiments on a healthy subject are carried out to demonstrate the performance of the controller and the feasibility of the CDWRR on wrist motion training or assistance.

Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation-Vision-Based Control for Precise Reaching Motion of Upper Limb.

PubMed

Oguntosin, Victoria W; Mori, Yoshiki; Kim, Hyejong; Nasuto, Slawomir J; Kawamura, Sadao; Hayashi, Yoshikatsu

2017-01-01

We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments.

Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation—Vision-Based Control for Precise Reaching Motion of Upper Limb

PubMed Central

Oguntosin, Victoria W.; Mori, Yoshiki; Kim, Hyejong; Nasuto, Slawomir J.; Kawamura, Sadao; Hayashi, Yoshikatsu

2017-01-01

We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments. PMID:28736514

A cable-driven wrist robotic rehabilitator using a novel torque-field controller for human motion training

NASA Astrophysics Data System (ADS)

Chen, Weihai; Cui, Xiang; Zhang, Jianbin; Wang, Jianhua

2015-06-01

Rehabilitation technologies have great potentials in assisted motion training for stroke patients. Considering that wrist motion plays an important role in arm dexterous manipulation of activities of daily living, this paper focuses on developing a cable-driven wrist robotic rehabilitator (CDWRR) for motion training or assistance to subjects with motor disabilities. The CDWRR utilizes the wrist skeletal joints and arm segments as the supporting structure and takes advantage of cable-driven parallel design to build the system, which brings the properties of flexibility, low-cost, and low-weight. The controller of the CDWRR is designed typically based on a virtual torque-field, which is to plan "assist-as-needed" torques for the spherical motion of wrist responding to the orientation deviation in wrist motion training. The torque-field controller can be customized to different levels of rehabilitation training requirements by tuning the field parameters. Additionally, a rapidly convergent parameter self-identification algorithm is developed to obtain the uncertain parameters automatically for the floating wearable structure of the CDWRR. Finally, experiments on a healthy subject are carried out to demonstrate the performance of the controller and the feasibility of the CDWRR on wrist motion training or assistance.

14 CFR 29.395 - Control system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Control system. (a) The reaction to the loads prescribed in § 29.397 must be provided by— (1) The control... its limit of motion); (4) The attachment of the control system to the rotor blade pitch control horn... of its motion); and (5) The attachment of the control system to the control surface horn (with the...

14 CFR 29.395 - Control system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Control system. (a) The reaction to the loads prescribed in § 29.397 must be provided by— (1) The control... its limit of motion); (4) The attachment of the control system to the rotor blade pitch control horn... of its motion); and (5) The attachment of the control system to the control surface horn (with the...

Altered motor control patterns in whiplash and chronic neck pain.

PubMed

Woodhouse, Astrid; Vasseljen, Ottar

2008-06-20

Persistent whiplash associated disorders (WAD) have been associated with alterations in kinesthetic sense and motor control. The evidence is however inconclusive, particularly for differences between WAD patients and patients with chronic non-traumatic neck pain. The aim of this study was to investigate motor control deficits in WAD compared to chronic non-traumatic neck pain and healthy controls in relation to cervical range of motion (ROM), conjunct motion, joint position error and ROM-variability. Participants (n = 173) were recruited to three groups: 59 patients with persistent WAD, 57 patients with chronic non-traumatic neck pain and 57 asymptomatic volunteers. A 3D motion tracking system (Fastrak) was used to record maximal range of motion in the three cardinal planes of the cervical spine (sagittal, frontal and horizontal), and concurrent motion in the two associated cardinal planes relative to each primary plane were used to express conjunct motion. Joint position error was registered as the difference in head positions before and after cervical rotations. Reduced conjunct motion was found for WAD and chronic neck pain patients compared to asymptomatic subjects. This was most evident during cervical rotation. Reduced conjunct motion was not explained by current pain or by range of motion in the primary plane. Total conjunct motion during primary rotation was 13.9 degrees (95% CI; 12.2-15.6) for the WAD group, 17.9 degrees (95% CI; 16.1-19.6) for the chronic neck pain group and 25.9 degrees (95% CI; 23.7-28.1) for the asymptomatic group. As expected, maximal cervical range of motion was significantly reduced among the WAD patients compared to both control groups. No group differences were found in maximal ROM-variability or joint position error. Altered movement patterns in the cervical spine were found for both pain groups, indicating changes in motor control strategies. The changes were not related to a history of neck trauma, nor to current pain, but more likely due to long-lasting pain. No group differences were found for kinaesthetic sense.

Altered motor control patterns in whiplash and chronic neck pain

PubMed Central

Woodhouse, Astrid; Vasseljen, Ottar

2008-01-01

Background Persistent whiplash associated disorders (WAD) have been associated with alterations in kinesthetic sense and motor control. The evidence is however inconclusive, particularly for differences between WAD patients and patients with chronic non-traumatic neck pain. The aim of this study was to investigate motor control deficits in WAD compared to chronic non-traumatic neck pain and healthy controls in relation to cervical range of motion (ROM), conjunct motion, joint position error and ROM-variability. Methods Participants (n = 173) were recruited to three groups: 59 patients with persistent WAD, 57 patients with chronic non-traumatic neck pain and 57 asymptomatic volunteers. A 3D motion tracking system (Fastrak) was used to record maximal range of motion in the three cardinal planes of the cervical spine (sagittal, frontal and horizontal), and concurrent motion in the two associated cardinal planes relative to each primary plane were used to express conjunct motion. Joint position error was registered as the difference in head positions before and after cervical rotations. Results Reduced conjunct motion was found for WAD and chronic neck pain patients compared to asymptomatic subjects. This was most evident during cervical rotation. Reduced conjunct motion was not explained by current pain or by range of motion in the primary plane. Total conjunct motion during primary rotation was 13.9° (95% CI; 12.2–15.6) for the WAD group, 17.9° (95% CI; 16.1–19.6) for the chronic neck pain group and 25.9° (95% CI; 23.7–28.1) for the asymptomatic group. As expected, maximal cervical range of motion was significantly reduced among the WAD patients compared to both control groups. No group differences were found in maximal ROM-variability or joint position error. Conclusion Altered movement patterns in the cervical spine were found for both pain groups, indicating changes in motor control strategies. The changes were not related to a history of neck trauma, nor to current pain, but more likely due to long-lasting pain. No group differences were found for kinaesthetic sense. PMID:18570647

Analysis of Timing Control Mechanism of Utterance and Body Motion Using Dialogue between Human and Communication Robot

NASA Astrophysics Data System (ADS)

Takasugi, Shoji; Yamamoto, Tomohito; Muto, Yumiko; Abe, Hiroyuki; Miyake, Yoshihiro

The purpose of this study is to clarify the effects of timing control of utterance and body motion in human-robot interaction. Our previous study has already revealed the correlation of timing of utterance and body motion in human-human communication. Here we proposed a timing control model based on our previous research and estimated its influence to realize human-like communication using a questionnaire method. The results showed that the difference of effectiveness between the communication with the timing control model and that without it was observed. In addition, elderly people evaluated the communication with timing control much higher than younger people. These results show not only the importance of timing control of utterance and body motion in human communication but also its effectiveness for realizing human-like human-robot interaction.

Electron beam deflection control system of a welding and surface modification installation

NASA Astrophysics Data System (ADS)

Koleva, E.; Dzharov, V.; Gerasimov, V.; Tsvetkov, K.; Mladenov, G.

2018-03-01

In the present work, we examined the patterns of the electron beam motion when controlling the transverse with respect to the axis of the beam homogeneous magnetic field created by the coils of the deflection system the electron gun. During electron beam processes, the beam motion is determined the process type (welding, surface modification, etc.), the technological mode, the design dimensions of the electron gun and the shape of the processed samples. The electron beam motion is defined by the cumulative action of two cosine-like control signals generated by a functional generator. The signal control is related to changing the amplitudes, frequencies and phases (phase differences) of the generated voltages. We realized the motion control by applying a graphical user interface developed by us and an Arduino Uno programmable microcontroller. The signals generated were calibrated using experimental data from the available functional generator. The free and precise motion on arbitrary trajectories determines the possible applications of an electron beam process to carrying out various scientific research tasks in material processing.

Analysis of the Motion Control Methods for Stratospheric Balloon-Borne Gondola Platform

NASA Astrophysics Data System (ADS)

Wang, H. H.; Yuan, Z. H.; Wu, J.

2006-10-01

At present, gondola platform is one of the stratospheric balloon-borne platforms being in research focus at home and overseas. Comparing to other stratospheric balloon-borne platforms, such as airship platform, gondola platform has advantages of higher stability, rapid in motion regulation and lower energy cost but disadvantages of less supporting capacity and be incapable of fixation. While all platforms have the same goal of keeping them at accurate angle and right pose for the requirements of instruments and objects installed in the platforms, when platforms rotate round the ground level perpendicular. That is accomplishing motion control. But, platform control system has factors of low damper, excessive and uncertain disturbances by the reason of its being hung over balloon in the air, it is hard to achieve the desired control precision because platform is ease to deviate its benchmark motion. Thus, in the controlling procedure in order to get higher precision, it is crucial to perceive the platform's swing synchronously and rapidly, and restrain the influence of disturbances effectively, keep the platform's pose steadily. Furthermore, while the platform in the air regard control center in the ground as reference object, it is ultimate to select a appropriate reference frame and work out the coordinates and implement the adjustment by the PC104 controller. This paper introduces the methods of the motion control based on stratospheric balloon-borne gondola platform. Firstly, this paper compares the characteristic of the flywheel and CMG and specifies the key methods of obtaining two significant states which are 'orientation stability' state and 'orientation tracking' state for platform motion control procedure using CMG as the control actuator. These two states reduce the deviation amplitude of rotation and swing of gondola's motion relative to original motion due to stratospheric intense atmosphere disturbance. We define it as the first procedure. In next procedure, we use the transfer matrix of earth reference frame to geographic reference frame to transform the data measured by the magnetic orientation sensors and the gyroscope to the space orientations, then the PC104 controller use the space orientations value as feedback to complete revises.

Task-oriented training with computer gaming in people with rheumatoid arthritisor osteoarthritis of the hand: study protocol of a randomized controlled pilot trial

PubMed Central

2013-01-01

Background Significant restriction in the ability to participate in home, work and community life results from pain, fatigue, joint damage, stiffness and reduced joint range of motion and muscle strength in people with rheumatoid arthritis or osteoarthritis of the hand. With modest evidence on the therapeutic effectiveness of conventional hand exercises, a task-oriented training program via real life object manipulations has been developed for people with arthritis. An innovative, computer-based gaming platform that allows a broad range of common objects to be seamlessly transformed into therapeutic input devices through instrumentation with a motion-sense mouse has also been designed. Personalized objects are selected to target specific training goals such as graded finger mobility, strength, endurance or fine/gross dexterous functions. The movements and object manipulation tasks that replicate common situations in everyday living will then be used to control and play any computer game, making practice challenging and engaging. Methods/Design The ongoing study is a 6-week, single-center, parallel-group, equally allocated and assessor-blinded pilot randomized controlled trial. Thirty people with rheumatoid arthritis or osteoarthritis affecting the hand will be randomized to receive either conventional hand exercises or the task-oriented training. The purpose is to determine a preliminary estimation of therapeutic effectiveness and feasibility of the task-oriented training program. Performance based and self-reported hand function, and exercise compliance are the study outcomes. Changes in outcomes (pre to post intervention) within each group will be assessed by paired Student t test or Wilcoxon signed-rank test and between groups (control versus experimental) post intervention using unpaired Student t test or Mann–Whitney U test. Discussion The study findings will inform decisions on the feasibility, safety and completion rate and will also provide preliminary data on the treatment effects of the task-oriented training compared with conventional hand exercises in people with rheumatoid arthritis or osteoarthritis of the hand. Trial registration ClinicalTrials.gov: NCT01635582 PMID:23497529

Design and development of a motion compensator for the RSRA main rotor control

NASA Technical Reports Server (NTRS)

Jeffrey, P.; Huber, R.

1979-01-01

The RSRA, an experimental helicopter, is equipped with an active isolation system that allows the transmission to move relative to the fuselage. The purpose of the motion compensator is to prevent these motions from introducing unwanted signals to the main rotor control. A motion compensator concept was developed that has six-degree-of-freedom capability. The mechanism was implemented on RSRA and its performance verified by ground and flight tests.

Neural correlates of coherent and biological motion perception in autism.

PubMed

Koldewyn, Kami; Whitney, David; Rivera, Susan M

2011-09-01

Recent evidence suggests those with autism may be generally impaired in visual motion perception. To examine this, we investigated both coherent and biological motion processing in adolescents with autism employing both psychophysical and fMRI methods. Those with autism performed as well as matched controls during coherent motion perception but had significantly higher thresholds for biological motion perception. The autism group showed reduced posterior Superior Temporal Sulcus (pSTS), parietal and frontal activity during a biological motion task while showing similar levels of activity in MT+/V5 during both coherent and biological motion trials. Activity in MT+/V5 was predictive of individual coherent motion thresholds in both groups. Activity in dorsolateral prefrontal cortex (DLPFC) and pSTS was predictive of biological motion thresholds in control participants but not in those with autism. Notably, however, activity in DLPFC was negatively related to autism symptom severity. These results suggest that impairments in higher-order social or attentional networks may underlie visual motion deficits observed in autism. © 2011 Blackwell Publishing Ltd.

Neural correlates of coherent and biological motion perception in autism

PubMed Central

Koldewyn, Kami; Whitney, David; Rivera, Susan M.

2011-01-01

Recent evidence suggests those with autism may be generally impaired in visual motion perception. To examine this, we investigated both coherent and biological motion processing in adolescents with autism employing both psychophysical and fMRI methods. Those with autism performed as well as matched controls during coherent motion perception but had significantly higher thresholds for biological motion perception. The autism group showed reduced posterior Superior Temporal Sulcus (pSTS), parietal and frontal activity during a biological motion task while showing similar levels of activity in MT+/V5 during both coherent and biological motion trials. Activity in MT+/V5 was predictive of individual coherent motion thresholds in both groups. Activity in dorsolateral prefrontal cortex (DLPFC) and pSTS was predictive of biological motion thresholds in control participants but not in those with autism. Notably, however, activity in DLPFC was negatively related to autism symptom severity. These results suggest that impairments in higher-order social or attentional networks may underlie visual motion deficits observed in autism. PMID:21884323

A Unified Approach to Motion Control of Motion Robots

NASA Technical Reports Server (NTRS)

Seraji, H.

1994-01-01

This paper presents a simple on-line approach for motion control of mobile robots made up of a manipulator arm mounted on a mobile base. The proposed approach is equally applicable to nonholonomic mobile robots, such as rover-mounted manipulators and to holonomic mobile robots such as tracked robots or compound manipulators. The computational efficiency of the proposed control scheme makes it particularly suitable for real-time implementation.

Modification of hemiplegic compensatory gait pattern by symmetry-based motion controller of HAL.

PubMed

Kawamoto, Hiroaki; Kadone, Hideki; Sakurai, Takeru; Sankai, Yoshiyuki

2015-01-01

As one of several characteristics of hemiplegic patients after stroke, compensatory gait caused by affected limb is often seen. The purpose of this research is to apply a symmetry-based controller of a wearable type lower limb robot, Hybrid Assistive Limb (HAL) to hemiplegic patients with compensatory gait, and to investigate improvement of gait symmetry. The controller is designed respectively for swing phase and support phase according to characteristics of hemiplegic gait pattern. The controller during swing phase stores the motion of the unaffected limb and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. Moreover, the controller during support phase provides motion to extend hip and knee joints to support wearer's body. Clinical tests were conducted in order to assess the modification of gait symmetry. Our case study involved participation of one chronic stroke patient who performs abnormally-compensatory gait for both of the affected and unaffected limbs. As a result, the patient's gait symmetry was improved by providing motion support during the swing phase on the affected side and motion constraint during the support phase on the unaffected side. The study showed promising basis for the effectiveness of the controller for the future clinical study.

Visually guided control of movement in the context of multimodal stimulation

NASA Technical Reports Server (NTRS)

Riccio, Gary E.

1991-01-01

Flight simulation has been almost exclusively concerned with simulating the motions of the aircraft. Physically distinct subsystems are often combined to simulate the varieties of aircraft motion. Visual display systems simulate the motion of the aircraft relative to remote objects and surfaces (e.g., other aircraft and the terrain). 'Motion platform' simulators recreate aircraft motion relative to the gravitoinertial vector (i.e., correlated rotation and tilt as opposed to the 'coordinated turn' in flight). 'Control loaders' attempt to simulate the resistance of the aerodynamic medium to aircraft motion. However, there are few operational systems that attempt to simulate the motion of the pilot relative to the aircraft and the gravitoinertial vector. The design and use of all simulators is limited by poor understanding of postural control in the aircraft and its effect on the perception and control of flight. Analysis of the perception and control of flight (real or simulated) must consider that: (1) the pilot is not rigidly attached to the aircraft; and (2) the pilot actively monitors and adjusts body orientation and configuration in the aircraft. It is argued that this more complete approach to flight simulation requires that multimodal perception be considered as the rule rather than the exception. Moreover, the necessity of multimodal perception is revealed by emphasizing the complementarity rather than the redundancy among perceptual systems. Finally, an outline is presented for an experiment to be conducted at NASA ARC. The experiment explicitly considers possible consequences of coordination between postural and vehicular control.

Linear and angular control of circular walking in healthy older adults and subjects with cerebellar ataxia.

PubMed

Goodworth, Adam D; Paquette, Caroline; Jones, Geoffrey Melvill; Block, Edward W; Fletcher, William A; Hu, Bin; Horak, Fay B

2012-05-01

Linear and angular control of trunk and leg motion during curvilinear navigation was investigated in subjects with cerebellar ataxia and age-matched control subjects. Subjects walked with eyes open around a 1.2-m circle. The relationship of linear to angular motion was quantified by determining the ratios of trunk linear velocity to trunk angular velocity and foot linear position to foot angular position. Errors in walking radius (the ratio of linear to angular motion) also were quantified continuously during the circular walk. Relative variability of linear and angular measures was compared using coefficients of variation (CoV). Patterns of variability were compared using power spectral analysis for the trunk and auto-covariance analysis for the feet. Errors in radius were significantly increased in patients with cerebellar damage as compared to controls. Cerebellar subjects had significantly larger CoV of feet and trunk in angular, but not linear, motion. Control subjects also showed larger CoV in angular compared to linear motion of the feet and trunk. Angular and linear components of stepping differed in that angular, but not linear, foot placement had a negative correlation from one stride to the next. Thus, walking in a circle was associated with more, and a different type of, variability in angular compared to linear motion. Results are consistent with increased difficulty of, and role of the cerebellum in, control of angular trunk and foot motion for curvilinear locomotion.

“Global” visual training and extent of transfer in amblyopic macaque monkeys

PubMed Central

Kiorpes, Lynne; Mangal, Paul

2015-01-01

Perceptual learning is gaining acceptance as a potential treatment for amblyopia in adults and children beyond the critical period. Many perceptual learning paradigms result in very specific improvement that does not generalize beyond the training stimulus, closely related stimuli, or visual field location. To be of use in amblyopia, a less specific effect is needed. To address this problem, we designed a more general training paradigm intended to effect improvement in visual sensitivity across tasks and domains. We used a “global” visual stimulus, random dot motion direction discrimination with 6 training conditions, and tested for posttraining improvement on a motion detection task and 3 spatial domain tasks (contrast sensitivity, Vernier acuity, Glass pattern detection). Four amblyopic macaques practiced the motion discrimination with their amblyopic eye for at least 20,000 trials. All showed improvement, defined as a change of at least a factor of 2, on the trained task. In addition, all animals showed improvements in sensitivity on at least some of the transfer test conditions, mainly the motion detection task; transfer to the spatial domain was inconsistent but best at fine spatial scales. However, the improvement on the transfer tasks was largely not retained at long-term follow-up. Our generalized training approach is promising for amblyopia treatment, but sustaining improved performance may require additional intervention. PMID:26505868

Banding of NMR-derived Methyl Order Parameters: Implications for Protein Dynamics

PubMed Central

Sharp, Kim A.; Kasinath, Vignesh; Wand, A. Joshua

2014-01-01

Our understanding of protein folding, stability and function has begun to more explicitly incorporate dynamical aspects. Nuclear magnetic resonance has emerged as a powerful experimental method for obtaining comprehensive site-resolved insight into protein motion. It has been observed that methyl-group motion tends to cluster into three “classes” when expressed in terms of the popular Lipari-Szabo model-free squared generalized order parameter. Here the origins of the three classes or bands in the distribution of order parameters are examined. As a first step, a Bayesian based approach, which makes no a priori assumption about the existence or number of bands, is developed to detect the banding of O2axis values derived either from NMR experiments or molecular dynamics simulations. The analysis is applied to seven proteins with extensive molecular dynamics simulations of these proteins in explicit water to examine the relationship between O2 and fine details of the motion of methyl bearing side chains. All of the proteins studied display banding, with some subtle differences. We propose a very simple yet plausible physical mechanism for banding. Finally, our Bayesian method is used to analyze the measured distributions of methyl group motions in the catabolite activating protein and several of its mutants in various liganded states and discuss the functional implications of the observed banding to protein dynamics and function. PMID:24677353

Interaction of arch type and footwear on running mechanics.

PubMed

Butler, Robert J; Davis, Irene S; Hamill, Joseph

2006-12-01

Running shoes are designed to accommodate various arch types to reduce the risk of lower extremity injuries sustained during running. Yet little is known about the biomechanical changes of running in the recommended footwear that may allow for a reduction in injuries. To evaluate the effects of motion control and cushion trainer shoes on running mechanics in low- and high-arched runners. Controlled laboratory study. Twenty high-arched and 20 low-arched recreational runners (>10 miles per week) were recruited for the study. Three-dimensional kinematic and kinetics were collected as subjects ran at 3.5 ms(-1) +/- 5% along a 25-m runway. The motion control shoe evaluated was the New Balance 1122, and the cushioning shoe evaluated was the New Balance 1022. Repeated-measures analyses of variance were used to determine if low- and high-arched runners responded differently to motion control and cushion trainer shoes. A significant interaction was observed in the instantaneous loading rate such that the low-arched runners had a lower instantaneous loading rate in the motion control condition, and the high-arched runners had a lower instantaneous loading rate in the cushion trainer condition. Significant main effects for shoe were observed for peak positive tibial acceleration, peak-to-peak tibial acceleration, mean loading rate, peak eversion, and eversion excursion. These results suggest that motion control shoes control rearfoot motion better than do cushion trainer shoes. In addition, cushion trainer shoes attenuate shock better than motion control shoes do. However, with the exception of instantaneous loading rate, these benefits do not differ between arch type. Running footwear recommendations should be based on an individual's running mechanics. If a mechanical analysis is not available, footwear recommendations can be based empirically on the individual's arch type.

Motion control of 7-DOF arms - The configuration control approach

NASA Technical Reports Server (NTRS)

Seraji, Homayoun; Long, Mark K.; Lee, Thomas S.

1993-01-01

Graphics simulation and real-time implementation of configuration control schemes for a redundant 7-DOF Robotics Research arm are described. The arm kinematics and motion control schemes are described briefly. This is followed by a description of a graphics simulation environment for 7-DOF arm control on the Silicon Graphics IRIS Workstation. Computer simulation results are presented to demonstrate elbow control, collision avoidance, and optimal joint movement as redundancy resolution goals. The laboratory setup for experimental validation of motion control of the 7-DOF Robotics Research arm is then described. The configuration control approach is implemented on a Motorola-68020/VME-bus-based real-time controller, with elbow positioning for redundancy resolution. Experimental results demonstrate the efficacy of configuration control for real-time control.

Functional MRI evidence for fine motor praxis dysfunction in children with persistent speech disorders

PubMed Central

Redle, Erin; Vannest, Jennifer; Maloney, Thomas; Tsevat, Rebecca K.; Eikenberry, Sarah; Lewis, Barbara; Shriberg, Lawrence D.; Tkach, Jean; Holland, Scott K.

2014-01-01

Children with persistent speech disorders (PSD) often present with overt or subtle motor deficits; the possibility that speech disorders and motor deficits could arise from a shared neurological base is currently unknown. Functional MRI (fMRI) was used to examine the brain networks supporting fine motor praxis in children with PSD and without clinically identified fine motor deficits. Methods This case-control study included 12 children with PSD (mean age 7.42 years, 4 female) and 12 controls (mean age 7.44 years, 4 female). Children completed behavioral evaluations using standardized motor assessments and parent reported functional measures. During fMRI scanning, participants completed a cued finger tapping task contrasted passive listening. A general linear model approach identified brain regions associated with finger tapping in each group and regions that differed between groups. The relationship between regional fMRI activation and fine motor skill was assessed using a regression analysis. Results Children with PSD had significantly poorer results for rapid speech production and fine motor praxis skills, but did not differ on classroom functional skills. Functional MRI results showed that children with PSD had significantly more activation in the cerebellum during finger tapping. Positive correlations between performance on a fine motor praxis test and activation multiple cortical regions were noted for children with PSD but not for controls. Conclusions Over-activation in the cerebellum during a motor task may reflect a subtle abnormality in the non-speech motor neural circuitry in children with PSD. PMID:25481413

Fine structure of spectrum of twist-three operators in QCD

NASA Astrophysics Data System (ADS)

Belitsky, A. V.

1999-04-01

We unravel the structure of the spectrum of the anomalous dimensions of the quark-gluon twist-3 operators which are responsible for the multiparton correlations in hadrons and enter as a leading contribution to several physical cross sections. The method of analysis is based on the recent finding of a non-trivial integral of motion for the corresponding Hamiltonian problem in multicolour limit which results into exact integrability of the three-particle system. Quasiclassical expansion is used for solving the problem. We address the chiral-odd sector as a case of study.

Congenital amusia: a cognitive disorder limited to resolved harmonics and with no peripheral basis.

PubMed

Cousineau, Marion; Oxenham, Andrew J; Peretz, Isabelle

2015-01-01

Pitch plays a fundamental role in audition, from speech and music perception to auditory scene analysis. Congenital amusia is a neurogenetic disorder that appears to affect primarily pitch and melody perception. Pitch is normally conveyed by the spectro-temporal fine structure of low harmonics, but some pitch information is available in the temporal envelope produced by the interactions of higher harmonics. Using 10 amusic subjects and 10 matched controls, we tested the hypothesis that amusics suffer exclusively from impaired processing of spectro-temporal fine structure. We also tested whether the inability of amusics to process acoustic temporal fine structure extends beyond pitch by measuring sensitivity to interaural time differences, which also rely on temporal fine structure. Further tests were carried out on basic intensity and spectral resolution. As expected, pitch perception based on spectro-temporal fine structure was impaired in amusics; however, no significant deficits were observed in amusics' ability to perceive the pitch conveyed via temporal-envelope cues. Sensitivity to interaural time differences was also not significantly different between the amusic and control groups, ruling out deficits in the peripheral coding of temporal fine structure. Finally, no significant differences in intensity or spectral resolution were found between the amusic and control groups. The results demonstrate a pitch-specific deficit in fine spectro-temporal information processing in amusia that seems unrelated to temporal or spectral coding in the auditory periphery. These results are consistent with the view that there are distinct mechanisms dedicated to processing resolved and unresolved harmonics in the general population, the former being altered in congenital amusia while the latter is spared. Copyright © 2014 Elsevier Ltd. All rights reserved.

Kinematic performance of fine motor control in attention-deficit/hyperactivity disorder: the effects of comorbid developmental coordination disorder and core symptoms.

PubMed

Lee, I-Ching; Chen, Yung-Jung; Tsai, Chin-Liang

2013-02-01

The aims of this study were: (i) to determine whether differences exist in the fine motor fluency and flexibility of three groups (children with attention-deficit/hyperactivity disorder [ADHD], children in whom ADHD is comorbid with developmental coordination disorder [DCD] [denoted as ADHD+DCD], and a typically developing control group); and (ii) to clarify whether the degree of severity of core symptoms affects performance. The Peabody Picture Vocabulary Test-Revised, the Beery-Buktenica Development Test of Visual-Motor Integration and the Movement Assessment Battery for Children were used as prescreening tests. The Integrated Visual and Auditory+Plus test was utilized to assess subjects' attention. The redesigned fine motor tracking and pursuit tasks were administered to evaluate subjects' fine motor performance. No significant difference was found when comparing the performance of the Children with ADHD and the typically developing group. Significant differences existed between children in whom ADHD is comorbid with DCD and typically developing children. Children with ADHD demonstrated proper fine motor fluency and flexibility, and deficient performance occurred when ADHD was comorbid with developmental coordination disorder. Children with ADHD had more difficulty implementing closed-loop movements that required higher levels of cognitive processing than those of their typically developing peers. Also, deficits in fine motor control were more pronounced when ADHD was combined with movement coordination problems. The severity of core symptoms had a greater effect on children with ADHD's fine motor flexibility than did fluency performance. In children with pure ADHD, unsmooth movement performance was highly related to the severity of core symptoms. © 2012 The Authors. Pediatrics International © 2012 Japan Pediatric Society.

Laboratory Investigation on the Effects of Natural Fine Aggregates and Recycled Waste Tire Rubber in Pervious Concrete to Develop More Sustainable Pavement Materials

NASA Astrophysics Data System (ADS)

Bonicelli, Alessandra; Fuentes, Luis G.; Khalil Dawd Bermejo, Ibrahim

2017-10-01

Pervious concrete pavement is a recognized sustainable solution for urban roads. To enhance mechanical properties of pervious concrete material, in order to allow wider use of this technology, a lot of studies are going on all over the world. The use of a little percentage of fine aggregates is proven to increase the material resistance without an excessive reduction of permeability. This study aimed to evaluate the effect of replacing the fine virgin aggregates with r cycled tire rubber. 14 different mixes were analysed in terms of indirect tensile strength resistance, void content and density. Two different dimensions of crumb rubber were studied, as well as two different dosages, which were applied to different no-fine control mixes. All results were compared with the same control mixes containing natural fine aggregate. The mixes had a fixed granulometric curve but varied in water/cement ratio; this in order to evaluate the effect of recycled rubber depending to w/c ratio of the mix. An image analysis was also conducted to verify the rubber distribution in the mixture and the cracking surfaces. The experimental analysis showed that a correct proportioning of fine sand significantly increased the strength of the material. Moreover, the use of recycled waste tire rubber, gave interesting improvements respect to the no-fine control mixes, even though the developed resistance was lower respect to mixes containing mineral sand. This result was expected because of the cementing property of mineral sand. Although, the important result was that it was possible to use waste tire rubber in pervious concrete, with an appropriate dosage and granular dimension, for increasing the performance of traditional mix design, in order to achieve pavement materials more and more sustainable.

[Motion control of moving mirror based on fixed-mirror adjustment in FTIR spectrometer].

PubMed

Li, Zhong-bing; Xu, Xian-ze; Le, Yi; Xu, Feng-qiu; Li, Jun-wei

2012-08-01

The performance of the uniform motion of the moving mirror, which is the only constant motion part in FTIR spectrometer, and the performance of the alignment of the fixed mirror play a key role in FTIR spectrometer, and affect the interference effect and the quality of the spectrogram and may restrict the precision and resolution of the instrument directly. The present article focuses on the research on the uniform motion of the moving mirror and the alignment of the fixed mirror. In order to improve the FTIR spectrometer, the maglev support system was designed for the moving mirror and the phase detection technology was adopted to adjust the tilt angle between the moving mirror and the fixed mirror. This paper also introduces an improved fuzzy PID control algorithm to get the accurate speed of the moving mirror and realize the control strategy from both hardware design and algorithm. The results show that the development of the moving mirror motion control system gets sufficient accuracy and real-time, which can ensure the uniform motion of the moving mirror and the alignment of the fixed mirror.

Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

NASA Astrophysics Data System (ADS)

Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

2017-11-01

The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

SPARCLE: Electrostatic Dust Control Tool Proof of Concept

NASA Technical Reports Server (NTRS)

Clark, P. E.; Curtis, S. A.; Minetto, F.; Marshall, J.; Nuth, J.; Calle, C.

2010-01-01

Successful exploration of most planetary surfaces, with their impact-generated dusty regoliths, will depend on the capabilities to keep surfaces free of the performance-compromising dust. Once in contact with surfaces, whether set in motion by natural or mechanical means, regolith fines, or dust, behave like abrasive Velcro, coating surfaces, clogging mechanisms, making movement progressively more difticult, and being almost impossible to remove by mechanical mcans (brushing). The successful dust removal strategy will deal with dust dynamics resulting from interaction between Van der Waals and Coulombic forces. Here, proof of concept for an electrostatically-based concept for dust control tool is described and demonstrated. A low power focused electron beam is used in the presence of a small electrical field to increase the negative charge to mass ratio of a dusty surface until dust repulsion and attraction to a lower potential surface, acting as a dust collector, occurred. Our goal is a compact device of less than 5 kg mass and using less than 5 watts of power to be operational in less than 5 years with heritage from ionic sweepers for active spacecraft potential control (e.g ., on POLAR). Rovers could be fitted with devices that could hamess the removal of dust for sampling as part of the extended exploration process on Mercury, Mars, asteroids or outer solar system satellites, as well as the Moon.

Novices in surgery are the target group of a virtual reality training laboratory.

PubMed

Hassan, Iyad; Maschuw, Katja; Rothmund, Matthias; Koller, Michael; Gerdes, Berthold

2006-01-01

This study aims to establish which physicians represent the suitable target group of a virtual training laboratory. Novices (48 physicians with fewer than 10 laparoscopic operations) and intermediate trainees (19 physicians who performed 30-50 laparoscopic operations) participated in this study. Each participant performed the basic module 'clip application' at the beginning and after a 1-hour short training course on the LapSim. The course consisted of the tasks coordination, lift and grasp, clip application, cutting with diathermy and fine dissection at increasing difficulty levels. The time taken to complete the tasks, number of errors, and economy of motion parameters (path length and angular path) were analyzed. Following training with the simulator, novices completed the task significantly faster (p = 0.001), demonstrated a greater economy of motion [path length (p = 0.04) and angular path (p = 0.01)]. In contrast, the intermediate trainees showed a reduction of their errors, but without reaching statistical significance. They showed no improvement in economy of motion and completed the task significantly slower (p = 0.03). Novices, in comparison to intermediate trainees, tend to benefit most during their first exposure to a laparoscopy simulator.

The influence hydrogen atom addition has on charge switching during motion of the metal atom in endohedral Ca@C60H4 isomers

PubMed Central

Raggi, G.; Besley, E.; Stace, A. J.

2016-01-01

Density functional theory has been applied in a study of charge transfer between an endohedral calcium atom and the fullerene cage in Ca@C60H4 and [Ca@C60H4]+ isomers. Previous calculations on Ca@C60 have shown that the motion of calcium within a fullerene is accompanied by large changes in electron density on the carbon cage. Based on this observation, it has been proposed that a tethered endohedral fullerene might form the bases of a nanoswitch. Through the addition of hydrogen atoms to one hemisphere of the cage it is shown that, when compared with Ca@C60, asymmetric and significantly reduced energy barriers can be generated with respect to motion of the calcium atom. It is proposed that hydrogen atom addition to a fullerene might offer a route for creating a bi-stable nanoswitch that can be fine-tuned through the selection of an appropriate isomer and number of atoms attached to the cage of an endohedral fullerene. This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’. PMID:27501967

Multiresolution image registration in digital x-ray angiography with intensity variation modeling.

PubMed

Nejati, Mansour; Pourghassem, Hossein

2014-02-01

Digital subtraction angiography (DSA) is a widely used technique for visualization of vessel anatomy in diagnosis and treatment. However, due to unavoidable patient motions, both externally and internally, the subtracted angiography images often suffer from motion artifacts that adversely affect the quality of the medical diagnosis. To cope with this problem and improve the quality of DSA images, registration algorithms are often employed before subtraction. In this paper, a novel elastic registration algorithm for registration of digital X-ray angiography images, particularly for the coronary location, is proposed. This algorithm includes a multiresolution search strategy in which a global transformation is calculated iteratively based on local search in coarse and fine sub-image blocks. The local searches are accomplished in a differential multiscale framework which allows us to capture both large and small scale transformations. The local registration transformation also explicitly accounts for local variations in the image intensities which incorporated into our model as a change of local contrast and brightness. These local transformations are then smoothly interpolated using thin-plate spline interpolation function to obtain the global model. Experimental results with several clinical datasets demonstrate the effectiveness of our algorithm in motion artifact reduction.

Experimental Evaluation of the High-Speed Motion Vector Measurement by Combining Synthetic Aperture Array Processing with Constrained Least Square Method

NASA Astrophysics Data System (ADS)

Yokoyama, Ryouta; Yagi, Shin-ichi; Tamura, Kiyoshi; Sato, Masakazu

2009-07-01

Ultrahigh speed dynamic elastography has promising potential capabilities in applying clinical diagnosis and therapy of living soft tissues. In order to realize the ultrahigh speed motion tracking at speeds of over thousand frames per second, synthetic aperture (SA) array signal processing technology must be introduced. Furthermore, the overall system performance should overcome the fine quantitative evaluation in accuracy and variance of echo phase changes distributed across a tissue medium. On spatial evaluation of local phase changes caused by pulsed excitation on a tissue phantom, investigation was made with the proposed SA signal system utilizing different virtual point sources that were generated by an array transducer to probe each component of local tissue displacement vectors. The final results derived from the cross-correlation method (CCM) brought about almost the same performance as obtained by the constrained least square method (LSM) extended to successive echo frames. These frames were reconstructed by SA processing after the real-time acquisition triggered by the pulsed irradiation from a point source. The continuous behavior of spatial motion vectors demonstrated the dynamic generation and traveling of the pulsed shear wave at a speed of one thousand frames per second.

Fine motor skills in a population of children in remote Australia with high levels of prenatal alcohol exposure and Fetal Alcohol Spectrum Disorder.

PubMed

Doney, Robyn; Lucas, Barbara R; Watkins, Rochelle E; Tsang, Tracey W; Sauer, Kay; Howat, Peter; Latimer, Jane; Fitzpatrick, James P; Oscar, June; Carter, Maureen; Elliott, Elizabeth J

2017-11-21

Many children in the remote Fitzroy Valley region of Western Australia have prenatal alcohol exposure (PAE). Individuals with PAE can have neurodevelopmental impairments and be diagnosed with one of several types of Fetal Alcohol Spectrum Disorder (FASD). Fine motor skills can be impaired by PAE, but no studies have developed a comprehensive profile of fine motor skills in a population-based cohort of children with FASD. We aimed to develop a comprehensive profile of fine motor skills in a cohort of Western Australian children; determine whether these differed in children with PAE or FASD; and establish the prevalence of impairment. Children (n = 108, 7 to 9 years) were participants in a population-prevalence study of FASD in Western Australia. Fine motor skills were assessed using the Bruininks-Oseretsky Test of Motor Proficiency, which provided a Fine Motor Composite score, and evaluated Fine Manual Control (Fine Motor Precision; Fine Motor Integration) and Manual Coordination (Manual Dexterity; Upper-Limb Coordination). Descriptive statistics were reported for the overall cohort; and comparisons made between children with and without PAE and/or FASD. The prevalence of severe (≤ 2nd percentile) and moderate (≤16th percentile) impairments was determined. Overall, Fine Motor Composite scores were 'average' (M = 48.6 ± 7.4), as were Manual Coordination (M = 55.7 ± 7.9) and Fine Manual Control scores (M = 42.5 ± 6.2). Children with FASD had significantly lower Fine Motor Composite (M = 45.2 ± 7.7 p = 0.046) and Manual Coordination scores (M = 51.8 ± 7.3, p = 0.027) than children without PAE (Fine Motor Composite M = 49.8 ± 7.2; Manual Coordination M = 57.0 ± 7.7). Few children had severe impairment, but rates of moderate impairment were very high. Different types of fine motor skills should be evaluated in children with PAE or FASD. The high prevalence of fine motor impairment in our cohort, even in children without PAE, highlights the need for therapeutic intervention for many children in remote communities.

The research on visual industrial robot which adopts fuzzy PID control algorithm

NASA Astrophysics Data System (ADS)

Feng, Yifei; Lu, Guoping; Yue, Lulin; Jiang, Weifeng; Zhang, Ye

2017-03-01

The control system of six degrees of freedom visual industrial robot based on the control mode of multi-axis motion control cards and PC was researched. For the variable, non-linear characteristics of industrial robot`s servo system, adaptive fuzzy PID controller was adopted. It achieved better control effort. In the vision system, a CCD camera was used to acquire signals and send them to video processing card. After processing, PC controls the six joints` motion by motion control cards. By experiment, manipulator can operate with machine tool and vision system to realize the function of grasp, process and verify. It has influence on the manufacturing of the industrial robot.

Human motion planning based on recursive dynamics and optimal control techniques

NASA Technical Reports Server (NTRS)

Lo, Janzen; Huang, Gang; Metaxas, Dimitris

2002-01-01

This paper presents an efficient optimal control and recursive dynamics-based computer animation system for simulating and controlling the motion of articulated figures. A quasi-Newton nonlinear programming technique (super-linear convergence) is implemented to solve minimum torque-based human motion-planning problems. The explicit analytical gradients needed in the dynamics are derived using a matrix exponential formulation and Lie algebra. Cubic spline functions are used to make the search space for an optimal solution finite. Based on our formulations, our method is well conditioned and robust, in addition to being computationally efficient. To better illustrate the efficiency of our method, we present results of natural looking and physically correct human motions for a variety of human motion tasks involving open and closed loop kinematic chains.

Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

PubMed Central

Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

2014-01-01

Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution. PMID:25379546

Rotating drum tests of particle suspensions within a fines dispersion

NASA Astrophysics Data System (ADS)

Cabrera, Miguel Angel; Gollin, Devis; Kaitna, Roland; Wu, Wei

2014-05-01

Natural flows like mudflows, debris flow, and hyperconcentrated flows are commonly composed by a matrix of particles suspended in a viscous fluid. The nature of the interactions between particles immersed in a fluid is related to its size. While coarse particles (sand, gravel, and boulders) interact with each other or with the surrounding fluid, a dispersion of fine particles interacts with each other through colloidal forces or Brownian motion effects (Coussot and Piau, 1995, and Ancey and Jorrot, 2001). The predominance of one of the previous interactions defines the rheology of the flow. On this sense, experimental insight is required to validate the limits where the rheology of a dispersion of fines is valid. For this purpose, an experimental program in a rotating drum is performed over samples of sand, loess, and kaolin. The solid concentration and angular velocity of the rotating drum are varied. Height and normal loads are measured during flow. High-speed videos are performed to obtain the flow patterns of the mixtures. The experiments provide new laboratory evidence of granular mixture behaviour within an increased viscous fluid phase and its characterization. The results show an apparent threshold in terms of solid concentration, in which the mixtures started to behave as a shear-dependent material.

Motion direction discrimination training reduces perceived motion repulsion.

PubMed

Jia, Ke; Li, Sheng

2017-04-01

Participants often exaggerate the perceived angular separation between two simultaneously presented motion stimuli, which is referred to as motion repulsion. The overestimation helps participants differentiate between the two superimposed motion directions, yet it causes the impairment of direction perception. Since direction perception can be refined through perceptual training, we here attempted to investigate whether the training of a direction discrimination task changes the amount of motion repulsion. Our results showed a direction-specific learning effect, which was accompanied by a reduced amount of motion repulsion both for the trained and the untrained directions. The reduction of the motion repulsion disappeared when the participants were trained on a luminance discrimination task (control experiment 1) or a speed discrimination task (control experiment 2), ruling out any possible interpretation in terms of adaptation or training-induced attentional bias. Furthermore, training with a direction discrimination task along a direction 150° away from both directions in the transparent stimulus (control experiment 3) also had little effect on the amount of motion repulsion, ruling out the contribution of task learning. The changed motion repulsion observed in the main experiment was consistent with the prediction of the recurrent model of perceptual learning. Therefore, our findings demonstrate that training in direction discrimination can benefit the precise direction perception of the transparent stimulus and provide new evidence for the recurrent model of perceptual learning.

Targeted Muscle Reinnervation for Real-Time Myoelectric Control of Multifunction Artificial Arms

PubMed Central

Kuiken, Todd A.; Li, Guanglin; Lock, Blair A.; Lipschutz, Robert D.; Miller, Laura A.; Stubblefield, Kathy A.; Englehart, Kevin

2011-01-01

Context Improving the function of prosthetic arms remains a challenge, as access to the neural control information for the arm is lost during amputation. We have developed a surgical technique called targeted muscle reinnervation (TMR) which transfers residual arm nerves to alternative muscle sites. After reinnervation, these target muscles produce an electromyogram (EMG) on the surface of the skin that can be measured and used to control prosthetic arms. Objective Assess the performance of TMR upper-limb amputee patients using a pattern-recognition algorithm to decode EMG signals and control prosthetic arm motions. Design Surface EMG signals were recorded on participants and decoded using a pattern-recognition algorithm. The decoding program controlled the movement of a virtual prosthetic arm. Participants were instructed to perform various arm movements, and their abilities to control the virtual prosthetic arm were measured. In addition, TMR patients used the same control system to operate advanced arm prosthesis prototypes. Setting This study was conducted between January 2007 and January 2008 at the Rehabilitation Institute of Chicago. Participants This study included five patients with shoulder disarticulation or transhumeral amputations who received TMR surgery between February 2002 and October 2006. It also included five non-amputee (control) participants. Main Outcome Measure Performance metrics measured during virtual arm movements included motion-selection time, motion-completion time, and motion-completion (or `success') rate. Three of the TMR patients were also able to test advanced arm prostheses. Results TMR patients were able to repeatedly perform 10 different elbow, wrist and hand motions with the virtual prosthetic arm. For TMR patients, the average (standard deviation (SD)) motion-selection and motion-completion times for elbow and wrist movements were 0.22 s (0.06) and 1.29 s (0.15), respectively. These times were 0.06 s and 0.21 s longer than the average times of control participants. For TMR patients, the average (SD) motion-selection and motion-completion times for hand-grasp patterns were 0.38 s (0.12) and 1.54 s (0.27), respectively. TMR patients successfully completed an average (SD) of 96.3% (3.8) of elbow and wrist movements and 86.9% (13.9) of hand movements within 5 s, compared to 100% (0) and 96.7% (4.7) completed by controls. Three of the patients were able to demonstrate the use of this control system in advanced prostheses including motorized shoulders, elbows, wrists and hands. Conclusion These results suggest that reinnervated muscles can produce sufficient EMG information to control advanced artificial arms. PMID:19211469

Upper limb rehabilitation after spinal cord injury: a treatment based on a data glove and an immersive virtual reality environment.

PubMed

Dimbwadyo-Terrer, Iris; Trincado-Alonso, Fernando; de Los Reyes-Guzmán, Ana; Aznar, Miguel A; Alcubilla, Cesar; Pérez-Nombela, Soraya; Del Ama-Espinosa, Antonio; Polonio-López, Begoña; Gil-Agudo, Ángel

2016-08-01

Purpose state: The aim of this preliminary study was to test a data glove, CyberTouch™, combined with a virtual reality (VR) environment, for using in therapeutic training of reaching movements after spinal cord injury (SCI). Nine patients with thoracic SCI were selected to perform a pilot study by comparing two treatments: patients in the intervention group (IG) conducted a VR training based on the use of a data glove, CyberTouch™ for 2 weeks, while patients in the control group (CG) only underwent the traditional rehabilitation. Furthermore, two functional parameters were implemented in order to assess patient's performance of the sessions: normalized trajectory lengths and repeatability. Although no statistical significance was found, the data glove group seemed to obtain clinical changes in the muscle balance (MB) and functional parameters, and in the dexterity, coordination and fine grip tests. Moreover, every patient showed variations in at least one of the functional parameters, either along Y-axis trajectory or Z-axis trajectory. This study might be a step forward for the investigation of new uses of motion capture systems in neurorehabilitation, making it possible to train activities of daily living (ADLs) in motivational environments while measuring objectively the patient's functional evolution. Implications for Rehabilitation Key findings: A motion capture application based on a data glove is presented, for being used as a virtual reality tool for rehabilitation. This application has provided objective data about patient's functional performance. What the study has added: (1) This study allows to open new areas of research based on the use of different motion capture systems as rehabilitation tools, making it possible to train Activities of Daily Living in motivational environments. (2) Furthermore, this study could be a contribution for the development of clinical protocols to identify which types of patients will benefit most from the VR treatments, which interfaces are more suitable to be used in neurorehabilitation, and what types of virtual exercises will work best.

Dynamical simulation priors for human motion tracking.

PubMed

Vondrak, Marek; Sigal, Leonid; Jenkins, Odest Chadwicke

2013-01-01

We propose a simulation-based dynamical motion prior for tracking human motion from video in presence of physical ground-person interactions. Most tracking approaches to date have focused on efficient inference algorithms and/or learning of prior kinematic motion models; however, few can explicitly account for the physical plausibility of recovered motion. Here, we aim to recover physically plausible motion of a single articulated human subject. Toward this end, we propose a full-body 3D physical simulation-based prior that explicitly incorporates a model of human dynamics into the Bayesian filtering framework. We consider the motion of the subject to be generated by a feedback “control loop” in which Newtonian physics approximates the rigid-body motion dynamics of the human and the environment through the application and integration of interaction forces, motor forces, and gravity. Interaction forces prevent physically impossible hypotheses, enable more appropriate reactions to the environment (e.g., ground contacts), and are produced from detected human-environment collisions. Motor forces actuate the body, ensure that proposed pose transitions are physically feasible, and are generated using a motion controller. For efficient inference in the resulting high-dimensional state space, we utilize an exemplar-based control strategy that reduces the effective search space of motor forces. As a result, we are able to recover physically plausible motion of human subjects from monocular and multiview video. We show, both quantitatively and qualitatively, that our approach performs favorably with respect to Bayesian filtering methods with standard motion priors.

A Nonlinear, Human-Centered Approach to Motion Cueing with a Neurocomputing Solver

NASA Technical Reports Server (NTRS)

Telban, Robert J.; Cardullo, Frank M.; Houck, Jacob A.

2002-01-01

This paper discusses the continuation of research into the development of new motion cueing algorithms first reported in 1999. In this earlier work, two viable approaches to motion cueing were identified: the coordinated adaptive washout algorithm or 'adaptive algorithm', and the 'optimal algorithm'. In this study, a novel approach to motion cueing is discussed that would combine features of both algorithms. The new algorithm is formulated as a linear optimal control problem, incorporating improved vestibular models and an integrated visual-vestibular motion perception model previously reported. A control law is generated from the motion platform states, resulting in a set of nonlinear cueing filters. The time-varying control law requires the matrix Riccati equation to be solved in real time. Therefore, in order to meet the real time requirement, a neurocomputing approach is used to solve this computationally challenging problem. Single degree-of-freedom responses for the nonlinear algorithm were generated and compared to the adaptive and optimal algorithms. Results for the heave mode show the nonlinear algorithm producing a motion cue with a time-varying washout, sustaining small cues for a longer duration and washing out larger cues more quickly. The addition of the optokinetic influence from the integrated perception model was shown to improve the response to a surge input, producing a specific force response with no steady-state washout. Improved cues are also observed for responses to a sway input. Yaw mode responses reveal that the nonlinear algorithm improves the motion cues by reducing the magnitude of negative cues. The effectiveness of the nonlinear algorithm as compared to the adaptive and linear optimal algorithms will be evaluated on a motion platform, the NASA Langley Research Center Visual Motion Simulator (VMS), and ultimately the Cockpit Motion Facility (CMF) with a series of pilot controlled maneuvers. A proposed experimental procedure is discussed. The results of this evaluation will be used to assess motion cueing performance.

MO-B-201-00: Motion Management in Current Stereotactic Body Radiation Therapy (SBRT) Practice

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

NONE

The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on-going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects to these different imaging processes is a prerequisite for a decent motion management program. The commonly used motion control techniques to physically restrict tumor motion, if adopted correctly, effectively increase the conformity and accuracy of hypofractionated treatment. The effective application of such requires one to understand the mechanicsmore » of the application and the related physiology especially related to respiration. The image-guided radiation beam control, or tumor tracking, further realized the endeavor for precision-targeting. During tumor tracking, the respiratory motion is often constantly monitored by non-ionizing beam sources using the body surface as its surrogate. This then has to synchronize with the actual internal tumor motion. The latter is often accomplished by stereo X-ray imaging or similar techniques. With these advanced technologies, one may drastically reduce the treated volume and increase the clinicians’ confidence for a high fractional ablative radiation dose. However, the challenges in implementing the motion management may not be trivial and is dependent on each clinic case. This session of presentations is intended to provide an overview of the current techniques used in managing the tumor motion in SBRT, specifically for routine lung SBRT, proton based treatments, and newly-developed MR guided RT. Learning Objectives: Through this presentation, the audience will understand basic roles of commonly used imaging modalities for lung cancer studies; familiarize the major advantages and limitations of each discussed motion control methods; familiarize the major advantages and limitations of each discussed radiation beam control methodology and tumor tacking method; understand the key points in motion management for a high quality SBRT program.« less

MO-B-201-01: Overcoming the Challenges of Motion Management in Current Lung SBRT Practice

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

Shang, C.

The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on-going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects to these different imaging processes is a prerequisite for a decent motion management program. The commonly used motion control techniques to physically restrict tumor motion, if adopted correctly, effectively increase the conformity and accuracy of hypofractionated treatment. The effective application of such requires one to understand the mechanicsmore » of the application and the related physiology especially related to respiration. The image-guided radiation beam control, or tumor tracking, further realized the endeavor for precision-targeting. During tumor tracking, the respiratory motion is often constantly monitored by non-ionizing beam sources using the body surface as its surrogate. This then has to synchronize with the actual internal tumor motion. The latter is often accomplished by stereo X-ray imaging or similar techniques. With these advanced technologies, one may drastically reduce the treated volume and increase the clinicians’ confidence for a high fractional ablative radiation dose. However, the challenges in implementing the motion management may not be trivial and is dependent on each clinic case. This session of presentations is intended to provide an overview of the current techniques used in managing the tumor motion in SBRT, specifically for routine lung SBRT, proton based treatments, and newly-developed MR guided RT. Learning Objectives: Through this presentation, the audience will understand basic roles of commonly used imaging modalities for lung cancer studies; familiarize the major advantages and limitations of each discussed motion control methods; familiarize the major advantages and limitations of each discussed radiation beam control methodology and tumor tacking method; understand the key points in motion management for a high quality SBRT program.« less

MO-B-201-02: Motion Management for Proton Lung SBR

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

Flampouri, S.

The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on-going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects to these different imaging processes is a prerequisite for a decent motion management program. The commonly used motion control techniques to physically restrict tumor motion, if adopted correctly, effectively increase the conformity and accuracy of hypofractionated treatment. The effective application of such requires one to understand the mechanicsmore » of the application and the related physiology especially related to respiration. The image-guided radiation beam control, or tumor tracking, further realized the endeavor for precision-targeting. During tumor tracking, the respiratory motion is often constantly monitored by non-ionizing beam sources using the body surface as its surrogate. This then has to synchronize with the actual internal tumor motion. The latter is often accomplished by stereo X-ray imaging or similar techniques. With these advanced technologies, one may drastically reduce the treated volume and increase the clinicians’ confidence for a high fractional ablative radiation dose. However, the challenges in implementing the motion management may not be trivial and is dependent on each clinic case. This session of presentations is intended to provide an overview of the current techniques used in managing the tumor motion in SBRT, specifically for routine lung SBRT, proton based treatments, and newly-developed MR guided RT. Learning Objectives: Through this presentation, the audience will understand basic roles of commonly used imaging modalities for lung cancer studies; familiarize the major advantages and limitations of each discussed motion control methods; familiarize the major advantages and limitations of each discussed radiation beam control methodology and tumor tacking method; understand the key points in motion management for a high quality SBRT program.« less

Wrist range of motion and motion frequency during toy and game play with a joint-specific controller specially designed to provide neuromuscular therapy: A proof of concept study in typically developing children.

PubMed

Crisco, Joseph J; Schwartz, Joel B; Wilcox, Bethany; Brideau, Holly; Basseches, Benjamin; Kerman, Karen

2015-08-20

Upper extremities affected by hemiplegic cerebral palsy (CP) and other neuromuscular disorders have been demonstrated to benefit from therapy, and the greater the duration of the therapy, the greater the benefit. A great motivator for participating in and extending the duration of therapy with children is play. Our focus is on active motion therapy of the wrist and forearm. In this study we examine the wrist motions associated with playing with two toys and three computer games controlled by a specially-designed play controller. Twenty children (ages 5-11) with no diagnosis of a muscular disorder were recruited. The play controller was fitted to the wrist and forearm of each child and used to measure and log wrist flexion and extension. Play activity and enjoyment were quantified by average wrist range of motion (ROM), motion frequency measures, and a discrete visual scale. We found significant differences in the average wrist ROM and motion frequency among the toys and games, yet there were no differences in the level of enjoyment across all toys and games, which was high. These findings indicate which toys and games may elicit the greater number of goal-directed movements, and lay the foundation for our long-term goal to develop and evaluate innovative motion-specific play controllers that are engaging rehabilitative devices for enhancing therapy and promoting neural plasticity and functional recovery in children with CP. Copyright © 2015 Elsevier Ltd. All rights reserved.

Three axis electronic flight motion simulator real time control system design and implementation

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

Gao, Zhiyuan; Miao, Zhonghua, E-mail: zhonghua-miao@163.com; Wang, Xiaohua

2014-12-15

A three axis electronic flight motion simulator is reported in this paper including the modelling, the controller design as well as the hardware implementation. This flight motion simulator could be used for inertial navigation test and high precision inertial navigation system with good dynamic and static performances. A real time control system is designed, several control system implementation problems were solved including time unification with parallel port interrupt, high speed finding-zero method of rotary inductosyn, zero-crossing management with continuous rotary, etc. Tests were carried out to show the effectiveness of the proposed real time control system.

Three axis electronic flight motion simulator real time control system design and implementation.

PubMed

Gao, Zhiyuan; Miao, Zhonghua; Wang, Xuyong; Wang, Xiaohua

2014-12-01

A three axis electronic flight motion simulator is reported in this paper including the modelling, the controller design as well as the hardware implementation. This flight motion simulator could be used for inertial navigation test and high precision inertial navigation system with good dynamic and static performances. A real time control system is designed, several control system implementation problems were solved including time unification with parallel port interrupt, high speed finding-zero method of rotary inductosyn, zero-crossing management with continuous rotary, etc. Tests were carried out to show the effectiveness of the proposed real time control system.

Experimental validation of flexible robot arm modeling and control

NASA Technical Reports Server (NTRS)

Ulsoy, A. Galip

1989-01-01

Flexibility is important for high speed, high precision operation of lightweight manipulators. Accurate dynamic modeling of flexible robot arms is needed. Previous work has mostly been based on linear elasticity with prescribed rigid body motions (i.e., no effect of flexible motion on rigid body motion). Little or no experimental validation of dynamic models for flexible arms is available. Experimental results are also limited for flexible arm control. Researchers include the effects of prismatic as well as revolute joints. They investigate the effect of full coupling between the rigid and flexible motions, and of axial shortening, and consider the control of flexible arms using only additional sensors.

Autogenic-feedback training exercise is superior to promethazine for control of motion sickness symptoms

NASA Technical Reports Server (NTRS)

Cowings, P. S.; Toscano, W. B.

2000-01-01

Motion sickness symptoms affect approximately 50% of the crew during space travel and are commonly treated with intramuscular injections of promethazine. The purpose of this paper is to compare the effectiveness of three treatments for motion sickness: intramuscular injections (i.m.) of promethazine, a physiological training method (autogenic-feedback training exercise [AFTE]), and a no-treatment control. An earlier study tested the effects of promethazine on cognitive and psychomotor performance and motion sickness tolerance in a rotating chair. For the present paper, motion sickness tolerance, symptom reports, and physiological responses of these subjects were compared to matched subjects selected from an existing database who received either AFTE or no treatment. Three groups of 11 men, between the ages of 33 and 40 years, were matched on the number of rotations tolerated during their initial rotating-chair motion sickness test. The motion sickness test procedures and the 7-day interval between tests were the same for all subjects. The drug group was tested under four treatment conditions: baseline (no injections), a 25 mg dose of promethazine, a 50 mg dose of promethazine, and a placebo of sterile saline. AFTE subjects were given four 30-minute AFTE sessions before their second, third, and fourth motion sickness tests (6 hours total). The no-treatment control subjects were only given the four rotating-chair tests. Motion sickness tolerance was significantly increased after 4 hours of AFTE when compared to either 25 mg (p < 0.00003) or 50 mg (p < 0.00001) of promethazine. The control and promethazine groups did not differ. AFTE subjects reported fewer or no symptoms at higher rotational velocities than subjects in the control or promethazine groups. The primary physiological effect of promethazine was an inhibition of skin conductance level. The AFTE group showed significantly less heart rate and skin conductance variability during motion sickness tests administered after training.

Autogenic-feedback training exercise is superior to promethazine for control of motion sickness symptoms.

PubMed

Cowings, P S; Toscano, W B

2000-10-01

Motion sickness symptoms affect approximately 50% of the crew during space travel and are commonly treated with intramuscular injections of promethazine. The purpose of this paper is to compare the effectiveness of three treatments for motion sickness: intramuscular injections (i.m.) of promethazine, a physiological training method (autogenic-feedback training exercise [AFTE]), and a no-treatment control. An earlier study tested the effects of promethazine on cognitive and psychomotor performance and motion sickness tolerance in a rotating chair. For the present paper, motion sickness tolerance, symptom reports, and physiological responses of these subjects were compared to matched subjects selected from an existing database who received either AFTE or no treatment. Three groups of 11 men, between the ages of 33 and 40 years, were matched on the number of rotations tolerated during their initial rotating-chair motion sickness test. The motion sickness test procedures and the 7-day interval between tests were the same for all subjects. The drug group was tested under four treatment conditions: baseline (no injections), a 25 mg dose of promethazine, a 50 mg dose of promethazine, and a placebo of sterile saline. AFTE subjects were given four 30-minute AFTE sessions before their second, third, and fourth motion sickness tests (6 hours total). The no-treatment control subjects were only given the four rotating-chair tests. Motion sickness tolerance was significantly increased after 4 hours of AFTE when compared to either 25 mg (p < 0.00003) or 50 mg (p < 0.00001) of promethazine. The control and promethazine groups did not differ. AFTE subjects reported fewer or no symptoms at higher rotational velocities than subjects in the control or promethazine groups. The primary physiological effect of promethazine was an inhibition of skin conductance level. The AFTE group showed significantly less heart rate and skin conductance variability during motion sickness tests administered after training.

Continuous decoding of human grasp kinematics using epidural and subdural signals

NASA Astrophysics Data System (ADS)

Flint, Robert D.; Rosenow, Joshua M.; Tate, Matthew C.; Slutzky, Marc W.

2017-02-01

Objective. Restoring or replacing function in paralyzed individuals will one day be achieved through the use of brain-machine interfaces. Regaining hand function is a major goal for paralyzed patients. Two competing prerequisites for the widespread adoption of any hand neuroprosthesis are accurate control over the fine details of movement, and minimized invasiveness. Here, we explore the interplay between these two goals by comparing our ability to decode hand movements with subdural and epidural field potentials (EFPs). Approach. We measured the accuracy of decoding continuous hand and finger kinematics during naturalistic grasping motions in five human subjects. We recorded subdural surface potentials (electrocorticography; ECoG) as well as with EFPs, with both standard- and high-resolution electrode arrays. Main results. In all five subjects, decoding of continuous kinematics significantly exceeded chance, using either EGoG or EFPs. ECoG decoding accuracy compared favorably with prior investigations of grasp kinematics (mean ± SD grasp aperture variance accounted for was 0.54 ± 0.05 across all subjects, 0.75 ± 0.09 for the best subject). In general, EFP decoding performed comparably to ECoG decoding. The 7-20 Hz and 70-115 Hz spectral bands contained the most information about grasp kinematics, with the 70-115 Hz band containing greater information about more subtle movements. Higher-resolution recording arrays provided clearly superior performance compared to standard-resolution arrays. Significance. To approach the fine motor control achieved by an intact brain-body system, it will be necessary to execute motor intent on a continuous basis with high accuracy. The current results demonstrate that this level of accuracy might be achievable not just with ECoG, but with EFPs as well. Epidural placement of electrodes is less invasive, and therefore may incur less risk of encephalitis or stroke than subdural placement of electrodes. Accurately decoding motor commands at the epidural level may be an important step towards a clinically viable brain-machine interface.

Continuous decoding of human grasp kinematics using epidural and subdural signals

PubMed Central

Flint, Robert D.; Rosenow, Joshua M.; Tate, Matthew C.; Slutzky, Marc W.

2017-01-01

Objective Restoring or replacing function in paralyzed individuals will one day be achieved through the use of brain-machine interfaces (BMIs). Regaining hand function is a major goal for paralyzed patients. Two competing prerequisites for the widespread adoption of any hand neuroprosthesis are: accurate control over the fine details of movement, and minimized invasiveness. Here, we explore the interplay between these two goals by comparing our ability to decode hand movements with subdural and epidural field potentials. Approach We measured the accuracy of decoding continuous hand and finger kinematics during naturalistic grasping motions in five human subjects. We recorded subdural surface potentials (electrocorticography; ECoG) as well as with epidural field potentials (EFPs), with both standard- and high-resolution electrode arrays. Main results In all five subjects, decoding of continuous kinematics significantly exceeded chance, using either EGoG or EFPs. ECoG decoding accuracy compared favorably with prior investigations of grasp kinematics (mean± SD grasp aperture variance accounted for was 0.54± 0.05 across all subjects, 0.75± 0.09 for the best subject). In general, EFP decoding performed comparably to ECoG decoding. The 7–20 Hz and 70–115 Hz spectral bands contained the most information about grasp kinematics, with the 70–115 Hz band containing greater information about more subtle movements. Higher-resolution recording arrays provided clearly superior performance compared to standard-resolution arrays. Significance To approach the fine motor control achieved by an intact brain-body system, it will be necessary to execute motor intent on a continuous basis with high accuracy. The current results demonstrate that this level of accuracy might be achievable not just with ECoG, but with EFPs as well. Epidural placement of electrodes is less invasive, and therefore may incur less risk of encephalitis or stroke than subdural placement of electrodes. Accurately decoding motor commands at the epidural level may be an important step towards a clinically viable brain-machine interface. PMID:27900947

Comparison of Observed Spatio-temporal Aftershock Patterns with Earthquake Simulator Results

NASA Astrophysics Data System (ADS)

Kroll, K.; Richards-Dinger, K. B.; Dieterich, J. H.

2013-12-01

Due to the complex nature of faulting in southern California, knowledge of rupture behavior near fault step-overs is of critical importance to properly quantify and mitigate seismic hazards. Estimates of earthquake probability are complicated by the uncertainty that a rupture will stop at or jump a fault step-over, which affects both the magnitude and frequency of occurrence of earthquakes. In recent years, earthquake simulators and dynamic rupture models have begun to address the effects of complex fault geometries on earthquake ground motions and rupture propagation. Early models incorporated vertical faults with highly simplified geometries. Many current studies examine the effects of varied fault geometry, fault step-overs, and fault bends on rupture patterns; however, these works are limited by the small numbers of integrated fault segments and simplified orientations. The previous work of Kroll et al., 2013 on the northern extent of the 2010 El Mayor-Cucapah rupture in the Yuha Desert region uses precise aftershock relocations to show an area of complex conjugate faulting within the step-over region between the Elsinore and Laguna Salada faults. Here, we employ an innovative approach of incorporating this fine-scale fault structure defined through seismological, geologic and geodetic means in the physics-based earthquake simulator, RSQSim, to explore the effects of fine-scale structures on stress transfer and rupture propagation and examine the mechanisms that control aftershock activity and local triggering of other large events. We run simulations with primary fault structures in state of California and northern Baja California and incorporate complex secondary faults in the Yuha Desert region. These models produce aftershock activity that enables comparison between the observed and predicted distribution and allow for examination of the mechanisms that control them. We investigate how the spatial and temporal distribution of aftershocks are affected by changes to model parameters such as shear and normal stress, rate-and-state frictional properties, fault geometry, and slip rate.

Reference equations of motion for automatic rendezvous and capture

NASA Technical Reports Server (NTRS)

Henderson, David M.

1992-01-01

The analysis presented in this paper defines the reference coordinate frames, equations of motion, and control parameters necessary to model the relative motion and attitude of spacecraft in close proximity with another space system during the Automatic Rendezvous and Capture phase of an on-orbit operation. The relative docking port target position vector and the attitude control matrix are defined based upon an arbitrary spacecraft design. These translation and rotation control parameters could be used to drive the error signal input to the vehicle flight control system. Measurements for these control parameters would become the bases for an autopilot or feedback control system (FCS) design for a specific spacecraft.

Comprehension of handwriting development: Pen-grip kinetics in handwriting tasks and its relation to fine motor skills among school-age children.

PubMed

Lin, Yu-Chen; Chao, Yen-Li; Wu, Shyi-Kuen; Lin, Ho-Hsio; Hsu, Chieh-Hsiang; Hsu, Hsiao-Man; Kuo, Li-Chieh

2017-10-01

Numerous tools have been developed to evaluate handwriting performances by analysing written products. However, few studies have directly investigated kinetic performances of digits when holding a pen. This study thus attempts to investigate pen-grip kinetics during writing tasks of school-age children and explore the relationship between the kinetic factors and fine motor skills. This study recruited 181 children aged from 5 to 12 years old and investigated the effects of age on handwriting kinetics and the relationship between these and fine motor skills. The forces applied from the digits and pen-tip were measured during writing tasks via a force acquisition pen, and the children's fine motor performances were also evaluated. The results indicate that peak force and average force might not be direct indicators of handwriting performance for normally developing children at this age. Younger children showed larger force variation and lower adjustment frequency during writing, which might indicate they had poorer force control than the older children. Force control when handling a pen is significantly correlated with fine motor performance, especially in relation to the manual dexterity. A novel system is proposed for analysing school-age children's force control while handwriting. We observed the development of force control in relation to pen grip among the children with different ages in this study. The findings suggested that manipulation skill may be crucial when children are establishing their handwriting capabilities. © 2017 Occupational Therapy Australia.

Semi-automated vectorial analysis of anorectal motion by magnetic resonance defecography in healthy subjects and fecal incontinence.

PubMed

Noelting, J; Bharucha, A E; Lake, D S; Manduca, A; Fletcher, J G; Riederer, S J; Joseph Melton, L; Zinsmeister, A R

2012-10-01

Inter-observer variability limits the reproducibility of pelvic floor motion measured by magnetic resonance imaging (MRI). Our aim was to develop a semi-automated program measuring pelvic floor motion in a reproducible and refined manner. Pelvic floor anatomy and motion during voluntary contraction (squeeze) and rectal evacuation were assessed by MRI in 64 women with fecal incontinence (FI) and 64 age-matched controls. A radiologist measured anorectal angles and anorectal junction motion. A semi-automated program did the same and also dissected anorectal motion into perpendicular vectors representing the puborectalis and other pelvic floor muscles, assessed the pubococcygeal angle, and evaluated pelvic rotation. Manual and semi-automated measurements of anorectal junction motion (r = 0.70; P < 0.0001) during squeeze and evacuation were correlated, as were anorectal angles at rest, squeeze, and evacuation; angle change during squeeze or evacuation was less so. Semi-automated measurements of anorectal and pelvic bony motion were also reproducible within subjects. During squeeze, puborectalis injury was associated (P ≤ 0.01) with smaller puborectalis but not pelvic floor motion vectors, reflecting impaired puborectalis function. The pubococcygeal angle, reflecting posterior pelvic floor motion, was smaller during squeeze and larger during evacuation. However, pubococcygeal angles and pelvic rotation during squeeze and evacuation did not differ significantly between FI and controls. This semi-automated program provides a reproducible, efficient, and refined analysis of pelvic floor motion by MRI. Puborectalis injury is independently associated with impaired motion of puborectalis, not other pelvic floor muscles in controls and women with FI. © 2012 Blackwell Publishing Ltd.

Controlled Wake of a Moving Axisymmetric Bluff Body

NASA Astrophysics Data System (ADS)

Lee, E.; Vukasinovic, B.; Glezer, A.

2017-11-01

The aerodynamic loads exerted on a wire-mounted axisymmetric bluff body in prescribed rigid motion are controlled by fluidic manipulation of its near wake. The body is supported by a six-degree of freedom eight-wire traverse and its motion is controlled using a dedicated servo actuator and inline load cell for each wire. The instantaneous aerodynamic forces and moments on the moving body are manipulated by controlled interactions of an azimuthal array of integrated synthetic jet actuators with the cross flow to induce localized flow attachment over the body's aft end and thereby alter the symmetry of the wake. The coupled interactions between the wake structure and the effected aerodynamic loads during prescribed time-periodic and transitory (gust like) motions are investigated with emphasis on enhancing or diminishing the loads for maneuver control, and decoupling the body's motion from its far wake.

Neuroanatomical correlates of biological motion detection.

PubMed

Gilaie-Dotan, Sharon; Kanai, Ryota; Bahrami, Bahador; Rees, Geraint; Saygin, Ayse P

2013-02-01

Biological motion detection is both commonplace and important, but there is great inter-individual variability in this ability, the neural basis of which is currently unknown. Here we examined whether the behavioral variability in biological motion detection is reflected in brain anatomy. Perceptual thresholds for detection of biological motion and control conditions (non-biological object motion detection and motion coherence) were determined in a group of healthy human adults (n=31) together with structural magnetic resonance images of the brain. Voxel based morphometry analyzes revealed that gray matter volumes of left posterior superior temporal sulcus (pSTS) and left ventral premotor cortex (vPMC) significantly predicted individual differences in biological motion detection, but showed no significant relationship with performance on the control tasks. Our study reveals a neural basis associated with the inter-individual variability in biological motion detection, reliably linking the neuroanatomical structure of left pSTS and vPMC with biological motion detection performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

Practical controller design for ultra-precision positioning of stages with a pneumatic artificial muscle actuator

NASA Astrophysics Data System (ADS)

Tang, T. F.; Chong, S. H.

2017-06-01

This paper presents a practical controller design method for ultra-precision positioning of pneumatic artificial muscle actuator stages. Pneumatic artificial muscle (PAM) actuators are safe to use and have numerous advantages which have brought these actuators to wide applications. However, PAM exhibits strong non-linear characteristics, and these limitations lead to low controllability and limit its application. In practice, the non-linear characteristics of PAM mechanism are difficult to be precisely modeled, and time consuming to model them accurately. The purpose of the present study is to clarify a practical controller design method that emphasizes a simple design procedure that does not acquire plants parameters modeling, and yet is able to demonstrate ultra-precision positioning performance for a PAM driven stage. The practical control approach adopts continuous motion nominal characteristic trajectory following (CM NCTF) control as the feedback controller. The constructed PAM driven stage is in low damping characteristic and causes severe residual vibration that deteriorates motion accuracy of the system. Therefore, the idea to increase the damping characteristic by having an acceleration feedback compensation to the plant has been proposed. The effectiveness of the proposed controller was verified experimentally and compared with a classical PI controller in point-to-point motion. The experiment results proved that the CM NCTF controller demonstrates better positioning performance in smaller motion error than the PI controller. Overall, the CM NCTF controller has successfully to reduce motion error to 3µm, which is 88.7% smaller than the PI controller.

Asymmetry of neck motion and activation of the cervical paraspinal muscles during prone neck extension in subjects with unilateral posterior neck pain.

PubMed

Park, Kyue-Nam; Kwon, Oh-Yun; Kim, Su-Jung; Kim, Si-Hyun

2017-01-01

Although unilateral posterior neck pain (UPNP) is more prevalent than central neck pain, little is known about how UPNP affects neck motion and the muscle activation pattern during prone neck extension. To investigate whether deviation in neck motion and asymmetry of activation of the bilateral cervical paraspinal muscles occur during prone neck extension in subjects with UPNP compared to subjects without UPNP. This study recruited 20 subjects with UPNP and 20 age- and sex-matched control subjects without such pain. Neck motion and muscle onset time during prone neck extension were measured using a three-dimensional motion-analysis system and surface electromyography. The deviation during prone neck extension was greater in the UPNP group than in the controls (p < 0.05). Compared with the controls, cervical extensor muscle activation in the UPNP group was significantly delayed on the painful side during prone neck extension (p < 0.05). Subjects with UPNP showed greater asymmetry of neck motion and muscle activation during prone neck extension compared with the controls. This suggests that UPNP has specific effects on neck motion asymmetry and the functions of the cervical extensors, triggering a need for specific evaluation and exercises in the management of patients with UPNP.

Bimorphic polymeric photomechanical actuator

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

2006-01-01

A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

How NASA KSC Controls Interfaces with the use of Motion Skeletons and Product Structure

NASA Technical Reports Server (NTRS)

Jones, Corey

2013-01-01

This presentation will show how NASA KSC controls interfaces for Modular Product Architecture (MPA) using Locator Skeletons, Interface Skeletons, and Product Structure, to be combined together within a Motion Skeleton. The user will learn how to utilize skeleton models to communicate interface data, as successfully done at NASA KSC in their use of Motion Skeletons to control interfaces for multi-launch systems. There will be discussion of the methodology used to control design requirements through WTParts, and how to utilize product structure for non-CAD documents.

Optics derotator servo control system for SONG Telescope

NASA Astrophysics Data System (ADS)

Xu, Jin; Ren, Changzhi; Ye, Yu

2012-09-01

The Stellar Oscillations Network Group (SONG) is an initiative which aims at designing and building a groundbased network of 1m telescopes dedicated to the study of phenomena occurring in the time domain. Chinese standard node of SONG is an Alt-Az Telescope of F/37 with 1m diameter. Optics derotator control system of SONG telescope adopts the development model of "Industrial Computer + UMAC Motion Controller + Servo Motor".1 Industrial computer is the core processing part of the motion control, motion control card(UMAC) is in charge of the details on the motion control, Servo amplifier accepts the control commands from UMAC, and drives the servo motor. The position feedback information comes from the encoder, to form a closed loop control system. This paper describes in detail hardware design and software design for the optics derotator servo control system. In terms of hardware design, the principle, structure, and control algorithm of servo system based on optics derotator are analyzed and explored. In terms of software design, the paper proposes the architecture of the system software based on Object-Oriented Programming.

EMG and EPP-integrated human-machine interface between the paralyzed and rehabilitation exoskeleton.

PubMed

Yin, Yue H; Fan, Yuan J; Xu, Li D

2012-07-01

Although a lower extremity exoskeleton shows great prospect in the rehabilitation of the lower limb, it has not yet been widely applied to the clinical rehabilitation of the paralyzed. This is partly caused by insufficient information interactions between the paralyzed and existing exoskeleton that cannot meet the requirements of harmonious control. In this research, a bidirectional human-machine interface including a neurofuzzy controller and an extended physiological proprioception (EPP) feedback system is developed by imitating the biological closed-loop control system of human body. The neurofuzzy controller is built to decode human motion in advance by the fusion of the fuzzy electromyographic signals reflecting human motion intention and the precise proprioception providing joint angular feedback information. It transmits control information from human to exoskeleton, while the EPP feedback system based on haptic stimuli transmits motion information of the exoskeleton back to the human. Joint angle and torque information are transmitted in the form of air pressure to the human body. The real-time bidirectional human-machine interface can help a patient with lower limb paralysis to control the exoskeleton with his/her healthy side and simultaneously perceive motion on the paralyzed side by EPP. The interface rebuilds a closed-loop motion control system for paralyzed patients and realizes harmonious control of the human-machine system.

Switching PD-based sliding mode control for hovering of a tilting-thruster underwater robot.

PubMed

Jin, Sangrok; Bak, Jeongae; Kim, Jongwon; Seo, TaeWon; Kim, Hwa Soo

2018-01-01

This paper presents a switching PD-based sliding mode control (PD-SMC) method for the 6-degree-of-freedom (DOF) hovering motion of the underwater robot with tilting thrusters. Four thrusters of robot can be tilted simultaneously in the horizontal and vertical directions, and the 6-DOF motion is achieved by switching between two thruster configurations. Therefore, the tilting speed of thruster becomes the most essential parameter to determine the stability of hovering motion. Even though the previous PD control ensures stable hovering motion within a certain ranges of tilting speed, a PD-SMC is suggested in this paper by combining PD control with sliding mode control in order to achieve acceptable hovering performance even at the much lower tilting speeds. Also, the sign function in the sliding mode control is replaced by a sigmoid function to reduce undesired chattering. Simulations show that while PD control is effective only for tilting duration of 600 ms, the PD-based sliding mode control can guarantee the stable hovering motion of underwater robot even for the tilting duration of up to 1500 ms. Extensive experimental results confirm the hovering performance of the proposed PD-SMC method is much superior to that of PD method for much larger tilting durations.

[Methodical problems of monitoring of fine particulate matters in atmospheric air of residential areas].

PubMed

Karelin, A O; Lomtev, A Yu; Mozzhukhina, N A; Yeremin, G B; Nikonov, V A

Inhalation of fine particulate matters (PM and PM ) poses a threat for the health of population. Purpose of the study the analysis of the monitoring of fine particulate matters in the atmospheric air of Saint-Petersburg and identification of the main problems of the monitoring. Research methods methods of scientific hypothetical deductive cognition, sanitary-statistical methods, general logical methods and approaches of researches: analysis, synthesis, abstracting, generalization, induction. Results. The article represents the analysis of the monitoring of fine particulate matters in the atmospheric air of Saint- Petersburg. Only 11 in automatic monitoring stations out of 22 there is carried out the control of fine particulate matters: in 7 - PM and PM, and in 4 - PM The average year concentrations were below MAC in all the stations. The maximum concentrations achieved 3 MAC, but the repeatance of cases of exceedence of concentrations more than MAC was very rare. On the average of the city concentrations of PM were decreased from 0,8 MAC in 2006 and 1,1 MAC in 2007 to 0,5 MAC in 2013-14. The executed analysis revealed main problems of the monitoring of fine particulate matters in the Russian Federation. They include the absence of the usage 1of the officially approved methods of controlling of PM and PM in the atmospheric air until March 1, 2016, lack of the modern equipment for measurement of fine particulate matters. Conclusions. Therefore, the state of the monitoring of fine particulate matters in the atmospheric air in the Russian Federation fails to be satisfactory. It is necessary to improve system of the monitoring, create modern Russian appliances, methods and means for measurement of fine particulate matters concentrations in the atmospheric air.

Motion planning in velocity affine mechanical systems

NASA Astrophysics Data System (ADS)

Jakubiak, Janusz; Tchoń, Krzysztof; Magiera, Władysław

2010-09-01

We address the motion planning problem in specific mechanical systems whose linear and angular velocities depend affinely on control. The configuration space of these systems encompasses the rotation group, and the motion planning involves the system orientation. Derivation of the motion planning algorithm for velocity affine systems has been inspired by the continuation method. Performance of this algorithm is illustrated with examples of the kinematics of a serial nonholonomic manipulator, the plate-ball kinematics and the attitude control of a rigid body.

Sensory perception. [role of human vestibular system in dynamic space perception and manual vehicle control

NASA Technical Reports Server (NTRS)

1974-01-01

The effect of motion on the ability of men to perform a variety of control actions was investigated. Special attention was given to experimental and analytical studies of the dynamic characteristics of the otoliths and semicircular canals using a two axis angular motion simulator and a one axis linear motion simulator.

The influence of motion control shoes on the running gait of mature and young females.

PubMed

Lilley, Kim; Stiles, Vicky; Dixon, Sharon

2013-03-01

This study compared the running gait of mature and young females, and investigated the effect of a motion control shoe. First, it was hypothesised that in a neutral shoe, mature females would display significantly greater rearfoot eversion, knee internal rotation and external adductor moments when compared to a younger group. Secondly, the motion control shoe would reduce rearfoot eversion and knee internal rotation in both groups. Thirdly it was hypothesised that the motion control shoe would increase knee external adductor moment, through an increase in knee varus and moment arm. 15 mature (40-60 years) and 15 young (18-25 years) females performed 10 running trials at 3.5ms(-1)±5% over a force platform. Two shoes were tested, the Adidas Supernova Glide (neutral), and the Adidas Supernova Sequence (motion control). Ankle and knee joint dynamics were analysed for the right leg, and the mean of ten trials was calculated. Joint moments were calculated using inverse dynamics. In the neutral condition, mature females presented greater peak rearfoot eversion, knee internal rotation, and external adductor moments than young females (p<0.05). A motion control shoe significantly reduced peak rearfoot eversion and knee internal rotation among both groups (p<0.05). No between shoe differences in knee external adductor moment were observed. A motion control shoe is recommended to reduce risk of injury associated with rearfoot eversion and knee internal rotation in mature females. However since the knee external adductor moment is a variable commonly associated with medial knee loading it is suggested that alternative design features are required to influence this moment. Copyright © 2012 Elsevier B.V. All rights reserved.