Longitudinal coupling impedance imposed by a beam feedback in a synchrotron

International Nuclear Information System (INIS)

Ivanov, S.

1997-01-01

Commonly, a longitudinal beam feedback processes a slowly varying signal at zero intermediate frequency (a phase offset, an amplitude departure). Often, only a portion of the data confined in a picked-up band-pass beam signal is retained (like, say, in a purely phase feedback). Sometimes, a beam feedback employs different RF bands to pick up beam data and return a correction back to the beam. All the manipulations thus involved with signal spectra result in cross-talk between various beam-current and electric-field waves propagating along the orbit, which is shown to be described by an impedance matrix with, at most, three non-trivial elements per row. It is this matrix which gives the intuitive notion that a linear feedback is seen by a beam as an artificial coupling impedance controlled from the outside from a quantitative basis. This (impedance) approach has at least two plain advantages: (i) It allows one to mount the feedback's effect into the well-established theory of longitudinal coherent instabilities to use most of its inventory: beam transfer functions, threshold maps, handling of coupled-bunch motion, etc. (ii) The destabilizing effect of the beam environment, being available in standard terms of coupling impedances, is naturally taken into account since the early stages of feedback R and D. (orig.)

Intra-cavity decomposition of a dual-directional laser beam

CSIR Research Space (South Africa)

Naidoo, Darryl

2011-01-01

Full Text Available A method of decomposing a dual-directional laser beam into a forward propagating field and a backward propagating field for an apertured plano-concave cavity is presented. An intra-cavity aperture is a simple method of laser beam shaping as higher...

Fast digital transverse feedback system for bunch train operation in CESR

International Nuclear Information System (INIS)

Rogers, J.T.; Billing, M.G.; Dobbins, J.A.

1996-01-01

We have developed a time domain transverse feedback system with the high bandwidth needed to control transverse instabilities when the CESR e + e - collider is filled with trains of closely spaced bunches. This system is based on parallel digital processors and a stripline driver. It is capable of acting on arbitrary patterns of bunches having a minimum spacing of 14 ns. Several simplifying features have been introduced. A single shorted stripline kicker driven by one power amplifier is used to control both counter-rotating beams. The desired feedback phase is achieved by sampling the bunch position at a single location on two independently selectable beam revolutions. The system adapts to changes in the betatron tune, bunch pattern, or desired damping rate through the loading of new parameters into the digital processors via the CESR control system. The feedback system also functions as a fast gated bunch current monitor. Both vertical and horizontal loops are now used in CESR operation. The measured betatron damping rates with the transverse feedback system in operation are in agreement with the analytical prediction and a computer simulation developed in connection with this work. (author)

Fast digital transverse feedback system for bunch train operation in CESR

Energy Technology Data Exchange (ETDEWEB)

Rogers, J T; Billing, M G; Dobbins, J A [Cornell Univ., Ithaca, NY (United States). Lab. of Nuclear Studies; and others

1996-08-01

We have developed a time domain transverse feedback system with the high bandwidth needed to control transverse instabilities when the CESR e{sup +}e{sup -} collider is filled with trains of closely spaced bunches. This system is based on parallel digital processors and a stripline driver. It is capable of acting on arbitrary patterns of bunches having a minimum spacing of 14 ns. Several simplifying features have been introduced. A single shorted stripline kicker driven by one power amplifier is used to control both counter-rotating beams. The desired feedback phase is achieved by sampling the bunch position at a single location on two independently selectable beam revolutions. The system adapts to changes in the betatron tune, bunch pattern, or desired damping rate through the loading of new parameters into the digital processors via the CESR control system. The feedback system also functions as a fast gated bunch current monitor. Both vertical and horizontal loops are now used in CESR operation. The measured betatron damping rates with the transverse feedback system in operation are in agreement with the analytical prediction and a computer simulation developed in connection with this work. (author)

PLS beam position measurement and feedback system

International Nuclear Information System (INIS)

Huang, J.Y.; Lee, J.; Park, M.K.; Kim, J.H.; Won, S.C.

1992-01-01

A real-time orbit correction system is proposed for the stabilization of beam orbit and photon beam positions in Pohang Light Source. PLS beam position monitoring system is designed to be VMEbus compatible to fit the real-time digital orbit feedback system. A VMEbus based subsystem control computer, Mil-1553B communication network and 12 BPM/PS machine interface units constitute digital part of the feedback system. With the super-stable PLS correction magnet power supply, power line frequency noise is almost filtered out and the dominant spectra of beam obtit fluctuations are expected to appear below 15 Hz. Using DSP board in SCC for the computation and using an appropriate compensation circuit for the phase delay by the vacuum chamber, PLS real-time orbit correction system is realizable without changing the basic structure of PLS computer control system. (author)

Stochastic cooling and intra-beam scattering in RHIC

International Nuclear Information System (INIS)

Wei, J.

1993-01-01

During the storage of the heavy ion beam in the Relativistic Heavy Ion Collider (RHIC), the luminosity deterioration due to beam growth and particle loss caused by intra-beam scattering (IBS) is of primary concern. In this paper, the authors study compensation methods using bunched beam stochastic cooling. With longitudinal and transverse stochastic cooling of 4--8 GHz bandwidth, the longitudinal beam loss resulting from the inadequacy of the rf voltage can be eliminated, and the transverse normalized beam emittance can be confined to about 30π mm·mrad. With such an emittance, the β* at the crossing point can be lowered under 1 meter without exceeding the transverse aperture limit at the focusing triplets. The achievable luminosity can thus be significantly improved

Beam bunch feedback

International Nuclear Information System (INIS)

Lambertson, G.

1995-09-01

When the electromagnetic fields that are excited by the passage of a bundle of charged particles persist to act upon bunches that follow, then the motions of the bunches are coupled. This action between bunches circulating on a closed orbit can generate growing patterns of bunch excursions. Such growth can often be suppressed by feedback systems that detect the excursion and apply corrective forces to the bunches. To be addressed herein is feedback that acts on motions of the bunch body centers. In addition to being useful for suppressing the spontaneous growth of coupled-bunch motions, such feedback can be used to damp transients in bunches injected into an accelerator or storage ring; for hadrons which lack strong radiation damping, feedback is needed to avoid emittance growth through decoherence. Motions excited by noise in magnetic fields or accelerating rf can also be reduced by using this feedback. Whether the action is on motions that are transverse to the closed orbit or longitudinal, the arrangement is the same. Bunch position is detected by a pickup and that signal is processed and directed to a kicker that may act upon the same bunch or some other portion of the collective beam pattern. Transverse motion is an oscillation with angular frequency ν perpendicular ω o where ω o is the orbital frequency 2π line-integral o. Longitudinal synchrotron oscillation occurs at frequency ω s = ν s ω o . The former is much more rapid, ν perpendicular being on the order of 10 while ν s is typically about 10 minus 1 to 10 minus 2

Interface Prostheses With Classifier-Feedback-Based User Training.

Science.gov (United States)

Fang, Yinfeng; Zhou, Dalin; Li, Kairu; Liu, Honghai

2017-11-01

It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well as the centroids of the training samples, whose dimensionality is reduced to minimal number by dimension reduction. Clustering feedback provides a criterion that guides users to adjust motion gestures and muscle contraction forces intentionally. The experiment results have demonstrated that hand motion recognition accuracy increases steadily along the progress of the clustering-feedback-based user training, while conventional classifier-feedback methods, i.e., label feedback, hardly achieve any improvement. The result concludes that the use of proper classifier feedback can accelerate the process of user training, and implies prosperous future for the amputees with limited or no experience in pattern-recognition-based prosthetic device manipulation.It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well

A unified approach to global and local beam position feedback

International Nuclear Information System (INIS)

Chung, Y.

1994-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The global feedback system uses 40 BPMs and 40 correctors per plane. Singular value decomposition (SVD) of the response matrix is used for closed orbit correction. The local feedback system uses two X-ray BPMS, two rf BPMS, and the four-magnet local bump to control the angle and displacement of the X-ray beam from a bending magnet or an insertion device. Both the global and local feedback systems are based on digital signal processing (DSP) running at 4-kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. In this paper, we will discuss resolution of the conflict among multiple local feedback systems due to local bump closure error and decoupling of the global and local feedback systems to maximize correction efficiency. In this scheme, the global feedback system absorbs the local bump closure error and the local feedback systems compensate for the effect of global feedback on the local beamlines. The required data sharing between the global and local feedback systems is done through the fiber-optically networked reflective memory

Intra-laser-cavity microparticle sensing with a dual-wavelength distributed-feedback laser

NARCIS (Netherlands)

Bernhardi, Edward H.; van der Werf, Kees O; Hollink, Anton J F; Wörhoff, Kerstin; de Ridder, René M; Subramaniam, Vinod; Pollnau, Markus

An integrated intra-laser-cavity microparticle sensor based on a dual-wavelength distributed-feedback channel waveguide laser in ytterbium-doped amorphous aluminum oxide on a silicon substrate is demonstrated. Real-time detection and accurate size measurement of single micro-particles with diameters

A state variable approach to the BESSY II local beam-position-feedback system

International Nuclear Information System (INIS)

Gilpatrick, J.D.; Khan, S.; Kraemer, D.

1996-01-01

At the BESSY II facility, stability of the electron beam position and angle near insertion devices (IDs) is of utmost importance. Disturbances due to ground motion could result in unwanted broad-bandwidth beam-jitter which decreases the electron (and resultant photon) beam's effective brightness. Therefore, feedback techniques must be used. Operating over a frequency range of 100-Hz, a local feedback system will correct these beam-trajectory errors using the four bumps around IDs. This paper reviews how the state-variable feedback approach can be applied to real-time correction of these beam position and angle errors. A frequency-domain solution showing beam jitter reduction is presented. Finally, this paper reports results of a beam-feedback test at BESSY I

Feedback control and beam diagnostic algorithms for a multiprocessor DSP system

International Nuclear Information System (INIS)

Teytelman, D.; Claus, R.; Fox, J.; Hindi, H.; Linscott, I.; Prabhakar, S.

1996-09-01

The multibunch longitudinal feedback system developed for use by PEP-II, ALS and DAΦNE uses a parallel array of digital signal processors to calculate the feedback signals from measurements of beam motion. The system is designed with general-purpose programmable elements which allow many feedback operating modes as well as system diagnostics, calibrations and accelerator measurements. The overall signal processing architecture of the system is illustrated. The real-time DSP algorithms and off-line postprocessing tools are presented. The problems in managing 320 K samples of data collected in one beam transient measurement are discussed and the solutions are presented. Example software structures are presented showing the beam feedback process, techniques for modal analysis of beam motion(used to quantify growth and damping rates of instabilities) and diagnostic functions (such as timing adjustment of beam pick-up and kicker components). These operating techniques are illustrated with example results obtained from the system installed at the Advanced Light Source at LBL

Operation of the PEP transverse beam feedback

International Nuclear Information System (INIS)

Olson, C.W.; Paterson, J.M.; Pellegrin, J.L.; Rees, J.R.

1981-02-01

The PEP Storage Ring has been equipped with a wide band beam feedback system capable of damping the vertical and horizontal motion of six bunches. The oscillation detection is done at a symmetry point on the Storage Ring and feedback is applied at the same location one orbital period later. The signal is synchronously gated and the system appears as twelve independent feedback loops, operating on the two coordinates of each of the six bunches. Two beam deflection electrodes are driven each by a low-Q push-pull amplifier which is tuned at the 72nd harmonic of the revolution frequency and suppressed-carrier modulation is generated by a sequence of the detected bunch oscillations. The design parameters are reviewed as well as the salient features of the hardware, and the impact of this system on the machine operation is evaluated in the light of experimental results

Distortion of optical feedback signals in microchip Nd:YAG lasers subjected to external multi-beam interference feedback

International Nuclear Information System (INIS)

Yi-Dong, Tan; Shu-Lian, Zhang; Zhou, Ren; Cheng, Ren; Yi-Nan, Zhang

2010-01-01

This paper proposes a theoretical analysis for the characteristics of an external cavity Nd:YAG laser with feedback of multiple-beam interference, which is induced by the multi-reentrance of the light from the external Fabry–Perot cavity. The theoretical model considers the multiple beam interference of the external Fabry–Perot cavity. It is found that the optical feedback signals are distorted to pulse waveforms instead of the sinusoidal ones in conventional feedback. The experimental results are in good agreement with the theoretical analysis. The obtained theoretical and experimental results can advance the development of a laser feedback interferometer

Tutorial on beam-based feedback systems for linacs

International Nuclear Information System (INIS)

Hendrickson, L.; Allison, S.; Gromme, T.; Grossberg, P.; Himel, T.; Krauter, K.; MacKenzie, R.; Ross, M.; Sass, R.; Shoaee, H.

1994-08-01

A generalized fast feedback system stabilizes beams in the SLC. It performs measurements and modifies actuator settings to control beam states such as position, angle, energy and intensity on a pulse to pulse basis. An adaptive cascade feature allows communication between a series of linac loops, avoiding overcorrection problems. The system is based on the state space formalism of digital control theory. Due to the database-driven design, new loops are added without requiring software modifications. Recent enhancements support the monitoring and control of nonlinear states such as beam phase using excitation techniques. In over three years of operation, the feedback system has grown from its original eight loops to more than fifty loops, and it has been invaluable in stabilizing the machine

Intra-cavity metamorphosis of a Gaussian beam to flat-top distribution

CSIR Research Space (South Africa)

Naidoo, Darryl

2014-02-01

Full Text Available We explore an intra-cavity beam shaping approach to generate a Gaussian distribution by the metamorphosis of a Gaussian beam into a flat-top distribution on opposing mirrors. The concept is tested external to the cavity through the use of two...

Beam position feedback system for the advanced photon source

International Nuclear Information System (INIS)

Chung, Y.

1994-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and x-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4 kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and x-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back to the global orbit data to the local feedback systems. The effect of the eddy current induced in the relatively thick (1/2 in.) vacuum chamber by the ac corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the x-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will also be presented

Beam position feedback system for the advanced photon source

International Nuclear Information System (INIS)

Chung, Y.

1994-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4 kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the vacuum chamber eddy current induced by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will be presented. copyright 1994 American Institute of Physics

Beam position feedback system for the Advanced Photon Source

International Nuclear Information System (INIS)

Chung, Y.

1993-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the vacuum chamber eddy current induced by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will be presented

Beam position feedback system for the Advanced Photon Source

International Nuclear Information System (INIS)

Chung, Y.

1993-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the eddy current induced in the relatively thick (1/2 inch) vacuum chamber by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will also be presented

Evaluation of Augmented Reality Feedback in Surgical Training Environment.

Science.gov (United States)

Zahiri, Mohsen; Nelson, Carl A; Oleynikov, Dmitry; Siu, Ka-Chun

2018-02-01

Providing computer-based laparoscopic surgical training has several advantages that enhance the training process. Self-evaluation and real-time performance feedback are 2 of these advantages, which avoid dependency of trainees on expert feedback. The goal of this study was to investigate the use of a visual time indicator as real-time feedback correlated with the laparoscopic surgical training. Twenty novices participated in this study working with (and without) different presentations of time indicators. They performed a standard peg transfer task, and their completion times and muscle activity were recorded and compared. Also of interest was whether the use of this type of feedback induced any side effect in terms of motivation or muscle fatigue. Of the 20 participants, 15 (75%) preferred using a time indicator in the training process rather than having no feedback. However, time to task completion showed no significant difference in performance with the time indicator; furthermore, no significant differences in muscle activity or muscle fatigue were detected with/without time feedback. The absence of significant difference between task performance with/without time feedback shows that using visual real-time feedback can be included in surgical training based on user preference. Trainees may benefit from this type of feedback in the form of increased motivation. The extent to which this can influence training frequency leading to performance improvement is a question for further study.

Feedback-Training für Lehrärzte in der Allgemeinmedizin [Feedback training for general practitioners involved in teaching

Directory of Open Access Journals (Sweden)

Engeser, Peter

2010-02-01

Full Text Available [english] Background: Ever since the last amendment to the German Medical Licensing Act took effect in 2002, medical students may complete four months of the Practical Year (PY in general practices. Formative feedback between the teaching general practitioner (GP and the PY student is a key element in creating a learning environment. GPs involved in teaching therefore need further education in giving feedback.Methods: A 4-hour feedback training session for GPs involved in teaching which used standardized patients and students was developed and tested in a pilot study. In role plays, GPs experienced feedback situations. Using an evaluation questionnaire, changes in self-perceived feedback skills were assessed (familiarity of feedback rules, preparation for giving feedback to PY students, possibilities to improve communication skills in doctor–patient situations.Results: Sixteen GPs who were involved or interested in PY teaching participated in the feedback training program. Afterwards, participants said they felt more comfortable in giving formative feedback and more assured in their communication skills. The confidence in their own feedback improved, especially by taking the student’s part in the role plays. An exercise between a standardized patient and a standardized stubborn student was a challenge, but proved to be extremely useful.Conclusion: The opinions of the participating GPs to the feedback training underscore its importance. Therefore, we recommend integrating such a feedback training program into the education of GPs involved in teaching.[german] Hintergrund: Seit der letzten Novelle der Approbationsordnung 2002 besteht die Möglichkeit, ein Tertial des Praktischen Jahres (PJ in Hausarztpraxen zu absolvieren. Konstruktives Feedback zwischen Arzt und PJ-Studenten ist dabei ein zentrales Element in der Gestaltung des Lernumfeldes in der Arztpraxis. Es bedarf dahingehend einer Ausbildung der in die Lehre involvierten

Nuclear training and experience feedback in Sweden

International Nuclear Information System (INIS)

Olofsson, B.G.

1987-01-01

There are several different ways of educating and training the personnel at the Swedish nuclear power plants: centralized training in full-scale and part-task simulators; centralized education in the form of technical academic courses where computerized teaching is also used; extensive decentralized training out at the nuclear power plants, where compact simulators are also used; and experience feedback forms an important part of the training. Five performance indicators will be identified and the results will be presented. The excellent results are a good indication of the fact that well-executed education and training and smoothly functioning experience feedback give results

Coupled-Beam and Coupled-Bunch Instabilities

Energy Technology Data Exchange (ETDEWEB)

Burov, Alexey [Fermilab

2016-06-23

A problem of coupled-beam instability is solved for two multibunch beams with slightly different revolution frequencies, as in the Fermilab Recycler Ring (RR). Sharing of the inter-bunch growth rates between the intra-bunch modes is described. The general analysis is applied to the RR; possibilities to stabilize the beams by means of chromaticity, feedback and Landau damping are considered.

Optimal centralized and decentralized velocity feedback control on a beam

International Nuclear Information System (INIS)

Engels, W P; Elliott, S J

2008-01-01

This paper considers the optimization of a velocity feedback controller with a collocated force actuator, to minimize the kinetic energy of a simply supported beam. If the beam is excited at a single location, the optimum feedback gain varies with the position of the control system. It is shown that this variation depends partly on the location of the control force relative to the exciting force. If a distributed excitation is assumed, that is random in both time and space, a unique optimum value of the feedback gain can be found for a given control location. The effect of the control location on performance and the optimal feedback gain can then be examined and is found to be limited provided the control locations are not close to the ends of the beam. The optimization can also be performed for a multichannel velocity feedback system. Both a centralized and a decentralized controller are considered. It is shown that the difference in performance between a centralized and a decentralized controller is small, unless the control locations are closely spaced. In this case the centralized controller effectively feeds back a moment proportional to angular velocity as well as a force proportional to a velocity. It is also shown that the optimal feedback gain can be approximated on the basis of a limited model and that similar results can be achieved

Evaluation of strip-line pick-up system for the SPS wideband transverse feedback system

CERN Document Server

Kotzian, G; Steinhagen, R J; Valuch, D; Wehrle, U

2017-01-01

The proposed SPS Wideband Transverse Feedback sys- tem requires a wide-band pick-up system to be able to de- tect intra-bunch motion within the SPS proton bunches, captured and accelerated in a 200 MHz bucket. We present the electro-magnetic design of transverse beam position pick-up options optimised for installation in the SPS and evaluate their performance reach with respect to direct time domain sampling of the intra-bunch motion. The analy- sis also discusses the achieved subsystem responses of the associated cabling with new low dispersion smooth wall coaxial cables, wide-band generation of intensity and posi- tion signals by means of 180 degree RF hybrids as well as passive techniques to electronically suppress the beam off- set signal, needed to optimise the dynamic range and posi- tion resolution of the planned digital intra-bunch feedback system.

Effect of exercise training on in vivo lipolysis in intra-abdominal adipose tissue in rats

DEFF Research Database (Denmark)

Enevoldsen, L H; Stallknecht, B; Fluckey, J D

2000-01-01

Intra-abdominal obesity is associated with cardiovascular disease and non-insulin-dependent diabetes mellitus, and physical training has been suggested to alleviate these conditions. We compared epinephrine-stimulated lipolysis in vivo in three intra-abdominal adipose tissues (ATs: retroperitonea...... be beneficial in alleviating intra-abdominal obesity by enhancing lipolysis in intra-abdominal fat depots.......Intra-abdominal obesity is associated with cardiovascular disease and non-insulin-dependent diabetes mellitus, and physical training has been suggested to alleviate these conditions. We compared epinephrine-stimulated lipolysis in vivo in three intra-abdominal adipose tissues (ATs: retroperitoneal......: 73 +/- 12 (trained) vs. 14 +/- 4 (sedentary) ml. 100 g(-1). min(-1), P abdominal than in subcutaneous AT in both trained...

Intra-cortical excitability in healthy human subjects after tongue training

DEFF Research Database (Denmark)

Baad-Hansen, Lene; Blicher, Jakob; Lapitskaya, Natallia

2009-01-01

Training of specific muscles causes plastic changes in corticomotor pathways which may underlie the effect of various clinical rehabilitation procedures. The paired pulse transcranial magnetic stimulation (ppTMS) technique can be used to assess short interval intra-cortical inhibitory (SICI...... tongue muscles. In tongue motor cortex, bilateral SICI (P training. There were no significant effects of training on single MEPs or SICI/ICF (P > 0.063). The success rate improved during training (P ...) and intra-cortical facilitatory (ICF) networks. This study examined changes in SICI and ICF in tongue motor cortex after tongue training in 11 healthy volunteers using ppTMS. Paired pulse TMS was applied to the 'hot-spot' for the tongue motor cortex and motor-evoked potentials (MEPs) were recorded from...

High efficiency and high-energy intra-cavity beam shaping laser

International Nuclear Information System (INIS)

Yang, Hailong; Meng, Junqing; Chen, Weibiao

2015-01-01

We present a technology of intra-cavity laser beam shaping with theory and experiment to obtain a flat-top-like beam with high-pulse energy. A radial birefringent element (RBE) was used in a crossed Porro prism polarization output coupling resonator to modulate the phase delay radially. The reflectively of a polarizer used as an output mirror was variable radially. A flat-top-like beam with 72.5 mJ, 11 ns at 20 Hz was achieved by a side-pumped Nd:YAG zigzag slab laser, and the optical-to-optical conversion efficiency was 17.3%. (paper)

High efficiency and high-energy intra-cavity beam shaping laser

Science.gov (United States)

Yang, Hailong; Meng, Junqing; Chen, Weibiao

2015-09-01

We present a technology of intra-cavity laser beam shaping with theory and experiment to obtain a flat-top-like beam with high-pulse energy. A radial birefringent element (RBE) was used in a crossed Porro prism polarization output coupling resonator to modulate the phase delay radially. The reflectively of a polarizer used as an output mirror was variable radially. A flat-top-like beam with 72.5 mJ, 11 ns at 20 Hz was achieved by a side-pumped Nd:YAG zigzag slab laser, and the optical-to-optical conversion efficiency was 17.3%.

Fast feedback system for energy and beam stabilization

International Nuclear Information System (INIS)

R. Dickson; V. Lebedev

1999-01-01

The electron beams being delivered to targets of the Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson National Accelerator Facility (Jefferson Lab) are plagued with undesirable positional and energy fluctuations. These fluctuations primarily occur at harmonics of the power line frequency (60, 120, 180, etc. hertz), and their cause is rooted in electromagnetic fields generated by accelerator electronic equipment. It is possible to largely nullify these deviations by applying real time corrections to electromagnets and RF verniers along the beam line. This concept has been successfully applied at Jefferson Lab by extensively modifying the existing Beam Position Monitor (BPM) system with the integration of an algorithm that computes correction signals targeted at the power line harmonics. Many of the modifications required were due to the existing CEBAF BPM system not having the data acquisition bandwidth needed for this type of feedback system. This paper will describe the techniques required to transform the CEBAF standard BPM system into a high speed practical fast feedback system that coexists with the large scale control system--the Experimental Physics and Industrial Control System (EPICS)--that runs the CEBAF accelerator in daily operation

Individualized feedback during simulated laparoscopic training:a mixed methods study.

Science.gov (United States)

Ahlborg, Liv; Weurlander, Maria; Hedman, Leif; Nisel, Henry; Lindqvist, Pelle G; Felländer-Tsai, Li; Enochsson, Lars

2015-07-29

This study aimed to explore the value of individualized feedback on performance, flow and self-efficacy during simulated laparoscopy. Furthermore, we wished to explore attitudes towards feedback and simulator training among medical students. Sixteen medical students were included in the study and randomized to laparoscopic simulator training with or without feedback. A teacher provided individualized feedback continuously throughout the procedures to the target group. Validated questionnaires and scales were used to evaluate self-efficacy and flow. The Mann-Whitney U test was used to evaluate differences between groups regarding laparoscopic performance (instrument path length), self-efficacy and flow. Qualitative data was collected by group interviews and interpreted using inductive thematic analyses. Sixteen students completed the simulator training and questionnaires. Instrument path length was shorter in the feedback group (median 3.9 m; IQR: 3.3-4.9) as compared to the control group (median 5.9 m; IQR: 5.0-8.1), pfeedback group were more concentrated on the task and also more anxious. Both groups had high ambitions to succeed and also expressed the importance of getting feedback. The authenticity of the training scenario was important for the learning process. This study highlights the importance of individualized feedback during simulated laparoscopy training. The next step is to further optimize feedback and to transfer standardized and individualized feedback from the simulated setting to the operating room.

Effectiveness of feedback in a repeated spelling training

NARCIS (Netherlands)

Gruhn, C.M.S.; Segers, P.C.J.; Verhoeven, L.T.W.

2017-01-01

Effectiveness of feedback on strengthening lexical representations was investigated in a computerized spelling training by contrasting two different feedback conditions with a no feedback condition. Ninety-one Dutch fifth and sixth graders practiced spelling of 40 multisyllabic words with irregular

Intra-bunch-train transverse dynamics in the superconducting accelerators FLASH and European XFEL

Energy Technology Data Exchange (ETDEWEB)

Hellert, Thorsten

2017-11-15

FLASH and the European XFEL are linear accelerator driven SASE-FELs, operating in a pulsed mode with long bunch-trains. Multi-bunch FEL operation requires longitudinal and transverse stability within the bunch-train. The purpose of this work is to investigate the intra-bunch-train transverse dynamics at FLASH and XFEL. Key relationships of superconducting RF cavity operation, their misalignments and the resulting impact on the intra-bunch-train trajectory variation are described. In this thesis a numerical model is developed and simulations for different accelerating sections at FLASH and XFEL are performed. With the current operational setup significant intra-bunch-train trajectory variation must be considered, hence approaches for their reduction are discussed. The theoretical studies are compared to experimental results at FLASH. The observed trajectory variation during multi-bunch user runs is analyzed and related to causal intra-bunch-train variations of the RF and the following impact on the multi-bunch SASSE performance. Furthermore, HOM-based cavity misalignment measurements are performed and the deduction of misalignments from multi-bunch data is considered.

Intra-bunch-train transverse dynamics in the superconducting accelerators FLASH and European XFEL

International Nuclear Information System (INIS)

Hellert, Thorsten

2017-11-01

FLASH and the European XFEL are linear accelerator driven SASE-FELs, operating in a pulsed mode with long bunch-trains. Multi-bunch FEL operation requires longitudinal and transverse stability within the bunch-train. The purpose of this work is to investigate the intra-bunch-train transverse dynamics at FLASH and XFEL. Key relationships of superconducting RF cavity operation, their misalignments and the resulting impact on the intra-bunch-train trajectory variation are described. In this thesis a numerical model is developed and simulations for different accelerating sections at FLASH and XFEL are performed. With the current operational setup significant intra-bunch-train trajectory variation must be considered, hence approaches for their reduction are discussed. The theoretical studies are compared to experimental results at FLASH. The observed trajectory variation during multi-bunch user runs is analyzed and related to causal intra-bunch-train variations of the RF and the following impact on the multi-bunch SASSE performance. Furthermore, HOM-based cavity misalignment measurements are performed and the deduction of misalignments from multi-bunch data is considered.

Feedback in Videogame-based Adaptive Training

Science.gov (United States)

2011-05-01

G. (1985). The geometry tutor. Proceedings of the International Joint Conference on Artificial Intelligence . Los Altos, CA: Kaufmann. Anderson, R...Technical Report 1287 Feedback in Videogame -based Adaptive Training Iris D. Rivera Florida Institute of Technology...REPORT TYPE Final 3. DATES COVERED (from. . . to) August 2008 – April 2010 4. TITLE AND SUBTITLE Feedback in Videogame -based Adaptive

Beam stability in synchrotrons with digital filters in the feedback loop of a transverse damper

International Nuclear Information System (INIS)

Zhabitskij, V.M.

2009-01-01

The stability of an ion beam in synchrotrons with digital filters in the feedback loop of a transverse damper is treated. Solving the characteristic equation allows one to calculate the achievable damping rates as a function of instability growth rate, feedback gain and parameters of the signal processing. A transverse feedback system (TFS) is required in synchrotrons to stabilize the high intensity ion beams against transverse instabilities and to damp the beam injection errors. The TFS damper kicker (DK) corrects the transverse momentum of a bunch in proportion to its displacement from the closed orbit at the location of the beam position monitor (BPM). The digital signal processing unit in the feedback loop between BPM and DK ensures a condition to achieve optimal damping. Damping rates of the feedback systems with digital notch, Hilbert and all-pass filters are analyzed in comparison with those in an ideal feedback system

Cooling and squeezing the fluctuations of a nanomechanical beam by indirect quantum feedback control

International Nuclear Information System (INIS)

Zhang Jing; Liu Yuxi; Nori, Franco

2009-01-01

We study cooling and squeezing the fluctuations of a nanomechanical beam using quantum feedback control. In our model, the nanomechanical beam is coupled to a transmission line resonator via a superconducting quantum interference device. The leakage of the electromagnetic field from the transmission line resonator is measured using homodyne detection. This measured signal is then used to design a quantum feedback control signal to drive the electromagnetic field in the transmission line resonator. Although the control is imposed on the transmission line resonator, this quantum feedback control signal indirectly affects the thermal motion of the nanomechanical beam via the inductive beam-resonator coupling, making it possible to cool and squeeze the fluctuations of the beam, allowing it to approach the standard quantum limit.

FIRST BEAM TESTS OF THE APS MBA UPGRADE ORBIT FEEDBACK CONTROLLER

Energy Technology Data Exchange (ETDEWEB)

Sereno, N. S.; Arnold, N.; Brill, A.; Bui, H.; Carwardine, J.; Decker, G.; Deriy, B.; Emery, L.; Farnsworth, R.; Fors, T.; Keane, R.; Lenkszus, F.; Lill, R.; Paskvan, D.; Pietryla, A.; Shang, H.; Shoaf, S.; Veseli, S.; Wang, J.; Xu, S.; Yang, B.X.

2017-03-25

The new orbit feedback system required for the APS multi-bend acromat (MBA) ring must meet challenging beam stability requirements. The AC stability requirement is to correct rms beam motion to 10 % the rms beam size at the insertion device source points from 0.01 to 1000 Hz. The vertical plane represents the biggest challenge for AC stability which is required to be 400 nm rms for a 4 micron vertical beam size. In addition long term drift over a period of 7 days is required to be 1 micron or less at insertion de- vice BPMs and 2 microns for arc bpms. We present test re- sults of theMBA prototype orbit feedback controller (FBC) in the APS storage ring. In this test, four insertion device BPMs were configured to send data to the FBC for process- ing into four fast corrector setpoints. The configuration of four bpms and four fast correctors creates a 4-bump and the configuration of fast correctors is similar to what will be implemented in the MBA ring. We report on performance benefits of increasing the sampling rate by a factor of 15 to 22.6 kHz over the existing APS orbit feedback system, lim- itations due to existing storage ring hardware and extrapo- lation to theMBA orbit feedback design. FBC architecture, signal flow and processing design will also be discussed.

Implementation of intra-cavity beam shaping technique to enhance pump efficiency

CSIR Research Space (South Africa)

Litvin, IA

2012-02-01

Full Text Available In this work the author proposes an implementation of a new intra-cavity beam shaping technique to vary the intensity distribution of the fundamental mode in a resonator cavity while maintaining a constant intensity distribution at the output...

Beam-based Feedback Simulations for the NLC Linac

International Nuclear Information System (INIS)

Hendrickson, Linda

2000-01-01

Extensive beam-based feedback systems are planned as an integral part of the Next Linear Collider (NLC) control system. Wakefield effects are a significant influence on the feedback design, imposing both architectural and algorithmic constraints. Studies are in progress to assure the optimal selection of devices and to refine and confirm the algorithms for the system design. The authors show the results of initial simulations, along with evaluations of system response for various conditions of ground motion and other operational disturbances

Introducing a feedback training system for guided home rehabilitation

Directory of Open Access Journals (Sweden)

Disselhorst-Klug Catherine

2010-01-01

Full Text Available Abstract As the number of people requiring orthopaedic intervention is growing, individualized physiotherapeutic rehabilitation and adequate postoperative care becomes increasingly relevant. The chances of improvement in the patients condition is directly related to the performance and consistency of the physiotherapeutic exercises. In this paper a smart, cost-effective and easy to use Feedback Training System for home rehabilitation based on standard resistive elements is introduced. This ensures high accuracy of the exercises performed and offers guidance and control to the patient by offering direct feedback about the performance of the movements. 46 patients were recruited and performed standard physiotherapeutic training to evaluate the system. The results show a significant increase in the patient's ability to reproduce even simple physiotherapeutic exercises when being supported by the Feedback Training System. Thus physiotherapeutic training can be extended into the home environment whilst ensuring a high quality of training.

Introducing a feedback training system for guided home rehabilitation.

Science.gov (United States)

Kohler, Fabian; Schmitz-Rode, Thomas; Disselhorst-Klug, Catherine

2010-01-15

As the number of people requiring orthopaedic intervention is growing, individualized physiotherapeutic rehabilitation and adequate postoperative care becomes increasingly relevant. The chances of improvement in the patients condition is directly related to the performance and consistency of the physiotherapeutic exercises.In this paper a smart, cost-effective and easy to use Feedback Training System for home rehabilitation based on standard resistive elements is introduced. This ensures high accuracy of the exercises performed and offers guidance and control to the patient by offering direct feedback about the performance of the movements.46 patients were recruited and performed standard physiotherapeutic training to evaluate the system. The results show a significant increase in the patient's ability to reproduce even simple physiotherapeutic exercises when being supported by the Feedback Training System. Thus physiotherapeutic training can be extended into the home environment whilst ensuring a high quality of training.

[Feedback in relation to training of practical clinical skills

DEFF Research Database (Denmark)

Hansen, C.S.; Ringsted, Charlotte Vibeke

2008-01-01

Feedback has been identified as an essential component of motor learning. However, feedback principles derived from motor learning theories cannot uncritically be applied to clinical skills training because this knowledge is based primarily on the study of very simple motor skills. Research...... into feedback in relation to clinical skills training is currently limited. Theories on motor learning can serve as the basis for designing research in this domain, especially the importance of including retention tests when measuring permanent learning outcomes Udgivelsesdato: 2008/10/27...

Local beam position feedback experiments on the ESRF storage ring

International Nuclear Information System (INIS)

Chung, Y.; Kahana, E.; Kirchman, J.

1995-01-01

This paper describes the results of local beam position feedback experiments conducted on the ESRF storage ring using digital signal processing (DSP) under the trilateral agreement of collaboration among ESRF, APS, and SPring-8. Two rf beam position monitors (BPMS) in the, upstream and downstream of the insertion device (ID) and two x-ray BPMs in the sixth cell were used to monitor the electron beam and the x-ray beam emitted from the ID, respectively. The local bump coefficients were obtained using the technique of singular value decomposition (SVD) on the global response matrix for the bump magnets and all the available BPMs outside the local bump. The local response matrix was then obtained between the two three-magnet bumps and the position monitors. The data sampling frequency was 4 kHz and a proportional, integral, and derivative (PID) controller was used. The result indicates the closed-loop feedback bandwidth close to 100 Hz and clear attenuation (∼ -40 dB) of the 7-Hz beam motion due to girder vibration resonance. Comparison of the results using the rf BPMs and x-ray BPMs will be also discussed

Training Peer-Feedback Skills on Geometric Construction Tasks: Role of Domain Knowledge and Peer-Feedback Levels

Science.gov (United States)

Alqassab, Maryam; Strijbos, Jan-Willem; Ufer, Stefan

2018-01-01

Peer feedback is widely used to train assessment skills and to support collaborative learning of various learning tasks, but research on peer feedback in the domain of mathematics is limited. Although domain knowledge seems to be a prerequisite for peer-feedback provision, it only recently received attention in the peer-feedback literature. In…

Feedback system analysis for beam breakup in a multipass multisection electron linac

International Nuclear Information System (INIS)

Mosnier, A.; Aune, B.

1986-06-01

A recirculating electron accelerator based upon superconducting cavities technology is envisaged in different laboratories to produce a high duty cycle beam with energy in the GeV region. Beam break up is a severe limitation in this kind of accelerator due to the positive feedback of the returning beams. We present here an analysis based upon feedback system theory which takes into account the different cavities of the linac, the optics of the linac and of the recirculating path. An example is given for the Saclay proposal of a 2 GeV accelerator consisting of 4 passes in a 500 MeV, 100 m-long superconducting linac

The Application of Autogenic Feedback Training in a Smoking Termination Program.

Science.gov (United States)

Boullion, Jean K.; Chen, W. William

1980-01-01

Autogenic feedback training was an effective adjunct to a smoking termination program. An 81 percent reduction in smoking activity was found for the subjects who received the training. Achieving relaxation and reducing anxiety through autogenic feedback training helped subjects restore their self-confidence and deal with stress. (Author)

Accelerator and feedback control simulation using neural networks

International Nuclear Information System (INIS)

Nguyen, D.; Lee, M.; Sass, R.; Shoaee, H.

1991-05-01

Unlike present constant model feedback system, neural networks can adapt as the dynamics of the process changes with time. Using a process model, the ''Accelerator'' network is first trained to simulate the dynamics of the beam for a given beam line. This ''Accelerator'' network is then used to train a second ''Controller'' network which performs the control function. In simulation, the networks are used to adjust corrector magnetics to control the launch angle and position of the beam to keep it on the desired trajectory when the incoming beam is perturbed. 4 refs., 3 figs

Opportunistic beam training with hybrid analog/digital codebooks for mmWave systems

KAUST Repository

Eltayeb, Mohammed E.

2016-02-25

© 2015 IEEE. Millimeter wave (mmWave) communication is one solution to provide more spectrum than available at lower carrier frequencies. To provide sufficient link budget, mmWave systems will use beamforming with large antenna arrays at both the transmitter and receiver. Training these large arrays using conventional approaches taken at lower carrier frequencies, however, results in high overhead. In this paper, we propose a beam training algorithm that efficiently designs the beamforming vectors with low training overhead. Exploiting mmWave channel reciprocity, the proposed algorithm relaxes the need for an explicit feedback channel, and opportunistically terminates the training process when a desired quality of service is achieved. To construct the training beamforming vectors, a new multi-resolution codebook is developed for hybrid analog/digital architectures. Simulation results show that the proposed algorithm achieves a comparable rate to that obtained by exhaustive search solutions while requiring lower training overhead when compared to prior work.

Opportunistic beam training with hybrid analog/digital codebooks for mmWave systems

KAUST Repository

Eltayeb, Mohammed E.; Alkhateeb, Ahmed; Heath, Robert W.; Al-Naffouri, Tareq Y.

2016-01-01

© 2015 IEEE. Millimeter wave (mmWave) communication is one solution to provide more spectrum than available at lower carrier frequencies. To provide sufficient link budget, mmWave systems will use beamforming with large antenna arrays at both the transmitter and receiver. Training these large arrays using conventional approaches taken at lower carrier frequencies, however, results in high overhead. In this paper, we propose a beam training algorithm that efficiently designs the beamforming vectors with low training overhead. Exploiting mmWave channel reciprocity, the proposed algorithm relaxes the need for an explicit feedback channel, and opportunistically terminates the training process when a desired quality of service is achieved. To construct the training beamforming vectors, a new multi-resolution codebook is developed for hybrid analog/digital architectures. Simulation results show that the proposed algorithm achieves a comparable rate to that obtained by exhaustive search solutions while requiring lower training overhead when compared to prior work.

Feedback Specificity, Information Processing, and Transfer of Training

Science.gov (United States)

Goodman, Jodi S.; Wood, Robert E.; Chen, Zheng

2011-01-01

This study examines the effects of feedback specificity on transfer of training and the mechanisms through which feedback can enhance or inhibit transfer. We used concurrent verbal protocol methodology to elicit and operationalize the explicit information processing activities used by 48 trainees performing the Furniture Factory computer…

Tailored instructor feedback leads to more effective virtual-reality laparoscopic training.

Science.gov (United States)

Paschold, M; Huber, T; Zeißig, S R; Lang, H; Kneist, Werner

2014-03-01

Laparoscopic novices begin at different performance levels, and studies on tailored training concepts are warranted. The effect of verbal instructor feedback has been investigated with varying results, and its effectiveness in virtual-reality laparoscopic (VRL) simulations still is unclear. This study aimed to determine whether laparoscopic novices with lower initial performance statuses may profit from training with intensive instructor feedback. A prospective, single-blinded study was performed within a week-long curricular course. In this study, 20 medical students performed a complex bimanual maneuver on a VRL simulator. There was a division in performance levels, with a high-performer group (HPG) that received a better median score and a low-performer group (LPG). During the training phase, only the initial LPG received standardized instructor feedback in a one-to-one setting. The final assessment of skills for both groups involved performing the task without feedback at the end of the course. The HPG and LPG showed significantly different initial performance levels according global and categorized (time, economics, error) scores (p training concept with instructor feedback limited to the LPG. The tailored training was effective and economic for the laparoscopic novices and their teachers.

Adaptive cascaded beam-based feedback at the SLC

International Nuclear Information System (INIS)

Himel, T.; Allison, S.; Grossberg, P.; Hendrickson, L.; Sass, R.; Shoaee, H.

1993-05-01

The SLAC Linear Collider now has a total of twenty-four beam-steering feedback loops used to keep the electron and positron beams on their desired trajectories. Seven of these loops measure and control the same beam as it proceeds down the linac through the arcs to the final focus. Ideally each loop should correct only for disturbances that occur between it and the immediate upstream loop. In fact, in the original system each loop corrected for all upstream disturbances. This resulted in undesirable over-correction and ringing. We added MIMO (Multiple Input Multiple Output) adaptive noise cancellers to separate the signal we wish to correct from disturbances further up-stream. This adaptive control improved performance in the 1992 run

Interaction between beam control and rf feedback loops for high Q cavities an heavy beam loading. Revision A

International Nuclear Information System (INIS)

Mestha, L.K.; Kwan, C.M.; Yeung, K.S.

1994-04-01

An open-loop state space model of all the major low-level rf feedback control loops is derived. The model has control and state variables for fast-cycling machines to apply modern multivariable feedback techniques. A condition is derived to know when exactly we can cross the boundaries between time-varying and time-invariant approaches for a fast-cycling machine like the Low Energy Booster (LEB). The conditions are dependent on the Q of the cavity and the rate at which the frequency changes with time. Apart from capturing the time-variant characteristics, the errors in the magnetic field are accounted in the model to study the effects on synchronization with the Medium Energy Booster (MEB). The control model is useful to study the effects on beam control due to heavy beam loading at high intensities, voltage transients just after injection especially due to time-varying voltages, instability thresholds created by the cavity tuning feedback system, cross coupling between feedback loops with and without direct rf feedback etc. As a special case we have shown that the model agrees with the well known Pedersen model derived for the CERN PS booster. As an application of the model we undertook a detailed study of the cross coupling between the loops by considering all of them at once for varying time, Q and beam intensities. A discussion of the method to identify the coupling is shown. At the end a summary of the identified loop interactions is presented

Development of pattern aware unit (PAU) for the LCLS beam based fast feedback system

International Nuclear Information System (INIS)

Kim, K.H.; Allison, S.; Fairley, D.; Himel, T.M.; Krejcik, P.; Rogind, D.; Williams, E.

2012-01-01

LCLS is now successfully operating at its design beam repetition rate of 120 Hz, but in order to ensure stable beam operation at this high rate we have developed a new timing pattern aware EPICS controller for beam line actuators. Actuators that are capable of responding at 120 Hz are controlled by the new Pattern Aware Unit (PAU) as part of the beam-based feedback system. The beam at the LCLS is synchronized to the 60 Hz AC power line phase and is subject to electrical noise which differs according to which of the six possible AC phases is chosen from the 3-phase site power line. Beam operation at 120 Hz interleaves two of these 60 Hz phases and the feedback must be able to apply independent corrections to the beam pulse according to which of the 60 Hz timing patterns the pulse is synchronized to. The PAU works together with the LCLS Event Timing system which broadcasts a timing pattern that uniquely identifies each pulse when it is measured and allows the feedback correction to be applied to subsequent pulses belonging to the same timing pattern, or time slot, as it is referred to at SLAC. At 120 Hz operation this effectively provides us with two independent, but interleaved feedback loops. Other beam programs at the SLAC facility such as LCLS-II and FACET will be pulsed on other time slots and the PAUs in those systems will respond to their appropriate timing patterns. This paper describes the details of the PAU development: real-time requirements and achievement, scalability, and consistency. The operational results will also be described. (authors)

Feedback control for a train-like vehicle

International Nuclear Information System (INIS)

Micaelli, A.

1994-01-01

This paper presents a feedback nonlinear control law for a train-like vehicle (TLV) used in nuclear power-station maintenance. The front cart is either manual or automated guided. The rear carts are feedback controlled. The control objective is to ensure that the rear carts track the path produced (on-line) by the front cart. This controller was experimentally tested on the TLV-prototype. (authors). 4 figs., 4 refs

Time-Gating Processes in Intra-Cavity Mode-Locking Devices Like Saturable Absorbers and Kerr Cells

Science.gov (United States)

Prasad, Narasimha; Roychoudhuri, Chandrasekhar

2010-01-01

Photons are non-interacting entities. Light beams do not interfere by themselves. Light beams constituting different laser modes (frequencies) are not capable of re-arranging their energies from extended time-domain to ultra-short time-domain by themselves without the aid of light-matter interactions with suitable intra-cavity devices. In this paper we will discuss the time-gating properties of intra-cavity "mode-locking" devices that actually help generate a regular train of high energy wave packets.

The intensity feedback system at Heidelberg Ion-Beam Therapy Centre

Energy Technology Data Exchange (ETDEWEB)

Schoemers, Christian, E-mail: christian.schoemers@med.uni-heidelberg.de; Feldmeier, Eike; Naumann, Jakob; Panse, Ralf; Peters, Andreas; Haberer, Thomas

2015-09-21

At Heidelberg Ion-Beam Therapy Centre (HIT), more than 2500 tumour patients have been treated with charged particle beams since 2009 using the raster scanning method. The tumour is irradiated slice-by-slice, each slice corresponding to a different beam energy. For the particle dose of each raster point the pre-irradiation by more distal slices has to be considered. This leads to highly inhomogeneous dose distributions within one iso-energy slice. The particles are extracted from the synchrotron via transverse RF knock-out. A pure feed forward control cannot take into account fluence inhomogeneities or deal with intensity fluctuations. So far, fluctuations have been counteracted by a reduced scanning velocity. We now added a feedback loop to the extraction system. The dose monitoring ionisation chambers in front of the patient have been coupled to the extraction device in the synchrotron. Characterization and implementation of the intensity feedback system into the HIT facility is described here. By its implementation the treatment time has been reduced by 10% in average.

Effects of acoustic feedback training in elite-standard Para-Rowing.

Science.gov (United States)

Schaffert, Nina; Mattes, Klaus

2015-01-01

Assessment and feedback devices have been regularly used in technique training in high-performance sports. Biomechanical analysis is mainly visually based and so can exclude athletes with visual impairments. The aim of this study was to examine the effects of auditory feedback on mean boat speed during on-water training of visually impaired athletes. The German National Para-Rowing team (six athletes, mean ± s, age 34.8 ± 10.6 years, body mass 76.5 ± 13.5 kg, stature 179.3 ± 8.6 cm) participated in the study. Kinematics included boat acceleration and distance travelled, collected with Sofirow at two intensities of training. The boat acceleration-time traces were converted online into acoustic feedback and presented via speakers during rowing (sections with and without alternately). Repeated-measures within-participant factorial ANOVA showed greater boat speed with acoustic feedback than baseline (0.08 ± 0.01 m·s(-1)). The time structure of rowing cycles was improved (extended time of positive acceleration). Questioning of athletes showed acoustic feedback to be a supportive training aid as it provided important functional information about the boat motion independent of vision. It gave access for visually impaired athletes to biomechanical analysis via auditory information. The concept for adaptive athletes has been successfully integrated into the preparation for the Para-Rowing World Championships and Paralympics.

The effect of video-assisted oral feedback versus oral feedback on surgical communicative competences in undergraduate training.

Science.gov (United States)

Ruesseler, M; Sterz, J; Bender, B; Hoefer, S; Walcher, F

2017-08-01

Feedback can significantly improve future performance. Reviewing one's performance by video is discussed as useful adjunct to debriefing, particularly for non-technical skills. Communicative competencies are an essential part of daily clinical practice; thus should be taught and assessed during undergraduate training. The aim of this study was to compare the educational value of video-assisted feedback versus oral feedback in communicative competencies in the surgical context. Fourth-year medical students completed a 210-min training unit of 'taking patient's history and obtaining informed consents prior to surgery' using role plays. Oral feedback was received directly thereafter using agenda-led, outcome-based guidelines (ALOBA). In the study group, the role plays were video-taped and reviewed thereafter. Afterwards, students completed two OSCE stations, where they were assessed regarding their communicative competencies and the content of the clinical scenario. One-hundred students (49 receiving video-assisted feedback, 51 oral) participated in the study. Those receiving video-assisted feedback performed significantly better in overall score in both OSCE stations (p feedback offered a significant educational benefit over oral feedback alone during a simulated patient encounter in a surgical context.

A Comparison of Written, Vocal, and Video Feedback When Training Teachers

Science.gov (United States)

Luck, Kally M.; Lerman, Dorothea C.; Wu, Wai-Ling; Dupuis, Danielle L.; Hussein, Louisa A.

2018-01-01

We compared the effectiveness of and preference for different feedback strategies when training six special education teachers during a 5-day summer training program. In Experiment 1, teachers received written or vocal feedback while learning to implement two different types of preference assessments. In Experiment 2, we compared either written or…

Dynamic axial stabilization of counterpropagating beam-traps with feedback control

DEFF Research Database (Denmark)

Tauro, Sandeep; Bañas, Andrew Rafael; Palima, Darwin

2010-01-01

Optical trapping in a counter-propagating (CP) beam-geometry provides unique advantages in terms of working distance, aberration requirements and intensity hotspots. However, its axial performance is governed by the wave propagation of the opposing beams, which can limit the practical geometries....... Advanced implementation of this feedback-driven approach can help make CP-trapping resistant to a host of perturbations such as laser fluctuations, mechanical vibrations and other distortions emphasizing its experimental versatility....

An automatic beam steering system for the NSLS X-17T beam line using closed orbit feedback

International Nuclear Information System (INIS)

Nawrocky, R.J.; Ma, Li; Rarback, H.M.; Singh, O.V.; Yu, L.H.

1987-01-01

Initial observations of motion of the undulator radiation in the NSLS X-17T beam line clearly indicated that the beam had to be stabilized in both directions to be usable for the planned soft x-ray imaging experiments. The low frequency spectra of beam motion contained peaks in the range from dc to 60 Hz and at higher frequencies. A beam steering system employing closed orbit feedback has been designed and installed to stabilize the beam in both planes. In each plane of motion, beam position is measured with a beam position detector and a correction signal is fed back to a local four magnet orbit bump to dynamically control the angle of the radiation at the source. This paper describes the design and performance of the beam steering system

Effects of two types of intra-team feedback on developing a shared mental model in Command & Control teams

NARCIS (Netherlands)

Rasker, P.C.; Post, W.M.; Schraagen, J.M.C.

2000-01-01

In two studies, the effect of two types of intra-team feedback on developing a shared mental model in Command & Control teams was investigated. A distinction is made between performance monitoring and team self-correction. Performance monitoring is the ability of team members to monitor each other's

Ultra high-speed (508 MHz) beam position digital feedback system

International Nuclear Information System (INIS)

Kurokawa, Shin-ichi; Kametani, Masatsugu; Nakayama, Takahide; Moriyama, Kunio.

1997-01-01

The B-Factory which is constructed by National Laboratory for High Energy Physics is the device for elucidating the breakdown of symmetry of matter and antimatter by studying the behavior of B mesons which are generated in large quantity when the electrons and the positrons which are accelerated to light velocity level are collided. In order to maintain electron beam-positron beam bunch circling the ring at light velocity stably, the instability of the coupled bunch must be overcome. For this purpose, the ultrahigh speed beam position digital feedback control system was developed. This system is composed of the high speed input-output substrate using GaAs LSI, the feedback computation substrate using complementary metal oxide semiconductor and the memory mounted on it, and the real time operation device. The development of both substrates and their functions are explained. The real time data collection and the change of computation parameters for specific bunch in the real time operation device have become feasible. The signal transmission characteristics of this system are shown. As the result of the action test of this system, it was confirmed to work normally. (K.I.)

What the Logs Can Tell You: Mediation to Implement Feedback in Training

Science.gov (United States)

Maluf, David; Wiederhold, Gio; Abou-Khalil, Ali; Norvig, Peter (Technical Monitor)

2000-01-01

The problem addressed by Mediation to Implement Feedback in Training (MIFT) is to customize the feedback from training exercizes by exploiting knowledge about the training scenario, training objectives, and specific student/teacher needs. We achieve this by inserting an intelligent mediation layer into the information flow from observations collected during training exercises to the display and user interface. Knowledge about training objectives, scenarios, and tasks is maintained in the mediating layer. A designer constraint is that domain experts must be able to extend mediators by adding domain-specific knowledge that supports additional aggregations, abstractions, and views of the results of training exercises. The MIFT mediation concept is intended to be integrated with existing military training exercise management tools and reduce the cost of developing and maintaining separate feedback and evaluation tools for every training simulator and every set of customer needs. The MIFT Architecture is designed as a set of independently reusable components which interact with each other through standardized formalisms such as the Knowledge Interchange Format (KIF) and Knowledge Query and Manipulation Language (KQML).

Training Analysis and Feedback Aids (TAAF Aids) Study for Live Training Support

National Research Council Canada - National Science Library

Brown, Bill

1998-01-01

... they would otherwise spend observing, coaching, and facilitating the learning of exercise players. This study: (1) Identifies the impact of force modernization on future exercise control and training feedback functions...

Improvement of the beam quality of a broad-area diode laser using double feedback from two external mirrors

DEFF Research Database (Denmark)

Chi, M.; Bøgh, A.-S.; Thestrup, B.

2004-01-01

In this letter, a symmetric double-feedback configuration, to improve the beam quality of broad-area diode lasers is demonstrated. With this configuration, a symmetric double-lobed far field can be obtained, and this configuration leads to good beam quality. The beam quality factor M-2 of a diode...... laser with the emitting area 1 mumx200 mum is improved by using both the asymmetric single feedback and the symmetric double feedback. M-2 values of 4.3 for the asymmetric single-feedback laser system and 3.3 for the symmetric double-feedback laser system are obtained, whereas the M-2 value...... of the freely running laser is 42. The far and the near fields are also measured and compared for the three conditions. (C) 2004 American Institute of Physics....

Biodynamic feedback training to assure learning partial load bearing on forearm crutches.

Science.gov (United States)

Krause, Daniel; Wünnemann, Martin; Erlmann, Andre; Hölzchen, Timo; Mull, Melanie; Olivier, Norbert; Jöllenbeck, Thomas

2007-07-01

To examine how biodynamic feedback training affects the learning of prescribed partial load bearing (200N). Three pre-post experiments. Biomechanics laboratory in a German university. A volunteer sample of 98 uninjured subjects who had not used crutches recently. There were 24 subjects in experiment 1 (mean age, 23.2y); 64 in experiment 2 (mean age, 43.6y); and 10 in experiment 3 (mean age, 40.3y), parallelized by arm force. Video instruction and feedback training: In experiment 1, 2 varied instruction videos and reduced feedback frequency; in experiment 2, varied frequencies of changing tasks (contextual interference); and in experiment 3, feedback training (walking) and transfer (stair tasks). Vertical ground reaction force. Absolute error of practiced tasks was significantly reduced for all samples (Pstairs might be beneficial.

Beam excitation and damping with the transverse feedback system

International Nuclear Information System (INIS)

Pellegrin, J.L.; Rees, J.R.

1979-08-01

The questions often come up, ''What is the strength if the beam excitation system? How much damping can the transverse feedback provide?'' The design is now advanced enough to answer these questions; also, laboratory tests of some components have been conducted and we know what can be expected of the hardware. This paper discusses these questions

Perioperative feedback in surgical training: A systematic review.

Science.gov (United States)

McKendy, Katherine M; Watanabe, Yusuke; Lee, Lawrence; Bilgic, Elif; Enani, Ghada; Feldman, Liane S; Fried, Gerald M; Vassiliou, Melina C

2017-07-01

Changes in surgical training have raised concerns about residents' operative exposure and preparedness for independent practice. One way of addressing this concern is by optimizing teaching and feedback in the operating room (OR). The objective of this study was to perform a systematic review on perioperative teaching and feedback. A systematic literature search identified articles from 1994 to 2014 that addressed teaching, feedback, guidance, or debriefing in the perioperative period. Data was extracted according to ENTREQ guidelines, and a qualitative analysis was performed. Thematic analysis of the 26 included studies identified four major topics. Observation of teaching behaviors in the OR described current teaching practices. Identification of effective teaching strategies analyzed teaching behaviors, differentiating positive and negative teaching strategies. Perceptions of teaching behaviors described resident and attending satisfaction with teaching in the OR. Finally models for delivering structured feedback cited examples of feedback strategies and measured their effectiveness. This study provides an overview of perioperative teaching and feedback for surgical trainees and identifies a need for improved quality and quantity of structured feedback. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of exercise training on in vivo insulin-stimulated glucose uptake in intra-abdominal adipose tissue in rats

DEFF Research Database (Denmark)

Enevoldsen, L H; Stallknecht, B; Fluckey, J D

2000-01-01

Intra-abdominal obesity may be crucial in the pathogenesis of the insulin-resistance syndrome, and training may alleviate this condition. We compared insulin-mediated glucose uptake in vivo in three intra-abdominal adipose tissues (ATs; retroperitoneal, parametrial, and mesenteric) and in subcuta......Intra-abdominal obesity may be crucial in the pathogenesis of the insulin-resistance syndrome, and training may alleviate this condition. We compared insulin-mediated glucose uptake in vivo in three intra-abdominal adipose tissues (ATs; retroperitoneal, parametrial, and mesenteric...

Active training and driving-specific feedback improve older drivers' visual search prior to lane changes.

Science.gov (United States)

Lavallière, Martin; Simoneau, Martin; Tremblay, Mathieu; Laurendeau, Denis; Teasdale, Normand

2012-03-02

Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses) do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group). Their results were compared to a Control group (12 older drivers) who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot). In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes). These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

Effects of continuous visual feedback during sitting balance training in chronic stroke survivors.

Science.gov (United States)

Pellegrino, Laura; Giannoni, Psiche; Marinelli, Lucio; Casadio, Maura

2017-10-16

Postural control deficits are common in stroke survivors and often the rehabilitation programs include balance training based on visual feedback to improve the control of body position or of the voluntary shift of body weight in space. In the present work, a group of chronic stroke survivors, while sitting on a force plate, exercised the ability to control their Center of Pressure with a training based on continuous visual feedback. The goal of this study was to test if and to what extent chronic stroke survivors were able to learn the task and transfer the learned ability to a condition without visual feedback and to directions and displacement amplitudes different from those experienced during training. Eleven chronic stroke survivors (5 Male - 6 Female, age: 59.72 ± 12.84 years) participated in this study. Subjects were seated on a stool positioned on top of a custom-built force platform. Their Center of Pressure positions were mapped to the coordinate of a cursor on a computer monitor. During training, the cursor position was always displayed and the subjects were to reach targets by shifting their Center of Pressure by moving their trunk. Pre and post-training subjects were required to reach without visual feedback of the cursor the training targets as well as other targets positioned in different directions and displacement amplitudes. During training, most stroke survivors were able to perform the required task and to improve their performance in terms of duration, smoothness, and movement extent, although not in terms of movement direction. However, when we removed the visual feedback, most of them had no improvement with respect to their pre-training performance. This study suggests that postural training based exclusively on continuous visual feedback can provide limited benefits for stroke survivors, if administered alone. However, the positive gains observed during training justify the integration of this technology-based protocol in a well

Artificial feedback for remotely supervised training of motor skills

NARCIS (Netherlands)

van Dijk, Henk; Hermens, Hermanus J.

Electromyographic (EMG) biofeedback can be used to train motor functions at a distance, which makes therapy at home a possibility. To enable patients to train properly without the presence of a therapist, artificial feedback is considered essential. We studied the combined effect of age and timing

Measuring the electron beam energy in a magnetic bunch compressor

Energy Technology Data Exchange (ETDEWEB)

Hacker, Kirsten

2010-09-15

Within this thesis, work was carried out in and around the first bunch compressor chicane of the FLASH (Free-electron LASer in Hamburg) linear accelerator in which two distinct systems were developed for the measurement of an electron beams' position with sub-5 {mu}m precision over a 10 cm range. One of these two systems utilized RF techniques to measure the difference between the arrival-times of two broadband electrical pulses generated by the passage of the electron beam adjacent to a pickup antenna. The other system measured the arrival-times of the pulses from the pickup with an optical technique dependent on the delivery of laser pulses which are synchronized to the RF reference of the machine. The relative advantages and disadvantages of these two techniques are explored and compared to other available approaches to measure the same beam property, including a time-of-flight measurement with two beam arrival-time monitors and a synchrotron light monitor with two photomultiplier tubes. The electron beam position measurement is required as part of a measurement of the electron beam energy and could be used in an intra-bunch-train beam-based feedback system that would stabilize the amplitude of the accelerating field. By stabilizing the accelerating field amplitude, the arrival-time of the electron beam can be made more stable. By stabilizing the electron beam arrival-time relative to a stable reference, diagnostic, seeding, and beam-manipulation lasers can be synchronized to the beam. (orig.)

Measuring the electron beam energy in a magnetic bunch compressor

International Nuclear Information System (INIS)

Hacker, Kirsten

2010-09-01

Within this thesis, work was carried out in and around the first bunch compressor chicane of the FLASH (Free-electron LASer in Hamburg) linear accelerator in which two distinct systems were developed for the measurement of an electron beams' position with sub-5 μm precision over a 10 cm range. One of these two systems utilized RF techniques to measure the difference between the arrival-times of two broadband electrical pulses generated by the passage of the electron beam adjacent to a pickup antenna. The other system measured the arrival-times of the pulses from the pickup with an optical technique dependent on the delivery of laser pulses which are synchronized to the RF reference of the machine. The relative advantages and disadvantages of these two techniques are explored and compared to other available approaches to measure the same beam property, including a time-of-flight measurement with two beam arrival-time monitors and a synchrotron light monitor with two photomultiplier tubes. The electron beam position measurement is required as part of a measurement of the electron beam energy and could be used in an intra-bunch-train beam-based feedback system that would stabilize the amplitude of the accelerating field. By stabilizing the accelerating field amplitude, the arrival-time of the electron beam can be made more stable. By stabilizing the electron beam arrival-time relative to a stable reference, diagnostic, seeding, and beam-manipulation lasers can be synchronized to the beam. (orig.)

Optimising surgical training: use of feedback to reduce errors during a simulated surgical procedure.

LENUS (Irish Health Repository)

Boyle, Emily

2011-08-01

To assess the effect of proximate or immediate feedback during an intensive training session. The authors hypothesised that provision of feedback during a training session would improve performance and learning curves.

Active training and driving-specific feedback improve older drivers' visual search prior to lane changes

Directory of Open Access Journals (Sweden)

Lavallière Martin

2012-03-01

Full Text Available Abstract Background Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. Methods In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group. Their results were compared to a Control group (12 older drivers who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. Results After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot. In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes. Conclusions These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

How does culture affect experiential training feedback in exported Canadian health professional curricula?

Science.gov (United States)

Wilbur, Kerry; Mousa Bacha, Rasha; Abdelaziz, Somaia

2017-03-17

To explore feedback processes of Western-based health professional student training curricula conducted in an Arab clinical teaching setting. This qualitative study employed document analysis of in-training evaluation reports (ITERs) used by Canadian nursing, pharmacy, respiratory therapy, paramedic, dental hygiene, and pharmacy technician programs established in Qatar. Six experiential training program coordinators were interviewed between February and May 2016 to explore how national cultural differences are perceived to affect feedback processes between students and clinical supervisors. Interviews were recorded, transcribed, and coded according to a priori cultural themes. Document analysis found all programs' ITERs outlined competency items for students to achieve. Clinical supervisors choose a response option corresponding to their judgment of student performance and may provide additional written feedback in spaces provided. Only one program required formal face-to-face feedback exchange between students and clinical supervisors. Experiential training program coordinators identified that no ITER was expressly culturally adapted, although in some instances, modifications were made for differences in scopes of practice between Canada and Qatar.  Power distance was recognized by all coordinators who also identified both student and supervisor reluctance to document potentially negative feedback in ITERs. Instances of collectivism were described as more lenient student assessment by clinical supervisors of the same cultural background. Uncertainty avoidance did not appear to impact feedback processes. Our findings suggest that differences in specific cultural dimensions between Qatar and Canada have implications on the feedback process in experiential training which may be addressed through simple measures to accommodate communication preferences.

An Instructor's Diagnostic Aid for Feedback in Training.

Science.gov (United States)

Andrews, Dee H.; Uliano, Kevin C.

1988-01-01

Instructor's Diagnostic Aid for Feedback in Training (IDAFT) is a computer-assisted method based on error analysis, domains of learning, and events of instruction. Its use with Navy team instructors is currently being explored. (JOW)

Short structured feedback training is equivalent to a mechanical feedback device in two-rescuer BLS: a randomised simulation study.

Science.gov (United States)

Pavo, Noemi; Goliasch, Georg; Nierscher, Franz Josef; Stumpf, Dominik; Haugk, Moritz; Breckwoldt, Jan; Ruetzler, Kurt; Greif, Robert; Fischer, Henrik

2016-05-13

Resuscitation guidelines encourage the use of cardiopulmonary resuscitation (CPR) feedback devices implying better outcomes after sudden cardiac arrest. Whether effective continuous feedback could also be given verbally by a second rescuer ("human feedback") has not been investigated yet. We, therefore, compared the effect of human feedback to a CPR feedback device. In an open, prospective, randomised, controlled trial, we compared CPR performance of three groups of medical students in a two-rescuer scenario. Group "sCPR" was taught standard BLS without continuous feedback, serving as control. Group "mfCPR" was taught BLS with mechanical audio-visual feedback (HeartStart MRx with Q-CPR-Technology™). Group "hfCPR" was taught standard BLS with human feedback. Afterwards, 326 medical students performed two-rescuer BLS on a manikin for 8 min. CPR quality parameters, such as "effective compression ratio" (ECR: compressions with correct hand position, depth and complete decompression multiplied by flow-time fraction), and other compression, ventilation and time-related parameters were assessed for all groups. ECR was comparable between the hfCPR and the mfCPR group (0.33 vs. 0.35, p = 0.435). The hfCPR group needed less time until starting chest compressions (2 vs. 8 s, p feedback or by using a mechanical audio-visual feedback device was similar. Further studies should investigate whether extended human feedback training could further increase CPR quality at comparable costs for training.

Structured Feedback Training for Time-Out: Efficacy and Efficiency in Comparison to a Didactic Method.

Science.gov (United States)

Jensen, Scott A; Blumberg, Sean; Browning, Megan

2017-09-01

Although time-out has been demonstrated to be effective across multiple settings, little research exists on effective methods for training others to implement time-out. The present set of studies is an exploratory analysis of a structured feedback method for training time-out using repeated role-plays. The three studies examined (a) a between-subjects comparison to more a traditional didactic/video modeling method of time-out training, (b) a within-subjects comparison to traditional didactic/video modeling training for another skill, and (c) the impact of structured feedback training on in-home time-out implementation. Though findings are only preliminary and more research is needed, the structured feedback method appears across studies to be an efficient, effective method that demonstrates good maintenance of skill up to 3 months post training. Findings suggest, though do not confirm, a benefit of the structured feedback method over a more traditional didactic/video training model. Implications and further research on the method are discussed.

Instabilities simulations with wideband feedback systems: CMAD, HEADTAIL, WARP

CERN Document Server

Li, Kevin; Fox, J D; Pivi, M; Rivetta, C; Rumolo, G

2013-01-01

Transverse mode coupling (TMCI) and electron cloud instabilities (ECI) pose fundamental limitations on the acceptable beam intensities in the SPS at CERN. This in turn limits the ultimate achievable luminosity in the LHC. Therefore, future luminosity upgrades foresee methods for evading TMCI as well as ECI. Proposed approaches within the LHC Injector Upgrade (LIU) project include new optics with reduced transition energy as well as vacuum chamber coating techniques. As a complementary option, high bandwidth feedback systems may provide instability mitigation by actively damping the intra-bunch motion of unstable modes. In an effort to evaluate the potentials and limitations of such feedback systems and to characterise some of the specifications, a numerical model of a realistic feedback system has been developed and integrated into available instabilities simulation codes. Together with the implementation of this new feedback system model, CMAD and HEADTAIL have been used to investigate the impact of differen...

Analysis of beam feedback loops of RF acceleration system at TARN II

International Nuclear Information System (INIS)

Katayama, Takeshi.

1992-08-01

Two beam-feedback-loops are prepared for the frequency control of RF acceleration system at cooler-synchrotron TARN II. One is the phase-loop and the other the radial-position-loop. In the present paper, the effects of these loops on the beam dynamics in the synchrotron are studied on the basis of Laplace transformation approach as well as the numerical values for the synchrotron acceleration at TARN II. (author)

Attainment and retention of force moderation following laparoscopic resection training with visual force feedback.

Science.gov (United States)

Hernandez, Rafael; Onar-Thomas, Arzu; Travascio, Francesco; Asfour, Shihab

2017-11-01

Laparoscopic training with visual force feedback can lead to immediate improvements in force moderation. However, the long-term retention of this kind of learning and its potential decay are yet unclear. A laparoscopic resection task and force sensing apparatus were designed to assess the benefits of visual force feedback training. Twenty-two male university students with no previous experience in laparoscopy underwent relevant FLS proficiency training. Participants were randomly assigned to either a control or treatment group. Both groups trained on the task for 2 weeks as follows: initial baseline, sixteen training trials, and post-test immediately after. The treatment group had visual force feedback during training, whereas the control group did not. Participants then performed four weekly test trials to assess long-term retention of training. Outcomes recorded were maximum pulling and pushing forces, completion time, and rated task difficulty. Extreme maximum pulling force values were tapered throughout both the training and retention periods. Average maximum pushing forces were significantly lowered towards the end of training and during retention period. No significant decay of applied force learning was found during the 4-week retention period. Completion time and rated task difficulty were higher during training, but results indicate that the difference eventually fades during the retention period. Significant differences in aptitude across participants were found. Visual force feedback training improves on certain aspects of force moderation in a laparoscopic resection task. Results suggest that with enough training there is no significant decay of learning within the first month of the retention period. It is essential to account for differences in aptitude between individuals in this type of longitudinal research. This study shows how an inexpensive force measuring system can be used with an FLS Trainer System after some retrofitting. Surgical

Pre-training evaluation and feedback improved skills retention of basic life support in medical students.

Science.gov (United States)

Li, Qi; Zhou, Rong-hua; Liu, Jin; Lin, Jing; Ma, Er-Li; Liang, Peng; Shi, Ting-wei; Fang, Li-qun; Xiao, Hong

2013-09-01

Pre-training evaluation and feedback have been shown to improve medical students' skills acquisition of basic life support (BLS) immediately following training. The impact of such training on BLS skills retention is unknown. This study was conducted to investigate effects of pre-training evaluation and feedback on BLS skills retention in medical students. Three hundred and thirty 3rd year medical students were randomized to two groups, the control group (C group) and pre-training evaluation and feedback group (EF group). Each group was subdivided into four subgroups according to the time of retention-test (at 1-, 3-, 6-, 12-month following the initial training). After a 45-min BLS lecture, BLS skills were assessed (pre-training evaluation) in both groups before training. Following this, the C group received 45 min training. 15 min of group feedback corresponding to students' performance in pre-training evaluation was given only in the EF group that was followed by 30 min of BLS training. BLS skills were assessed immediately after training (post-test) and at follow up (retention-test). No skills difference was observed between the two groups in pre-training evaluation. Better skills acquisition was observed in the EF group (85.3 ± 7.3 vs. 68.1 ± 12.2 in C group) at post-test (p<0.001). In all retention-test, better skills retention was observed in each EF subgroup, compared with its paired C subgroup. Pre-training evaluation and feedback improved skills retention in the EF group for 12 months after the initial training, compared with the control group. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Stabilization of exact nonlinear Timoshenko beams in space by boundary feedback

Science.gov (United States)

Do, K. D.

2018-05-01

Boundary feedback controllers are designed to stabilize Timoshenko beams with large translational and rotational motions in space under external disturbances. The exact nonlinear partial differential equations governing motion of the beams are derived and used in the control design. The designed controllers guarantee globally practically asymptotically (and locally practically exponentially) stability of the beam motions at the reference state. The control design, well-posedness and stability analysis are based on various relationships between the earth-fixed and body-fixed coordinates, Sobolev embeddings, and a Lyapunov-type theorem developed to study well-posedness and stability for a class of evolution systems in Hilbert space. Simulation results are included to illustrate the effectiveness of the proposed control design.

SU-F-J-197: A Novel Intra-Beam Range Detection and Adaptation Strategy for Particle Therapy

Energy Technology Data Exchange (ETDEWEB)

Chen, M; Jiang, S; Shao, Y; Lu, W [UT Southwestern Medical Center, Dallas, TX (United States)

2016-06-15

Purpose: In-vivo range detection/verification is crucial in particle therapy for effective and safe delivery. The state-of-art techniques are not sufficient for in-vivo on-line range verification due to conflicts among patient dose, signal statistics and imaging time. We propose a novel intra-beam range detection and adaptation strategy for particle therapy. Methods: This strategy uses the planned mid-range spots as probing beams without adding extra radiation to patients. Such choice of probing beams ensures the Bragg peaks to remain inside the tumor even with significant range variation from the plan. It offers sufficient signal statistics for in-beam positron emission tomography (PET) due to high positron activity of therapeutic dose. The probing beam signal can be acquired and reconstructed using in-beam PET that allows for delineation of the Bragg peaks and detection of range shift with ease of detection enabled by single-layered spots. If the detected range shift is within a pre-defined tolerance, the remaining spots will be delivered as the original plan. Otherwise, a fast re-optimization using range-shifted beamlets and accounting for the probing beam dose is applied to consider the tradeoffs posed by the online anatomy. Simulated planning and delivery studies were used to demonstrate the effectiveness of the proposed techniques. Results: Simulations with online range variations due to shifts of various foreign objects into the beam path showed successful delineation of the Bragg peaks as a result of delivering probing beams. Without on-line delivery adaptation, dose distribution was significantly distorted. In contrast, delivery adaptation incorporating detected range shift recovered well the planned dose. Conclusion: The proposed intra-beam range detection and adaptation utilizing the planned mid-range spots as probing beams, which illuminate the beam range with strong and accurate PET signals, is a safe, practical, yet effective approach to address range

Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics

CERN Document Server

Steinhagen, R J; Boland, M J; Lucas, T G; Rassool, R P

2013-01-01

The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators, the use of optical diagnostic techniques is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependablemeans to measure signals derived from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN’s CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The amplifica...

Design of active feedback controller used in the infrared beam line of SSRF

International Nuclear Information System (INIS)

Zhang Yongli; Tong Yajun; Zhang Zhaohong; Chen Min; Jiang Jianguo; Gong Peirong

2014-01-01

Background: The infrared beam line consists of many kinds of optical components that are susceptible to the external mechanical vibration, which will be further amplified by the long optical paths to seriously destroy the stability of infrared beam position. Purpose: The active feedback controller is used to stabilize the infrared beam position disturbed by the external environment. Methods: The design of the active feedback controller used in the infrared beam line of SSRF was proposed in this paper firstly, which included its background, light-path layout and operating process. Subsequently, the selections of the crucial components such as detector and actuator were discussed in details. Finally, the correction compensator design and its experimental test were also presented. The correction compensator design was realized by utilizing the frequency response method, and tested in time domain, frequency domain and mathematical model simulation of the controlled object. Results: The experimental tests included time domain step response signal of the controller, the time domain signal and its relevant magnitude spectrum in frequency domain due to the light source simulation vibration. Conclusion: The results show that the maximum effective operating band is 250 Hz and the maximum steady error is 5 μm. (authors)

A perspective on the role and utility of haptic feedback in laparoscopic skills training.

Science.gov (United States)

Singapogu, Ravikiran; Burg, Timothy; Burg, Karen J L; Smith, Dane E; Eckenrode, Amanda H

2014-01-01

Laparoscopic surgery is a minimally invasive surgical technique with significant potential benefits to the patient, including shorter recovery time, less scarring, and decreased costs. There is a growing need to teach surgical trainees this emerging surgical technique. Simulators, ranging from simple "box" trainers to complex virtual reality (VR) trainers, have emerged as the most promising method for teaching basic laparoscopic surgical skills. Current box trainers require oversight from an expert surgeon for both training and assessing skills. VR trainers decrease the dependence on expert teachers during training by providing objective, real-time feedback and automatic skills evaluation. However, current VR trainers generally have limited credibility as a means to prepare new surgeons and have often fallen short of educators' expectations. Several researchers have speculated that the missing component in modern VR trainers is haptic feedback, which refers to the range of touch sensations encountered during surgery. These force types and ranges need to be adequately rendered by simulators for a more complete training experience. This article presents a perspective of the role and utility of haptic feedback during laparoscopic surgery and laparoscopic skills training by detailing the ranges and types of haptic sensations felt by the operating surgeon, along with quantitative studies of how this feedback is used. Further, a number of research studies that have documented human performance effects as a result of the presence of haptic feedback are critically reviewed. Finally, key research directions in using haptic feedback for laparoscopy training simulators are identified.

Lack of transfer of skills after virtual reality simulator training with haptic feedback.

Science.gov (United States)

Våpenstad, Cecilie; Hofstad, Erlend Fagertun; Bø, Lars Eirik; Kuhry, Esther; Johnsen, Gjermund; Mårvik, Ronald; Langø, Thomas; Hernes, Toril Nagelhus

2017-12-01

Virtual reality (VR) simulators enrich surgical training and offer training possibilities outside of the operating room (OR). In this study, we created a criterion-based training program on a VR simulator with haptic feedback and tested it by comparing the performances of a simulator group against a control group. Medical students with no experience in laparoscopy were randomly assigned to a simulator group or a control group. In the simulator group, the candidates trained until they reached predefined criteria on the LapSim ® VR simulator (Surgical Science AB, Göteborg, Sweden) with haptic feedback (Xitact TM IHP, Mentice AB, Göteborg, Sweden). All candidates performed a cholecystectomy on a porcine organ model in a box trainer (the clinical setting). The performances were video rated by two surgeons blinded to subject training status. In total, 30 students performed the cholecystectomy and had their videos rated (N = 16 simulator group, N = 14 control group). The control group achieved better video rating scores than the simulator group (p training program did not transfer skills to the clinical setting. Poor mechanical performance of the simulated haptic feedback is believed to have resulted in a negative training effect.

Effect of feedback and noise on fast ion instability

International Nuclear Information System (INIS)

Chao, A.W.; Stupakov, G.V.

1997-07-01

One can use a feedback system to suppress the fast ion instability. However, the feedback noise (and also other sources of noise in the machine) continuously excites the transient oscillations in the electron beam that are amplified through the electron interaction with the ions. We calculate the equilibrium level of these oscillations under the influence of the feedback and show how they grow exponentially from the head to the tail of the bunch train in a linear theory. Nonlinear saturation effects are assume negligible

Self-modulation of an intense electron beam in an injector of a linac with a feedback

International Nuclear Information System (INIS)

Ajzatskij, N.I.

1989-01-01

This paper reports the results of the analysis of the time structure of the beam versus the RF power supplied to the injector of the linac with a feedback. Using a nonstationary model of acceleration, we have performed a mathematical simulation of the dynamics of prebunched electron beam acceleration. The results of the mathematical simulation demonstrate that in the self-modulation acceleration regime of a linac with feedbacks there exists a possibility of adjusting the current pulse length, the pulse-to-pulse time being nearly the same. 4 refs., 2 figs

Survey on multisensory feedback virtual reality dental training systems.

Science.gov (United States)

Wang, D; Li, T; Zhang, Y; Hou, J

2016-11-01

Compared with traditional dental training methods, virtual reality training systems integrated with multisensory feedback possess potentials advantages. However, there exist many technical challenges in developing a satisfactory simulator. In this manuscript, we systematically survey several current dental training systems to identify the gaps between the capabilities of these systems and the clinical training requirements. After briefly summarising the components, functions and unique features of each system, we discuss the technical challenges behind these systems including the software, hardware and user evaluation methods. Finally, the clinical requirements of an ideal dental training system are proposed. Future research/development areas are identified based on an analysis of the gaps between current systems and clinical training requirements. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Real-time feedback of dynamic foot pressure index for gait training of toe-walking children with spastic diplegia.

Science.gov (United States)

Pu, Fang; Ren, Weiyan; Fan, Xiaoya; Chen, Wei; Li, Shuyu; Li, Deyu; Wang, Yu; Fan, Yubo

2017-09-01

The aim of this study was to determine whether and how real-time feedback of dynamic foot pressure index (DFPI) could be used to correct toe-walking gait in spastic diplegic children with dynamic equinus. Thirteen spastic diplegic children with dynamic equinus were asked to wear a monitoring device to record their ambulation during daily gait, conventional training gait, and feedback training gait. Parameters based on their DFPI and stride duration were compared among the three test conditions. The results with feedback training were significantly better for all DFPI parameters in comparison to patients' daily gait and showed significant improvements in DFPI for toe-walking gait and percentage of normal gait in comparison to conventional training methods. Moreover, stride duration under two training gaits was longer than patient's daily gait, but there was no significant difference between the two training gaits. Although the stride duration for the two training gaits was similar, gait training with real-time feedback of DFPI did produce noticeably superior results by increasing heel-loading impulse of toe-walking gait and percentage of normal gait in comparison to convention training methods. However, its effectiveness was still impacted by the motion limitations of diplegic children. Implications for Rehabilitation The DFPI-based gait training feedback system introduced in this study was shown to be more effective at toe-walking gait rehabilitation training over conventional training methods. The feedback system accomplished superior improvement in correcting toe-walking gait, but its effectiveness in an increasing heel-loading impulse in normal gait was still limited by the motion limitations of diplegic children. Stride duration of normal gait and toe-walking gait was similar under conventional and feedback gait training.

The super collider transverse feedback system for suppression of the emittance growth and beam instabilities

International Nuclear Information System (INIS)

Lebedev, V.A.

1993-01-01

A super collider transverse feedback system designed to suppress injection errors, emittance growth due to external noises, and beam instabilities is considered. It is supposed that the feedback system should consist of two circuits: an injection damper operating just after injection and a super damper. To damp the emittance growth, the superdamper has to operate with the ultimate decrement close to the revolution frequency. The physics of such a feedback system and its main limitations are discussed. 9 refs.; 21 figs.; 1 tab

Instabilities simulations with wideband feedback systems: CMAD, HEADTAIL, WARP

International Nuclear Information System (INIS)

Li, Kevin; Cesaratto, J; Fox, J D; Pivi, M; Rivetta, C; Rumolo, G

2013-01-01

Transverse mode coupling (TMCI) and electron cloud instabilities (ECI) pose fundamental limitations on the acceptable beam intensities in the SPS at CERN. This in turn limits the ultimate achievable luminosity in the LHC. Therefore, future luminosity upgrades foresee methods for evading TMCI as well as ECI. Proposed approaches within the LHC Injector Upgrade (LIU) project include new optics with reduced transition energy as well as vacuum chamber coating techniques. As a complementary option, high bandwidth feedback systems may provide instability mitigation by actively damping the intra-bunch motion of unstable modes. In an effort to evaluate the potentials and limitations of such feedback systems and to characterise some of the specifications, a numerical model of a realistic feedback system has been developed and integrated into available instabilities simulation codes. Together with the implementation of this new feedback system model, CMAD and HEADTAIL have been used to investigate the impact of different wideband feedback systems on ECI in the SPS. In this paper, we present some details on the numerical model of the realistic feedback system and its implementation as well as the results obtained from the simulation study using this model together with the instability codes. (author)

Learning outcomes using video in supervision and peer feedback during clinical skills training

DEFF Research Database (Denmark)

Lauridsen, Henrik Hein; Toftgård, Rie Castella; Nørgaard, Cita

supervision of clinical skills (formative assessment). Demonstrations of these principles will be presented as video podcasts during the session. The learning outcomes of video supervision and peer-feedback were assessed in an online questionnaire survey. Results Results of the supervision showed large self......Objective New technology and learning principles were introduced in a clinical skills training laboratory (iLab). The intension was to move from apprenticeship to active learning principles including peer feedback and supervision using video. The objective of this study was to evaluate student...... learning outcomes in a manual skills training subject using video during feedback and supervision. Methods The iLab classroom was designed to fit four principles of teaching using video. Two of these principles were (a) group work using peer-feedback on videos produced by the students and, (b) video...

Treatment of Childhood Migraine Using Autogenic Feedback Training.

Science.gov (United States)

Labbe, Elise L.

1984-01-01

Compared autogenic feedback training with a waiting-list control group as a treatment for children (N=28) with migraine headaches. Children in the treatment condition were significantly improved at the end of treatment and at one-month and six-month follow-up. No improvement was found for the children in the control condition. (BH)

Training simulated patients: evaluation of a training approach using self-assessment and peer/tutor feedback to improve performance.

Science.gov (United States)

Perera, Jennifer; Perera, Joachim; Abdullah, Juriah; Lee, Nagarajah

2009-06-29

Most medical schools use simulated patients (SPs) for teaching. In this context the authenticity of role play and quality of feedback provided by SPs is of paramount importance. The available literature on SP training mostly addresses instructor led training where the SPs are given direction on their roles. This study focuses on the use of peer and self evaluation as a tool to train SPs. SPs at the medical school participated in a staff development and training programme which included a) self-assessment of their performance while observing video-tapes of their role play using a structured guide and b) peer group assessment of their performance under tutor guidance. The pre and post training performance in relation to authenticity of role play and quality of feedback was blindly assessed by students and tutors using a validated instrument and the scores were compared. A focus group discussion and a questionnaire assessed acceptability of the training programme by the SPs. The post-training performance assessment scores were significantly higher (p performance. More studies on these methods of training may further refine SP training and lead to improvement of SP performance which in turn may positively impact medical education.

Visual feedback training using WII Fit improves balance in Parkinson's disease.

Science.gov (United States)

Zalecki, Tomasz; Gorecka-Mazur, Agnieszka; Pietraszko, Wojciech; Surowka, Artur D; Novak, Pawel; Moskala, Marek; Krygowska-Wajs, Anna

2013-01-01

Postural instability including imbalance is the most disabling long term problem in Parkinson's disease (PD) that does not respond to pharmacotherapy. This study aimed at investigating the effectiveness of a novel visual-feedback training method, using Wii Fit balance board in improving balance in patients with PD. Twenty four patients with moderate PD were included in the study which comprised of a 6-week home-based balance training program using Nintendo Wii Fit and balance board. The PD patients significantly improved their results in Berg Balance Scale, Tinnet's Performance-Oriented Mobility Assessment, Timed Up-and-Go, Sit-to-stand test, 10-Meter Walk test and Activities-specific Balance Confidence scale at the end of the programme. This study suggests that visual feedback training using Wii-Fit with balance board could improve dynamic and functional balance as well as motor disability in PD patients.

Multi-bunch Feedback Systems

International Nuclear Information System (INIS)

Lonza, M; Schmickler, H

2014-01-01

Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. We first introduce coupled-bunch instabilities, analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedback systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback systems. The main components of a feedback system and the related issues will also be analysed. Finally, we shall focus on digital feedback systems, their characteristics, and features, as well as on how they can be concretely exploited for both the optimization of feedback performance and for beam dynamics studies

Feedback to suppress beam instabilities in future proton rings

International Nuclear Information System (INIS)

Lambertson, G.R.

1985-05-01

Criteria for the design of feedback systems to suppress coherent beam instabilities are presented. These address starting amplitudes, diffusion from noise during damping or long storage, and choice of kicker. As a model for future accelerators, specifications of the proposed 20 TeV SSC are used to calculate parameters of systems to control expected instabilities. A scenario and hardware to stabilize the transverse mode-coupling instability is examined. The scale of the systems is large but not out of scale with the large ring. 9 refs., 4 tabs

Progress In Transverse Feedbacks and Related Diagnostics for Hadron Machines

CERN Document Server

Hofle, W

2013-01-01

Today Hadron Accelerators with high intensity and high brightness beams increasingly rely on transverse feedback systems for the control of instabilities and the preservation of the transverse emittance. With particular emphasis, but not limited to, the CERN Hadron Accelerator Chain, the progress made in recent years, and the performances achieved are reviewed. Hadron colliders such as the LHC represent a particular challenge as they ask for low noise electronic systems in these feedbacks for acceptable emittance growth. Achievements of the LHC transverse feedback system used for damping injection oscillations and to provide stability throughout the cycle are summarized. This includes its use for abort gap and injection cleaning as well as transverse blow-up for diagnostics purposes. Beyond systems already in operation, advances in technology and modern digital signal processing with increasingly higher digitization rates have made systems conceivable to cure intra-bunch motion. With its capabilities to both ...

The influence of verbal training and visual feedback on manual wheelchair propulsion.

Science.gov (United States)

DeGroot, Keri K; Hollingsworth, Holly H; Morgan, Kerri A; Morris, Carrie L; Gray, David B

2009-03-01

To determine if verbal training with visual feedback improved manual wheelchair propulsion; to examine propulsion differences between an individual with paraplegia and an individual with tetraplegia. Quasi-experimental study: Nine manual wheelchair-using adults participated in propulsion assessments and training. Baseline propulsion performance was measured on several tasks on different surfaces. Participants were trained on a wheelchair treadmill with verbal and visual feedback to increase push length, reduce push frequency and to modify propulsion pattern. Handrim biomechanics were measured with an instrumented wheel. Changes in propulsion were assessed. Differences in propulsion characteristics between a participant with paraplegia and a participant with tetraplegia were examined. Push length increased (p propulsion characteristics between a participant with paraplegia and a participant with tetraplegia. Verbal training may produce changes in push biomechanics of manual wheelchair users. Longer training periods may be needed to sustain propulsion changes. Findings from this study support other studies that have shown propulsion differences between people with tetraplegia and paraplegia. Propulsion training for populations with upper-extremity impairments warrants further study.

Autogenic-feedback training - A treatment for motion and space sickness

Science.gov (United States)

Cowings, Patricia S.

1990-01-01

A training method for preventing the occurrence of motion sickness in humans, called autogenic-feedback training (AFT), is described. AFT is based on a combination of biofeedback and autogenic therapy which involves training physiological self-regulation as an alternative to pharmacological management. AFT was used to reliably increase tolerance to motion-sickness-inducing tests in both men and women ranging in age from 18 to 54 years. The effectiveness of AFT is found to be significantly higher than that of protective adaptation training. Data obtained show that there is no apparent effect from AFT on measures of vestibular perception and no side effects.

Autogenic-feedback training: A countermeasure for orthostatic intolerance

Science.gov (United States)

Cowings, Patricia S.; Toscano, William B.; Kamiya, Joe; Miller, Neal E.; Pickering, Thomas G.

1991-01-01

NASA has identified cardiovascular deconditioning as a serious biomedical problem associated with long-duration exposure to microgravity in space. High priority has been given to the development of countermeasures for this disorder and the resulting orthostatic intolerance experienced by crewmembers upon their return to the 1g norm of Earth. The present study was designed to examine the feasibility of training human subjects to control their own cardiovascular responses to gravitational stimulation (i.e., a tilt table). Using an operant conditioning procedure, Autogenic-Feedback Training (AFT), we would determine if subjects could learn to increase their own blood pressure voluntarily.

Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

Science.gov (United States)

Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

2015-01-01

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability. PMID:25946173

Audio-Visual Feedback for Self-monitoring Posture in Ballet Training

DEFF Research Database (Denmark)

Knudsen, Esben Winther; Hølledig, Malte Lindholm; Bach-Nielsen, Sebastian Siem

2017-01-01

An application for ballet training is presented that monitors the posture position (straightness of the spine and rotation of the pelvis) deviation from the ideal position in real-time. The human skeletal data is acquired through a Microsoft Kinect v2. The movement of the student is mirrored......-coded. In an experiment with 9-12 year-old dance students from a ballet school, comparing the audio-visual feedback modality with no feedback leads to an increase in posture accuracy (p

Multi-bunch Feedback Systems

OpenAIRE

Lonza, M.; Schmickler, H.

2016-01-01

Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides importa...

A 4 GS/sec Instability Feedback Processing System for Intra-bunch Instabilities

CERN Document Server

Dusatko, J; Fox, J D; Pollock, K; Rivetta, C H; Turgut, O; Hofle, W

2013-01-01

We present the architecture and implementation overview of a proof-of-principle digital signal processing system developed to study control of Electron-Cloud and Transverse Mode Coupling Instabilities (TMCI) in the CERN SPS. This system is motivated by intensity increases planned as part of the High Luminosity LHC upgrade. It is based on a reconfigurable processing architecture which samples intra-bunch motion and applies correction signals at a 4GSa/s rate, allowing multiple samples across a single 3.2ns SPS bunch. This initial demonstration system is a rapidly developed prototype consisting of both commercial and custom- designed hardware that implements feedback control on a single bunch. It contains a high speed ADC and DAC, capable of sampling at up to 4GSa/s, with a 16-tap FIR control filter for each bunch sample slice. Other system features include a timing subsystem to synchronize the sampling to the injection and the bunch 1 markers, the capability of generating arbitrary time domain signals to drive...

Transfer of Training: The Role of Feedback in Supportive Social Networks

Science.gov (United States)

Van den Bossche, Piet; Segers, Mien; Jansen, Niekie

2010-01-01

The transfer of training to the workplace often fails to occur. The authors argue that feedback generated within the work environment about the application of newly learned skills in the workplace helps to close the gap between the current performance and the desired goal of full application of what is learned during training. This study takes a…

Implementation status of the global and local beam position feedback systems for the Advanced Photon Source storage ring

International Nuclear Information System (INIS)

Chung, Y.; Barr, D.; Decker, G.; Galayda, J.; Kirchman, J.; Lenkszus, F.; Lumpkin, A.; Votaw, A.J.

1995-01-01

The Advanced Photon Source (APS) is implementing an extensive beam position feedback system for both global and local stabilization of particle and photon beams based on digital signal processing. The description and operational experience of the system will be given in this paper. In particular, we will discuss the underlying fundamental principles, hardware layout, controls interface, and automatic software generation for multiple digital signal processors (DSPS) distributed in 20 VME crates around the ring. The feedback system runs at 4-kHz sampling frequency in order to achieve the correction bandwidth of approximately 100 Hz. For the maximum correction efficiency and resolution of conflicts among multiple local feedback systems due to the local bump closure error, the global and local feedback systems are combined into a single unified system. This novel approach is made possible through data sharing among the global and local systems via the fiber-optically networked reflective memories

FY1995 study of feedback type gait training system; 1995 nendo feedback gata hoko kuren sochi ni kansuru kenkyu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The purpose of this project is to develop and demonstrate the utility of feedback type gait training equipment designed for the measurement and evaluation by a walking training of the aged or patient. As similar concepts of walking training, a locomotion in the water for the aged is applied in rehabilitation. Our development of this study established the system of a suspending mechanism which revolves around the prop, and a walking on the circular type force plate by the aged or patient. It is possible to detect a walking reaction force of several patients from force plate simultaneously. And then, the data from force plate makes feedback signal to put up the patient like a buoyancy in the water. Concerning the evaluations of walking pattern a step range, a hanging ratio and a walking speed, etc. are acquired for each patient by the acknowledgment base. This system is actively able to perform a walking training continuously compared with conventional passive gait equipment. (NEDO)

Effects of Training and Feedback on Teachers' Use of Classroom Preventive Practices

Science.gov (United States)

Artman-Meeker, Kathleen M.; Hemmeter, Mary Louise

2013-01-01

This study examined the effects of in-service training with performance feedback on preschool teachers' use of classroom preventive practices. Three practices designed to prevent challenging behavior were selected: transition preparations, rule reminders, and social-emotional teaching strategies. Following a brief training on each practice,…

Training simulated patients: evaluation of a training approach using self-assessment and peer/tutor feedback to improve performance

Directory of Open Access Journals (Sweden)

Abdullah Juriah

2009-06-01

Full Text Available Abstract Background Most medical schools use simulated patients (SPs for teaching. In this context the authenticity of role play and quality of feedback provided by SPs is of paramount importance. The available literature on SP training mostly addresses instructor led training where the SPs are given direction on their roles. This study focuses on the use of peer and self evaluation as a tool to train SPs. Methods SPs at the medical school participated in a staff development and training programme which included a self-assessment of their performance while observing video-tapes of their role play using a structured guide and b peer group assessment of their performance under tutor guidance. The pre and post training performance in relation to authenticity of role play and quality of feedback was blindly assessed by students and tutors using a validated instrument and the scores were compared. A focus group discussion and a questionnaire assessed acceptability of the training programme by the SPs. Results The post-training performance assessment scores were significantly higher (p Conclusion Use of structured self-reflective and peer-interactive, practice based methods of SP training is recommended to improve SP performance. More studies on these methods of training may further refine SP training and lead to improvement of SP performance which in turn may positively impact medical education.

Parametric feedback cooling of a single atom inside on optical cavity

International Nuclear Information System (INIS)

Tatjana Wilk

2014-01-01

An optical cavity can be used as a kind of intensifier to study radiation features of an atom, which are hard to detect in free space, like squeezing. Such experiments make use of strong coupling between atom and cavity mode, which experimentally requires the atom to be well localized in the cavity mode. This can be achieved using feedback on the atomic motion: from intensity variations of a probe beam transmitted through the cavity information about the atomic motion is gained, which is used to synchronously modulate the trapping potential holding the atom, leading to cooling and better localization. Here, we report on efficient parametric feedback cooling of a single atom held in an intra-cavity standing wave dipole trap. In contrast to previous feedback strategies, this scheme cools the fast axial oscillation of the atom as well as the slower radial motion. (author)

Feedback Systems for Linear Colliders

International Nuclear Information System (INIS)

1999-01-01

Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have been investigated, and improvements have been made. For the Next Linear Collider (NLC), extensive feedback systems are planned as an integral part of the design. Feedback requirements for JLC (the Japanese Linear Collider) are essentially identical to NLC; some of the TESLA requirements are similar but there are significant differences. For NLC, algorithms which incorporate improvements upon the SLC implementation are being prototyped. Specialized systems for the damping rings, rf and interaction point will operate at high bandwidth and fast response. To correct for the motion of individual bunches within a train, both feedforward and feedback systems are planned. SLC experience has shown that feedback systems are an invaluable operational tool for decoupling systems, allowing precision tuning, and providing pulse-to-pulse diagnostics. Feedback systems for the NLC will incorporate the key SLC features and the benefits of advancing technologies

Multi-Bunch Simulations of the ILC for Luminosity Performance Studies

CERN Document Server

White, Glen; Walker, Nicholas J

2005-01-01

To study the luminosity performance of the International Linear Collider (ILC) with different design parameters, a simulation was constructed that tracks a multi-bunch representation of the beam from the Damping Ring extraction through to the Interaction Point. The simulation code PLACET is used to simulate the LINAC, MatMerlin is used to track through the Beam Delivery System and GUINEA-PIG for the beam-beam interaction. Included in the simulation are ground motion and wakefield effects, intra-train fast feedback and luminosity-based feedback systems. To efficiently study multiple parameters/multiple seeds, the simulation is deployed on the Queen Mary High-Throughput computing cluster at Queen Mary, University of London, where 100 simultaneous simulation seeds can be run.

The value of haptic feedback in conventional and robot-assisted minimal invasive surgery and virtual reality training: a current review.

Science.gov (United States)

van der Meijden, O A J; Schijven, M P

2009-06-01

Virtual reality (VR) as surgical training tool has become a state-of-the-art technique in training and teaching skills for minimally invasive surgery (MIS). Although intuitively appealing, the true benefits of haptic (VR training) platforms are unknown. Many questions about haptic feedback in the different areas of surgical skills (training) need to be answered before adding costly haptic feedback in VR simulation for MIS training. This study was designed to review the current status and value of haptic feedback in conventional and robot-assisted MIS and training by using virtual reality simulation. A systematic review of the literature was undertaken using PubMed and MEDLINE. The following search terms were used: Haptic feedback OR Haptics OR Force feedback AND/OR Minimal Invasive Surgery AND/OR Minimal Access Surgery AND/OR Robotics AND/OR Robotic Surgery AND/OR Endoscopic Surgery AND/OR Virtual Reality AND/OR Simulation OR Surgical Training/Education. The results were assessed according to level of evidence as reflected by the Oxford Centre of Evidence-based Medicine Levels of Evidence. In the current literature, no firm consensus exists on the importance of haptic feedback in performing minimally invasive surgery. Although the majority of the results show positive assessment of the benefits of force feedback, results are ambivalent and not unanimous on the subject. Benefits are least disputed when related to surgery using robotics, because there is no haptic feedback in currently used robotics. The addition of haptics is believed to reduce surgical errors resulting from a lack of it, especially in knot tying. Little research has been performed in the area of robot-assisted endoscopic surgical training, but results seem promising. Concerning VR training, results indicate that haptic feedback is important during the early phase of psychomotor skill acquisition.

The effect of peer-group size on the delivery of feedback in basic life support refresher training: a cluster randomized controlled trial.

Science.gov (United States)

Cho, Youngsuk; Je, Sangmo; Yoon, Yoo Sang; Roh, Hye Rin; Chang, Chulho; Kang, Hyunggoo; Lim, Taeho

2016-07-04

Students are largely providing feedback to one another when instructor facilitates peer feedback rather than teaching in group training. The number of students in a group affect the learning of students in the group training. We aimed to investigate whether a larger group size increases students' test scores on a post-training test with peer feedback facilitated by instructor after video-guided basic life support (BLS) refresher training. Students' one-rescuer adult BLS skills were assessed by a 2-min checklist-based test 1 year after the initial training. A cluster randomized controlled trial was conducted to evaluate the effect of student number in a group on BLS refresher training. Participants included 115 final-year medical students undergoing their emergency medicine clerkship. The median number of students was 8 in the large groups and 4 in the standard group. The primary outcome was to examine group differences in post-training test scores after video-guided BLS training. Secondary outcomes included the feedback time, number of feedback topics, and results of end-of-training evaluation questionnaires. Scores on the post-training test increased over three consecutive tests with instructor-led peer feedback, but not differ between large and standard groups. The feedback time was longer and number of feedback topics generated by students were higher in standard groups compared to large groups on the first and second tests. The end-of-training questionnaire revealed that the students in large groups preferred the smaller group size compared to their actual group size. In this BLS refresher training, the instructor-led group feedback increased the test score after tutorial video-guided BLS learning, irrespective of the group size. A smaller group size allowed more participations in peer feedback.

Multi-bunch feedback systems

CERN Document Server

Lonza, M

2008-01-01

Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. The advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. The lecture will first introduce coupled-bunch instabilities analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedbacks systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback sy...

Multi-bunch Feedback Systems

CERN Document Server

Lonza, M.

2014-12-19

Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. We first introduce coupled-bunch instabilities, analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedback systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback systems. The main co...

Video Feedback in Key Word Signing Training for Preservice Direct Support Staff

Science.gov (United States)

Rombouts, Ellen; Meuris, Kristien; Maes, Bea; De Meyer, Anne-Marie; Zink, Inge

2016-01-01

Purpose: Research has demonstrated that formal training is essential for professionals to learn key word signing. Yet, the particular didactic strategies have not been studied. Therefore, this study compared the effectiveness of verbal and video feedback in a key word signing training for future direct support staff. Method: Forty-nine future…

Feedback systems in the SLC

International Nuclear Information System (INIS)

Thompson, K.A.; Jobe, R.K.; Johnson, R.; Phinney, N.

1987-02-01

Two classes of computer-controlled feedback have been implemented to stabilize parameters in subsystems of the SLC: (1) ''slow'' (time scales ∼ minutes) feedback, and (2) ''fast'', i.e., pulse-to-pulse, feedback. The slow loops run in a single FEEDBACK process in the SLC host VAX, which acquires signals and sets control parameters via communication with the database and the network of normal SLC microprocessors. Slow loops exist to stabilize beam energy and energy spread, beam position and angle, and timing of kicker magnets, and to compensate for changes in the phase length of the rf drive line. The fast loops run in dedicated microprocessors, and may sample and/or feedback on particular parameters as often as every pulse of the SLC beam. The first implementations of fast feedback are to control transverse beam blow-up and to stabilize the energy and energy spread of bunches going into the SLC arcs. The overall architecture of the feedback software and the operator interface for controlling loops are discussed

Attention training through gaze-contingent feedback: Effects on reappraisal and negative emotions.

Science.gov (United States)

Sanchez, Alvaro; Everaert, Jonas; Koster, Ernst H W

2016-10-01

Reappraisal is central to emotion regulation but its mechanisms are unclear. This study tested the theoretical prediction that emotional attention bias is linked to reappraisal of negative emotion-eliciting stimuli and subsequent emotional responding using a novel attentional control training. Thirty-six undergraduates were randomly assigned to either the control or the attention training condition and were provided with different task instructions while they performed an interpretation task. Whereas control participants freely created interpretations, participants in the training condition were instructed to allocate attention toward positive words to efficiently create positive interpretations (i.e., recruiting attentional control) while they were provided with gaze-contingent feedback on their viewing behavior. Transfer to attention bias and reappraisal success was evaluated using a dot-probe task and an emotion regulation task which were administered before and after the training. The training condition was effective at increasing attentional control and resulted in beneficial effects on the transfer tasks. Analyses supported a serial indirect effect with larger attentional control acquisition in the training condition leading to negative attention bias reduction, in turn predicting greater reappraisal success which reduced negative emotions. Our results indicate that attentional mechanisms influence the use of reappraisal strategies and its impact on negative emotions. The novel attention training highlights the importance of tailored feedback to train attentional control. The findings provide an important step toward personalized delivery of attention training. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

"Booster" training: evaluation of instructor-led bedside cardiopulmonary resuscitation skill training and automated corrective feedback to improve cardiopulmonary resuscitation compliance of Pediatric Basic Life Support providers during simulated cardiac arrest.

Science.gov (United States)

Sutton, Robert M; Niles, Dana; Meaney, Peter A; Aplenc, Richard; French, Benjamin; Abella, Benjamin S; Lengetti, Evelyn L; Berg, Robert A; Helfaer, Mark A; Nadkarni, Vinay

2011-05-01

To investigate the effectiveness of brief bedside "booster" cardiopulmonary resuscitation (CPR) training to improve CPR guideline compliance of hospital-based pediatric providers. Prospective, randomized trial. General pediatric wards at Children's Hospital of Philadelphia. Sixty-nine Basic Life Support-certified hospital-based providers. CPR recording/feedback defibrillators were used to evaluate CPR quality during simulated pediatric arrest. After a 60-sec pretraining CPR evaluation, subjects were randomly assigned to one of three instructional/feedback methods to be used during CPR booster training sessions. All sessions (training/CPR manikin practice) were of equal duration (2 mins) and differed only in the method of corrective feedback given to participants during the session. The study arms were as follows: 1) instructor-only training; 2) automated defibrillator feedback only; and 3) instructor training combined with automated feedback. Before instruction, 57% of the care providers performed compressions within guideline rate recommendations (rate >90 min(-1) and 38 mm); and 36% met overall CPR compliance (rate and depth within targets). After instruction, guideline compliance improved (instructor-only training: rate 52% to 87% [p .01], and overall CPR compliance, 43% to 78% [p CPR compliance, 35% to 96% [p training combined with automated feedback: rate 48% to 100% [p CPR compliance, 30% to 100% [p CPR instruction, most certified Pediatric Basic Life Support providers did not perform guideline-compliant CPR. After a brief bedside training, CPR quality improved irrespective of training content (instructor vs. automated feedback). Future studies should investigate bedside training to improve CPR quality during actual pediatric cardiac arrests.

Beam monitors and transverse feedback system of TRISTAN Main Ring

International Nuclear Information System (INIS)

Ieiri, T.; Ishii, H.; Kishiro, J.; Mizumachi, Y.; Mori, K.; Nakajima, K.; Ogata, A.; Shintake, T.; Tejima, M.

1987-01-01

The construction of 30 GeV TRISTAN Main Ring (MR) started in 1983 soon after the commissioning of 8 GeV Accumulation Ring (AR). The authors prepared 392 position monitors, 6 synchrotron radiation monitors, 9 screen monitors, 2 DCCT's, 3 scrapers, 12 bunch monitors, transverse feedback systems for two beams and DC separators. Since the required monitoring devices of AR and MR are almost the same, the experiences in AR were very useful in the design of MR monitors. However, machine parameters of two rings are very different and the authors had to review the performance of each item. From the monitor point of view the most important is the difference of revolution frequency; 794.6 kHz for AR and 99.33 kHz for MR. This means that average beam current of MR is 1/8 as small as AR current with the same bunch number and intensity. Therefore, the sensitivity of each monitor must be better in MR. The second difference is that MR should be used as a collider from the beginning. Therefore they must prepare for multi-beam and multi-bunch operation

Engineering the on-axis intensity of Bessel beam by a feedback tuning loop

Science.gov (United States)

Li, Runze; Yu, Xianghua; Yang, Yanlong; Peng, Tong; Yao, Baoli; Zhang, Chunmin; Ye, Tong

2018-02-01

The Bessel beam belongs to a typical class of non-diffractive optical fields that are characterized by their invariant focal profiles along the propagation direction. However, ideal Bessel beams only rigorously exist in theory; Bessel beams generated in the lab are quasi-Bessel beams with finite focal extensions and varying intensity profiles along the propagation axis. The ability to engineer the on-axis intensity profile to the desired shape is essential for many applications. Here we demonstrate an iterative optimization-based approach to engineering the on-axis intensity of Bessel beams. The genetic algorithm is used to demonstrate this approach. Starting with a traditional axicon phase mask, in the design process, the computed on-axis beam profile is fed into a feedback tuning loop of an iterative optimization process, which searches for an optimal radial phase distribution that can generate a generalized Bessel beam with the desired onaxis intensity profile. The experimental implementation involves a fine-tuning process that adjusts the originally targeted profile so that the optimization process can optimize the phase mask to yield an improved on-axis profile. Our proposed method has been demonstrated in engineering several zeroth-order Bessel beams with customized on-axis profiles. High accuracy and high energy throughput merit its use in many applications.

Robust output feedback cruise control for high-speed train movement with uncertain parameters

International Nuclear Information System (INIS)

Li Shu-Kai; Yang Li-Xing; Li Ke-Ping

2015-01-01

In this paper, the robust output feedback cruise control for high-speed train movement with uncertain parameters is investigated. The dynamic of a high-speed train is modeled by a cascade of cars connected by flexible couplers, which is subject to rolling mechanical resistance, aerodynamic drag and wind gust. Based on Lyapunov’s stability theory, the sufficient condition for the existence of the robust output feedback cruise control law is given in terms of linear matrix inequalities (LMIs), under which the high-speed train tracks the desired speed, the relative spring displacement between the two neighboring cars is stable at the equilibrium state, and meanwhile a small prescribed H ∞ disturbance attenuation level is guaranteed. One numerical example is given to illustrate the effectiveness of the proposed methods. (paper)

Autogenic-Feedback Training Exercise (AFTE) Method and System

Science.gov (United States)

Cowings, Patricia S. (Inventor)

1997-01-01

The Autogenic-Feedback Training Exercise (AFTE) method of the present invention is a combined application of physiologic and perceptual training techniques. such as autogenic therapy and biofeedback. This combined therapy approach produces a methodology that is appreciably more effective than either of the individual techniques used separately. The AFTE method enables sufficient magnitude of control necessary to significantly reduce the behavioral and physiologic reactions to severe environmental stressors. It produces learned effects that are persistent over time and are resistant to extinction and it can be administered in a short period of time. The AFTE method may be used efficiently in several applications, among which are the following: to improve pilot and crew performance during emergency flying conditions; to train people to prevent the occurrence of nausea and vomiting associated with motion and sea sickness, or morning sickness in early pregnancy; as a training method for preventing or counteracting air-sickness symptoms in high-performance military aircraft; for use as a method for cardiovascular training, as well as for multiple other autonomic responses, which may contribute to the alleviation of Space Motion Sickness (SMS) in astronauts and cosmonauts; training people suffering from migraine or tension headaches to control peripheral blood flow and reduce forehead and/or trapezius muscle tension; training elderly people suffering from fecal incontinence to control their sphincter muscles; training cancer patients to reduce the nauseagenic effects of chemotherapy; and training patients with Chronic Intestinal Pseudo-obstruction (CIP).

RF feedback for KEKB

Energy Technology Data Exchange (ETDEWEB)

Ezura, Eizi; Yoshimoto, Shin-ichi; Akai, Kazunori [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

1996-08-01

This paper describes the present status of the RF feedback development for the KEK B-Factory (KEKB). A preliminary experiment concerning the RF feedback using a parallel comb-filter was performed through a choke-mode cavity and a klystron. The RF feedback has been tested using the beam of the TRISTAN Main Ring, and has proved to be effective in damping the beam instability. (author)

Plasma measurement by feedback-stabilized dual-beam laser interferometer

International Nuclear Information System (INIS)

Yasuda, Akio; Kawahata, Kazuo; Kanai, Yasubumi.

1982-03-01

The plasma density in a dynamic magneto arcjet is measured by a stabilized dual-beam laser interferometer proposed by the authors. The fringe shift for a 0.63 μm beam of He-Ne laser is used to stabilize the interferometer against the effect of mechanical vibration by means of a feedback controlled speaker coil, while the other beam of 3.39 μm, for which the effect of mechanical vibrations is excluded, is used to measure plasma density. Stability of --1/500 of one fringe for 0.63 μm is obtained during a long period for frequencies lower than a few Hertz. Stability for higher frequencies, which determines the accuracy of the present measurement, is limited to --1/30 of one fringe for 0.63 μm, which corresponds to --1/200 of one fringe and a line electron density of --1.5 x 10 14 cm - 2 for 3.39 μm, by acoustic noise picked up by the speaker coil. The advantage of this technique over the single-laser technique is that the frequency response of the interferometer extends down to zero frequency. Since the effect of the neutral gas background is practically reduced to zero, the present interferometer is to be applied advantageously to the diagnostics of the plasma produced in high pressure gases. (author)

Sensory Feedback Training for Improvement of Finger Perception in Cerebral Palsy

Directory of Open Access Journals (Sweden)

Tobias Blumenstein

2015-01-01

Full Text Available Purpose. To develop and to test a feedback training system for improvement of tactile perception and coordination of fingers in children and youth with cerebral palsy. Methods. The fingers of 7 probands with cerebral palsy of different types and severity were stimulated using small vibration motors integrated in the fingers of a hand glove. The vibration motors were connected through a microcontroller to a computer and to a response 5-button keyboard. By pressing an appropriate keyboard button, the proband must indicate in which finger the vibration was felt. The number of incorrect responses and the reaction time were measured for every finger. The perception and coordination of fingers were estimated before and after two-week training using both clinical tests and the measurements. Results. Proper functioning of the developed system in persons with cerebral palsy was confirmed. The tactile sensation of fingers was improved in five of seven subjects after two weeks of training. There was no clear tendency towards improvement of selective use of fingers. Conclusion. The designed feedback system could be used to train tactile perception of fingers in children and youth with cerebral palsy. An extensive study is required to confirm these findings.

The College of Anaesthetists of Ireland Simulation Training programme: a descriptive report and analysis of course participants' feedback.

Science.gov (United States)

Cafferkey, Aine; Coyle, Elizabeth; Greaney, David; Harte, Sinead; Hayes, Niamh; Langdon, Miriam; Straub, Birgitt; Burlacu, Crina

2018-03-20

Simulation-based education is a modern training modality that allows healthcare professionals to develop knowledge and practice skills in a safe learning environment. The College of Anaesthetists of Ireland (CAI) was the first Irish postgraduate medical training body to introduce mandatory simulation training into its curriculum. Extensive quality assurance and improvement data has been collected on all simulation courses to date. Describe The College of Anaesthetists of Ireland Simulation Training (CAST) programme and report the analysis of course participants' feedback. A retrospective review of feedback forms from four simulation courses from March 2010 to August 2016 took place. Qualitative and quantitative data from 1069 participants who attended 112 courses was analysed. Feedback was overall very positive. Course content and delivery were deemed to be appropriate. Participants agreed that course participation would influence their future practice. A statistically significant difference (P simulation training in specialist anaesthesia training in Ireland.

Sensor-based balance training with motion feedback in people with mild cognitive impairment.

Science.gov (United States)

Schwenk, Michael; Sabbagh, Marwan; Lin, Ivy; Morgan, Pharah; Grewal, Gurtej S; Mohler, Jane; Coon, David W; Najafi, Bijan

2016-01-01

Some individuals with mild cognitive impairment (MCI) experience not only cognitive deficits but also a decline in motor function, including postural balance. This pilot study sought to estimate the feasibility, user experience, and effects of a novel sensor-based balance training program. Patients with amnestic MCI (mean age 78.2 yr) were randomized to an intervention group (IG, n = 12) or control group (CG, n = 10). The IG underwent balance training (4 wk, twice a week) that included weight shifting and virtual obstacle crossing. Real-time visual/audio lower-limb motion feedback was provided from wearable sensors. The CG received no training. User experience was measured by a questionnaire. Postintervention effects on balance (center of mass sway during standing with eyes open [EO] and eyes closed), gait (speed, variability), cognition, and fear of falling were measured. Eleven participants (92%) completed the training and expressed fun, safety, and helpfulness of sensor feedback. Sway (EO, p = 0.04) and fear of falling (p = 0.02) were reduced in the IG compared to the CG. Changes in other measures were nonsignificant. Results suggest that the sensor-based training paradigm is well accepted in the target population and beneficial for improving postural control. Future studies should evaluate the added value of the sensor-based training compared to traditional training.

A web-based feedback study on optimization-based training and analysis of human decision making

Directory of Open Access Journals (Sweden)

Michael Engelhart

2017-05-01

Full Text Available The question “How can humans learn efficiently to make decisions in a complex, dynamic, and uncertain environment” is still a very open question. We investigate what effects arise when feedback is given in a computer-simulated microworld that is controlled by participants. This has a direct impact on training simulators that are already in standard use in many professions, e.g., for flight simulators for pilots, and a potential impact on a better understanding of human decision making in general. Our study is based on a benchmark microworld with an economic framing, the IWR Tailorshop. N=94 participants played four rounds of the microworld, each 10 months, via a web interface. We propose a new approach to quantify performance and learning, which is based on a mathematical model of the microworld and optimization. Six participant groups receive different kinds of feedback in a training phase, then results in a performance phase without feedback are analyzed. As a main result, feedback of optimal solutions in training rounds improved model knowledge, early learning, and performance, especially when this information is encoded in a graphical representation (arrows.

Low-level feedback control for the phase regulation of CLIC Drive Beam Klystrons

CERN Document Server

AUTHOR|(SzGeCERN)752526

2015-01-01

The requirement of luminosity loss below 1% raises tight tolerances for the phase and power stability of the CLIC drive beam (DB) klystrons and consequently for the high voltage pulse ripple of the modulators. A low-level RF (LLRF) feedback system needs to be developed and combined with the modulator in order to guarantee the phase and amplitude tolerances. To this aim, three feedback control strategies were investigated, i) Proportional Integral (PI) controller, ii) Linear Quadratic Integral Regulator (LQI) and iii) Model Predictive Controller (MPC). The klystron, as well as the incident phase noise were modelled and used for the design and evaluation of the controllers. First simulation results are presented along with future steps and directions.

The effect of metacognitive monitoring feedback on performance in a computer-based training simulation.

Science.gov (United States)

Kim, Jung Hyup

2018-02-01

This laboratory experiment was designed to study the effect of metacognitive monitoring feedback on performance in a computer-based training simulation. According to prior research on metacognition, the accurate checking of learning is a critical part of improving the quality of human performance. However, only rarely have researchers studied the learning effects of the accurate checking of retrospective confidence judgments (RCJs) during a computer-based military training simulation. In this study, we provided participants feedback screens after they had completed a warning task and identification task in a radar monitoring simulation. There were two groups in this experiment. One group (group A) viewed the feedback screens with the flight path of all target aircraft and the triangular graphs of both RCJ scores and human performance together. The other group (group B) only watched the feedback screens with the flight path of all target aircraft. There was no significant difference in performance improvement between groups A and B for the warning task (Day 1: group A - 0.347, group B - 0.305; Day 2: group A - 0.488, group B - 0.413). However, the identification task yielded a significant difference in performance improvement between these groups (Day 1: group A - 0.174, group B - 0.1555; Day 2: group A - 0.324, group B - 0.199). The results show that debiasing self-judgment of the identification task produces a positive training effect on learners. The findings of this study will be beneficial for designing an advanced instructional strategy in a simulation-based training environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

“Booster” training: Evaluation of instructor-led bedside cardiopulmonary resuscitation skill training and automated corrective feedback to improve cardiopulmonary resuscitation compliance of Pediatric Basic Life Support providers during simulated cardiac arrest

Science.gov (United States)

Sutton, Robert M.; Niles, Dana; Meaney, Peter A.; Aplenc, Richard; French, Benjamin; Abella, Benjamin S.; Lengetti, Evelyn L.; Berg, Robert A.; Helfaer, Mark A.; Nadkarni, Vinay

2013-01-01

Objective To investigate the effectiveness of brief bedside “booster” cardiopulmonary resuscitation (CPR) training to improve CPR guideline compliance of hospital-based pediatric providers. Design Prospective, randomized trial. Setting General pediatric wards at Children’s Hospital of Philadelphia. Subjects Sixty-nine Basic Life Support–certified hospital-based providers. Intervention CPR recording/feedback defibrillators were used to evaluate CPR quality during simulated pediatric arrest. After a 60-sec pretraining CPR evaluation, subjects were randomly assigned to one of three instructional/feedback methods to be used during CPR booster training sessions. All sessions (training/CPR manikin practice) were of equal duration (2 mins) and differed only in the method of corrective feedback given to participants during the session. The study arms were as follows: 1) instructor-only training; 2) automated defibrillator feedback only; and 3) instructor training combined with automated feedback. Measurements and Main Results Before instruction, 57% of the care providers performed compressions within guideline rate recommendations (rate >90 min−1 and 38 mm); and 36% met overall CPR compliance (rate and depth within targets). After instruction, guideline compliance improved (instructor-only training: rate 52% to 87% [p .01], and overall CPR compliance, 43% to 78% [p CPR compliance, 35% to 96% [p training combined with automated feedback: rate 48% to 100% [p CPR compliance, 30% to 100% [p CPR instruction, most certified Pediatric Basic Life Support providers did not perform guideline-compliant CPR. After a brief bedside training, CPR quality improved irrespective of training content (instructor vs. automated feedback). Future studies should investigate bedside training to improve CPR quality during actual pediatric cardiac arrests. PMID:20625336

Balance Training Enhances Vestibular Function and Reduces Overactive Proprioceptive Feedback in Elderly

Directory of Open Access Journals (Sweden)

Isabella K. Wiesmeier

2017-08-01

Full Text Available Objectives: Postural control in elderly people is impaired by degradations of sensory, motor, and higher-level adaptive mechanisms. Here, we characterize the effects of a progressive balance training program on these postural control impairments using a brain network model based on system identification techniques.Methods and Material: We analyzed postural control of 35 healthy elderly subjects and compared findings to data from 35 healthy young volunteers. Eighteen elderly subjects performed a 10 week balance training conducted twice per week. Balance training was carried out in static and dynamic movement states, on support surfaces with different elastic compliances, under different visual conditions and motor tasks. Postural control was characterized by spontaneous sway and postural reactions to pseudorandom anterior-posterior tilts of the support surface. Data were interpreted using a parameter identification procedure based on a brain network model.Results: With balance training, the elderly subjects significantly reduced their overly large postural reactions and approximated those of younger subjects. Less significant differences between elderly and young subjects' postural control, namely larger spontaneous sway amplitudes, velocities, and frequencies, larger overall time delays and a weaker motor feedback compared to young subjects were not significantly affected by the balance training.Conclusion: Balance training reduced overactive proprioceptive feedback and restored vestibular orientation in elderly. Based on the assumption of a linear deterioration of postural control across the life span, the training effect can be extrapolated as a juvenescence of 10 years. This study points to a considerable benefit of a continuous balance training in elderly, even without any sensorimotor deficits.

Using DCM pitch modulation and feedback to improve long term X-ray beam stability

International Nuclear Information System (INIS)

Bloomer, C; Dent, A; Diaz-Moreno, S; Dolbnya, I; Pedersen, U; Rehm, G; Tang, C; Thomas, C

2013-01-01

In this paper we demonstrate significant improvements to the stability of the monochromatic X-ray beam intensity on several beamlines at Diamond, using a modulation of the pitch axis of the DCM with a piezoelectric actuator. The modulation is detected on an intensity diagnostic (e.g. an ion chamber) using a software lock-in technique. The detected amplitude and phase are used in a feedback to keep the DCM at the peak of the rocking curve, or any arbitrary position 'off-peak' which might be desired to detune the DCM and reject unwanted harmonics. A major advantage of this software based system is the great flexibility offered, using standard, readily available instrumentation. Measurements of the short and long-term performance of the feedback on several beamlines are presented, and the limitations of such a feedback are discussed.

Electron bunch train excited higher-order modes in a superconducting RF cavity

Science.gov (United States)

Gao, Yong-Feng; Huang, Sen-Lin; Wang, Fang; Feng, Li-Wen; Zhuang, De-Hao; Lin, Lin; Zhu, Feng; Hao, Jian-Kui; Quan, Sheng-Wen; Liu, Ke-Xin

2017-04-01

Higher-order mode (HOM) based intra-cavity beam diagnostics has been proved effective and convenient in superconducting radio-frequency (SRF) accelerators. Our recent research shows that the beam harmonics in the bunch train excited HOM spectrum, which have much higher signal-to-noise ratio than the intrinsic HOM peaks, may also be useful for beam diagnostics. In this paper, we will present our study on bunch train excited HOMs, including a theoretical model and recent experiments carried out based on the DC-SRF photoinjector and SRF linac at Peking University. Supported by National Natural Science Foundation of China (11275014)

Effectiveness of a training program in supervisors' ability to provide feedback on residents' communication skills

NARCIS (Netherlands)

Junod Perron, N.; Nendaz, M.; Louis-Simonet, M.; Sommer, J.; Gut, A.; Baroffio, A.; Dolmans, D.; Vleuten, C.P.M. van der

2013-01-01

Teaching communication skills (CS) to residents during clinical practice remains problematic. Direct observation followed by feedback is a powerful way to teach CS in clinical practice. However, little is known about the effect of training on feedback skills in this field. Controlled studies are

The prophylactic effect of neck irradiation combined with intra-oral electron beam irradiation for early tongue cancer

International Nuclear Information System (INIS)

Kawamori, Jiro; Kamata, Rikisaburo; Sanuki, Eiichi

1993-01-01

Between 1967 and 1988, 102 patients with Stage T1-2N0 squamous cell carcinoma of the tongue were treated with uneven fractional irradiation therapy (intra-oral electron beam irradiation with and without prophylactic ipsilateral upper neck irradiation at the Dept. of Radiology, Nihon University School of Medicine. Of 102 primary lesions, 89 cases were controlled with this therapy. In this study, these 89 cases were investigated in order to analyze the prophylactic effect of upper neck irradiation. Of the 89 patients, 42 received only intra-oral electron beam irradiation, while the remaining 47 received a combination of intra-oral electron beam irradiation and prophylactic irradiation to the ipsilateral upper neck. Twenty three of the 89 (25.8%) developed metastasis to the neck after the radiotherapy. A breakdown of these 23 cases reveals that 3/21 (14.3%) received 40-50 Gy to the neck, 9/26 (34.6%) received 20-40 Gy to the neck, and 11/42 (26.2%) received no irradiation to the neck (p<0.05 between first and second groups, and between first and third groups). The neck metastasis was classified into one of three categories based on the region in which it first appeared (ipsilateral upper neck, ipsilateral lower neck or contralateral neck). The first metastasis was seen in the ipsilateral upper neck, in the ipsilateral lower neck and in the contralateral neck in 17, 4 and 2 patients, respectively. In 1/19 who had received 40-50 Gy, in 5/21 who had received 20-40 Gy and in 11/42 who had not received neck irradiation the first metastasis appeared in the ipsilateral upper neck. The five year survival rate was 94%, 75% and 85% in the patients receiving 40-50 Gy, 20-40 Gy and no neck irradiation, respectively. These results suggest that prophylactic irradiation of 40-50 Gy to the ipsilateral upper neck might decrease the incidence of neck metastasis and slightly prolong survival time. (author)

End-task versus in-task feedback to increase procedural learning retention during spinal anaesthesia training of novices.

Science.gov (United States)

Lean, Lyn Li; Hong, Ryan Yee Shiun; Ti, Lian Kah

2017-08-01

Communication of feedback during teaching of practical procedures is a fine balance of structure and timing. We investigate if continuous in-task (IT) or end-task feedback (ET) is more effective in teaching spinal anaesthesia to medical students. End-task feedback was hypothesized to improve both short-term and long-term procedural learning retention as experiential learning promotes active learning after encountering errors during practice. Upon exposure to a 5-min instructional video, students randomized to IT or ET feedbacks were trained using a spinal simulator mannequin. A blinded expert tested the students using a spinal anaesthesia checklist in the short term (immediate) and long-term (average 4 months). Sixty-five students completed the training and testing. There were no differences in demographics of age or gender within IT or ET distributions. Both short-term and long-term learning retention of spinal anaesthesia ET feedback proved to be better (P feedback. The time taken for ET students was shorter at long-term testing. End-task feedback improves both short-term and long-term procedural learning retention.

Joint opportunistic beam and spectrum selection schemes for spectrum sharing systems with limited feedback

KAUST Repository

Sayed, Mostafa M.

2014-11-01

Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing an unlicensed secondary user (SU) to share the spectrum with a licensed primary user (PU) under acceptable interference levels to the primary receiver (PU-Rx). In this paper, we consider a secondary link composed of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx). The secondary link is allowed to share the spectrum with a primary network composed of multiple PUs communicating over distinct frequency spectra with a primary base station. We develop a transmission scheme where the SU-Tx initially broadcasts a set of random beams over all the available primary spectra for which the PU-Rx sends back the index of the spectrum with the minimum interference level, as well as information that describes the interference value, for each beam. Based on the feedback information on the PU-Rx, the SU-Tx adapts the transmitted beams and then resends the new beams over the best primary spectrum for each beam to the SU-Rx. The SU-Rx selects the beam that maximizes the received signal-to-interference-plus-noise ratio (SINR) to be used in transmission over the next frame. We consider three cases for the level of feedback information describing the interference level. In the first case, the interference level is described by both its magnitude and phase; in the second case, only the magnitude is considered; and in the third case, we focus on a q-bit description of its magnitude. In the latter case, we propose a technique to find the optimal quantizer thresholds in a mean-square-error sense. We also develop a statistical analysis for the SINR statistics and the capacity and bit error rate of the secondary link and present numerical results that study the impact of the different system parameters.

Determination and evaluation of intra fractional and set-up changes during radiotherapy to the cervical carcinoma using cone beam computed tomography

International Nuclear Information System (INIS)

Pathak, Pankaj; Kumar, Rajesh; Birbiya, Narendra; Mishra, Praveen Kumar; Singh, Manisha; Mishra, Pankaj Kumar

2017-01-01

To confirm the accuracy of the location of the Fudicial markings in relation to the actual isocentre of the irradiated volume due to Intra-fractional and Set-Up changes in Cancer Cervix with the help of Cone Beam computed Tomography (CBCT)

Computational Model of a Positive BDNF Feedback Loop in Hippocampal Neurons Following Inhibitory Avoidance Training

Science.gov (United States)

Zhang, Yili; Smolen, Paul; Alberini, Cristina M.; Baxter, Douglas A.; Byrne, John H.

2016-01-01

Inhibitory avoidance (IA) training in rodents initiates a molecular cascade within hippocampal neurons. This cascade contributes to the transition of short- to long-term memory (i.e., consolidation). Here, a differential equation-based model was developed to describe a positive feedback loop within this molecular cascade. The feedback loop begins…

Training based on mirror visual feedback influences transcallosal communication.

Science.gov (United States)

Avanzino, Laura; Raffo, Alessia; Pelosin, Elisa; Ogliastro, Carla; Marchese, Roberta; Ruggeri, Piero; Abbruzzese, Giovanni

2014-08-01

Mirror visual feedback (MVF) therapy has been demonstrated to be successful in neurorehabilitation, probably inducing neuroplasticity changes in the primary motor cortex (M1). However, it is not known whether MVF training influences the hemispheric balance between the M1s. This topic is of extreme relevance when MVF training is applied to stroke rehabilitation, as the competitive interaction between the two hemispheres induces abnormal interhemispheric inhibition (IHI) that weakens motor function in stroke patients. In the present study, we evaluated, in a group of healthy subjects, the effect of motor training and MVF training on the excitability of the two M1s and the IHI between M1s. The IHI from the 'active' M1 to the opposite M1 (where 'active' means the M1 contralateral to the moving hand in the motor training and the M1 of the seen hand in the MVF training) increased, after training, in both the experimental conditions. Only after motor training did we observe an increase in the excitability of the active M1. Our findings show that training based on MVF may influence the excitability of the transcallosal pathway and support its use in disorders where abnormal IHI is a potential target, such as stroke, where an imbalance between the affected and unaffected M1s has been documented. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Development and feasibility of a patient feedback programme to improve consultation skills in general practice training

NARCIS (Netherlands)

Reinders, M.E.; Blankenstein, A.H.; van Marwijk, H.W.J.; Schleypen, H.; Schoonheim, P.L.; Stalman, W.A.B.

2008-01-01

Objective: To develop an attractive and effective patient feedback training programme for general practice trainees (GPTs). Methods: First, an exploratory study was conducted in which patients and GPTs were interviewed after they had worked with patient feedback. This contributed to the development

Autogenic Feedback Training (Body FORTRAN) for Musically Gifted Students at Bonita Vista High School.

Science.gov (United States)

Lane, John M.

1982-01-01

The Gifted Self-Understanding Assessment Battery (GSAB) was given to 34 (27 females, 7 males) music students (aged 15-17) at Bonita Vista High School in Chula Vista (California). Biofeedback training and assessment were followed by individual counseling for Autogenic Feedback Training (AFT) to achieve improvement of the individual's own well…

Intra-abdominal pressure during swimming.

Science.gov (United States)

Moriyama, S; Ogita, F; Huang, Z; Kurobe, K; Nagira, A; Tanaka, T; Takahashi, H; Hirano, Y

2014-02-01

The present study aimed to determine the intra-abdominal pressure during front crawl swimming at different velocities in competitive swimmers and to clarify the relationships between stroke indices and changes in intra-abdominal pressure. The subjects were 7 highly trained competitive collegiate male swimmers. Intra-abdominal pressure was measured during front crawl swimming at 1.0, 1.2 and 1.4 m · s(-1) and during the Valsalva maneuver. Intra-abdominal pressure was taken as the difference between minimum and maximum values, and the mean of 6 stable front crawl stroke cycles was used. Stroke rate and stroke length were also measured as stroke indices. There were significant differences in stroke rate among all velocities (P pressure and stroke rate or stroke length (P pressure and stroke indices when controlling for swimming velocity. These findings do not appear to support the effectiveness of trunk training performed by competitive swimmers aimed at increasing intra-abdominal pressure. © Georg Thieme Verlag KG Stuttgart · New York.

Feedback-stabilized dual-beam laser interferometer for plasma measurements

International Nuclear Information System (INIS)

Yasuda, A.; Kanai, Y.; Kusunoki, J.; Kawahata, K.; Takeda, S.

1980-01-01

A stabilized laser interferometer is proposed with two beams as the light source. The fringe shift for a 0.63 μm beam of a He--Ne laser is used to stabilize the interferometer against the effect of mechanical vibrations via a feedback controlled speaker coil, while another beam of 3.39 μm, for which consequently the effect of the mechanical vibrations is excluded, is used to measure the plasma density. A stability of approx.1/500 of one fringe for 0.63 μm is obtained during a long period for frequencies lower than a few Hz. The stability for higher frequencies is limited to approx.1/30 of one fringe for 0.63 μm, which correspondes to approx.1/200 of one fringe for 3.39 μm, by the acoustic noise picked up by the speaker coil. Furthermore, the total accuracy is limited by the detector noise to approx.1/60 of one fringe for 3.39 μm, which corresponds to a line electron density of approx.5 x 10 14 cm -2 . The detector noise may be reduced by cooling the detector. The advantage of this technique over the single-laser technique is that the frequency response of the interferometer extends down to zero frequency. The interferometer is tested with the measurement of a plasma in a dynamic magnetic arcjet. Since the effect of the neutral gas background is reduced in the present interferometer, the application has an advantage for the diagnostics of plasmas produced in high pressure gases

Target and orbit feedback simulations of a muSR beam line at BNL

Energy Technology Data Exchange (ETDEWEB)

MacKay, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-07-28

Well-polarized positive surface muons are a tool to measure the magnetic properties of materials since the precession rate of the spin can be determined from the observation of the positron directions when the muons decay. For a dc beam an ideal µSR flux for surface µ⁺ should be about 40 kHz/mm². In this report we show how this flux could be achieved in a beam line using the AGS complex at BNL for a source of protons. We also determined that an orbit feedback system with a pair of thin silicon position monitors and kickers would miss the desired flux by at least an order of magnitude, even with perfect time resolution and no multiple scattering.

Effect of position feedback during task-oriented upper-limb training after stroke: Five-case pilot study

NARCIS (Netherlands)

Molier, B.I.; Prange, Grada Berendina; Krabben, T.; Stienen, Arno; van der Kooij, Herman; Buurke, Jaap; Jannink, M.J.A.; Hermens, Hermanus J.

2011-01-01

Feedback is an important element in motor learning during rehabilitation therapy following stroke. The objective of this pilot study was to better understand the effect of position feedback during task-oriented reach training of the upper limb in people with chronic stroke. Five subjects

Perception of CPR quality: Influence of CPR feedback, Just-in-Time CPR training and provider role.

Science.gov (United States)

Cheng, Adam; Overly, Frank; Kessler, David; Nadkarni, Vinay M; Lin, Yiqun; Doan, Quynh; Duff, Jonathan P; Tofil, Nancy M; Bhanji, Farhan; Adler, Mark; Charnovich, Alex; Hunt, Elizabeth A; Brown, Linda L

2015-02-01

Many healthcare providers rely on visual perception to guide cardiopulmonary resuscitation (CPR), but little is known about the accuracy of provider perceptions of CPR quality. We aimed to describe the difference between perceived versus measured CPR quality, and to determine the impact of provider role, real-time visual CPR feedback and Just-in-Time (JIT) CPR training on provider perceptions. We conducted secondary analyses of data collected from a prospective, multicenter, randomized trial of 324 healthcare providers who participated in a simulated cardiac arrest scenario between July 2012 and April 2014. Participants were randomized to one of four permutations of: JIT CPR training and real-time visual CPR feedback. We calculated the difference between perceived and measured quality of CPR and reported the proportion of subjects accurately estimating the quality of CPR within each study arm. Participants overestimated achieving adequate chest compression depth (mean difference range: 16.1-60.6%) and rate (range: 0.2-51%), and underestimated chest compression fraction (0.2-2.9%) across all arms. Compared to no intervention, the use of real-time feedback and JIT CPR training (alone or in combination) improved perception of depth (pCPR quality was poor for chest compression depth (0-13%), rate (5-46%) and chest compression fraction (60-63%). Perception of depth is more accurate in CPR providers versus team leaders (27.8% vs. 7.4%; p=0.043) when using real-time feedback. Healthcare providers' visual perception of CPR quality is poor. Perceptions of CPR depth are improved by using real-time visual feedback and with prior JIT CPR training. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Autogenic Feedback Training Applications for Man in Space

Science.gov (United States)

Cowings, Patricia S.; Wade, Charles E. (Technical Monitor)

1994-01-01

Finding an effective treatment for the motion sickness-like symptoms that occur in space has become a high priority for NASA. This paper reviews the back-round research and procedures of an experiment designed to prevent space motion sickness in shuttle crewmembers. The preventive method used, Autogenic - Feedback Training (AFT) involves training subjects to control voluntarily several of their own physiological responses to environmental stressors. AFT has been used reliably to increase tolerance to motion sickness during around based tests in over 300 men and women under a variety of conditions that induce motion sickness, and preliminary evidence from space suggests that AFT may be an effective treatment for space motion sickness as well. Other applications of AFT described include; (1) a potential treatment for post flight orthostatic intolerance, a serious biomedical problem resulting from long duration exposure to micro-g and (2) improving pilot performance during emergency flying conditions.

Intra-cavity generation of superpositions of Laguerre-Gaussian beams

CSIR Research Space (South Africa)

Naidoo, Darryl

2012-01-01

Full Text Available In this paper we demonstrate experimentally the intra-cavity generation of a coherent superposition of Laguerre–Gaussian modes of zero radial order but opposite azimuthal order. The superposition is created with a simple intra-cavity stop...

Feedback Simulation for Acupressure Training and Skill Assessment.

Science.gov (United States)

Noll, Eric; Romeiser, Jamie; Shodhan, Shivam; Madariaga, Maria Cecilia; Guo, Xiaojun; Rizwan, Sabeen; Al-Bizri, Ehab; Bennett-Guerrero, Elliott

2017-08-01

Previous acupressure studies have yielded varying results. This could be due to differences in the amount of pressure applied to the acupressure point (acupoint) by study personnel within a study as well as between studies. Standardizing the level of pressure applied at an acupoint could improve clinical care and future research. As part of an ongoing randomized clinical trial of postoperative acupressure, five trainees were asked to perform 2 minutes of acupressure and light touch sessions on a simulator. The applied weight was recorded every minute. Individual skill assessment was performed using cumulative sum analysis. Six pretraining and 20 posttraining measurements in each acupressure and light touch group were compared with an expert's simulation values. Before training (baseline), there was significant difference in applied weight (grams) between the expert [5705 (636)] and five trainees [2998 (798), P = 0.004]. Four of the five trainees crossed the lower decision limit assessing proficiency in the acupressure group, and all five trainees were successful in the light touch group. The trainees' average number of measurements needed to cross the lower decision limit (H0), that is, defining that an individual failure rate does not statistically differ from the acceptable failure rate, was 21.3 measurements for acupressure. After this feedback simulation, trainees' scores showed no significant difference (P > 0.05) when assessed against the expert. Feedback simulation for acupressure training and skill assessment, evaluated by cumulative sum analysis, may help in improving the standardization of acupressure therapy performed during clinical practice or research.

A method for selection of beam angles robust to intra-fractional motion in proton therapy of lung cancer

DEFF Research Database (Denmark)

Casares-Magaz, Oscar; Toftegaard, Jakob; Muren, Ludvig P.

2014-01-01

that are robust to patient-specific patterns of intra-fractional motion. Material and methods. Using four-dimensional computed tomography (4DCT) images of three lung cancer patients we evaluated the impact of the WEPL changes on target dose coverage for a series of coplanar single-beam plans. The plans were...... reduction was associated with the mean difference between the WEPL and the phase-averaged WEPL computed for all beam rays across all possible gantry-couch angle combinations. Results. The gantry-couch angle maps showed areas of both high and low WEPL variation, with overall quite similar patterns yet...... presented a 4DCT-based method to quantify WEPL changes during the breathing cycle. The method identified proton field gantry-couch angle combinations that were either sensitive or robust to WEPL changes. WEPL variations along the beam path were associated with target under-dosage....

Fast feedback for linear colliders

International Nuclear Information System (INIS)

Hendrickson, L.; Adolphsen, C.; Allison, S.; Gromme, T.; Grossberg, P.; Himel, T.; Krauter, K.; MacKenzie, R.; Minty, M.; Sass, R.

1995-01-01

A fast feedback system provides beam stabilization for the SLC. As the SLC is in some sense a prototype for future linear colliders, this system may be a prototype for future feedbacks. The SLC provides a good base of experience for feedback requirements and capabilities as well as a testing ground for performance characteristics. The feedback system controls a wide variety of machine parameters throughout the SLC and associated experiments, including regulation of beam position, angle, energy, intensity and timing parameters. The design and applications of the system are described, in addition to results of recent performance studies

Can the feedback of patient assessments, brief training, or their combination, improve the interpersonal skills of primary care physicians? A systematic review.

Science.gov (United States)

Cheraghi-Sohi, Sudeh; Bower, Peter

2008-08-21

Improving quality of primary care is a key focus of international health policy. Current quality improvement efforts place a large focus on technical, clinical aspects of quality, but a comprehensive approach to quality improvement should also include interpersonal care. Two methods of improving the quality of interpersonal care in primary care have been proposed. One involves the feedback of patient assessments of interpersonal care to physicians, and the other involves brief training and education programmes. This study therefore reviewed the efficacy of (i) feedback of real patient assessments of interpersonal care skills, (ii) brief training focused on the improvement of interpersonal care (iii) interventions combining both (i) and (ii) Systematic review of randomised controlled trials. Three electronic databases were searched (CENTRAL, Medline and Embase) and augmented by searches of the bibliographies of retrieved articles. The quality of studies was appraised and results summarised in narrative form. Nine studies were included (two patient based feedback studies and seven brief training studies). Of the two feedback studies, one reported a significant positive effect. Only one training study reported a significant positive effect. There is limited evidence concerning the effects of patient based feedback. There is reasonable evidence that brief training as currently delivered is not effective, although the evidence is not definitive, due to the small number of trials and the variation in the training methods and goals. The lack of effectiveness of these methods may reflect a number of issues, such as differences in the effectiveness of the interventions in experienced practitioners and those in training, the lack of theory linking feedback to behaviour change, failure to provide sufficient training or to use a comprehensive range of behaviour change techniques. Further research into both feedback and brief training interventions is required before these

Can the feedback of patient assessments, brief training, or their combination, improve the interpersonal skills of primary care physicians? A systematic review

Directory of Open Access Journals (Sweden)

Bower Peter

2008-08-01

Full Text Available Abstract Background Improving quality of primary care is a key focus of international health policy. Current quality improvement efforts place a large focus on technical, clinical aspects of quality, but a comprehensive approach to quality improvement should also include interpersonal care. Two methods of improving the quality of interpersonal care in primary care have been proposed. One involves the feedback of patient assessments of interpersonal care to physicians, and the other involves brief training and education programmes. This study therefore reviewed the efficacy of (i feedback of real patient assessments of interpersonal care skills, (ii brief training focused on the improvement of interpersonal care (iii interventions combining both (i and (ii Methods Systematic review of randomised controlled trials. Three electronic databases were searched (CENTRAL, Medline and Embase and augmented by searches of the bibliographies of retrieved articles. The quality of studies was appraised and results summarised in narrative form. Results Nine studies were included (two patient based feedback studies and seven brief training studies. Of the two feedback studies, one reported a significant positive effect. Only one training study reported a significant positive effect. Conclusion There is limited evidence concerning the effects of patient based feedback. There is reasonable evidence that brief training as currently delivered is not effective, although the evidence is not definitive, due to the small number of trials and the variation in the training methods and goals. The lack of effectiveness of these methods may reflect a number of issues, such as differences in the effectiveness of the interventions in experienced practitioners and those in training, the lack of theory linking feedback to behaviour change, failure to provide sufficient training or to use a comprehensive range of behaviour change techniques. Further research into both feedback

Broadband feedback systems for the damping of coherent beam instabilities in the stretcher ring ELSA

International Nuclear Information System (INIS)

Roth, Andre

2012-12-01

At the Electron Stretcher Facility ELSA an upgrade of the internal beam current up to 200 mA would be desirable in order to increase the intensity of the extracted electron beam for the future experimental hadron physics program. However, such an upgrade is mainly limited by the excitation of coherent beam instabilities in the stretcher ring. As active counteraction, broadband bunch-by-bunch feedback-systems for the longitudinal, as well as for both transverse planes were installed. After detection of the motion of each of the 27 4 stored bunches via beam position monitors, the systems determine independent correction signals for each bunch using digital signal processors. The amplified correction signals are applied to the beam by means of broadband longitudinal and transverse kicker structures. The detailed setup, the commissioning procedure and measurement results of the damping performance of the systems are presented. In addition, the operation of the longitudinal system during the fast energy ramp of 4 GeV/s from 1.2 GeV to 3.2 GeV is investigated.

Using Video Modeling with Voiceover Instruction Plus Feedback to Train Staff to Implement Direct Teaching Procedures.

Science.gov (United States)

Giannakakos, Antonia R; Vladescu, Jason C; Kisamore, April N; Reeve, Sharon A

2016-06-01

Direct teaching procedures are often an important part of early intensive behavioral intervention for consumers with autism spectrum disorder. In the present study, a video model with voiceover (VMVO) instruction plus feedback was evaluated to train three staff trainees to implement a most-to-least direct (MTL) teaching procedure. Probes for generalization were conducted with untrained direct teaching procedures (i.e., least-to-most, prompt delay) and with an actual consumer. The results indicated that VMVO plus feedback was effective in training the staff trainees to implement the MTL procedure. Although additional feedback was required for the staff trainees to show mastery of the untrained direct teaching procedures (i.e., least-to-most and prompt delay) and with an actual consumer, moderate to high levels of generalization were observed.

Intra-cavity vortex beam generation

CSIR Research Space (South Africa)

Naidoo, Darryl

2011-08-01

Full Text Available at exploring the methods of generating optical vortex beams. We will discuss a typical extra-cavity approach that harnesses digital holography through the use of a SLM. We consider vortex beam generation as the fundamental mode of a monolithic microchip laser...-cavity phase diffractive elements can result in the desired mode as the fundamental mode of the cavity with pure modal quality. This approach, although very attractive is insufficient for the generation of these modes in monolithic microchip lasers. A...

Asymmetric noise sensitivity of pulse trains in an excitable microlaser with delayed optical feedback

Science.gov (United States)

Terrien, Soizic; Krauskopf, Bernd; Broderick, Neil G. R.; Andréoli, Louis; Selmi, Foued; Braive, Rémy; Beaudoin, Grégoire; Sagnes, Isabelle; Barbay, Sylvain

2017-10-01

A semiconductor micropillar laser with delayed optical feedback is considered. In the excitable regime, we show that a single optical perturbation can trigger a train of pulses that is sustained for a finite duration. The distribution of the pulse train duration exhibits an exponential behavior characteristic of a noise-induced process driven by uncorrelated white noise present in the system. The comparison of experimental observations with theoretical and numerical analysis of a minimal model yields excellent agreement. Importantly, the random switch-off process takes place between two attractors of different nature: an equilibrium and a periodic orbit. Our analysis shows that there is a small time window during which the pulsations are very sensitive to noise, and this explains the observed strong bias toward switch-off. These results raise the possibility of all optical control of the pulse train duration that may have an impact for practical applications in photonics and may also apply to the dynamics of other noise-driven excitable systems with delayed feedback.

Feedback in Clinical Education, Part I: Characteristics of Feedback Provided by Approved Clinical Instructors

Science.gov (United States)

Nottingham, Sara; Henning, Jolene

2014-01-01

Context Providing students with feedback is an important component of athletic training clinical education; however, little information is known about the feedback that Approved Clinical Instructors (ACIs; now known as preceptors) currently provide to athletic training students (ATSs). Objective To characterize the feedback provided by ACIs to ATSs during clinical education experiences. Design Qualitative study. Setting One National Collegiate Athletic Association Division I athletic training facility and 1 outpatient rehabilitation clinic that were clinical sites for 1 entry-level master's degree program accredited by the Commission on Accreditation of Athletic Training Education. Patients or Other Participants A total of 4 ACIs with various experience levels and 4 second-year ATSs. Data Collection and Analysis Extensive field observations were audio recorded, transcribed, and integrated with field notes for analysis. The constant comparative approach of open, axial, and selective coding was used to inductively analyze data and develop codes and categories. Member checking, triangulation, and peer debriefing were used to promote trustworthiness of the study. Results The ACIs gave 88 feedback statements in 45 hours and 10 minutes of observation. Characteristics of feedback categories included purpose, timing, specificity, content, form, and privacy. Conclusions Feedback that ACIs provided included several components that made each feedback exchange unique. The ACIs in our study provided feedback that is supported by the literature, suggesting that ACIs are using current recommendations for providing feedback. Feedback needs to be investigated across multiple athletic training education programs to gain more understanding of certain areas of feedback, including frequency, privacy, and form. PMID:24143902

Autogenic Feedback Training Exercise: Controlling Physiological Responses to Mitigate Motion Sickness

Science.gov (United States)

Walton, Nia; Spencer, Telissa; Cowings, Patricia; Toscano, William B.

2018-01-01

During space travel approximately 50 of the crew experience symptoms of motion sickness that can range from mild forms of nausea or dizziness to severe malaise and vomiting1. Developing an effective treatment for these symptoms has become a priority of the National Aeronautics and Space Administration (NASA). Autogenic-Feedback Training Exercise (AFTE) is a nonpharmacological countermeasure for mitigating motion sickness. It involves training subjects to control physiological responses in high stress environments2. The primary goal of this experiment is to evaluate the effectiveness of AFTE for increasing tolerance to motion sickness in high stress environments.

The Effects and Perceptions of Trained Peer Feedback in L2 Speaking: Impact on Revision and Speaking Quality

Science.gov (United States)

Rodríguez-González, Eva; Castañeda, Martha E.

2018-01-01

The present study examined the impact of trained peer feedback on Spanish as a second language (L2) in terms of language performance, nature of feedback, and perceptions of peer feedback in speaking tasks. Participants in the study included 17 intermediate L2 Spanish learners enrolled in a conversation course that incorporated peer feedback…

Autogenic Feedback Training (Body Fortran) with Biofeedback and the Computer for Self-Improvement and Change.

Science.gov (United States)

Cassel, Russell N.; Sumintardja, Elmira Nasrudin

1983-01-01

Describes autogenic feedback training, which provides the basis whereby an individual is able to improve on well being through use of a technique described as "body fortran," implying that you program self as one programs a computer. Necessary requisites are described including relaxation training and the management of stress. (JAC)

Feedback control of laser welding based on frequency analysis of light emissions and adaptive beam shaping

Czech Academy of Sciences Publication Activity Database

Mrňa, Libor; Šarbort, Martin; Řeřucha, Šimon; Jedlička, Petr

2012-01-01

Roč. 39, NOV (2012), s. 784-791 ISSN 1875-3892. [LANE 2012. Laser Assisted Net Shape Engineering /7./ International Conference on Photonic Technologies. Fürth, 12.11.2012-15.12.2012] Institutional support: RVO:68081731 Keywords : laser welding * feedback control * frequency analysis * adaptive beam shaping Subject RIV: BH - Optics, Masers, Lasers

Autogenic-Feedback Training for the Control of Space Motion Sickness

Science.gov (United States)

Cowings, Patricia S.; Toscano, W. B.

1994-01-01

This paper presents case-studies of 9 shuttle crewmembers (prime and alternates) and one U.S. Navy F-18 pilot, as they participated in all preflight training and testing activities in support of a life sciences flight experiment aboard Spacelab-J, and Spacelab-3. The primary objective of the flight experiment was to determine if Autogenic-feedback training (AFT), a physiological self-regulation training technique would be an effective treatment for motion sickness and space motion sickness in these crewmembers. Additional objectives of this study involved the examining human physiological responses to motion sickness on Earth and in space, as well as developing predictive criteria for susceptibility to space motion sickness based on ground-based data. Comparisons of these crewmembers are made to a larger set of subjects from previous experiments (treatment and "test-only" controls subjects). This paper describes all preflight methods, results and proposed changes for future tests.

Active vibration control of clamped beams using positive position feedback controllers with moment pair

International Nuclear Information System (INIS)

Shin, Chang Joo; Jeong, Weui Bong; Hong, Chin Suk

2012-01-01

This paper investigates the active vibration control of clamp beams using positive position feedback (PPF) controllers with a sensor/ moment pair actuator. The sensor/moment pair actuator which is the non-collocated configuration leads to instability of the control system when using the direct velocity feedback (DVFB) control. To alleviate the instability problem, a PPF controller is considered in this paper. A parametric study of the control system with PPF controller is first conducted to characterize the effects of the design parameters (gain and damping ratio in this paper) on the stability and performance. The gain of the controller is found to affect only the relative stability. Increasing the damping ratio of the controller slightly improves the stability condition while the performance gets worse. In addition, the higher mode tuned PPF controller affects the system response at the lower modes significantly. Based on the characteristics of PPF controllers, a multi-mode controllable SISO PPF controller is then considered and tuned to different modes (in this case, three lowest modes) numerically and experimentally. The multi-mode PPF controller can be achieved to have a high gain margin. Moreover, it reduces the vibration of the beam significantly. The vibration levels at the tuned modes are reduced by about 11 dB

Improvement in dose escalation using off-line and on-line image feedback in the intensity modulated beam design for prostate cancer treatment

International Nuclear Information System (INIS)

Yan, D.; Birkner, M.; Nuesslin, F.; Wong, J.; Martinez, A.

2001-01-01

Purpose: To test the capability of dose escalation in the IMRT process where the organ/patient temporal geometric variation, measured using either off-line or on-line treatment CT and portal images, are adapted for the optimal design of intensity modulated beam. Materials and Methods: Retrospective study was performed on five prostate cancer patients with multiple CT scans (14∼17/patient) and daily portal images obtained during the treatment course. These images were used to determine the displacements of each subvolume in the organs of interest caused by the daily patient setup and internal organ motion/deformation. The temporal geometric information was processed in order of treatment time and fed into an inverse planning system. The inverse planning engine was specifically implemented to adapt the design of intensity modulated beam to the temporal subvolume displacement and patient internal density changes. Three image feedback strategies were applied to each patient and evaluated with respect to the capability of safe dose escalation. The first one is off-line image feedback, which designs the beam intensity based on the patient images measured within the first week of treatment. The second is an on-line 'the target of the day' strategy, which designs the beam intensity in daily bases by using 'the image of the day' alone. The last one is also the on-line based. However, it designs the instantaneous beam intensity based on also dose distribution in each organ of interest received prior to the current treatment. For each of the treatment strategies, the minimum dose delivered to the CTV was determined by applying the identical normal tissue constraints of partial dose/volumes. This minimum dose was used to represent the treatment dose for each patient. Results: The off-line strategy appears feasible after 5 days of image feedback. The average treatment dose among the patients can be 10% higher than the one in the conventional IMRT treatment where the inverse

Effect of beam expansion loss in a carbon nanotube-doped PVA film on passively mode-locked erbium-doped fiber lasers with different feedback ratios

International Nuclear Information System (INIS)

Cheng, Kuang-Nan; Chi, Yu-Chieh; Cheng, Chih-Hsien; Lin, Yung-Hsiang; Lo, Jui-Yung; Lin, Gong-Ru

2014-01-01

The effect of beam expansion induced divergent loss in a single-wall carbon nanotube (SWCNT) doped polyvinyl alcohol (PVA) based ultrafast saturable absorber (SA) film thickness on the passive mode-locking (PML) performances of erbium-doped fiber lasers are demonstrated. The variation on the PML pulsewidth of the EDFL is discussed by changing the SWCNT-PVA SA film thicknesses, together with adjusting the pumping power and the intra-cavity feedback ratio. An almost 6 dB increment of divergent loss when enlarging the SWCNT-PVA based SA film thickness from 30–130 µm is observed. When shrinking the SA thickness to 30 µm at the largest pumping power of 52.5 mW, the optical spectrum red-shifts to 1558.8 nm with its 3 dB spectral linewidth broadening up to 2.7 nm, while the pulse has already entered the soliton regime with multi-order Kelly sidebands aside the spectral shoulder. The soliton pulsewidth is as short as 790 fs, which is much shorter than those obtained with other thicker SWCNT doped PVA polymer film based SAs; therefore, the peak power from the output of the PML-EDFL is significantly enlarged accompanied by a completely suppressed residual continuous-wave level to achieve the largest on/off extinction ratio. The main mechanism of pulse shortening with reducing thickness of SWCNT doped PVA polymer film based SA is attributed to the limited beam expansion as well as the enlarged modulation depth, which results in shortened soliton pulsewidth with a clean dc background, and broadened spectrum with enriched Kelly sidebands. The increase of total SWCNT amount in the thicker SA inevitably causes a higher linear absorption; hence, the mode-locking threshold also rises accordingly. By enlarging pumping power from 38.5–52.5 mW, the highest ascent on pulse extinction of up to 32 dB is observed among all kinds of feedback conditions. Nevertheless, the enlargement on the extinction slightly decays with increasing the feedback ratio from 30–90

RHIC 10 Hz global orbit feedback system

International Nuclear Information System (INIS)

Michnoff, R.; Arnold, L.; Carboni, L.; Cerniglia, P.; Curcio, A.; DeSanto, L.; Folz, C.; Ho, C.; Hoff, L.; Hulsart, R.; Karl, R.; Luo, Y.; Liu, C.; MacKay, W.; Mahler, G.; Meng, W.; Mernick, K.; Minty, M.; Montag, C.; Olsen, R.; Piacentino, J.; Popken, P.; Przybylinski, R.; Ptitsyn, V.; Ritter, J.; Schoenfeld, R.; Thieberger, P.; Tuozzolo, J.; Weston, A.; White, J.; Ziminski, P.; Zimmerman, P.

2011-01-01

Vibrations of the cryogenic triplet magnets at the Relativistic Heavy Ion Collider (RHIC) are suspected to be causing the horizontal beam perturbations observed at frequencies around 10 Hz. Several solutions to counteract the effect have been considered in the past, including a local beam feedback system at each of the two experimental areas, reinforcing the magnet base support assembly, and a mechanical servo feedback system. However, the local feedback system was insufficient because perturbation amplitudes outside the experimental areas were still problematic, and the mechanical solutions are very expensive. A global 10 Hz orbit feedback system consisting of 36 beam position monitors (BPMs) and 12 small dedicated dipole corrector magnets in each of the two 3.8 km circumference counter-rotating rings has been developed and commissioned in February 2011. A description of the system architecture and results with beam will be discussed.

Broadband feedback systems for the damping of coherent beam instabilities in the stretcher ring ELSA; Breitbandige Feedback-Systeme zur Daempfung kohaerenter Strahlinstabilitaeten am Stretcherring ELSA

Energy Technology Data Exchange (ETDEWEB)

Roth, Andre

2012-12-15

At the Electron Stretcher Facility ELSA an upgrade of the internal beam current up to 200 mA would be desirable in order to increase the intensity of the extracted electron beam for the future experimental hadron physics program. However, such an upgrade is mainly limited by the excitation of coherent beam instabilities in the stretcher ring. As active counteraction, broadband bunch-by-bunch feedback-systems for the longitudinal, as well as for both transverse planes were installed. After detection of the motion of each of the 27 4 stored bunches via beam position monitors, the systems determine independent correction signals for each bunch using digital signal processors. The amplified correction signals are applied to the beam by means of broadband longitudinal and transverse kicker structures. The detailed setup, the commissioning procedure and measurement results of the damping performance of the systems are presented. In addition, the operation of the longitudinal system during the fast energy ramp of 4 GeV/s from 1.2 GeV to 3.2 GeV is investigated.

Interspecific competition of early successional plant species in ex-arable fields as influenced by plant-soil feedback

OpenAIRE

Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.

2015-01-01

Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from early-stage ex-arable fields to examine how intra- and interspecific plant–soil feedbacks affect the performance of 10 conditioning species and the focal species, Jacobaea vulgaris. Plants were grown alon...

NASA-Navy Telemedicine: Autogenic Feedback Training Exercises for Motion Sickness

Science.gov (United States)

Acromite, Michael T.; Cowings, Patricia; Toscano, William; Davis, Carl; Porter, Henry O.

2010-01-01

Airsickness is the most significant medical condition affecting naval aviation training. A 2001 study showed that airsickness was reported in 81% of naval aviation students and was associated with 82% of below average flight scores. The cost to a single training air-wing was over $150,000 annually for fuel and maintenance costs alone. Resistent cases are sent to the Naval Aerospace Medical Institute (NAMI) for evaluation and desensitization in the self-paced airsickness desensitization (SPAD) program. This approach is 75% successful, but can take up to 8 weeks at a significant travel cost. NASA Ames Research Center's Autogenic Feedback Training Exercises (AFTE) uses physiological and biofeedback training for motion sickness prevention. It has a remote capability that has been used from Moffett Field, CA to Atlanta, GA . AFTE is administered in twelve (30-minute) training sessions. The success rate for the NASA AFTE program has been over 85%. Methods: Implementation Phases: Phase I: Transfer NASA AFTE to NAMI; NASA will remotely train aviation students at NAMI. Phase II: NAMI-centered AFTE application with NASA oversight. Phase III: NAMI-centered AFTE to remotely train at various Navy sites. Phase IV: NAMI to offer Tri-service application and examine research opportunities. Results: 1. Use available telemedicine connectivity between NAMI and NASA. 2. Save over $2,000 per student trained. 3. Reduce aviation training attrition. 4. Provide standardization of multi-location motion sickness training. 5. Future tri-service initiatives. 6. Data to NASA and Navy for QA and research opportunities.

INTRA-RATER RELIABILITY OF THE MULTIPLE SINGLE-LEG HOP-STABILIZATION TEST AND RELATIONSHIPS WITH AGE, LEG DOMINANCE AND TRAINING.

Science.gov (United States)

Sawle, Leanne; Freeman, Jennifer; Marsden, Jonathan

2017-04-01

Balance is a complex construct, affected by multiple components such as strength and co-ordination. However, whilst assessing an athlete's dynamic balance is an important part of clinical examination, there is no gold standard measure. The multiple single-leg hop-stabilization test is a functional test which may offer a method of evaluating the dynamic attributes of balance, but it needs to show adequate intra-tester reliability. The purpose of this study was to assess the intra-rater reliability of a dynamic balance test, the multiple single-leg hop-stabilization test on the dominant and non-dominant legs. Intra-rater reliability study. Fifteen active participants were tested twice with a 10-minute break between tests. The outcome measure was the multiple single-leg hop-stabilization test score, based on a clinically assessed numerical scoring system. Results were analysed using an Intraclass Correlations Coefficient (ICC 2,1 ) and Bland-Altman plots. Regression analyses explored relationships between test scores, leg dominance, age and training (an alpha level of p = 0.05 was selected). ICCs for intra-rater reliability were 0.85 for the dominant and non-dominant legs (confidence intervals = 0.62-0.95 and 0.61-0.95 respectively). Bland-Altman plots showed scores within two standard deviations. A significant correlation was observed between the dominant and non-dominant leg on balance scores (R 2 =0.49, ptest demonstrated strong intra-tester reliability with active participants. Younger participants who trained more, have better balance scores. This test may be a useful measure for evaluating the dynamic attributes of balance. 3.

Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke.

Science.gov (United States)

Secoli, Riccardo; Milot, Marie-Helene; Rosati, Giulio; Reinkensmeyer, David J

2011-04-23

Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task. Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error. Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke. Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for the hemiparetic arm, suggesting that the increased demands associated

LHC Beam Instrumentation: Beam Profile Measurements (2/3)

CERN Document Server

CERN. Geneva

2014-01-01

The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. These lectures will introduce these systems and comment on their contributions to the various stages of beam operation. They will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

Autogenic-feedback training: A preventive method for space adaptation syndrome

Science.gov (United States)

Cowings, Patricia S.; Sharp, Joseph C.; Toscano, William B.; Kamiya, Joe; Miller, Neal E.

1987-01-01

The progress made to date on the reduction of data for Spacelab 3 Shuttle experiment, No. 3AFT23 is reported. Four astronauts participated as subjects in this experiment. Crewmen A and B served as treatment subjects (i.e., received preflight training for control of their own motion sickness symptoms) and Crewmen C and D served as control (i.e., did not receive training). A preliminary evaluation of Autogenic Feedback Training (AFT) was made from visual inspections of graphs that were generated from the preflight and inflight and inflight physiological data which included: (1) Baseline rotating chair tests for all crewmen; (2) Posttraining rotating chair tests of treatment groups subjects; (3) Preflight data from Joint Integrated Simulations for all crewmen; and (4) Flight data for all crewmen during mission days 0 through 4, and mission day 6 for treatment subjects only. A summary of the findings suggested by these data is outlined.

Computer-aided training sensorimotor cortex functions in humans before the upper limb transplantation using virtual reality and sensory feedback.

Science.gov (United States)

Kurzynski, Marek; Jaskolska, Anna; Marusiak, Jaroslaw; Wolczowski, Andrzej; Bierut, Przemyslaw; Szumowski, Lukasz; Witkowski, Jerzy; Kisiel-Sajewicz, Katarzyna

2017-08-01

One of the biggest problems of upper limb transplantation is lack of certainty as to whether a patient will be able to control voluntary movements of transplanted hands. Based on findings of the recent research on brain cortex plasticity, a premise can be drawn that mental training supported with visual and sensory feedback can cause structural and functional reorganization of the sensorimotor cortex, which leads to recovery of function associated with the control of movements performed by the upper limbs. In this study, authors - based on the above observations - propose the computer-aided training (CAT) system, which generating visual and sensory stimuli, should enhance the effectiveness of mental training applied to humans before upper limb transplantation. The basis for the concept of computer-aided training system is a virtual hand whose reaching and grasping movements the trained patient can observe on the VR headset screen (visual feedback) and whose contact with virtual objects the patient can feel as a touch (sensory feedback). The computer training system is composed of three main components: (1) the system generating 3D virtual world in which the patient sees the virtual limb from the perspective as if it were his/her own hand; (2) sensory feedback transforming information about the interaction of the virtual hand with the grasped object into mechanical vibration; (3) the therapist's panel for controlling the training course. Results of the case study demonstrate that mental training supported with visual and sensory stimuli generated by the computer system leads to a beneficial change of the brain activity related to motor control of the reaching in the patient with bilateral upper limb congenital transverse deficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tactile feedback is an effective instrument for the training of grasping with a prosthesis at low- and medium-force levels.

Science.gov (United States)

De Nunzio, Alessandro Marco; Dosen, Strahinja; Lemling, Sabrina; Markovic, Marko; Schweisfurth, Meike Annika; Ge, Nan; Graimann, Bernhard; Falla, Deborah; Farina, Dario

2017-08-01

Grasping is a complex task routinely performed in an anticipatory (feedforward) manner, where sensory feedback is responsible for learning and updating the internal model of grasp dynamics. This study aims at evaluating whether providing a proportional tactile force feedback during the myoelectric control of a prosthesis facilitates learning a stable internal model of the prosthesis force control. Ten able-bodied subjects controlled a sensorized myoelectric prosthesis performing four blocks of consecutive grasps at three levels of target force (30, 50, and 70%), repeatedly closing the fully opened hand. In the first and third block, the subjects received tactile and visual feedback, respectively, while during the second and fourth block, the feedback was removed. The subjects also performed an additional block with no feedback 1 day after the training (Retest). The median and interquartile range of the generated forces was computed to assess the accuracy and precision of force control. The results demonstrated that the feedback was indeed an effective instrument for the training of prosthesis control. After the training, the subjects were still able to accurately generate the desired force for the low and medium target (30 and 50% of maximum force available in a prosthesis), despite the feedback being removed within the session and during the retest (low target force). However, the training was substantially less successful for high forces (70% of prosthesis maximum force), where subjects exhibited a substantial loss of accuracy as soon as the feedback was removed. The precision of control decreased with higher forces and it was consistent across conditions, determined by an intrinsic variability of repeated myoelectric grasping. This study demonstrated that the subject could rely on the tactile feedback to adjust the motor command to the prosthesis across trials. The subjects adjusted the mean level of muscle activation (accuracy), whereas the precision could not

Effectiveness of a Training Program in Supervisors' Ability to Provide Feedback on Residents' Communication Skills

Science.gov (United States)

Junod Perron, Noelle; Nendaz, Mathieu; Louis-Simonet, Martine; Sommer, Johanna; Gut, Anne; Baroffio, Anne; Dolmans, Diana; van der Vleuten, Cees

2013-01-01

Teaching communication skills (CS) to residents during clinical practice remains problematic. Direct observation followed by feedback is a powerful way to teach CS in clinical practice. However, little is known about the effect of training on feedback skills in this field. Controlled studies are scarce as well as studies that go beyond…

Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

International Nuclear Information System (INIS)

Joyce, Bryan S; Tarazaga, Pablo A

2014-01-01

The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity. (papers)

Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

Science.gov (United States)

Joyce, Bryan S.; Tarazaga, Pablo A.

2014-07-01

The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity.

Vertical and pitching resonance of train cars moving over a series of simple beams

Science.gov (United States)

Yang, Y. B.; Yau, J. D.

2015-02-01

The resonant response, including both vertical and pitching motions, of an undamped sprung mass unit moving over a series of simple beams is studied by a semi-analytical approach. For a sprung mass that is very small compared with the beam, we first simplify the sprung mass as a constant moving force and obtain the response of the beam in closed form. With this, we then solve for the response of the sprung mass passing over a series of simple beams, and validate the solution by an independent finite element analysis. To evaluate the pitching resonance, we consider the cases of a two-axle model and a coach model traveling over rough rails supported by a series of simple beams. The resonance of a train car is characterized by the fact that its response continues to build up, as it travels over more and more beams. For train cars with long axle intervals, the vertical acceleration induced by pitching resonance dominates the peak response of the train traveling over a series of simple beams. The present semi-analytical study allows us to grasp the key parameters involved in the primary/sub-resonant responses. Other phenomena of resonance are also discussed in the exemplar study.

Particle tracking code of simulating global RF feedback

International Nuclear Information System (INIS)

Mestha, L.K.

1991-09-01

It is well known in the ''control community'' that a good feedback controller design is deeply rooted in the physics of the system. For example, when accelerating the beam we must keep several parameters under control so that the beam travels within the confined space. Important parameters include the frequency and phase of the rf signal, the dipole field, and the cavity voltage. Because errors in these parameters will progressively mislead the beam from its projected path in the tube, feedback loops are used to correct the behavior. Since the feedback loop feeds energy to the system, it changes the overall behavior of the system and may drive it to instability. Various types of controllers are used to stabilize the feedback loop. Integrating the beam physics with the feedback controllers allows us to carefully analyze the beam behavior. This will not only guarantee optimal performance but will also significantly enhance the ability of the beam control engineer to deal effectively with the interaction of various feedback loops. Motivated by this theme, we developed a simple one-particle tracking code to simulate particle behavior with feedback controllers. In order to achieve our fundamental objective, we can ask some key questions: What are the input and output parameters? How can they be applied to the practical machine? How can one interface the rf system dynamics such as the transfer characteristics of the rf cavities and phasing between the cavities? Answers to these questions can be found by considering a simple case of a single cavity with one particle, tracking it turn-by-turn with appropriate initial conditions, then introducing constraints on crucial parameters. Critical parameters are rf frequency, phase, and amplitude once the dipole field has been given. These are arranged in the tracking code so that we can interface the feedback system controlling them

Nonlinear free vibration control of beams using acceleration delayed-feedback control

International Nuclear Information System (INIS)

Alhazza, Khaled A; Alajmi, Mohammed; Masoud, Ziyad N

2008-01-01

A single-mode delayed-feedback control strategy is developed to reduce the free vibrations of a flexible beam using a piezoelectric actuator. A nonlinear variational model of the beam based on the von Kàrmàn nonlinear type deformations is considered. Using Galerkin's method, the resulting governing partial differential equations of motion are reduced to a system of nonlinear ordinary differential equations. A linear model using the first mode is derived and is used to characterize the damping produced by the controller as a function of the controller's gain and delay. Three-dimensional figures showing the damping magnitude as a function of the controller gain and delay are presented. The characteristic damping of the controller as predicted by the linear model is compared to that calculated using direct long-time integration of a three-mode nonlinear model. Optimal values of the controller gain and delay using both methods are obtained, simulated and compared. To validate the single-mode approximation, numerical simulations are performed using a three-mode full nonlinear model. Results of the simulations demonstrate an excellent controller performance in mitigating the first-mode vibration

Force feedback and basic laparoscopic skills

NARCIS (Netherlands)

Chmarra, M.K.; Dankelman, J.; Van den Dobbelsteen, J.J.; Jansen, F.W.

2008-01-01

Background - Not much is known about the exact role offorce feedback in laparoscopy. This study aimed to determine whether force feedback influences movements of instruments during training in laparoscopic tasks and whether force feedback is required for training in basic laparoscopic force

Operational Applications of Autogenic Feedback Training Exercise as a Treatment for Airsickness in the Military

Science.gov (United States)

Gebreyesus, Fiyore; Cowings, Patricia S.; Toscano, William B.

2012-01-01

Airsickness is experienced by about 50% of military aviators some time in their career. Aviators who suffer from recurrent episodes of airsickness are typically referred to the Naval Aerospace Medical Institute (NAMI) at Pensacola where they undergo extensive evaluation and 8 weeks of training in the Self-Paced Airsickness Desensitization (SPAD) program. Researchers at NASA Ames have developed an alternative mitigation training program, Autogenic Feedback Training Exercise (AFTE) that has demonstrated an 80% success rate for improving motion sickness tolerance.

Beam tuning and stabilization using beam phase measurements at GANIL

International Nuclear Information System (INIS)

Chabert, A.; Loyer, F.; Sauret, J.

1984-06-01

Owing to the great sensitivity of the beam phase to the various parameters, on line beam phase measurements proved to be a very efficient way of tuning and stabilizing the beam of the multi-accelerator complex. We recall the system which allows to obtain the different kinds of accurate measurements we need and describe the main applications: - tuning process (buncher and SSC's RF phase determination, setting of the required radial beam phase law in the SSC's); - stabilization of the beam by loops, the basic principle of which being to keep constant the beam central phase all along the machine by adjusting RF voltages or magnetic fields. Feedback loops are described and comparative results with and without feedback are given

Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke

Directory of Open Access Journals (Sweden)

Reinkensmeyer David J

2011-04-01

Full Text Available Abstract Background Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task. Methods Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error. Results Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke. Conclusions Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for

Effect of Continuous Motion Parameter Feedback on Laparoscopic Simulation Training: A Prospective Randomized Controlled Trial on Skill Acquisition and Retention.

Science.gov (United States)

Buescher, Julian Frederik; Mehdorn, Anne-Sophie; Neumann, Philipp-Alexander; Becker, Felix; Eichelmann, Ann-Kathrin; Pankratius, Ulrich; Bahde, Ralf; Foell, Daniel; Senninger, Norbert; Rijcken, Emile

To investigate the effect of motion parameter feedback on laparoscopic basic skill acquisition and retention during a standardized box training curriculum. A Lap-X Hybrid laparoscopic simulator was designed to provide individual and continuous motion parameter feedback in a dry box trainer setting. In a prospective controlled trial, surgical novices were randomized into 2 groups (regular box group, n = 18, and Hybrid group, n = 18) to undergo an identical 5-day training program. In each group, 7 standardized tasks on laparoscopic basic skills were completed twice a day on 4 consecutive days in fixed pairs. Additionally, each participant performed a simulated standard laparoscopic cholecystectomy before (day 1) and after training (day 5) on a LAP Mentor II virtual reality (VR) trainer, allowing an independent control of skill progress in both groups. A follow-up assessment of skill retention was performed after 6 weeks with repetition of both the box tasks and VR cholecystectomy. Muenster University Hospital Training Center, Muenster, Germany. Medical students without previous surgical experience. Laparoscopic skills in both groups improved significantly during the training period, measured by the overall task performance time. The 6 week follow-up showed comparable skill retention in both groups. Evaluation of the VR cholecystectomies demonstrated significant decrease of operation time (p Simulation training on both trainers enables reliable acquisition of laparoscopic basic skills. Furthermore, individual and continuous motion feedback improves laparoscopic skill enhancement significantly in several aspects. Thus, training systems with feedback of motion parameters should be considered to achieve long-term improvement of motion economy among surgical trainees. Copyright © 2017 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Feedback or biofeedback to augment pelvic floor muscle training for urinary incontinence in women: shortened version of a Cochrane systematic review

NARCIS (Netherlands)

Herderschee, Roselien; Hay-Smith, E. C. Jean; Herbison, G. Peter; Roovers, Jan Paul; Heineman, Maas Jan

2013-01-01

Feedback and biofeedback (BF) are common adjuncts to pelvic floor muscle training (PFMT) for women with stress, urgency, and mixed urinary incontinence (UI). An up to date systematic review of adjunctive feedback or BF was needed to guide practice and further research. To determine whether feedback

Local orbit feedback

International Nuclear Information System (INIS)

Anon.

1991-01-01

Critically aligned experiments are sensitive to small changes in the electron beam orbit. At the NSLS storage rings, the electron beam and photon beam motions have been monitored over the past several years. In the survey conducted in 1986 by the NSLS Users Executive Committee, experimenters requested the vertical beam position variation and the vertical angle variation, within a given fill, remain within 10 μm and 10 μr, respectively. This requires improvement in the beam stability by about one order of magnitude. At the NSLS and SSRL storage rings, the beam that is originally centered on the position monitor by a dc orbit correction is observed to have two kinds of motion: a dc drift over a storage period of several hours and a beam bounce about its nominal position. These motions are a result of the equilibrium orbit not being held perfectly stable due to time-varying errors introduced into the magnetic guide field by power supplies, mechanical vibration of the magnets, cooling water temperature variations, etc. The approach to orbit stabilization includes (1) identifying and suppressing as many noise sources on the machine as possible, (2) correcting the beam position globally (see Section 6) by controlling a number of correctors around the circumference of the machine, and (3) correcting the beam position and angle at a given source location by position feedback using local detectors and local orbit bumps. The third approach, called Local Orbit Feedback will be discussed in this section

Effects of optical feedback in a birefringence-Zeeman dual frequency laser at high optical feedback levels

International Nuclear Information System (INIS)

Mao Wei; Zhang Shulian

2007-01-01

Optical feedback effects are studied in a birefringence-Zeeman dual frequency laser at high optical feedback levels. The intensity modulation features of the two orthogonally polarized lights are investigated in both isotropic optical feedback (IOF) and polarized optical feedback (POF). In IOF, the intensities of both beams are modulated simultaneously, and four zones, i.e., the e-light zone, the o-light and e-light zone, the o-light zone, and the no-light zone, are formed in a period corresponding to a half laser wavelength displacement of the feedback mirror. In POF, the two orthogonally polarized lights will oscillate alternately. Strong mode competition can be observed, and it affects the phase difference between the two beams greatly. The theoretical analysis is presented, which is in good agreement with the experimental results. The potential use of the experimental results is also discussed

TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

Energy Technology Data Exchange (ETDEWEB)

Wang, Haipeng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Guo, Jiquan [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Rimmer, Robert A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, Shaoheng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-05-01

The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability. We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.

Intra-operative radiotherapy in oncology

International Nuclear Information System (INIS)

Gerard, J.P.; Braillon, G.; Sentenac, I.; Calvo, F.; Dubois, J.B.; Saint-Aubert, B.; Guillemin, C.; Roussel, A.

1991-01-01

This article is about a treatment used more and more frequently in the world, for some neoplasms: Intra-operative radiotherapy under electron beams. The main neoplasms concerned by this treatment are the stomach, pancreas, rectum, bladder, uterus cervix neoplasms and peritoneal sarcoma [fr

LHC Beam Instrumentation: Beam Position and Intensity Measurements (1/3)

CERN Multimedia

CERN. Geneva

2014-01-01

The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. These lectures will introduce these systems and comment on their contributions to the various stages of beam operation. They will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

LHC Beam Instrumentation: Beam Loss and Tune Measurements (3/3)

CERN Multimedia

CERN. Geneva

2014-01-01

The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. These lectures will introduce these systems and comment on their contributions to the various stages of beam operation. They will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

Closed orbit feedback with digital signal processing

International Nuclear Information System (INIS)

Chung, Y.; Kirchman, J.; Lenkszus, F.

1994-01-01

The closed orbit feedback experiment conducted on the SPEAR using the singular value decomposition (SVD) technique and digital signal processing (DSP) is presented. The beam response matrix, defined as beam motion at beam position monitor (BPM) locations per unit kick by corrector magnets, was measured and then analyzed using SVD. Ten BPMs, sixteen correctors, and the eight largest SVD eigenvalues were used for closed orbit correction. The maximum sampling frequency for the closed loop feedback was measured at 37 Hz. Using the proportional and integral (PI) control algorithm with the gains Kp = 3 and K I = 0.05 and the open-loop bandwidth corresponding to 1% of the sampling frequency, a correction bandwidth (-3 dB) of approximately 0.8 Hz was achieved. Time domain measurements showed that the response time of the closed loop feedback system for 1/e decay was approximately 0.25 second. This result implies ∼ 100 Hz correction bandwidth for the planned beam position feedback system for the Advanced Photon Source storage ring with the projected 4-kHz sampling frequency

Long-term intensive gymnastic training induced changes in intra- and inter-network functional connectivity: an independent component analysis.

Science.gov (United States)

Huang, Huiyuan; Wang, Junjing; Seger, Carol; Lu, Min; Deng, Feng; Wu, Xiaoyan; He, Yuan; Niu, Chen; Wang, Jun; Huang, Ruiwang

2018-01-01

Long-term intensive gymnastic training can induce brain structural and functional reorganization. Previous studies have identified structural and functional network differences between world class gymnasts (WCGs) and non-athletes at the whole-brain level. However, it is still unclear how interactions within and between functional networks are affected by long-term intensive gymnastic training. We examined both intra- and inter-network functional connectivity of gymnasts relative to non-athletes using resting-state fMRI (R-fMRI). R-fMRI data were acquired from 13 WCGs and 14 non-athlete controls. Group-independent component analysis (ICA) was adopted to decompose the R-fMRI data into spatial independent components and associated time courses. An automatic component identification method was used to identify components of interest associated with resting-state networks (RSNs). We identified nine RSNs, the basal ganglia network (BG), sensorimotor network (SMN), cerebellum (CB), anterior and posterior default mode networks (aDMN/pDMN), left and right fronto-parietal networks (lFPN/rFPN), primary visual network (PVN), and extrastriate visual network (EVN). Statistical analyses revealed that the intra-network functional connectivity was significantly decreased within the BG, aDMN, lFPN, and rFPN, but increased within the EVN in the WCGs compared to the controls. In addition, the WCGs showed uniformly decreased inter-network functional connectivity between SMN and BG, CB, and PVN, BG and PVN, and pDMN and rFPN compared to the controls. We interpret this generally weaker intra- and inter-network functional connectivity in WCGs during the resting state as a result of greater efficiency in the WCGs' brain associated with long-term motor skill training.

Analysis of Feedback in after Action Reviews

Science.gov (United States)

1987-06-01

CONNTSM Page INTRODUCTIUN . . . . . . . . . . . . . . . . . . . A Perspective on Feedback. . ....... • • ..... • 1 Overviev of %,•urrent Research...part of their training program . The AAR is in marked contrast to the critique method of feedback which is often used in military training. The AAR...feedback is task-inherent feedback. Task-inherent feedback refers to human-machine interacting systems, e.g., computers , where in a visual tracking task

Development of the Corrective Feedback Instrument: A Tool for Use in Counselor Training Groups.

Science.gov (United States)

Hulse-Killacky, Diana; Page, Betsy J.

1994-01-01

Presents an instrument for measuring emotional barriers that can inhibit giving, receiving, and exchanging corrective feedback in counselor training groups. Also assesses leader behaviors that can help group members address those barriers. Testing showed that the instrument can be used to identify group member concerns. (RJM)

Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.

Science.gov (United States)

Leving, Marika T; Vegter, Riemer J K; Hartog, Johanneke; Lamoth, Claudine J C; de Groot, Sonja; van der Woude, Lucas H V

2015-01-01

It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process. 17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability. The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group. These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear

Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.

Directory of Open Access Journals (Sweden)

Marika T Leving

Full Text Available It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process.17 Participants received visual feedback-based practice (feedback group and 15 participants received regular practice (natural learning group. Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block and optimize it in the prescribed direction (2nd 4-min block. To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability.The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group.These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not

Comparative effectiveness of audit-feedback versus additional physician communication training to improve cancer screening for patients with limited health literacy.

Science.gov (United States)

Price-Haywood, Eboni G; Harden-Barrios, Jewel; Cooper, Lisa A

2014-08-01

We designed a continuing medical education (CME) program to teach primary care physicians (PCP) how to engage in cancer risk communication and shared decision making with patients who have limited health literacy (HL). We evaluated whether training PCPs, in addition to audit-feedback, improves their communication behaviors and increases cancer screening among patients with limited HL to a greater extent than only providing clinical performance feedback. Four-year cluster randomized controlled trial. Eighteen PCPs and 168 patients with limited HL who were overdue for colorectal/breast/cervical cancer screening. Communication intervention PCPs received skills training that included standardized patient (SP) feedback on counseling behaviors. All PCPs underwent chart audits of patients' screening status semiannually up to 24 months and received two annual performance feedback reports. PCPs experienced three unannounced SP encounters during which SPs rated PCP communication behaviors. We examined between-group differences in changes in SP ratings and patient knowledge of cancer screening guidelines over 12 months; and changes in patient cancer screening rates over 24 months. There were no group differences in SP ratings of physician communication at baseline. At follow-up, communication intervention PCPs were rated higher in general communication about cancer risks and shared decision making related to colorectal cancer screening compared to PCPs who only received performance feedback. Screening rates increased among patients of PCPs in both groups; however, there were no between-group differences in screening rates except for mammography. The communication intervention did not improve patient cancer screening knowledge. Compared to audit and feedback alone, including PCP communication training increases PCP patient-centered counseling behaviors, but not cancer screening among patients with limited HL. Larger studies must be conducted to determine whether lack of

Measurement of inter and intra fraction organ motion in radiotherapy using cone beam CT projection images

International Nuclear Information System (INIS)

Marchant, T E; Amer, A M; Moore, C J

2008-01-01

A method is presented for extraction of intra and inter fraction motion of seeds/markers within the patient from cone beam CT (CBCT) projection images. The position of the marker is determined on each projection image and fitted to a function describing the projection of a fixed point onto the imaging panel at different gantry angles. The fitted parameters provide the mean marker position with respect to the isocentre. Differences between the theoretical function and the actual projected marker positions are used to estimate the range of intra fraction motion and the principal motion axis in the transverse plane. The method was validated using CBCT projection images of a static marker at known locations and of a marker moving with known amplitude. The mean difference between actual and measured motion range was less than 1 mm in all directions, although errors of up to 5 mm were observed when large amplitude motion was present in an orthogonal direction. In these cases it was possible to calculate the range of motion magnitudes consistent with the observed marker trajectory. The method was shown to be feasible using clinical CBCT projections of a pancreas cancer patient

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator

DEFF Research Database (Denmark)

Strandbygaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde

2013-01-01

% vs 49%; P = 0.004). Men used less time (in minutes) than women (P = 0.037), but no sex difference was observed for repetitions (P = 0.20). Participants in the intervention group had higher self-perception regarding surgical skills after the trial (P = 0.011). CONCLUSIONS:: Instructor feedback...... increases the efficiency when training a complex operational task on a virtual reality simulator; time and repetitions used to achieve a predefined proficiency level were significantly reduced in the group that received instructor feedback compared with the control group. Trial registration number: NCT......OBJECTIVE:: To investigate the impact of instructor feedback versus no instructor feedback when training a complex operational task on a laparoscopic virtual reality simulator. BACKGROUND:: Simulators are now widely accepted as a training tool, but there is insufficient knowledge about how much...

Interactive balance training integrating sensor-based visual feedback of movement performance: a pilot study in older adults.

Science.gov (United States)

Schwenk, Michael; Grewal, Gurtej S; Honarvar, Bahareh; Schwenk, Stefanie; Mohler, Jane; Khalsa, Dharma S; Najafi, Bijan

2014-12-13

Wearable sensor technology can accurately measure body motion and provide incentive feedback during exercising. The aim of this pilot study was to evaluate the effectiveness and user experience of a balance training program in older adults integrating data from wearable sensors into a human-computer interface designed for interactive training. Senior living community residents (mean age 84.6) with confirmed fall risk were randomized to an intervention (IG, n = 17) or control group (CG, n = 16). The IG underwent 4 weeks (twice a week) of balance training including weight shifting and virtual obstacle crossing tasks with visual/auditory real-time joint movement feedback using wearable sensors. The CG received no intervention. Outcome measures included changes in center of mass (CoM) sway, ankle and hip joint sway measured during eyes open (EO) and eyes closed (EC) balance test at baseline and post-intervention. Ankle-hip postural coordination was quantified by a reciprocal compensatory index (RCI). Physical performance was quantified by the Alternate-Step-Test (AST), Timed-up-and-go (TUG), and gait assessment. User experience was measured by a standardized questionnaire. After the intervention sway of CoM, hip, and ankle were reduced in the IG compared to the CG during both EO and EC condition (p = .007-.042). Improvement was obtained for AST (p = .037), TUG (p = .024), fast gait speed (p = . 010), but not normal gait speed (p = .264). Effect sizes were moderate for all outcomes. RCI did not change significantly. Users expressed a positive training experience including fun, safety, and helpfulness of sensor-feedback. Results of this proof-of-concept study suggest that older adults at risk of falling can benefit from the balance training program. Study findings may help to inform future exercise interventions integrating wearable sensors for guided game-based training in home- and community environments. Future studies should evaluate the

Effect of information feedback on training standing up following stroke: a pilot feasibility study.

Science.gov (United States)

Stanton, Rosalyn; Ada, Louise; Dean, Catherine M; Preston, Elisabeth

2016-12-01

The ability to stand up is reduced following stroke. Traditional biofeedback is effective in improving the performance of lower limb activities. The aim of this study was to investigate the feasibility of and potential for information feedback from a simple inexpensive device to improve the ability to stand up from a chair in people following stroke. A single-group study with pre-post measures design was used. Twenty people with hemiplegic stroke in inpatient rehabilitation received 10 sessions over 2 weeks of information feedback about foot placement during training of standing up. Progression involved increasing repetitions, increasing difficulty and fading feedback. Feasibility was determined by adherence, time taken, acceptability and safety. Clinical outcomes were the time taken to stand up, quality and foot position measured using the 5-Times-Sit-To-Stand-Test and carryover into daily activities measured by covert observation. The study was feasible with 97% of sessions completed, taking 19 (SD 6) to 25 (SD 10) minutes. Participants understood (4.6/5), found useful (4.6/5), challenging (4.4/5) and would recommend (4.7/5) the training. The time to stand up 5 times decreased by 24 (95% CI -48 to -1) s, and the quality of standing improved by 1.0/10.0 (95% CI 0.2 to 1.8). Carryover of the correct foot placement occurred to real life, with the beginning foot position correct 2.1/3.0 (95% CI 1.6 to 2.6) and end foot position correct 1.8/3.0 (95% CI 1.2 to 2.4) occasions. The training is feasible and has the potential to improve the ability to stand up.

Feedback in Clinical Education, Part II: Approved Clinical Instructor and Student Perceptions of and Influences on Feedback

Science.gov (United States)

Nottingham, Sara; Henning, Jolene

2014-01-01

Context: Approved Clinical Instructors (ACIs; now known as preceptors) are expected to provide feedback to athletic training students (ATSs) during clinical education experiences. Researchers in other fields have found that clinical instructors and students often have different perceptions of actual and ideal feedback and that several factors may influence the feedback exchanges between instructors and students. However, understanding of these issues in athletic training education is minimal. Objective: To investigate the current characteristics and perceptions of and the influences on feedback exchanges between ATSs and ACIs. Design: Qualitative study. Setting: One entry-level master's degree program accredited by the Commission on Accreditation of Athletic Training Education. Patients or Other Participants: Four ACIs and 4 second-year ATSs. Data Collection and Analysis: Individual, semistructured interviews were conducted with participants and integrated with field notes and observations for analysis. We used the constant comparative approach to inductively analyze data and develop codes and categories. Member checking, triangulation, and peer debriefing were used to promote trustworthiness of the study. Results: Participants described that feedback plays an important role in clinical education and has several purposes related to improving performance. The ACIs and ATSs also discussed several preferred characteristics of feedback. Participants identified 4 main influences on their feedback exchanges, including the ACI, the ATS, personalities, and the learning environment. Conclusions: The ACIs and ATSs had similar perceptions of ideal feedback in addition to the actual feedback that was provided during their clinical education experiences. Most of the preferences for feedback were aligned with recommendations in the literature, suggesting that existing research findings are applicable to athletic training clinical education. Several factors influenced the

Comparison between gas puffing and supersonic molecular beam injection in plasma density feedback experiments in EAST

International Nuclear Information System (INIS)

Zheng, Xingwei; Li, Jiangang; Hu, Jiansheng; Li, Jiahong; Ding, Rui; Cao, Bin; Wu, Jinhua

2013-01-01

To achieve desirable plasma density control, a supersonic molecular beam injection (SMBI) feedback control system has been developed recently for the EAST tokamak. The performance of the SMBI and gas puffing (GP) feedback systems were used and compared. The performance of pulse width mode is better than that of pulse amplitude mode when GP was used for density feedback control. During one-day experiments, the variation of gas input and wall retention can be clarified into two stages. In the first stage the retention ratio is as high as 80–90%, and the gas input is about an order of 10 22 D 2 . However, in the second stage, the retention ratio is at a range of 50–70%. The gas input of a single discharge is small and the net wall retention grows slowly. The results of the SMBI feedback control experiment was analyzed. The shorter delay time of SMBI makes it faster at feeding back control the plasma density. The result showed that, compared with GP, the gas input of SMBI was decreased ∼30% and the wall retention was reduced ∼40%. This shows SMBI's advantage for the long pulse high density discharges in EAST. (paper)

The role of haptic feedback in laparoscopic simulation training.

Science.gov (United States)

Panait, Lucian; Akkary, Ehab; Bell, Robert L; Roberts, Kurt E; Dudrick, Stanley J; Duffy, Andrew J

2009-10-01

Laparoscopic virtual reality simulators are becoming a ubiquitous tool in resident training and assessment. These devices provide the operator with various levels of realism, including haptic (or force) feedback. However, this feature adds significantly to the cost of the devices, and limited data exist assessing the value of haptics in skill acquisition and development. Utilizing the Laparoscopy VR (Immersion Medical, Gaithersburg, MD), we hypothesized that the incorporation of force feedback in the simulated operative environment would allow superior trainee performance compared with performance of the same basic skills tasks in a non-haptic model. Ten medical students with minimal laparoscopic experience and similar baseline skill levels as proven by performance of two fundamentals of laparoscopic surgery (FLS) tasks (peg transfer and cutting drills) voluntarily participated in the study. Each performed two tasks, analogous to the FLS drills, on the Laparoscopy VR at 3 levels of difficulty, based on the established settings of the manufacturer. After achieving familiarity with the device and tasks, the students completed the drills both with and without force feedback. Data on completion time, instrument path length, right and left hand errors, and grasping tension were analyzed. The scores in the haptic-enhanced simulation environment were compared with the scores in the non-haptic model and analyzed utilizing Student's t-test. The peg transfer drill showed no difference in performance between the haptic and non-haptic simulations for all metrics at all three levels of difficulty. For the more complex cutting exercise, the time to complete the tasks was significantly shorter when force feedback was provided, at all levels of difficulty (158+/-56 versus 187+/-51 s, 176+/-49 versus 222+/-68 s, and 275+/-76 versus 422+/-220 s, at levels 1, 2, and 3, respectively, Psimulation did not demonstrate an appreciable performance improvement among our trainees. These data

RF feedback development for the PEP-II B Factory

Energy Technology Data Exchange (ETDEWEB)

Corredoura, P.; Sapozhnikov, L.; Tighe, R.

1994-06-01

In PEP-II heavy beam loading along with a relatively long revolution period combine to strongly drive lower coupled-bunch modes through interaction with the fundamental cavity mode. Feedback techniques can be applied to reduce the cavity impedance seen by the beam. Several RF feedback loops are planned to reduce the growth rates down to a level which can be damped by the relatively low power bunch-by-bunch longitudinal feedback system. This paper describes the RF feedback loops as well as hardware tests using a 500 kW klystron, analog and digital feedback loops, and a low power test cavity.

RF feedback development for the PEP-II B Factory

International Nuclear Information System (INIS)

Corredoura, P.; Sapozhnikov, L.; Tighe, R.

1994-06-01

In PEP-II heavy beam loading along with a relatively long revolution period combine to strongly drive lower coupled-bunch modes through interaction with the fundamental cavity mode. Feedback techniques can be applied to reduce the cavity impedance seen by the beam. Several RF feedback loops are planned to reduce the growth rates down to a level which can be damped by the relatively low power bunch-by-bunch longitudinal feedback system. This paper describes the RF feedback loops as well as hardware tests using a 500 kW klystron, analog and digital feedback loops, and a low power test cavity

Simulation of e-cloud driven instability and its attenuation using a simulated feedback system in the CERN SPS

International Nuclear Information System (INIS)

Vay, J.-L.; Furman, M.A.

2010-01-01

Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS, and a feedback system to control the single-bunch instabilities is under active development. We present the latest improvements to the WARP-POSINST simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS. Simulations using an idealized feedback system exhibit adequate mitigation of the instability providing that the cutoff of the feedback bandwidth is at or above 450 MHz. Artifacts from numerical noise of the injected distribution of electrons in the modeling of portions of bunch trains are discussed, and benchmarking of WARP against POSINST and HEADTAIL are presented.

Static and transient beam loading of a synchrotron

International Nuclear Information System (INIS)

Zhang, S.Y.; Weng, W.T.

1992-01-01

In a synchrotron, when the beam induced current is comparable to the driver current, the RF cavity is subjected to beam loading perturbation and corrective steps have to be implemented to regain beam stability. In this paper, the static and transient beam loading will be studied. We first discuss the static beam loading, which includes the cavity detuning condition, the stability condition, and the generator power dissipation. The beam current induced beam phase deviation is used as criterion to study the transient beam loading. The upgraded and the old AGS RF system parameters are used as an example to demonstrate how to choose cavity and generator parameters to satisfy the stability requirements under the beam loading. The dynamic models for the beam loading with beam control, and the beam loading with fast power amplifier feedback are presented and analyzed. It is shown that the beam phase and radial feedbacks alone are insufficient for the transient beam loading compensation, but the fast power amplifier feedback can provide effective correction on the beam loading. The limitation of the fast feedback and the beam loading with tuning and AVC loops are also discussed

Autogenic-feedback training improves pilot performance during emergency flying conditions

Science.gov (United States)

Kellar, Michael A.; Folen, Raymond A.; Cowings, Patricia S.; Toscano, William B.; Hisert, Glen L.

1994-01-01

Studies have shown that autonomous mode behavior is one cause of aircraft fatalities due to pilot error. In such cases, the pilot is in a high state of psychological and physiological arousal and tends to focus on one problem, while ignoring more critical information. This study examined the effect of training in physiological self-recognition and regulation, as a means of improving crew cockpit performance. Seventeen pilots were assigned to the treatment and control groups matched for accumulated flight hours. The treatment group comprised three pilots of HC-130 Hercules aircraft and four HH-65 Dolphin helicopter pilots; the control group comprised three pilots of HC-130's and six Dolphin helicopter pilots. During an initial flight, physiological data were recorded for each crew member and individual crew performance was rated by an instructor pilot. Eight crewmembers were then taught to regulate their own physiological response levels using Autogenic-Feedback Training (AFT). The remaining subjects received no training. During a second flight, treatment subjects showed significant improvement in performance, while controls did not improve. The results indicate that AFT management of high states of physiological arousal may improve pilot performance during emergency flying conditions.

Effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability.

Science.gov (United States)

Nam, Seung-Min; Kim, Kyoung; Lee, Do Youn

2018-01-01

[Purpose] This study examined the effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability. [Subjects and Methods] Twenty eight adults with functional ankle instability, divided randomly into an experimental group, which performed visual feedback balance training for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Bio rescue was used for balance ability. It measured limit of stability at one minute. For ankle instability was measured using Cumberland ankle instability tool (CAIT). This measure was performed before and after the experiments in each group. [Results] The experimental group had significant increase in the Limit of Stability and CAIT score. The control group had significant increase in CAIT score. While the Limit of Stability increased without significance. [Conclusion] In conclusion, visual feedback balance training can be recommended as a treatment method for patients with functional ankle instability.

The fast correction coil feedback control system

International Nuclear Information System (INIS)

Coffield, F.; Caporaso, G.; Zentler, J.M.

1989-01-01

A model-based feedback control system has been developed to correct beam displacement errors in the Advanced Test Accelerator (ATA) electron beam accelerator. The feedback control system drives an X/Y dipole steering system that has a 40-MHz bandwidth and can produce ±300-Gauss-cm dipole fields. A simulator was used to develop the control algorithm and to quantify the expected performance in the presence of beam position measurement noise and accelerator timing jitter. The major problem to date has been protecting the amplifiers from the voltage that is inductively coupled to the steering bars by the beam. 3 refs., 8 figs

Ambulatory Feedback System

Science.gov (United States)

Finger, Herbert; Weeks, Bill

1985-01-01

This presentation discusses instrumentation that will be used for a specific event, which we hope will carry on to future events within the Space Shuttle program. The experiment is the Autogenic Feedback Training Experiment (AFTE) scheduled for Spacelab 3, currently scheduled to be launched in November, 1984. The objectives of the AFTE are to determine the effectiveness of autogenic feedback in preventing or reducing space adaptation syndrome (SAS), to monitor and record in-flight data from the crew, to determine if prediction criteria for SAS can be established, and, finally, to develop an ambulatory instrument package to mount the crew throughout the mission. The purpose of the Ambulatory Feedback System (AFS) is to record the responses of the subject during a provocative event in space and provide a real-time feedback display to reinforce the training.

Radiographical measurements for distal intra-articular fractures of the radius using plain radiographs and cone beam computed tomography images

Energy Technology Data Exchange (ETDEWEB)

Suojaervi, Nora; Lindfors, N. [Helsinki University Central Hospital, Department of Hand Surgery, Helsinki (Finland); Sillat, T.; Koskinen, S.K. [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital, Department of Radiology, Helsinki (Finland)

2015-12-15

Operative treatment of an intra-articular distal radius fracture is one of the most common procedures in orthopedic and hand surgery. The intra- and interobserver agreement of common radiographical measurements of these fractures using cone beam computed tomography (CBCT) and plain radiographs were evaluated. Thirty-seven patients undergoing open reduction and volar fixation for a distal radius fracture were studied. Two radiologists analyzed the preoperative radiographs and CBCT images. Agreement of the measurements was subjected to intra-class correlation coefficient and the Bland-Altman analyses. Plain radiographs provided a slightly poorer level of agreement. For fracture diastasis, excellent intraobserver agreement was achieved for radiographs and good or excellent agreement for CBCT, compared to poor interobserver agreement (ICC 0.334) for radiographs and good interobserver agreement (ICC 0.621) for CBCT images. The Bland-Altman analyses indicated a small mean difference between the measurements but rather large variation using both imaging methods, especially in angular measurements. For most of the measurements, radiographs do well, and may be used in clinical practice. Two different measurements by the same reader or by two different readers can lead to different decisions, and therefore a standardization of the measurements is imperative. More detailed analysis of articular surface needs cross-sectional imaging modalities. (orig.)

Radiographical measurements for distal intra-articular fractures of the radius using plain radiographs and cone beam computed tomography images.

Science.gov (United States)

Suojärvi, Nora; Sillat, T; Lindfors, N; Koskinen, S K

2015-12-01

Operative treatment of an intra-articular distal radius fracture is one of the most common procedures in orthopedic and hand surgery. The intra- and interobserver agreement of common radiographical measurements of these fractures using cone beam computed tomography (CBCT) and plain radiographs were evaluated. Thirty-seven patients undergoing open reduction and volar fixation for a distal radius fracture were studied. Two radiologists analyzed the preoperative radiographs and CBCT images. Agreement of the measurements was subjected to intra-class correlation coefficient and the Bland-Altman analyses. Plain radiographs provided a slightly poorer level of agreement. For fracture diastasis, excellent intraobserver agreement was achieved for radiographs and good or excellent agreement for CBCT, compared to poor interobserver agreement (ICC 0.334) for radiographs and good interobserver agreement (ICC 0.621) for CBCT images. The Bland-Altman analyses indicated a small mean difference between the measurements but rather large variation using both imaging methods, especially in angular measurements. For most of the measurements, radiographs do well, and may be used in clinical practice. Two different measurements by the same reader or by two different readers can lead to different decisions, and therefore a standardization of the measurements is imperative. More detailed analysis of articular surface needs cross-sectional imaging modalities.

Controlled Transverse Blow-up of Highenergy Proton Beams for Aperture Measurements and Loss Maps

CERN Document Server

Hӧfle, W; Redaelli, S; Schmidt, R; Valuch, D; Wollmann, D; Zerlauth, M

2012-01-01

A technique was developed to blow-up transversely in a controlled way high energy proton beams in the LHC. The technique is based on band limited white noise excitation that is injected into the transverse damper feedback loop. The injected signal can be gated to selectively blow-up individual trains of bunches. The speed of transverse blow-up can be precisely controlled. This opens the possibility to perform safely and efficiently aperture measurements and loss maps with high intensity bunch trains well above stored beam energies that are considered to be safe. In particular, lengthy procedures for measurements at top energy, otherwise requiring multiple fills of individual bunches, can be avoided. In this paper, the method is presented and results from beam measurements are discussed and compared with alternative blowup methods.

Diamond Light Source Booster fast orbit feedback system

International Nuclear Information System (INIS)

Gayadeen, S.; Duncan, S.R.; Christou, C.; Heron, M.T.; Rowland, J.

2012-01-01

The Fast Orbit Feedback system that has been installed on the Diamond Light Source Storage ring has been replicated on the Booster synchrotron in order to provide a test bed for the development of the Storage Ring controller design. To realise this the Booster is operated in DC mode. The electron beam is regulated in two planes using the Fast Orbit Feedback system, which takes the beam position from 22 beam position monitors for each plane, and calculates offsets to 44 corrector power supplies at a sample rate of 10 kHz. This paper describes the design and realization of the controller for the Booster Fast Orbit Feedback, presents results from the implementation and considers future development

Autogenic-Feedback Training: A Potential Treatment for Orthostatic Intolerance in Aerospace Crews

Science.gov (United States)

Cowings, P. S.; Toscano, W. B.; Miller, N. E.; Pickering, T. G.; Shapiro, D.; Stevenson, J.; Maloney, S.; Knapp, J.

1994-01-01

Postflight orthostatic intolerance has been identified as a serious biomedical problem associated with long-duration exposure to microgravity in space. High priority has been given to the development of countermeasures for this disorder that are both effective and practical. A considerable body of clinical research has demonstrated that people can be taught to increase their own blood pressure voluntarily, and that this is an effective treatment for chronic orthostatic intolerance in paralyzed patients. The current pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using an operant conditioning procedure, autogenic-feedback training (AFT), three men and two women participated in four to nine training (15-30-minute) sessions. At the end of training, the average increase in systolic and diastolic pressure, as well as mean arterial pressures, that the subjects made ranged between 20 and 50 mm Hg under both supine and 45 deg head-up tilt conditions. These findings indicate that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight orthostatic intolerance. Furthermore, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanisms of orthostatic intolerance.

Simulation study on control of spill structure of slow extracted beam from a medical synchrotron with feed-forward and feedback using a fast quadruple magnet and RF-knockout system

Energy Technology Data Exchange (ETDEWEB)

Muraoka, Ryo; Nakanishi, Tetsuya, E-mail: nakanishi.tetsuya@nihon-u.ac.jp

2017-02-21

A feedback control of the spill structure for the slow beam extraction from the medical synchrotron using a fast quadruple and radio frequency (RF)-knockout (QAR method) is studied to obtain the designed spill structure. In addition the feed-forward control is used so that the feedback control is performed effectively. In this extraction method, the spill of several ms are extracted continuously with an interval time of less than 1 ms. Beam simulation showed that a flat spill structure was effectively obtained with feed-forward and feedback control system as well as a step-wise structure which is useful for the shortening of an irradiation time in a spot scanning operation. The effect of current ripples from main quadruple magnet's power supplies could be also reduced with the feedback control application.

Can providing feedback on driving behavior and training on parental vigilant care affect male teen drivers and their parents?

Science.gov (United States)

Farah, Haneen; Musicant, Oren; Shimshoni, Yaara; Toledo, Tomer; Grimberg, Einat; Omer, Haim; Lotan, Tsippy

2014-08-01

This study focuses on investigating the driving behavior of young novice male drivers during the first year of driving (three months of accompanied driving and the following nine months of solo driving). The study's objective is to examine the potential of various feedback forms on driving to affect young drivers' behavior and to mitigate the transition from accompanied to solo driving. The study examines also the utility of providing parents with guidance on how to exercise vigilant care regarding their teens' driving. Driving behavior was evaluated using data collected by In-Vehicle Data Recorders (IVDR), which document events of extreme g-forces measured in the vehicles. IVDR systems were installed in 242 cars of the families of young male drivers, however, only 217 families of young drivers aged 17-22 (M=17.5; SD=0.8) completed the one year period. The families were randomly allocated into 4 groups: (1) Family feedback: In which all the members of the family were exposed to feedback on their own driving and on that of the other family members; (2) Parental training: in which in addition to the family feedback, parents received personal guidance on ways to enhance vigilant care regarding their sons' driving; (3) Individual feedback: In which family members received feedback only on their own driving behavior (and were not exposed to the data on other family members); (4) CONTROL: Group that received no feedback at all. The feedback was provided to the different groups starting from the solo period, thus, the feedback was not provided during the supervised period. The data collected by the IVDRs was first analyzed using analysis of variance in order to compare the groups with respect to their monthly event rates. Events' rates are defined as the number of events in a trip divided by its duration. This was followed by the development and estimation of random effect negative binomial models that explain the monthly event rates of young drivers and their parents

Bunch-motion feedback for B-factories

International Nuclear Information System (INIS)

Lambertson, G.R.

1992-09-01

The colliding electron and positron beams in a B-factory must have average current of one ampere or more to produce the required luminosity. The high current interacts with structures in the beam tube to drive strong coupled-bunch (c.b.) instabilities. To suppress these instabilities requires negative feedback of the bunch motions. Beam impedances arising from strong rf cavity modes should first be reduced to make the required feedback damping rate practical and the cost economical. In what follows, control of transverse motions will be discussed first, then longitudinal. We shall use the parameters of the 3.1 GeV ring of PEP-II to illustrate the general requirements

Operation of PEP longitudinal feedback system

International Nuclear Information System (INIS)

Allen, M.A.; Karvonen, L.G.; McConnell, R.A.; Schwarz, H.

1981-03-01

In order to suppress longitudinal coupled-bunch oscillations which might limit the capabilities of PEP, the 18 GeV e + e - storage ring at SLAC, a longitudinal feedback system is utilized. A frequency domain feedback system was chosen with the frequency spectrum of the stored beam being sampled close to a symmetry point in the ring where the feedback cavity itself is also located. The symmetry point chosen is symmetry point 5 which lies half-way between interaction regions 4 and 6. The system has been installed in PEP and is now operational. However, at stored currents up to the maximum stored in PEP to date at 14.5 GeV (approximately 40 mA in 6 bunches), the ring has been stable to all modes of longitudinal coupled-bunch oscillations both barycentric and the other fundamental modes. By deliberately detuning the main accelerating cavities, small multibunch oscillations can be introduced which, in turn, can be damped by the feedback system. Under optimized beam conditions the feedback system could be adjusted to positive feedback and excite oscillations with relatively small power to the feedback cavity. This will be described along with other details of the system

A simulation study of the global orbit feedback system for Pohang light source

International Nuclear Information System (INIS)

Kim, Kukhee; Shim, Kyuyeol; Cho, Moohyun; Namkung, Won; Ko, In Soo; Choi, Jinhyuk

2000-01-01

This paper describes the simulation of the global orbit feedback system using the singular value decomposition (SVD) method, the error minimization method, and the neural network method. Instead of facing unacceptable correction result raised occasionally in the SVD method, we choose the error minimization method for the global orbit feedback. This method provides minimum orbit errors while avoiding unacceptable corrections, and keeps the orbit within the dynamic aperture of the storage ring. We simulate the Pohang Light Source (PLS) storage ring using the Methodical Accelerator Design (MAD) code that generates the orbit distortions for the error minimization method and the learning data set for neural network method. In order to compare the effectiveness of the neural network method with others, a neural network is trained by the learning algorithm using the learning data set. The global response matrix with a minimum error and the trained neural network are used to the global orbit feedback system. The simulation shows that a selection of beam position monitors (BPMs) is very sensitive in the reduction of rms orbit distortions, and the random choice gives better results than any other cases. (author)

Temperature feedback control for long-term carrier-envelope phase locking

Science.gov (United States)

Chang, Zenghu [Manhattan, KS; Yun, Chenxia [Manhattan, KS; Chen, Shouyuan [Manhattan, KS; Wang, He [Manhattan, KS; Chini, Michael [Manhattan, KS

2012-07-24

A feedback control module for stabilizing a carrier-envelope phase of an output of a laser oscillator system comprises a first photodetector, a second photodetector, a phase stabilizer, an optical modulator, and a thermal control element. The first photodetector may generate a first feedback signal corresponding to a first portion of a laser beam from an oscillator. The second photodetector may generate a second feedback signal corresponding to a second portion of the laser beam filtered by a low-pass filter. The phase stabilizer may divide the frequency of the first feedback signal by a factor and generate an error signal corresponding to the difference between the frequency-divided first feedback signal and the second feedback signal. The optical modulator may modulate the laser beam within the oscillator corresponding to the error signal. The thermal control unit may change the temperature of the oscillator corresponding to a signal operable to control the optical modulator.

Integrating 360° behavior-orientated feedback in communication skills training for medical undergraduates: concept, acceptance and students' self-ratings of communication competence.

Science.gov (United States)

Engerer, Cosima; Berberat, Pascal O; Dinkel, Andreas; Rudolph, Baerbel; Sattel, Heribert; Wuensch, Alexander

2016-10-18

Feedback is considered a key didactic element in medical education, especially for teaching of communication skills. This study investigates the impact of a best evidence-based practice feedback concept within the context of communication skills training (CST). We evaluate this concept for acceptance and changes in students self-ratings of communication competence. Our CST integrating feedback process comprises a short theoretical introduction presenting standards for good communication and a constructive 360° feedback from three perspectives: feedback from peers, from standardized patients (SPs), and from a trainer. Feed-forward process was facilitated for documenting suggestions for improvements based on observable behaviors to maximize learning benefits. Our CST was applied to four groups of eight or nine students. We assessed the data on students' acceptance using a 6-point scale ranging from very good (1) to poor (6), applied a forced choice question to rank didactic items, and assessed changes in student' self-ratings of their communication competence on a 10-cm visual analogue scale (VAS). Thirty-four medical undergraduates (82 % female, 18 % male) in their first clinical year, with an average age of 21.4 years (SD = 1.0), participated in the new training. The concept achieved high acceptance from good to very good: overall impression (M = 1.56), sufficient interaction for discussion (M = 1.15), and constructive learning atmosphere (M = 1.18). Specific elements, such as practical training with SPs (M = 1.18) and feedback by SPs (M = 1.12), showed highest acceptance. The forced choice ranking placed all feedback elements at the top of the list (feedback (FB) by SPs, rank 2; FB by trainer, rank 3; FB by colleagues, rank 4), whereas theoretical elements were at the bottom (theoretical introduction, rank 7; memory card, rank 9). Overall, student self-ratings of communication competence significantly improved in nine of the ten

Haptically facilitated bimanual training combined with augmented visual feedback in moderate to severe hemiplegia.

Science.gov (United States)

Boos, Amy; Qiu, Qinyin; Fluet, Gerard G; Adamovich, Sergei V

2011-01-01

This study describes the design and feasibility testing of a hand rehabilitation system that provides haptic assistance for hand opening in moderate to severe hemiplegia while subjects attempt to perform bilateral hand movements. A cable-actuated exoskeleton robot assists the subjects in performing impaired finger movements but is controlled by movement of the unimpaired hand. In an attempt to combine the neurophysiological stimuli of bilateral movement and action observation during training, visual feedback of the impaired hand is replaced by feedback of the unimpaired hand, either by using a sagittaly oriented mirror or a virtual reality setup with a pair of virtual hands presented on a flat screen controlled with movement of the unimpaired hand, providing a visual image of their paretic hand moving normally. Joint angles for both hands are measured using data gloves. The system is programmed to maintain a symmetrical relationship between the two hands as they respond to commands to open and close simultaneously. Three persons with moderate to severe hemiplegia secondary to stroke trained with the system for eight, 30 to 60 minute sessions without adverse events. Each demonstrated positive motor adaptations to training. The system was well tolerated by persons with moderate to severe upper extremity hemiplegia. Further testing of its effects on motor ability with a broader range of clinical presentations is indicated.

Interspecific competition of early successional plant species in ex-arable fields as influenced by plant–soil feedback

NARCIS (Netherlands)

Jing, Y.; Bezemer, T.M.; Putten, van der W.H.

2015-01-01

Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from

Interspecific competition of early successional plant species in ex-arable fields as influenced by plant-soil feedback

NARCIS (Netherlands)

Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.

2015-01-01

Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from

Does Feedback Design Matter? A Neurofeedback Study Comparing Immersive Virtual Reality and Traditional Training Screens in Elderly

Directory of Open Access Journals (Sweden)

Silvia Erika Kober

2017-09-01

Full Text Available Neurofeedback (NF is a Brain-Computer Interface (BCI application, in which the brain activity is fed back to the user in real-time enabling voluntary brain control. In this context, the significance of the feedback design is mainly unexplored. Highly immersive feedback scenarios using virtual reality (VR technique are available. However, their effects on subjective user experience as well as on objective outcome measures remain open. In the present article, we discuss the general pros and cons of using VR as feedback modality in BCI applications. Furthermore, we report on the results of an empirical study, in which the effects of traditional two-dimensional and three-dimensional VR based feedback scenarios on NF training performance and user experience in healthy older individuals and neurologic patients were compared. In conclusion, we suggest indications and contraindications of immersive VR feedback designs in BCI applications. Our results show that findings in healthy individuals are not always transferable to patient populations having an impact on serious game and feedback design.

Z-transform description of feedback acting on a coupled beam

International Nuclear Information System (INIS)

Talman, R.

1993-01-01

The power of the formalism of digital control systems for the analysis and cure of accelerator instabilities is demonstrated. The Z-transform can be said to be even more appropriate for accelerators than it is for digital control circuits because a beam position monitor (BPM) is inherently restricted to sampling once per turn and there is no possibility of obtaining more nearly continuous-time performance by increasing the sampling rate. Also interactions of a beam bunch with a fixed structure in the accelerator can most accurately be described as a sampling process. The traditional formalisms of accelerator physics and digital control systems contain numerous results which can be seen to be the same after having deciphered the differences of terminology, but once that is done standard results from the theory of control system can be applied to accelerator problems. An important requirement is to describe the betatron motion by a difference equation-coupled motion requires a fourth order difference equation. These equations are handled easily by the Z-transform. In the analysis of servomechanisms with sampling elements the Z-transform plays the same role as does the Laplace transform L in the analysis of time-continuous servomechanisms. Just as feedback stabilization of analog circuits against instability can be achieved by adjusting the positions in the complex s plane of the poles of L(s), so also do the poles in the complex z plane of Z(z) have a similar interpretation in accelerators. An incidental dividend accompanying this approach is the mathematically satisfactory generalization of ''Courant-Snyder formalism'' to include damping

Vibrotactile Feedback for Brain-Computer Interface Operation

Directory of Open Access Journals (Sweden)

Febo Cincotti

2007-01-01

Full Text Available To be correctly mastered, brain-computer interfaces (BCIs need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrangements, was specified. In three studies with 33 subjects (including 3 with spinal cord injury, we compared vibrotactile and visual feedback, addressing: (I the feasibility of subjects' training to master their EEG rhythms using tactile feedback; (II the compatibility of this form of feedback in presence of a visual distracter; (III the performance in presence of a complex visual task on the same (visual or different (tactile sensory channel. The stimulation protocol we developed supports a general usage of the tactors; preliminary experimentations. All studies indicated that the vibrotactile channel can function as a valuable feedback modality with reliability comparable to the classical visual feedback. Advantages of using a vibrotactile feedback emerged when the visual channel was highly loaded by a complex task. In all experiments, vibrotactile feedback felt, after some training, more natural for both controls and SCI users.

The Effect of Concurrent Visual Feedback on Controlling Swimming Speed

Directory of Open Access Journals (Sweden)

Szczepan Stefan

2016-03-01

Full Text Available Introduction. Developing the ability to control the speed of swimming is an important part of swimming training. Maintaining a defined constant speed makes it possible for the athlete to swim economically at a low physiological cost. The aim of this study was to determine the effect of concurrent visual feedback transmitted by the Leader device on the control of swimming speed in a single exercise test. Material and methods. The study involved a group of expert swimmers (n = 20. Prior to the experiment, the race time for the 100 m distance was determined for each of the participants. In the experiment, the participants swam the distance of 100 m without feedback and with visual feedback. In both variants, the task of the participants was to swim the test distance in a time as close as possible to the time designated prior to the experiment. In the first version of the experiment (without feedback, the participants swam the test distance without receiving real-time feedback on their swimming speed. In the second version (with visual feedback, the participants followed a beam of light moving across the bottom of the swimming pool, generated by the Leader device. Results. During swimming with visual feedback, the 100 m race time was significantly closer to the time designated. The difference between the pre-determined time and the time obtained was significantly statistically lower during swimming with visual feedback (p = 0.00002. Conclusions. Concurrently transmitting visual feedback to athletes improves their control of swimming speed. The Leader device has proven useful in controlling swimming speed.

On the tip of the tongue: learning typing and pointing with an intra-oral computer interface.

Science.gov (United States)

Caltenco, Héctor A; Breidegard, Björn; Struijk, Lotte N S Andreasen

2014-07-01

To evaluate typing and pointing performance and improvement over time of four able-bodied participants using an intra-oral tongue-computer interface for computer control. A physically disabled individual may lack the ability to efficiently control standard computer input devices. There have been several efforts to produce and evaluate interfaces that provide individuals with physical disabilities the possibility to control personal computers. Training with the intra-oral tongue-computer interface was performed by playing games over 18 sessions. Skill improvement was measured through typing and pointing exercises at the end of each training session. Typing throughput improved from averages of 2.36 to 5.43 correct words per minute. Pointing throughput improved from averages of 0.47 to 0.85 bits/s. Target tracking performance, measured as relative time on target, improved from averages of 36% to 47%. Path following throughput improved from averages of 0.31 to 0.83 bits/s and decreased to 0.53 bits/s with more difficult tasks. Learning curves support the notion that the tongue can rapidly learn novel motor tasks. Typing and pointing performance of the tongue-computer interface is comparable to performances of other proficient assistive devices, which makes the tongue a feasible input organ for computer control. Intra-oral computer interfaces could provide individuals with severe upper-limb mobility impairments the opportunity to control computers and automatic equipment. Typing and pointing performance of the tongue-computer interface is comparable to performances of other proficient assistive devices, but does not cause fatigue easily and might be invisible to other people, which is highly prioritized by assistive device users. Combination of visual and auditory feedback is vital for a good performance of an intra-oral computer interface and helps to reduce involuntary or erroneous activations.

Commissioning of FPGA-based Transverse and Longitudinal Bunch-by-Bunch Feedback System for the TLS

International Nuclear Information System (INIS)

Hu, K. H.; Kuo, C. H.; Lau, W. K.; Yeh, M. S.; Hsu, S. Y.; Chou, P. J.; Wang, M. H.; Lee, Demi; Chen, Jenny; Wang, C. J.; Hsu, K. T.; Kobayashi, K.; Nakamura, T.; Dehler, M.

2006-01-01

Multi-bunch instabilities deteriorate beam quality, increasing beam emittance, or even causing beam loss in the synchrotron light source. The feedback system is essential to suppress multi-bunch instabilities caused by the impedances of beam ducts, and trapped ions. A new FPGA based transverse and longitudinal bunch-by-bunch feedback system have been commissioned at the Taiwan Light Source recently, A single feedback loop is used to simultaneously suppress the horizontal and the vertical multi-bunch instabilities. Longitudinal instabilities caused by cavity-like structures are suppressed by the longitudinal feedback loop. The same FPGA processor is employed in the transverse feedback and the longitudinal feedback system respectively. Diagnostic memory is included in the system to capture the bunch oscillation signal, which supports various studies

RF feedback simulation for the PEP-II B Factory

International Nuclear Information System (INIS)

Tighe, R.

1994-06-01

A model, of the beam and RF system for PEP-11 has been developed to allow both time-domain simulation and frequency-domain analysis of the complete system. The model includes the full set of feedback loops and nonlinear elements such as the beam and klystron. The model may be used to predict beam and feedback stability in the presence of nonlinearities through time-domain simulation as well as system frequency response about a given operating point

High Power Diode Lasers with External Feedback: Overview and Prospects

DEFF Research Database (Denmark)

Chi, Mingjun; Petersen, Paul Michael

2012-01-01

In summary, different external-cavity feedback techniques to improve the spatial beam quality and narrow the linewidth of the output beam from both BALs and TDLs are presented. Broad-area diode laser system with external-cavity feedback around 800 nm can produce several Watts of output power...... with a good beam quality. Tapered diode laser systems with external-cavity feedback around 800 and 1060 nm can deliver more than 2 W output power with diffraction-limited beam quality and can be operated in single-longitudinal mode. These high-brightness, narrow linewidth, and tunable external-cavity diode...... lasers emerge as the next generation of compact lasers that have the potential of replacing conventional high power laser systems in many existing applications....

Generalized fast feedback system in the SLC

International Nuclear Information System (INIS)

Hendrickson, L.; Allison, S.; Gromme, T.; Himel, T.; Krauter, K.; Rouse, F.; Sass, R.; Shoaee, H.

1991-11-01

A generalized fast feedback system has been developed to stabilize beams at various locations in the SLC. The system is designed to perform measurements and change actuator settings to control beam states such as position, angle and energy on a pulse to pulse basis. The software design is based on the state space formalism of digital control theory. The system is database-driven, facilitating the addition of new loops without requiring additional software. A communications system, KISNet, provides fast communications links between microprocessors for feedback loops which involve multiple micros. Feedback loops have been installed in seventeen locations throughout the SLC and have proven to be invaluable in stabilizing the machine

Positron emission tomography for the dose monitoring of intra-fractionally moving targets in ion beam therapy

International Nuclear Information System (INIS)

Stuetzer, Kristin

2014-01-01

Ion beam therapy (IBT) is a promising treatment option in radiotherapy. The characteristic physical and biological properties of light ion beams allow for the delivery of highly tumor conformal dose distributions. Related to the sparing of surrounding healthy tissue and nearby organs at risk, it is feasible to escalate the dose in the tumor volume to reach higher tumor control and survival rates. Remarkable clinical outcome was achieved with IBT for radio-resistant, deep-seated, static and well fixated tumor entities. Presumably, more patients could benefit from the advantages of IBT if it would be available for more frequent tumor sites. Those located in the thorax and upper abdominal region are commonly subjected to intra-fractional, respiration related motion. Different motion-compensated dose delivery techniques have been developed for active field shaping with scanned pencil beams and are at least available under experimental conditions at the GSI Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt, Germany. Since minor unexpected anatomical changes e.g. related to patient mispositioning, tumour shrinkage or tissue swelling could already lead to remarkable deviations between planned and delivered dose distribution, a valuable dose monitoring system is desired for IBT. So far, positron emission tomography (PET) is the only in vivo, in situ and non-invasive qualitative dose monitoring method applied under clinical conditions. Conclusions about the delivered dose distribution can be drawn indirectly from a comparison between two β + -activity distributions: the measured one and an expected one generated by a Monte-Carlo simulation. Dedicated phantoms mainly made up of polymethyl methacrylate (PMMA) and a motion table for regular one-dimensional (1D) motion patterns have been designed and manufactured for the experiments. Furthermore, the general applicability of the 4D MLEM algorithm for more complex motion patterns has been demonstrated by the

Feedback reliability calculation for an iterative block decision feedback equalizer

OpenAIRE

Huang, G; Nix, AR; Armour, SMD

2009-01-01

A new class of iterative block decision feedback equalizer (IB-DFE) was pioneered by Chan and Benvenuto. Unlike the conventional DFE, the IB-DFE is optimized according to the reliability of the feedback (FB) symbols. Since the use of the training sequence (TS) for feedback reliability (FBR) estimation lowers the bandwidth efficiency, FBR estimation without the need for additional TS is of considerable interest. However, prior FBR estimation is limited in the literature to uncoded M-ary phases...

Single mode solid state distributed feedback dye laser fabricated by grey scale electron beam lithography on dye doped SU-8 resist

DEFF Research Database (Denmark)

Balslev, Søren; Rasmussen, Torben; Shi, Peixiong

2005-01-01

We demonstrate grey scale electron beam lithography on functionalized SU-8 resist for fabrication of single mode solid state dye laser devices. The resist is doped with Rhodamine 6G perchlorate and the lasers are based on a first order Bragg grating distributed feedback resonator. The lasers...

Self-tracking optical beam monitor

International Nuclear Information System (INIS)

Miyahara, T.; Mitsuhashi, T.

1992-01-01

A new optical beam monitor with a self-tracking system was constructed and tested at an undulator beam line of the Photon Factory. The monitor has a feedback system to receive a constant part of the radiation and gives a large range of linearity. The beam position is read out through a linear encoder to detect the self-tracking movement of a pair of photocathodes. The monitor except the feedback system is totally bakeable and UHV compatible and can be installed at a VUV or a soft x-ray beam line

Beam-beam effects under the influence of external noise

International Nuclear Information System (INIS)

Ohmi, K

2014-01-01

Fast external noise, which gives fluctuation into the beam orbit, is discussed in connection with beam-beam effects. Phase noise from crab cavities and detection devices (position monitor) and kicker noise from the bunch by bunch feedback system are the sources. Beam-beam collisions with fast orbit fluctuations with turn by turn or multi-turn correlations, cause emittance growth and luminosity degradation. We discuss the tolerance of the noise amplitude for LHC and HL-LHC

The Effects of Training, Feedback, and Participant Involvement in Behavioral Safety Observations on Office Ergonomic Behavior

Science.gov (United States)

Sasson, Joseph R.; Austin, John

2005-01-01

Eleven computer terminal operators participated in an experiment that assessed effects of several interventions aimed at increasing safe ergonomic performance. All participants received ergonomics training and performance feedback while six of them collected observations of safe behavior among the remaining five participants. Effects of…

Noisy visual feedback training impairs detection of self-generated movement error: implications for anosognosia for hemiplegia

Directory of Open Access Journals (Sweden)

Catherine ePreston

2014-06-01

Full Text Available Anosognosia for hemiplegia (AHP is characterised as a disorder in which patients are unaware of their contralateral motor deficit. Many current theories for unawareness in AHP are based on comparator model accounts of the normal experience of agency. According to such models, while small mismatches between predicted and actual feedback allow unconscious fine-tuning of normal actions, mismatches that surpass an inherent threshold reach conscious awareness and inform judgements of agency (whether a given movement is produced by the self or another agent. This theory depends on a threshold for consciousness that is greater than the intrinsic noise in the system to reduce the occurrence of incorrect rejections of self-generated movements and maintain a fluid experience of agency. Pathological increases to this threshold could account for reduced motor awareness following brain injury, including AHP. The current experiment tested this hypothesis in healthy controls by exposing them to training in which noise was applied the visual feedback of their normal reaches. Subsequent self/other attribution tasks without noise revealed a decrease in the ability to detect manipulated (other feedback compared to training without noise. This suggests a slackening of awareness thresholds in the comparator model that may help to explain clinical observations of decreased action awareness following stroke.

Rf beam loading in the Brookhaven AGS with booster injection

International Nuclear Information System (INIS)

Zhang, S.Y.; Raka, E.; Weng, W.T.

1992-01-01

Multi-batch bunched beam loading during injection from the Booster to the AGS will be discussed. The full intensity beam injection to the upgraded AGS rf system with beam phase and radial feedbacks will be studied. It is shown that a beam phase feedback is necessary in order to guarantee a predictable hewn behavior after the first batch injection, otherwise the initial phase deviation for the following batch injections cannot be controlled. However, the effectiveness of the phase feedback control of the transient beam loading may be limited by an emittance blow up in the process. It is shown that a fast power amplifier feedback with a moderate gain can significantly reduce the transient effect of the bunched beam injection

Modeling the interaction of a heavily beam loaded SRF cavity with its low-level RF feedback loops

Science.gov (United States)

Liu, Zong-Kai; Wang, Chaoen; Chang, Lung-Hai; Yeh, Meng-Shu; Chang, Fu-Yu; Chang, Mei-Hsia; Chang, Shian-Wen; Chen, Ling-Jhen; Chung, Fu-Tsai; Lin, Ming-Chyuan; Lo, Chih-Hung; Yu, Tsung-Chi

2018-06-01

A superconducting radio frequency (SRF) cavity provides superior stability to power high intensity light sources and can suppress coupled-bunch instabilities due to its smaller impedance for higher order modes. Because of these features, SRF cavities are commonly used for modern light sources, such as the TLS, CLS, DLS, SSRF, PLS-II, TPS, and NSLS-II, with an aggressive approach to operate the light sources at high beam currents. However, operating a SRF cavity at high beam currents may result with unacceptable stability problems of the low level RF (LLRF) system, due to drifts of the cavity resonant frequency caused by unexpected perturbations from the environment. As the feedback loop gets out of control, the cavity voltage may start to oscillate with a current-dependent characteristic frequency. Such situations can cause beam abort due to the activation of the interlock protection system, i.e. false alarm of quench detection. This malfunction of the light source reduces the reliability of SRF operation. Understanding this unstable mechanism to prevent its appearance becomes a primary task in the pursuit of highly reliable SRF operation. In this paper, a Pedersen model, including the response of the LLRF system, was used to simulate the beam-cavity interaction of a SRF cavity under heavy beam loading. Causes for the onset of instability at high beam current will be discussed as well as remedies to assure the design of a stable LLRF system.

De kunst van goede feedback : Training voor effectieve peerfeedback

NARCIS (Netherlands)

Lindner, Jorieke

Het is in het onderwijs belangrijk om op een effectieve manier feedback te geven op uitgevoerde opdrachten. Studenten kunnen deze feedback gebruiken om hun vaardigheden te verbeteren en zo gericht een doelniveau bereiken. Traditioneel geeft vooral de docent feedback, maar ook feedback van

Individualized exergame training improves postural control in advanced degenerative spinocerebellar ataxia: A rater-blinded, intra-individually controlled trial.

Science.gov (United States)

Schatton, Cornelia; Synofzik, Matthis; Fleszar, Zofia; Giese, Martin A; Schöls, Ludger; Ilg, Winfried

2017-06-01

Treatment options are rare in degenerative ataxias, especially in advanced, multisystemic disease. Exergame training might offer a novel treatment strategy, but its effectiveness has not been investigated in advanced stages. We examined the effectiveness of a 12-week home-based training with body-controlled videogames in 10 young subjects with advanced degenerative ataxia unable or barely able to stand. Training was structured in two 6-weeks phases, allowing to adapt the training according to individual training progress. Rater-blinded clinical assessment (Scale for the Assessment and Rating of Ataxia; SARA), individual goal-attainment scoring (GAS), and quantitative movement analysis were performed two weeks before training, immediately prior to training, and after training phases 1 and 2 (intra-individual control design). This study is registered with ClinicalTrials.gov, NCT02874911). After intervention, ataxia symptoms were reduced (SARA -2.5 points, p training (p = 0.04). Goal attainment during daily living was higher than expected (GAS: 0.45). Movement analysis revealed reduced body sway while sitting (p training-induced improvements in posture control mechanisms. This study provides first evidence that, even in advanced stages, subjects with degenerative ataxia may benefit from individualized training, with effects translating into daily living and improving underlying control mechanisms. The proposed training strategy can be performed at home, is motivating and facilitates patient self-empowerment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interactive balance training integrating sensor-based visual feedback of movement performance: a pilot study in older adults

OpenAIRE

Schwenk, Michael; Grewal, Gurtej S; Honarvar, Bahareh; Schwenk, Stefanie; Mohler, Jane; Khalsa, Dharma S; Najafi, Bijan

2014-01-01

Background Wearable sensor technology can accurately measure body motion and provide incentive feedback during exercising. The aim of this pilot study was to evaluate the effectiveness and user experience of a balance training program in older adults integrating data from wearable sensors into a human-computer interface designed for interactive training. Methods Senior living community residents (mean age 84.6) with confirmed fall risk were randomized to an intervention (IG, n?=?17) or contro...

Generalized fast feedback system in the SLC

International Nuclear Information System (INIS)

Hendrickson, L.; Allison, S.; Gromme, T.; Himel, T.; Krauter, K.; Rouse, F.; Sass, R.; Shoaee, H.

1992-01-01

A generalized fast feedback system has been developed to stabilize beams at various locations in the SLC. The system is designed to perform measurements and change actuator settings to control beam states such as position, angle and energy on a pulse to pulse basis. The software design is based on the state space formalism of digital control theory. The system is database-driven, facilitating the addition of new loops without requiring additional software. A communications system, KISNet, provides fast communications links between microprocessors for feedback loops which involve multiple micros. Feedback loops have been installed in seventeen locations throughout the SLC and have proven to be invaluable in stabilizing the machine. (author)

Operation of the transverse feedback system at the CERN SPS

International Nuclear Information System (INIS)

Bossart, R.; Louwerse, R.; Mourier, J.; Vos, L.

1987-01-01

To prevent transverse instabilities at high beam intensity in the SPS, the transverse feedback system for damping the betatron oscillations has been upgraded for larger damping decrements and for increased system's bandwidth. The feedback loop now contains a digital delay line cancellor, so that the damper works with a velocity feedback Δx/Δt, unaffected by the closed orbit position x at the pick-up station. The digital processing of the feedback signal facilitates nonlinear feedback techniques such as antidamping and ''band-bang'' feedback. The ''bang-bang'' feedback provides the maximum possible damping rate of the injection oscillations in the SPS-collider, in order to minimize the emittance increase caused by filamentation. The antidamping nonlinearity provides small continuous beam oscillations of 50 μm amplitude for tracking the machine tune Q with a phase locked loop

Physician performance feedback in a Canadian academic center.

Science.gov (United States)

Garvin, Dennis; Worthington, James; McGuire, Shaun; Burgetz, Stephanie; Forster, Alan J; Patey, Andrea; Gerin-Lajoie, Caroline; Turnbull, Jeffrey; Roth, Virginia

2017-10-02

Purpose This paper aims at the implementation and early evaluation of a comprehensive, formative annual physician performance feedback process in a large academic health-care organization. Design/methodology/approach A mixed methods approach was used to introduce a formative feedback process to provide physicians with comprehensive feedback on performance and to support professional development. This initiative responded to organization-wide engagement surveys through which physicians identified effective performance feedback as a priority. In 2013, physicians primarily affiliated with the organization participated in a performance feedback process, and physician satisfaction and participant perceptions were explored through participant survey responses and physician leader focus groups. Training was required for physician leaders prior to conducting performance feedback discussions. Findings This process was completed by 98 per cent of eligible physicians, and 30 per cent completed an evaluation survey. While physicians endorsed the concept of a formative feedback process, process improvement opportunities were identified. Qualitative analysis revealed the following process improvement themes: simplify the tool, ensure leaders follow process, eliminate redundancies in data collection (through academic or licensing requirements) and provide objective quality metrics. Following physician leader training on performance feedback, 98 per cent of leaders who completed an evaluation questionnaire agreed or strongly agreed that the performance feedback process was useful and that training objectives were met. Originality/value This paper introduces a physician performance feedback model, leadership training approach and first-year implementation outcomes. The results of this study will be useful to health administrators and physician leaders interested in implementing physician performance feedback or improving physician engagement.

Successful Beam-Beam Tuneshift Compensation

Energy Technology Data Exchange (ETDEWEB)

Bishofberger, Kip Aaron [Univ. of California, Los Angeles, CA (United States)

2005-01-01

The performance of synchrotron colliders has been limited by the beam-beam limit, a maximum tuneshift that colliding bunches could sustain. Due to bunch-to-bunch tune variation and intra-bunch tune spread, larger tuneshifts produce severe emittance growth. Breaking through this constraint has been viewed as impossible for several decades. This dissertation introduces the physics of ultra-relativistic synchrotrons and low-energy electron beams, with emphasis placed on the limits of the Tevatron and the needs of a tuneshift-compensation device. A detailed analysis of the Tevatron Electron Lens (T_EL) is given, comparing theoretical models to experimental data whenever possible. Finally, results of Tevatron operations with inclusion of the T_EL are presented and analyzed. It is shown that the T_EL provides a way to shatter the previously inescapable beam-beam limit.

SU-E-J-82: Intra-Fraction Proton Beam-Range Verification with PET Imaging: Feasibility Studies with Monte Carlo Simulations and Statistical Modeling

Energy Technology Data Exchange (ETDEWEB)

Lou, K [U.T M.D. Anderson Cancer Center, Houston, TX (United States); Rice University, Houston, TX (United States); Mirkovic, D; Sun, X; Zhu, X; Poenisch, F; Grosshans, D; Shao, Y [U.T M.D. Anderson Cancer Center, Houston, TX (United States); Clark, J [Rice University, Houston, TX (United States)

2014-06-01

Purpose: To study the feasibility of intra-fraction proton beam-range verification with PET imaging. Methods: Two phantoms homogeneous cylindrical PMMA phantoms (290 mm axial length, 38 mm and 200 mm diameter respectively) were studied using PET imaging: a small phantom using a mouse-sized PET (61 mm diameter field of view (FOV)) and a larger phantom using a human brain-sized PET (300 mm FOV). Monte Carlo (MC) simulations (MCNPX and GATE) were used to simulate 179.2 MeV proton pencil beams irradiating the two phantoms and be imaged by the two PET systems. A total of 50 simulations were conducted to generate 50 positron activity distributions and correspondingly 50 measured activity-ranges. The accuracy and precision of these activity-ranges were calculated under different conditions (including count statistics and other factors, such as crystal cross-section). Separate from the MC simulations, an activity distribution measured from a simulated PET image was modeled as a noiseless positron activity distribution corrupted by Poisson counting noise. The results from these two approaches were compared to assess the impact of count statistics on the accuracy and precision of activity-range calculations. Results: MC Simulations show that the accuracy and precision of an activity-range are dominated by the number (N) of coincidence events of the reconstructed image. They are improved in a manner that is inversely proportional to 1/sqrt(N), which can be understood from the statistical modeling. MC simulations also indicate that the coincidence events acquired within the first 60 seconds with 10{sup 9} protons (small phantom) and 10{sup 10} protons (large phantom) are sufficient to achieve both sub-millimeter accuracy and precision. Conclusion: Under the current MC simulation conditions, the initial study indicates that the accuracy and precision of beam-range verification are dominated by count statistics, and intra-fraction PET image-based beam-range verification is

Beam loading

OpenAIRE

Boussard, Daniel

1987-01-01

We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superco...

The Effectiveness of Internet-Based Peer Feedback Training on Chinese EFL College Students' Writing Proficiency

Science.gov (United States)

Jiang, Jiahong; Yu, Yibing

2014-01-01

English writing, an indispensable skill in English learning, plays an important role in improving learners' language proficiency. With the wide spread and use of wired or wireless internet, EFL students can easily help and be helped with English writing. Therefore, the application of internet-based peer feedback training on writing to foreign or…

Daresbury SRS Positional Feedback Systems

CERN Document Server

Smith, S L

2000-01-01

The Daresbury SRS is a second generation synchrotron radiation source which ramps from its injection energy of 600 MeV to 2.0 GeV. Beam orbit feedback systems have been in routine operation on the SRS since 1994 and are now an essential element in delivering stable photon beams to experimental stations. The most recent enhancements to these systems have included the introduction of a ramp servo system to provide the orbit control demanded by the installation of two new narrow gap insertion device and development of the vertical orbit feedback system to cope with an increasing number of photon beamlines. This paper summaries the current status of these systems and briefly discusses proposed developments.

'Peer feedback' voor huisartsopleiders

NARCIS (Netherlands)

Damoiseaux, R A M J; Truijens, L

2016-01-01

In medical specialist training programmes it is common practice for residents to provide feedback to their medical trainers. The problem is that due to its anonymous nature, the feedback often lacks the specificity necessary to improve the performance of trainers. If anonymity is to be abolished,

Klystron equalization for RF feedback

International Nuclear Information System (INIS)

Corredoura, P.

1993-01-01

The next generation of colliding beam storage rings support higher luminosities by significantly increasing the number of bunches and decreasing the spacing between respective bunches. The heavy beam loading requires large RF cavity detuning which drives several lower coupled bunch modes very strongly. One technique which has proven to be very successful in reducing the coupled bunch mode driving impedance is RF feedback around the klystron-cavity combination. The gain and bandwidth of the feedback loop is limited by the group delay around the feedback loop. Existing klystrons on the world market have not been optimized for this application and contribute a large portion of the total loop group delay. This paper describes a technique to reduce klystron group delay by adding an equalizing filter to the klystron RF drive. Such a filter was built and tested on a 500 kill klystron as part of the on going PEP-II R ampersand D effort here at SLAC

Auditory feedback improves heart rate moderation during moderate-intensity exercise.

Science.gov (United States)

Shaykevich, Alex; Grove, J Robert; Jackson, Ben; Landers, Grant J; Dimmock, James

2015-05-01

The objective of this study is to determine whether exposure to automated HR feedback can produce improvements in the ability to regulate HR during moderate-intensity exercise and to evaluate the persistence of these improvements after feedback is removed. Twenty healthy adults performed 10 indoor exercise sessions on cycle ergometers over 5 wk after a twice-weekly schedule. During these sessions (FB), participants received auditory feedback designed to maintain HR within a personalized, moderate-intensity training zone between 70% and 80% of estimated maximum HR. All feedback was delivered via a custom mobile software application. Participants underwent an initial assessment (PREFB) to measure their ability to maintain exercise intensity defined by the training zone without use of feedback. After completing the feedback training, participants performed three additional assessments identical to PREFB at 1 wk (POST1), 2 wk (POST2), and 4 wk (POST3) after their last feedback session. Time in zone (TIZ), defined as the ratio of the time spent within the training zone divided by the overall time of exercise, rate of perceived exertion, instrumental attitudes, and affective attitudes were then evaluated to assess results using two-way, mixed-model ANOVA with sessions and gender as factors. Training with feedback significantly improved TIZ (P moderate-intensity exercise in healthy adults.

Impact of real-time fMRI working memory feedback training on the interactions between three core brain networks.

Science.gov (United States)

Zhang, Qiushi; Zhang, Gaoyan; Yao, Li; Zhao, Xiaojie

2015-01-01

Working memory (WM) refers to the temporary holding and manipulation of information during the performance of a range of cognitive tasks, and WM training is a promising method for improving an individual's cognitive functions. Our previous work demonstrated that WM performance can be improved through self-regulation of dorsal lateral prefrontal cortex (PFC) activation using real-time functional magnetic resonance imaging (rtfMRI), which enables individuals to control local brain activities volitionally according to the neurofeedback. Furthermore, research concerning large-scale brain networks has demonstrated that WM training requires the engagement of several networks, including the central executive network (CEN), the default mode network (DMN) and the salience network (SN), and functional connectivity within the CEN and DMN can be changed by WM training. Although a switching role of the SN between the CEN and DMN has been demonstrated, it remains unclear whether WM training can affect the interactions between the three networks and whether a similar mechanism also exists during the training process. In this study, we investigated the dynamic functional connectivity between the three networks during the rtfMRI feedback training using independent component analysis (ICA) and correlation analysis. The results indicated that functional connectivity within and between the three networks were significantly enhanced by feedback training, and most of the changes were associated with the insula and correlated with behavioral improvements. These findings suggest that the insula plays a critical role in the reorganization of functional connectivity among the three networks induced by rtfMRI training and in WM performance, thus providing new insights into the mechanisms of high-level functions and the clinical treatment of related functional impairments.

Peer-Feedback-Aufgaben in der Übersetzerausbildung

DEFF Research Database (Denmark)

Heine, Carmen

. Peer Feedback Dialog mit TAPs und retrospektivem Interview oder Peer Feedback mit integriertem Selbstbeobachtungsprotokoll) für zukünftige, didaktische Feedbackansätze im Übersetzungsunterricht. Literatur Flanagan, M., & Heine, C. (2015). Peer-feedback as a Translation Training Tool in Web......-based Communication. Hermes, 54, 115-136. Lindgren, E., Sullivan, K., P. H., Deutschmann, M., & Steinvall, A. (2009). Supporting Learner Reflection in the Language Translation Class. International Journal of Information Communication Technologies and Human Development (IJICTHD), 1(3), 26-48. Wang, K., & Han, C. (2013......). Accomplishment in the multitude of counsellors: Peer feedback in translation training. Translation & Interpreting, 5(2), 62-75....

LFSC - Linac Feedback Simulation Code

Energy Technology Data Exchange (ETDEWEB)

Ivanov, Valentin; /Fermilab

2008-05-01

The computer program LFSC (Feedback Simulation Code>) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output.

Virtual Proprioception for eccentric training.

Science.gov (United States)

LeMoyne, Robert; Mastroianni, Timothy

2017-07-01

Wireless inertial sensors enable quantified feedback, which can be applied to evaluate the efficacy of therapy and rehabilitation. In particular eccentric training promotes a beneficial rehabilitation and strength training strategy. Virtual Proprioception for eccentric training applies real-time feedback from a wireless gyroscope platform enabled through a software application for a smartphone. Virtual Proprioception for eccentric training is applied to the eccentric phase of a biceps brachii strength training and contrasted to a biceps brachii strength training scenario without feedback. During the operation of Virtual Proprioception for eccentric training the intent is to not exceed a prescribed gyroscope signal threshold based on the real-time presentation of the gyroscope signal, in order to promote the eccentric aspect of the strength training endeavor. The experimental trial data is transmitted wireless through connectivity to the Internet as an email attachment for remote post-processing. A feature set is derived from the gyroscope signal for machine learning classification of the two scenarios of Virtual Proprioception real-time feedback for eccentric training and eccentric training without feedback. Considerable classification accuracy is achieved through the application of a multilayer perceptron neural network for distinguishing between the Virtual Proprioception real-time feedback for eccentric training and eccentric training without feedback.

Sonification and haptic feedback in addition to visual feedback enhances complex motor task learning.

Science.gov (United States)

Sigrist, Roland; Rauter, Georg; Marchal-Crespo, Laura; Riener, Robert; Wolf, Peter

2015-03-01

Concurrent augmented feedback has been shown to be less effective for learning simple motor tasks than for complex tasks. However, as mostly artificial tasks have been investigated, transfer of results to tasks in sports and rehabilitation remains unknown. Therefore, in this study, the effect of different concurrent feedback was evaluated in trunk-arm rowing. It was then investigated whether multimodal audiovisual and visuohaptic feedback are more effective for learning than visual feedback only. Naïve subjects (N = 24) trained in three groups on a highly realistic virtual reality-based rowing simulator. In the visual feedback group, the subject's oar was superimposed to the target oar, which continuously became more transparent when the deviation between the oars decreased. Moreover, a trace of the subject's trajectory emerged if deviations exceeded a threshold. The audiovisual feedback group trained with oar movement sonification in addition to visual feedback to facilitate learning of the velocity profile. In the visuohaptic group, the oar movement was inhibited by path deviation-dependent braking forces to enhance learning of spatial aspects. All groups significantly decreased the spatial error (tendency in visual group) and velocity error from baseline to the retention tests. Audiovisual feedback fostered learning of the velocity profile significantly more than visuohaptic feedback. The study revealed that well-designed concurrent feedback fosters complex task learning, especially if the advantages of different modalities are exploited. Further studies should analyze the impact of within-feedback design parameters and the transferability of the results to other tasks in sports and rehabilitation.

An analysis of beam parameters on proton-acoustic waves through an analytic approach.

Science.gov (United States)

Kipergil, Esra Aytac; Erkol, Hakan; Kaya, Serhat; Gulsen, Gultekin; Unlu, Mehmet Burcin

2017-06-21

It has been reported that acoustic waves are generated when a high-energy pulsed proton beam is deposited in a small volume within tissue. One possible application of proton-induced acoustics is to get real-time feedback for intra-treatment adjustments by monitoring such acoustic waves. A high spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution for the proton-induced acoustic wave is presented to reveal the dependence of the signal on the beam parameters; then it is combined with an analytic approximation of the Bragg curve. The influence of the beam energy, pulse duration and beam diameter variation on the acoustic waveform are investigated. Further analysis is performed regarding the Fourier decomposition of the proton-acoustic signals. Our results show that the smaller spill time of the proton beam upsurges the amplitude of the acoustic wave for a constant number of protons, which is hence beneficial for dose monitoring. The increase in the energy of each individual proton in the beam leads to the spatial broadening of the Bragg curve, which also yields acoustic waves of greater amplitude. The pulse duration and the beam width of the proton beam do not affect the central frequency of the acoustic wave, but they change the amplitude of the spectral components.

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized trial.

Science.gov (United States)

Strandbygaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde; Winkel, Per; Larsen, Christian Rifbjerg; Ringsted, Charlotte; Gluud, Christian; Grantcharov, Teodor; Ottesen, Bent; Sorensen, Jette Led

2013-05-01

To investigate the impact of instructor feedback versus no instructor feedback when training a complex operational task on a laparoscopic virtual reality simulator. : Simulators are now widely accepted as a training tool, but there is insufficient knowledge about how much feedback is necessary, which is useful for sustainable implementation. A randomized trial complying with CONSORT Statement. All participants had to reach a predefined proficiency level for a complex operational task on a virtual reality simulator. The intervention group received standardized instructor feedback a maximum of 3 times. The control group did not receive instructor feedback. Participants were senior medical students without prior laparoscopic experience (n = 99). Outcome measures were time, repetitions, and performance score to reach a predefined proficiency level. Furthermore, influence of sex and perception of own surgical skills were examined. Time (in minutes) and repetitions were reduced in the intervention group (162 vs 342 minutes; P less time (in minutes) than women (P = 0.037), but no sex difference was observed for repetitions (P = 0.20). Participants in the intervention group had higher self-perception regarding surgical skills after the trial (P = 0.011). Instructor feedback increases the efficiency when training a complex operational task on a virtual reality simulator; time and repetitions used to achieve a predefined proficiency level were significantly reduced in the group that received instructor feedback compared with the control group. NCT01497782.

COMMISSIONING OF THE DIGITAL TRANSVERSE BUNCH-BY-BUNCH FEEDBACK SYSTEM FOR THE TLS

International Nuclear Information System (INIS)

HU, K.H.; KUO, C.H.; CHOU, P.J.; LEE, D.; HSU, S.Y.; CHEN, J.; WANG, C.J.; HSU, K.T.; KOBAYASHI, K.; NAKAMURA, T.; CHAO, A.W.; WENG, W.T.

2006-01-01

Multi-bunch instabilities degrade beam quality through increased beam emittance, energy spread and even beam loss. Feedback systems are used to suppress multi-bunch instabilities associated with the resistive wall of the beam ducts, cavity-like structures, and trapped ions. A new digital transverse bunch-by-bunch feedback system has recently been commissioned at the Taiwan Light Source, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance and improves damping for transverse instability at high currents, such that top-up operation is achieved. After a coupled-bunch transverse instability was suppressed, more than 350 mA was successfully stored during preliminary commissioning. In this new system, a single feedback loop simultaneously suppresses both horizontal and vertical multi-bunch instabilities. Investigating the characteristics of the feedback loop and further improving the system performances are the next short-term goals. The feedback system employs the latest generation of field-programmable gate array (FPGA) processor to process bunch signals. Memory has been installed to capture up to 250 msec of bunch oscillation signal, considering system diagnostics suitable to support various beam physics studies

Amount of kinematic feedback affects learning of speech motor skills.

Science.gov (United States)

Ballard, Kirrie J; Smith, Heather D; Paramatmuni, Divija; McCabe, Patricia; Theodoros, Deborah G; Murdoch, Bruce E

2012-01-01

Knowledge of Performance (KP) feedback, such as biofeedback or kinematic feedback, is used to provide information on the nature and quality of movement responses for the purpose of guiding active learning or rehabilitation of motor skills. It has been proposed that KP feedback may interfere with long-term learning when provided throughout training. Here, twelve healthy English-speaking adults were trained to produce a trilled Russian [r] in words with KP kinematic feedback using electropalatography (EPG) and without KP (noKP). Five one-hour training sessions were provided over one week with testing pretraining and one day and one week posttraining. No group differences were found at pretraining or one day post training for production accuracy. A group by time interaction supported the hypothesis that providing kinematic feedback continually during skill acquisition interferes with retention.

Electroencephalogy (EEG) Feedback in Decision-Making

Science.gov (United States)

2015-08-26

Electroencephalogy ( EEG ) Feedback In Decision- Making The goal of this project is to investigate whether Electroencephalogy ( EEG ) can provide useful...feedback when training rapid decision-making. More specifically, EEG will allow us to provide online feedback about the neural decision processes...Electroencephalogy ( EEG ) Feedback In Decision-Making Report Title The goal of this project is to investigate whether Electroencephalogy ( EEG ) can provide useful

Autogenic-feedback training: A potential treatment for post-flight orthostatic intolerance in aerospace crews

Science.gov (United States)

Cowings, Patricia S.; Toscano, William B.; Miller, Neil E.; Pickering, Thomas G.; Shapiro, David

1993-01-01

Postflight orthostatic intolerance was identified as a serious biomedical problem associated with long duration exposure to microgravity in space. High priority was given to the development of countermeasures for this disorder which are both effective and practical. A considerable body of clinical research demonstrated that people can be taught to increase their own blood pressure voluntarily and that this is an effective treatment for chronic orthostatic intolerance in paralyzed patients. The present pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using an operant conditioning procedure, Autogenic-Feedback Training (AFT), three men and two women participated in four to nine (15-30 training sessions). At the end of training, the average increase in systolic and diastolic pressure, as well as mean arterial pressures that the subjects made, ranged between 20 and 5O mmHg under both supine and 45 deg head-up tilt conditions. These findings suggest that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight orthostatic intolerance. Further, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanisms of orthostatic intolerance.

An audiovisual feedback device for compression depth, rate and complete chest recoil can improve the CPR performance of lay persons during self-training on a manikin

International Nuclear Information System (INIS)

Krasteva, Vessela; Jekova, Irena; Didon, Jean-Philippe

2011-01-01

This study aims to contribute to the scarce data available about the abilities of untrained lay persons to perform hands-only cardio-pulmonary resuscitation (CPR) on a manikin and the improvement of their skills during training with an autonomous CPR feedback device. The study focuses on the following questions: (i) Is there a need for such a CPR training device? (ii) How adequate are the embedded visual feedback and audio guidance for training of lay persons who learn and correct themselves in real time without instructor guidance? (iii) What is the achieved effect of only 3 min of training? This is a prospective study in which 63 lay persons (volunteers) received a debriefing to basic life support and then performed two consecutive 3 min trials of hands-only CPR on a manikin. The pre-training skills of the lay persons were tested in trial 1. The training process with audio guidance and visual feedback from a cardio compression control device (CC-Device) was recorded in trial 2. After initial debriefing for correct chest compressions (CC) with rate 85–115 min −1 , depth 3.8–5.4 cm and complete recoil, in trial 1 the lay persons were able to perform CC without feedback at mean rate 95.9 ± 18.9 min −1 , mean depth 4.13 ± 1.5 cm, with low proportions of 'correct depth', 'correct rate' and 'correct recoil' at 33%, 43%, 87%, resulting in the scarce proportion of 14% for compressions, which simultaneously fulfill the three quality criteria ('correct all'). In trial 2, the training process by the CC-Device was established by the significant improvement of the CC skills until the 60th second of training, when 'correct depth', 'correct rate' and 'correct recoil' attained the plateau of the highest quality at 82%, 90%, 96%, respectively, resulting in 73% 'correct all' compressions within 3 min of training. The training was associated with reduced variance of the mean rate 102.4 ± 4

Feedback is good or bad? Medical residents’ points of view on feedback in clinical education

Directory of Open Access Journals (Sweden)

LEILA BAZRAFKAN

2013-04-01

Full Text Available Introduction: Feedback is very important in education and can help quality in the training process and orient the trainees in clinical contexts. This study aimed to assess the residents’ points of view about feedback in clinical education at Shiraz University of Medical Sciences. Methods: The sample of this study included 170 medical residents attending medical workshops in Shiraz University of Medical Sciences. The residents filled a valid and reliable questionnaire containing 21 items on their perceptions of the feedback they got throughout the workshops. The data were analyzed using SPSS version 14. Results: The study revealed that residents, generally, have a positive perception of feedback in their training. The highest score belonged to the items such as “feedback was applicable to future work”, “feedback corrected my behavior”, “feedback worked as a motivation for education” and “feedback was specific in one subject”. Residents who had a negative feedback experience also increased their efforts to learn. The Surgery residents acquired the highest scores while radiology residents got the lowest. The difference between these groups was statistically significant (P = 0.000. Conclusion: The highest mean score belonged to internal medicine residents. This shows that residents believe that obstetrics & gynecology ward is a ward in which the formative assessment is much more powerful in comparison to the other three major wards. The surgery ward received the lowest score for formative assessment and this shows that the feedback in surgery ward is very low.

Is transverse feedback necessary for the SSC emittance preservation? (Vibration noise analysis and feedback parameters optimization)

International Nuclear Information System (INIS)

Parkhomchuk, V.V.; Shiltsev, V.D.

1993-06-01

The paper considers the Superconducting Super Collider (SSC) site ground motion measurements as well as data from accelerators worldwide about noises that worsen beam performance. Unacceptably fast emittance growth due to these noises is predicted for the SSC. A transverse feedback system was found to be the only satisfactory alternative to prevent emittance decay. Optimization of the primary feedback parameters was done

Efficacy of home-based visuomotor feedback training in stroke patients with chronic hemispatial neglect.

Science.gov (United States)

Rossit, Stéphanie; Benwell, Christopher S Y; Szymanek, Larissa; Learmonth, Gemma; McKernan-Ward, Laura; Corrigan, Elaine; Muir, Keith; Reeves, Ian; Duncan, George; Birschel, Philip; Roberts, Margaret; Livingstone, Katrina; Jackson, Hazel; Castle, Pauline; Harvey, Monika

2017-01-24

Hemispatial neglect is a severe cognitive condition frequently observed after a stroke, associated with unawareness of one side of space, disability and poor long-term outcome. Visuomotor feedback training (VFT) is a neglect rehabilitation technique that involves a simple, inexpensive and feasible training of grasping-to-lift rods at the centre. We compared the immediate and long-term effects of VFT vs. a control training when delivered in a home-based setting. Twenty participants were randomly allocated to an intervention (who received VFT) or a control group (n = 10 each). Training was delivered for two sessions by an experimenter and then patients self-administered it for 10 sessions over two weeks. Outcome measures included the Behavioural Inattention Test (BIT), line bisection, Balloons Test, Landmark task, room description task, subjective straight-ahead pointing task and the Stroke Impact Scale. The measures were obtained before, immediately after the training sessions and after four-months post-training. Significantly greater short and long-term improvements were obtained after VFT when compared to control training in line bisection, BIT and spatial bias in cancellation. VFT also produced improvements on activities of daily living. We conclude that VFT is a feasible, effective, home-based rehabilitation method for neglect patients that warrants further investigation with well-designed randomised controlled trials on a large sample of patients.

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator

DEFF Research Database (Denmark)

Oestergaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde

2012-01-01

of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational...

A Potential Treatment for Post-Flight Orthostatic Intolerance in Aero-Space Crews: Autogenic-Feedback Training

Science.gov (United States)

Cowings, P. S.; Toscano, W. B.; Miller, N. E.; Pickering, T. G.; Shapiro, D.

1994-01-01

Postflight orthostatic intolerance has been identified as a serious biomedical problem associated with long duration exposure to microgravity in space. High priority has been given to the development of countermeasures for this disorder which are both effective and practical. A considerable body of clinical research has demonstrated that people can be taught to increase their own blood pressure voluntarily and that this is an effective treatment for chronic Orthostatic intolerance in paralyzed patients. The present pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using in operant conditioning procedure, Autogenic-Feedback Training (AFT), three men and two women participated in four to nine (15-30 training sessions). At the end of training ranged between 20 and 50 mm Hg under both supine and 450 head-up tilt conditions. These findings suggest that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight Orthostatic intolerance. Further, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanisms of orthostatic intolerance.

Balance and Gait Training With Augmented Feedback Improves Balance Confidence in People With Parkinson's Disease: A Randomized Controlled Trial.

Science.gov (United States)

Shen, Xia; Mak, Margaret K Y

2014-07-01

Background Fear of falling has been identified as an important and independent fall-risk predictor in patients with Parkinson's disease (PD). However, there are inconsistent findings on the effects of balance and gait training on balance confidence. Objective To explore whether balance and gait training with augmented feedback can enhance balance confidence in PD patients immediately after treatment and at 3- and 12-month follow-ups. Methods A total of 51 PD patients were randomly assigned to a balance and gait training (BAL) group or to an active control (CON) group. The BAL group received balance and gait training with augmented feedback, whereas CON participants received lower-limb strength training for 12 weeks. Outcome measures included Activities-Specific Balance Confidence (ABC) Scale, limits-of-stability test, single-leg-stance test, and spatiotemporal gait characteristics. All tests were administered before intervention (Pre), immediately after training (Post), and at 3 months (Post3m) and 12 months (Post12m) after treatment completion. Results The ABC score improved marginally at Post and significantly at Post3m and Post12m only in the BAL group (P point excursion at Post, but only the BAL group maintained the improvement at Post3m. The BAL group maintained significantly longer time-to-loss-of-balance during the single-leg stance test than the CON group at Post3m and Post12m (P balance confidence and balance and gait performance in patients with PD. © The Author(s) 2014.

Slow Orbit Feedback at the ALS Using Matlab

International Nuclear Information System (INIS)

Portmann, G.

1999-01-01

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 global 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

Injection Related Background due to the Transverse Feedback

International Nuclear Information System (INIS)

Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.

2008-01-01

The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part

RF feedback simulation results for PEP-II

International Nuclear Information System (INIS)

Tighe, R.; Corredoura, P.

1995-06-01

A model of the RF feedback system for PEP-II has been developed to provide time-domain simulation and frequency-domain analysis of the complete system. The model includes the longitudinal beam dynamics, cavity fundamental resonance, feedback loops, and the nonlinear klystron operating near saturation. Transients from an ion clearing gap and a reference phase modulation from the longitudinal feedback system are also studied. Growth rates are predicted and overall system stability examined

Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

Directory of Open Access Journals (Sweden)

F. J. Cullinan

2015-11-01

Full Text Available The Compact Linear Collider (CLIC requires beam position monitors (BPMs with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3 at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2/3  ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

Science.gov (United States)

Cullinan, F. J.; Boogert, S. T.; Farabolini, W.; Lefevre, T.; Lunin, A.; Lyapin, A.; Søby, L.; Towler, J.; Wendt, M.

2015-11-01

The Compact Linear Collider (CLIC) requires beam position monitors (BPMs) with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3) at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2 /3 ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

Beam loading

CERN Document Server

Gamp, Alexander

2013-01-01

We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

Beam loading

International Nuclear Information System (INIS)

Gamp, Alexander

2013-01-01

We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed. (author)

Theoretical treatment of transverse feedback systems with memory

International Nuclear Information System (INIS)

Cornacchia, M.; Wang, J.M.

1981-01-01

The differential equation of the dipole moment of coherent oscillations in the presence of a feedback system is derived. The analysis, which starts in the time domain, is extended to the frequency domain; this allows a straightforward derivation of the damping rate for both coasting and bunched beams. The damping rate is expressed in terms of the transfer function of the feedback system and in a general form which takes into account the β-function and betatron phase modulation along the beam trajectory, the effect of memory arising from the finiteness of the system bandwidth, the effect of the time delay and of the betatron phase advance between detector and kicker. Some examples of the dependence of the damping rate on the feedback parameters are given

Simulation of a transverse feedback system for the SSRF storage ring

International Nuclear Information System (INIS)

Jiang Bocheng; Chinese Academy of Sciences, Beijing; Liu Guimin; Zhao Zhentang

2007-01-01

Resistive wall instability is a serious problem in many light sources. An active transverse feedback system (TFS) is required to operate the machine in a good condition when beam current is high. In order to investigate beam dynamics with TFS turned on, we developed a TFS simulation program. The feedback effectiveness for the Shanghai Synchrotron Radiation Facility (SSRF) storage ring is simulated under various conditions such as closed orbit distortion included, beam position monitor reading errors added, and finite-duration impulse-response filter strategy changed. (authors)

Who wants feedback? An investigation of the variables influencing residents' feedback-seeking behavior in relation to night shifts.

Science.gov (United States)

Teunissen, Pim W; Stapel, Diederik A; van der Vleuten, Cees; Scherpbier, Albert; Boor, Klarke; Scheele, Fedde

2009-07-01

The literature on feedback in clinical medical education has predominantly treated trainees as passive recipients. Past research has focused on how clinical supervisors can use feedback to improve a trainee's performance. On the basis of research in social and organizational psychology, the authors reconceptualized residents as active seekers of feedback. They investigated what individual and situational variables influence residents' feedback-seeking behavior on night shifts. Early in 2008, the authors sent obstetrics-gynecology residents in the Netherlands--both those in their first two years of graduate training and those gaining experience between undergraduate and graduate training--a questionnaire that assessed four predictor variables (learning and performance goal orientation, and instrumental and supportive leadership), two mediator variables (perceived feedback benefits and costs), and two outcome variables (frequency of feedback inquiry and monitoring). They used structural equation modeling software to test a hypothesized model of relationships between variables. The response rate was 76.5%. Results showed that residents who perceive more feedback benefits report a higher frequency of feedback inquiry and monitoring. More perceived feedback costs result mainly in more feedback monitoring. Residents with a higher learning goal orientation perceive more feedback benefits and fewer costs. Residents with a higher performance goal orientation perceive more feedback costs. Supportive physicians lead residents to perceive more feedback benefits and fewer costs. This study showed that some residents actively seek feedback. Residents' feedback-seeking behavior partially depends on attending physicians' supervisory style. Residents' goal orientations influence their perceptions of the benefits and costs of feedback-seeking.

Does real-time objective feedback and competition improve performance and quality in manikin CPR training--a prospective observational study from several European EMS.

Science.gov (United States)

Smart, J R; Kranz, K; Carmona, F; Lindner, T W; Newton, A

2015-10-15

Previous studies have reported that the quality of cardiopulmonary resuscitation (CPR) is important for patient survival. Real time objective feedback during manikin training has been shown to improve CPR performance. Objective measurement could facilitate competition and help motivate participants to improve their CPR performance. The aims of this study were to investigate whether real time objective feedback on manikins helps improve CPR performance and whether competition between separate European Emergency Medical Services (EMS) and between participants at each EMS helps motivation to train. Ten European EMS took part in the study and was carried out in two stages. At Stage 1, each EMS provided 20 pre-hospital professionals. A questionnaire was completed and standardised assessment scenarios were performed for adult and infant out of hospital cardiac arrest (OHCA). CPR performance was objectively measured and recorded but no feedback given. Between Stage 1 and 2, each EMS was given access to manikins for 6 months and instructed on how to use with objective real-time CPR feedback available. Stage 2 was undertaken and was a repeat of Stage 1 with a questionnaire with additional questions relating to usefulness of feedback and the competition nature of the study (using a 10 point Likert score). The EMS that improved the most from Stage 1 to Stage 2 was declared the winner. An independent samples Student t-test was used to analyse the objective CPR metrics with the significance level taken as p Competition between EMS organisations recorded a mean score of 5.8 and competition between participants recorded a mean score of 6.0. The results suggest that the use of real time objective feedback can significantly help improve CPR performance. Competition, especially between participants, appeared to encourage staff to practice and this study suggests that competition might have a useful role to help motivate staff to perform CPR training.

Feedback correction of injection errors using digital signal-processing techniques

Directory of Open Access Journals (Sweden)

N. S. Sereno

2007-01-01

Full Text Available Efficient transfer of electron beams from one accelerator to another is important for 3rd-generation light sources that operate using top-up. In top-up mode, a constant amount of charge is injected at regular intervals into the storage ring to replenish beam lost primarily due to Touschek scattering. Top-up therefore requires that the complex of injector accelerators that fill the storage ring transport beam with a minimum amount of loss. Injection can be a source of significant beam loss if not carefully controlled. In this note we describe a method of processing injection transient signals produced by beam-position monitors and using the processed data in feedback. Feedback control using the technique described here has been incorporated in the Advanced Photon Source (APS booster synchrotron to correct injection transients.

The Effect of Intra- Versus Post-Interview Feedback during Simulated Practice Interviews about Child Abuse

Science.gov (United States)

Powell, Martine B.; Fisher, Ronald P.; Hughes-Scholes, Carolyn H.

2008-01-01

Objective: This study compared the effectiveness of two types of instructor feedback (relative to no feedback) on investigative interviewers' ability to adhere to open-ended questions in simulated practice interviews about child abuse. Method: In one condition, feedback was provided at the end of each practice interview. In the other, the…

Fast Beam-Based BPM Calibration

International Nuclear Information System (INIS)

Bertsche, Kirk

2012-01-01

The Alignment Diagnostic System (ADS) of the LCLS undulator system indicates that the 33 undulator quadrupoles have extremely high position stability over many weeks. However, beam trajectory straightness and lasing efficiency degrade more quickly than this. A lengthy Beam Based Alignment (BBA) procedure must be executed every two to four weeks to re-optimize the X-ray beam parameters. The undulator system includes RF cavity Beam Position Monitors (RFBPMs), several of which are utilized by an automatic feedback system to align the incoming electron-beam trajectory to the undulator axis. The beam trajectory straightness degradation has been traced to electronic drifts of the gain and offset of the BPMs used in the beam feedback system. To quickly recover the trajectory straightness, we have developed a fast beam-based procedure to recalibrate the BPMs. This procedure takes advantage of the high-precision monitoring capability of the ADS, which allows highly repeatable positioning of undulator quadrupoles. This report describes the ADS, the position stability of the LCLS undulator quadrupoles, and some results of the new recovery procedure.

Commissioning of the APS real-time orbit feedback system

International Nuclear Information System (INIS)

Carwardine, J.; Decker, G.; Evans, K. Jr.; Hillman, A.; Lenkszus, F.; Merl, R.; Pietryla, A.

1997-01-01

A unified global and local closed-orbit feedback system has been implemented at the Advanced Photon Source in order to stabilize both particle and photon beams. Beam stability requirements in the band up to 50 Hz are 17 microm in the horizontal plane and 4.4 microm vertically. Orbit feedback algorithms are implemented digitally using multiple digital signal processors, with computing power distributed in 20 VME crates around the storage ring. Each crate communicates with all others via a fast reflective memory network. The system has access to 320 rf beam position monitors together with x-ray beam position monitors in both insertion device and bending magnet beamlines. Up to 317 corrector magnets are available to the system. The global system reduces horizontal rms beam motion at the x-ray source points by more than a factor of two in the frequency band from 10 mHz to 50 Hz

Evaluating performance of a user-trained MR lung tumor autocontouring algorithm in the context of intra- and interobserver variations.

Science.gov (United States)

Yip, Eugene; Yun, Jihyun; Gabos, Zsolt; Baker, Sarah; Yee, Don; Wachowicz, Keith; Rathee, Satyapal; Fallone, B Gino

2018-01-01

Real-time tracking of lung tumors using magnetic resonance imaging (MRI) has been proposed as a potential strategy to mitigate the ill-effects of breathing motion in radiation therapy. Several autocontouring methods have been evaluated against a "gold standard" of a single human expert user. However, contours drawn by experts have inherent intra- and interobserver variations. In this study, we aim to evaluate our user-trained autocontouring algorithm with manually drawn contours from multiple expert users, and to contextualize the accuracy of these autocontours within intra- and interobserver variations. Six nonsmall cell lung cancer patients were recruited, with institutional ethics approval. Patients were imaged with a clinical 3 T Philips MR scanner using a dynamic 2D balanced SSFP sequence under free breathing. Three radiation oncology experts, each in two separate sessions, contoured 130 dynamic images for each patient. For autocontouring, the first 30 images were used for algorithm training, and the remaining 100 images were autocontoured and evaluated. Autocontours were compared against manual contours in terms of Dice's coefficient (DC) and Hausdorff distances (d H ). Intra- and interobserver variations of the manual contours were also evaluated. When compared with the manual contours of the expert user who trained it, the algorithm generates autocontours whose evaluation metrics (same session: DC = 0.90(0.03), d H  = 3.8(1.6) mm; different session DC = 0.88(0.04), d H  = 4.3(1.5) mm) are similar to or better than intraobserver variations (DC = 0.88(0.04), and d H  = 4.3(1.7) mm) between two sessions. The algorithm's autocontours are also compared to the manual contours from different expert users with evaluation metrics (DC = 0.87(0.04), d H  = 4.8(1.7) mm) similar to interobserver variations (DC = 0.87(0.04), d H  = 4.7(1.6) mm). Our autocontouring algorithm delineates tumor contours (algorithm may be a key component of the real

myTIPreport and Training for Independent Practice: A Tool for Real-Time Workplace Feedback for Milestones and Procedural Skills.

Science.gov (United States)

Connolly, AnnaMarie; Goepfert, Alice; Blanchard, Anita; Buys, Elizabeth; Donnellan, Nicole; Amundsen, Cindy L; Galvin, Shelley L; Kenton, Kimberly

2018-02-01

Few tools currently exist for effective, accessible delivery of real-time, workplace feedback in the clinical setting. We developed and implemented a real-time, web-based tool for performance-based feedback in the clinical environment. The tool (myTIPreport) was designed for performance-based feedback to learners on the Accreditation Council for Graduate Medical Education (ACGME) Milestones and procedural skills. "TIP" stands for "Training for Independent Practice." We implemented myTIPreport in obstetrics and gynecology (Ob-Gyn) and female pelvic medicine and reconstructive surgery (FPMRS) programs between November 2014 and May 2015. Residents, fellows, teachers, and program directors completed preimplementation and postimplementation surveys on their perceptions of feedback. Preimplementation surveys were completed by 656 participants of a total of 980 learners and teachers in 19 programs (12 Ob-Gyn and 7 FPMRS). This represented 72% (273 of 378) of learners and 64% (383 of 602) of teachers. Seventy percent of participants (381 of 546) reported having their own individual processes for real-time feedback; the majority (79%, 340 of 430) described these processes as informal discussions . Over 6 months, one-third of teachers and two-thirds of learners used the myTIPreport tool a total of 4311 times. Milestone feedback was recorded 944 times, and procedural feedback was recorded 3367 times. Feedback addressed all ACGME Milestones and procedures programmed into myTIPreport. Most program directors reported that tool implementation was successful. The majority of learners successfully received workplace feedback using myTIPreport. This web-based tool, incorporating procedures and ACGME Milestones, may be an important transition from other feedback formats.

Feedback scheme for kink instability in ERL based electron ion collider

International Nuclear Information System (INIS)

Hao, Y.; Litvinenko, V.N.; Ptitsyn, V.

2011-01-01

Kink instability presents one of the limiting factors from achieving higher luminosity in ERL based electron ion collider (EIC). However, we can take advantage of the flexibility of the linac and design a feedback system to cure the instability. This scheme raises the threshold of kink instability dramatically and provides opportunity for higher luminosity. We studied the effectiveness of this system and its dependence on the amplitude and phase of the feedback. In this paper we present results of theses studies of this scheme and describe its theoretical and practical limitations. The main advantage of an energy recovery linac (ERL) based electron ion collider (EIC) over a ring-ring type counterpart is the higher achievable luminosity. In ERL-based version, one electron beam collides with the opposing ion beam only once so that the beam-beam parameter can largely exceed the usual limitation in an electron collider ring, while the beam-beam parameter for the ion beam remains small values. The resulting luminosity may be enhanced by one order of magnitude. The beam dynamics related challenges also arise as the luminosity boost in ERL based EIC due to the significant beam-beam effect on the electron beam. The effects on the electron beam include the additional large beam-beam tune shift and nonlinear emittance growth, which are discussed. The ion beam may develop a head-tail type instability, referred as 'kink instability', through the interaction with the electron beam. In this paper, we discuss the feasibility of an active feedback system to mitigate the kink instability, by taking advantage of the flexibility of ERL. Throughout the paper, we will discuss the collision between proton and electron beam. Any other ion species can be scaled by its charge Z and ion mass A.

Characterization of a microDiamond detector in high-dose-per-pulse electron beams for intra operative radiation therapy.

Science.gov (United States)

Di Venanzio, C; Marinelli, Marco; Tonnetti, A; Verona-Rinati, G; Falco, M D; Pimpinella, M; Ciccotelli, A; De Stefano, S; Felici, G; Marangoni, F

2015-12-01

To characterize a synthetic diamond dosimeter (PTW Freiburg microDiamond 60019) in high dose-per-pulse electron beams produced by an Intra Operative Radiation Therapy (IORT) dedicated accelerator. The dosimetric properties of the microDiamond were assessed under 6, 8 and 9 MeV electron beams by a NOVAC11 mobile accelerator (Sordina IORT Technologies S.p.A.). The characterization was carried out with dose-per-pulse ranging from 26 to 105 mGy per pulse. The microDiamond performance was compared with an Advanced Markus ionization chamber and a PTW silicon diode E in terms of dose linearity, percentage depth dose (PDD) curves, beam profiles and output factors. A good linearity of the microDiamond response was verified in the dose range from 0.2 Gy to 28 Gy. A sensitivity of 1.29 nC/Gy was measured under IORT electron beams, resulting within 1% with respect to the one obtained in reference condition under (60)Co gamma irradiation. PDD measurements were found in agreement with the ones by the reference dosimeters, with differences in R50 values below 0.3 mm. Profile measurements evidenced a high spatial resolution of the microDiamond, slightly worse than the one of the silicon diode. The penumbra widths measured by the microDiamond resulted approximately 0.5 mm larger than the ones by the Silicon diode. Output factors measured by the microDiamond were found within 2% with those obtained by the Advanced Markus down to 3 cm diameter field sizes. The microDiamond dosimeter was demonstrated to be suitable for precise dosimetry in IORT applications under high dose-per-pulse conditions. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

The Prestressed Track Beam Testing Technology of Shanghai Electromagnetic Levitation Train

Directory of Open Access Journals (Sweden)

Qing-biao WANG

2013-07-01

Full Text Available Shanghai electromagnetic levitation train (maglev is the first one that is constructed and operated commercially in the world. Many technological problems have to be tackled during its construction, and the most difficult problem in the civil engineering part is the making of prestressed track beam. It requires high precision because of its special function. The stretching control of the pre-tensioning force and the post-tensioning force in the making of prestressed track beam is most important during the construction. This paper introduces and analyses the technical features of vibrating wire sensors as well as the development, the research and the application of force sensor for pulling force measurement of anchor cable.

Intra-event correlations and the statistical moments of the identified particle multiplicity distributions in the RHIC beam energy scan data collected by STAR

Science.gov (United States)

Llope, W. J.; STAR Collaboration

2013-10-01

Specific products of the statistical moments of the multiplicity distributions of identified particles can be directly compared to susceptibility ratios obtained from lattice QCD calculations. They may also diverge for nuclear systems formed close to a possible QCD critical point due to the phenomenon of critical opalescence. Of particular interest are the moments products for net-protons, net-kaons, and net-charge, as these are considered proxies for conserved quantum numbers. The moments products have been measured by the STAR experiment for Au+Au collisions at seven beam energies ranging from 7.7 to 200 GeV. In this presentation, the experimental results are compared to data-based calculations in which the intra-event correlations of the numbers of positive and negative particles are broken by construction. The importance of intra-event correlations to the moments products values for net-protons, net-kaons, and net-charge can thus be evaluated. Work supported by the U.S. Dept of Energy under grant DE-PS02-09ER09.

Use of a Real-Time Training Software (Laerdal QCPR®) Compared to Instructor-Based Feedback for High-Quality Chest Compressions Acquisition in Secondary School Students: A Randomized Trial.

Science.gov (United States)

Cortegiani, Andrea; Russotto, Vincenzo; Montalto, Francesca; Iozzo, Pasquale; Meschis, Roberta; Pugliesi, Marinella; Mariano, Dario; Benenati, Vincenzo; Raineri, Santi Maurizio; Gregoretti, Cesare; Giarratano, Antonino

2017-01-01

High-quality chest compressions are pivotal to improve survival from cardiac arrest. Basic life support training of school students is an international priority. The aim of this trial was to assess the effectiveness of a real-time training software (Laerdal QCPR®) compared to a standard instructor-based feedback for chest compressions acquisition in secondary school students. After an interactive frontal lesson about basic life support and high quality chest compressions, 144 students were randomized to two types of chest compressions training: 1) using Laerdal QCPR® (QCPR group- 72 students) for real-time feedback during chest compressions with the guide of an instructor who considered software data for students' correction 2) based on standard instructor-based feedback (SF group- 72 students). Both groups had a minimum of a 2-minute chest compressions training session. Students were required to reach a minimum technical skill level before the evaluation. We evaluated all students at 7 days from the training with a 2-minute chest compressions session. The primary outcome was the compression score, which is an overall measure of chest compressions quality calculated by the software expressed as percentage. 125 students were present at the evaluation session (60 from QCPR group and 65 from SF group). Students in QCPR group had a significantly higher compression score (median 90%, IQR 81.9-96.0) compared to SF group (median 67%, IQR 27.7-87.5), p = 0.0003. Students in QCPR group performed significantly higher percentage of fully released chest compressions (71% [IQR 24.5-99.0] vs 24% [IQR 2.5-88.2]; p = 0.005) and better chest compression rate (117.5/min [IQR 106-123.5] vs 125/min [115-135.2]; p = 0.001). In secondary school students, a training for chest compressions based on a real-time feedback software (Laerdal QCPR®) guided by an instructor is superior to instructor-based feedback training in terms of chest compression technical skill acquisition. Australian

Stability of longitudinal bunch length feedback for heavy-ion synchrotrons

Directory of Open Access Journals (Sweden)

D. Lens

2013-03-01

Full Text Available In heavy-ion synchrotrons such as the SIS18 at Helmholtzzentrum für Schwerionenforschung, Helmholtz Centre for Heavy Ion Research (GSI, coherent oscillations of the particle bunches are damped by rf feedback systems to increase the stability and to improve the beam quality. In the longitudinal direction, important modes are the coherent longitudinal dipole and quadrupole oscillation. In this paper we present a new and rigorous approach to analyze the longitudinal feedback to damp these modes. The results are applied to the rf feedback loop at GSI that damps the quadrupole mode. The stability analysis is compared with simulations and is in good agreement with results of a beam experiment. Finally, we summarize practical implications for the operation of the feedback system regarding performance and stability.

Combined feedforward and feedback control of end milling system

OpenAIRE

Čuš, Franc; Župerl, Uroš; Balič, Jože

2012-01-01

Purpose: Purpose of this paper. An intelligent control system is presented that uses a combination of feedforward and feedback for cutting force control in end milling.Design/methodology/approach: The network is trained by the feedback output that is minimized during training and most control action for disturbance rejection is finally performed by the rapid feedforward action of the network.Findings: The feedback controller corrects for errors caused by external disturbances. The feedforward...

Feedback systems for linear colliders

CERN Document Server

Hendrickson, L; Himel, Thomas M; Minty, Michiko G; Phinney, N; Raimondi, Pantaleo; Raubenheimer, T O; Shoaee, H; Tenenbaum, P G

1999-01-01

Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have been investigated, and improvements have been made. For the Next Linear Collider (NLC), extensive feedback systems are planned as an intregal part of the design. Feedback requiremetns for JLC (the Japanese Linear Collider) are essentially identical to NLC; some of the TESLA requirements are similar but there are significant differences. For NLC, algorithms which incorporate improvements upon the SLC implementation are being prototyped. Specialized systems for the damping rings, rf and interaction point will operate at hi...

Vibrotactile Feedback for Brain-Computer Interface Operation

OpenAIRE

Cincotti, Febo; Kauhanen, Laura; Aloise, Fabio; Palomäki, Tapio; Caporusso, Nicholas; Jylänki, Pasi; Mattia, Donatella; Babiloni, Fabio; Vanacker, Gerolf; Nuttin, Marnix; Marciani, Maria Grazia; Millán, José del R.

2007-01-01

To be correctly mastered, brain-computer interfaces (BCIs) need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrangements, was specified. In three studies with 33 subjects (i...

A standardised questionnaire for evaluating hospital-based rotations in general practice vocational training.

Science.gov (United States)

Viniol, Annika; Lommler-Thamer, Martina; Baum, Erika; Banzhoff, Norbert Donner

2015-05-01

The residency period of vocational training is a fundamental component for a general practitioner's (GP's) qualification. During the residency, teaching is given by consultants and staff from different medical disciplines who do not necessarily know the GP registrar's training objectives. To develop a standardised feedback questionnaire to evaluate residency attachments and enable GP registrars and their supervisors to discuss the actual training environment and areas for improvement. A cross-sectional study was carried out to assess GP registrars' ratings of items preselected by an expert group to reflect important elements in high-quality vocational training. We recruited GP registrars in Germany via mailing lists and online discussion forums and used the importance-severity-score method to score the content and importance of the selected items. On the basis of these ratings, we eliminated 74 items. This version of the questionnaire then underwent an intra-observer-reliability evaluation by the same GP registrars after eight weeks. Items with a correlation of less than 0.4 (Pearson correlation coefficient) were dropped or rephrased. Our initial questionnaire featured 117 potential items. We reduced this to 43 items after the first study; two additional items were dropped following the reliability test. To our knowledge, this is the first standardised feedback questionnaire evaluating the residency period of vocational training. We hope our work will improve the quality of GPs' vocational training. The importance-severity-score method is a fast and efficient method for developing instruments using personal judgement to evaluate constructs.

Feedback in Videogame-Based Adaptive Training

Science.gov (United States)

Rivera, Iris Daliz

2010-01-01

The field of training has been changing rapidly due to advances in technology such as videogame-based adaptive training. Videogame-based adaptive training has provided flexibility and adaptability for training in cost-effective ways. Although this method of training may have many benefits for the trainee, current research has not kept up to pace…

ORBIT FEEDBACK CONTROL FOR THE LHC Prototyping at the SPS

CERN Document Server

Steinhagen, Ralph J

2004-01-01

The Large Hadron Collider (LHC) is the next generation proton collider that is presently built at CERN. The LHC will be installed in the former LEP (Large Electron Positron Collider) tunnel. The presence of a high intensity beam in an environment of cryogenic magnets requires an excellent control of particle losses from the beam. Eventually the performance of the LHC may be limited by the ability to control the beam losses. The performance of the LHC cleaning system depends critically on the beam position stability. Ground motion, field and alignment imperfections and beam manipulations may cause orbit movements. The role of the future LHC Orbit Feedback System is the minimisation of closed orbit perturbations by periodically measuring and steering the transverse beam position back to its reference position. This diploma thesis focuses on the design and prototyping of an orbit feedback system at the SPS. The design is based on a separation of the steering problem into space and time. While the correction in s...

First years experience of LHC Beam Instrumentation

CERN Document Server

Jones, O R

2011-01-01

The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. This paper will comment on all of these systems and on their contributions to the various stages of beam commissioning. It will include details on: the beam position system and its use for realtime global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; synchrotron light diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

Evaluation of multimodal feedback effects on improving rowing competencies

Directory of Open Access Journals (Sweden)

Korman Maria

2011-12-01

Full Text Available This study focused on the selection and preliminary evaluation of different types of modal and information feedback in virtual environment to facilitate acquisition and transfer of a complex motor-cognitive skill of rowing. Specifically, we addressed the effectiveness of immediate information feedback provided visually as compared to sensory haptic feedback on the improvement in hands kinematics and changes in cognitive load during the course of learning the basic rowing technique. Several pilot experiments described in this report lead to the evaluation and optimization of the training protocol, to enhance facilitatory effects of adding visual and haptic feedback during training.

LFSC - Linac Feedback Simulation Code

International Nuclear Information System (INIS)

Ivanov, Valentin; Fermilab

2008-01-01

The computer program LFSC ( ) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output

Seismic response of an arch-beam interacting with sequential moving train loads

Czech Academy of Sciences Publication Activity Database

Yau, J. D.; Frýba, Ladislav; Urushadze, Shota

2016-01-01

Roč. 24, č. 3 (2016), s. 419-425 ISSN 1023-2796 R&D Projects: GA ČR(CZ) GC13-34405J Institutional support: RVO:68378297 Keywords : arch beam * high-speed train * resonance * earthquake Subject RIV: JM - Building Engineering Impact factor: 0.305, year: 2016 http://jmst.ntou.edu.tw/marine/24-3/419-425.pdf

Beam beam tune shifts for 36 bunch operation in the Tevatron

International Nuclear Information System (INIS)

Bagley, P.

1996-10-01

We are preparing to upgrade the Tevatron Collider from 6 to 36 bunch operation. The 36 bunches are in 3 ''trains'' of 12 bunches. The spacing between bunches within a train is 21 RF buckets (53.106 MHz) and 139 empty buckets separate the trains. Because the 36 bunches are not evenly spaced around the machine, the different bunches within a train pass the opposing bunches at different points in the ring and so feel different beam beam effects. Through most of the machine the beams have helical separation, so these are mainly long range beam beam effects. As a first, very simple step, we've looked at the differences in the tunes of the different anti-proton (anti p) bunches. During the 36 bunch studies in Fall 1995, we used a new tune measurement system to measure these in several different machine conditions. We compare these measurements to calculations of the tunes for a anti p with zero transverse and longitudinal oscillation amplitudes. We discuss experimental problems, and the assumptions, approximations, and effects included in the calculations. Our main intent is to gain confidence that we can accurately model beam beam effects in the Tevatron

Beam instability Workshop - plenary sessions

International Nuclear Information System (INIS)

2001-01-01

The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions

Beam instability Workshop - plenary sessions

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.

Does Practice Make Perfect? Role of Training and Feedback in Improving Scientists' Presentation Skills

Science.gov (United States)

Tankersley, R. A.; Bourexis, P.; Kaser, J. S.

2011-12-01

Within the research and academic communities there is a growing interest in improving the communication skills of scientists, especially their ability to communicate the substance and importance of their research to general audiences. To address this need, we developed an intensive, two-day workshop [Presentation Boot Camp (PBC)] that focuses on presenting scientific concepts and research findings more effectively to both scientific/technical audiences and the general public. Through a series of interactive sessions, participants receive training in planning and preparing presentations that communicate messages more clearly and effectively and that have a lasting impact on the audience. Topics include: knowing and identifying the needs of the audience, highlighting big ideas and take-home messages, designing effective visuals, decoding complex concepts with diagrams, and displaying data in meaningful ways. PBC attendees also receive training in the use and application of the Presentation Skills Protocol (PSP) and associated rubric for evaluating the effectiveness of scientific presentations. The PSP was originally developed as part of a NSF Graduate Teaching Fellows in K-12 Education Program (GK-12) to assess and track the impact of the GK-12 experience on the communication skills of Graduate Teaching Fellows. The PSP focuses on eleven presentation skill sets, including organization, accuracy, relevance, message, language, equity, delivery, technology, use of time, questions, and presence. The associated rubric operationally defines each of the skill sets at three categorical levels of competence: (1) proficient, (2) developing, and (3) needs attention. The PSP may be used to (1) provide scientists with regular and consistent feedback on the quality and effectiveness of their classroom and research presentations and (2) design professional development activities and training programs that target specific presentation skills. However, our evaluation results indicate

Validity evidence and reliability of a simulated patient feedback instrument.

NARCIS (Netherlands)

Schlegel, C.; Woermann, U.; Rethans, J.J.; Vleuten, C.P.M. van der

2012-01-01

BACKGROUND: In the training of healthcare professionals, one of the advantages of communication training with simulated patients (SPs) is the SP's ability to provide direct feedback to students after a simulated clinical encounter. The quality of SP feedback must be monitored, especially because it

Tactile feedback improves auditory spatial localization

Directory of Open Access Journals (Sweden)

Monica eGori

2014-10-01

Full Text Available Our recent studies suggest that congenitally blind adults have severely impaired thresholds in an auditory spatial-bisection task, pointing to the importance of vision in constructing complex auditory spatial maps (Gori et al., 2014. To explore strategies that may improve the auditory spatial sense in visually impaired people, we investigated the impact of tactile feedback on spatial auditory localization in 48 blindfolded sighted subjects. We measured auditory spatial bisection thresholds before and after training, either with tactile feedback, verbal feedback or no feedback. Audio thresholds were first measured with a spatial bisection task: subjects judged whether the second sound of a three sound sequence was spatially closer to the first or the third sound. The tactile-feedback group underwent two audio-tactile feedback sessions of 100 trials, where each auditory trial was followed by the same spatial sequence played on the subject’s forearm; auditory spatial bisection thresholds were evaluated after each session. In the verbal-feedback condition, the positions of the sounds were verbally reported to the subject after each feedback trial. The no-feedback group did the same sequence of trials, with no feedback. Performance improved significantly only after audio-tactile feedback. The results suggest that direct tactile feedback interacts with the auditory spatial localization system, possibly by a process of cross-sensory recalibration. Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially coherent. Our results suggest that the tactile system can be used to recalibrate the auditory sense of space. These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

Longitudinal feedback system for PEP

International Nuclear Information System (INIS)

Allen, M.A.; Cornacchia, M.; Millich, A.

1979-02-01

Whether the wide bandwidth longitudinal feedback system described in this paper is made to act on the individual modes in frequency domain or on the individual bunches in time domain, it represents a clean and efficient way of damping the longitudinal oscillations without influencing other beam parameters such as bunch shape or synchrotron frequency distribution. The frequency domain feedback presents the advantage of providing information on which modes are unstable and on their risetimes, which may be helpful in locating dangerous resonators in the ring

Commissioning experience from PEP-II HER longitudinal feedback

International Nuclear Information System (INIS)

Prabhakar, S.; Teytelman, D.; Fox, J.; Young, A.; Corredoura, P.; Tighe, R.

1998-06-01

The DSP-based bunch-by-bunch feedback system installed in the PEP-II HER has been used to damp HOM-induced instabilities at beam currents up to 6-5 mA during commissioning. Beam pseudospectra calcualted from feedback system data indicate the presence of coupled bunch modes that oincide with the 0-M-2 cavity HOM. Bunch current and synchronous phase measurements are also extracted from the data. These measurements reveal the impedance seen by the beam at revolution harmonics. The impedance peak at 3*frev indicates incorrect parking of the idle cavities, and explains the observed instability of mode 3. Bunch synchrotron tunes are calculated from lorentzian fits to the data. Bunch-to-bunch time variation due to the cavity transient is shown to be large enough to result in Landau damping of coupled bunch modes

Technology-Assisted Rehabilitation of Writing Skills in Parkinson’s Disease: Visual Cueing versus Intelligent Feedback

Directory of Open Access Journals (Sweden)

Evelien Nackaerts

2017-01-01

Full Text Available Recent research showed that visual cueing can have both beneficial and detrimental effects on handwriting of patients with Parkinson’s disease (PD and healthy controls depending on the circumstances. Hence, using other sensory modalities to deliver cueing or feedback may be a valuable alternative. Therefore, the current study compared the effects of short-term training with either continuous visual cues or intermittent intelligent verbal feedback. Ten PD patients and nine healthy controls were randomly assigned to one of these training modes. To assess transfer of learning, writing performance was assessed in the absence of cueing and feedback on both trained and untrained writing sequences. The feedback pen and a touch-sensitive writing tablet were used for testing. Both training types resulted in improved writing amplitudes for the trained and untrained sequences. In conclusion, these results suggest that the feedback pen is a valuable tool to implement writing training in a tailor-made fashion for people with PD. Future studies should include larger sample sizes and different subgroups of PD for long-term training with the feedback pen.

Simulation of Low Velocity Impact Induced Inter- and Intra-Laminar Damage of Composite Beams Based on XFEM

Science.gov (United States)

Sun, Wei; Guan, Zhidong; Li, Zengshan

2017-12-01

In this paper, the Inter-Fiber Fracture (IFF) criterion of Puck failure theory based on the eXtended Finite Element Method (XFEM) was implemented in ABAQUS code to predict the intra-laminar crack initiation of unidirectional (UD) composite laminate. The transverse crack path in the matrix can be simulated accurately by the presented method. After the crack initiation, the propagation of the crack is simulated by Cohesive Zoom Model (CZM), in which the displacement discontinuities and stress concentration caused by matrix crack is introduced into the finite element (FE) model. Combined with the usage of the enriched element interface, which can be used to simulate the inter-laminar delamination crack, the Low Velocity Impact (LVI) induced damage of UD composite laminate beam with a typical stacking of composite laminates [05/903]S is studied. A complete crack initiation and propagation process was simulated and the numerical results obtained by the XFEM are consistent with the experimental results.

Autogenic feedback training experiment: A preventative method for space motion sickness

Science.gov (United States)

Cowings, Patricia S.

1993-01-01

Space motion sickness is a disorder which produces symptoms similar to those of motion sickness on Earth. This syndrome has affected approximately 50 percent of all astronauts and cosmonauts exposed to microgravity in space, but it differs from what is commonly known as motion sickness in a number of critical ways. There is currently no ground-based method for predicting susceptibility to motion sickness in space. Antimotion sickness drugs have had limited success in preventing or counteracting symptoms in space, and frequently caused debilitating side effects. The objectives were: (1) to evaluate the effectiveness of Autogenic-Feedback Training as a countermeasure for space motion sickness; (2) to compare physiological data and in-flight symptom reports to ground-based motion sickness data; and (3) to predict susceptibility to space motion sickness based on pre-flight data of each treatment group crew member.

Factors affecting learning of vector math from computer-based practice: Feedback complexity and prior knowledge

Directory of Open Access Journals (Sweden)

Andrew F. Heckler

2016-06-01

Full Text Available In experiments including over 450 university-level students, we studied the effectiveness and time efficiency of several levels of feedback complexity in simple, computer-based training utilizing static question sequences. The learning domain was simple vector math, an essential skill in introductory physics. In a unique full factorial design, we studied the relative effects of “knowledge of correct response” feedback and “elaborated feedback” (i.e., a general explanation both separately and together. A number of other factors were analyzed, including training time, physics course grade, prior knowledge of vector math, and student beliefs about both their proficiency in and the importance of vector math. We hypothesize a simple model predicting how the effectiveness of feedback depends on prior knowledge, and the results confirm this knowledge-by-treatment interaction. Most notably, elaborated feedback is the most effective feedback, especially for students with low prior knowledge and low course grade. In contrast, knowledge of correct response feedback was less effective for low-performing students, and including both kinds of feedback did not significantly improve performance compared to elaborated feedback alone. Further, while elaborated feedback resulted in higher scores, the learning rate was at best only marginally higher because the training time was slightly longer. Training time data revealed that students spent significantly more time on the elaborated feedback after answering a training question incorrectly. Finally, we found that training improved student self-reported proficiency and that belief in the importance of the learned domain improved the effectiveness of training. Overall, we found that computer based training with static question sequences and immediate elaborated feedback in the form of simple and general explanations can be an effective way to improve student performance on a physics essential skill

360-degree feedback for medical trainees

DEFF Research Database (Denmark)

Holm, Ellen; Holm, Kirsten; Sørensen, Jette Led

2015-01-01

feedback and assessment. In order to secure reliability 8-15 respondents are needed. It is a matter of discussion whether the respondents should be chosen by the trainee or by a third part, and if respondents should be anonymous. The process includes a feedback session with a trained supervisor....

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized educational trial.

Science.gov (United States)

Oestergaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde; Winkel, Per; Larsen, Christian Rifbjerg; Ringsted, Charlotte; Gluud, Christian; Grantcharov, Teodor; Ottesen, Bent; Soerensen, Jette Led

2012-02-28

Several studies have found a positive effect on the learning curve as well as the improvement of basic psychomotor skills in the operating room after virtual reality training. Despite this, the majority of surgical and gynecological departments encounter hurdles when implementing this form of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational tasks on a virtual reality simulator. The study population consists of medical students on their 4th to 6th year without prior laparoscopic experience. The study is conducted in a skills laboratory at a centralized university hospital. Based on a sample size estimation 98 participants will be randomized to an intervention group or a control group. Both groups have to achieve a predefined proficiency level when conducting a laparoscopic salpingectomy using a surgical virtual reality simulator. The intervention group receives standardized instructor feedback of 10 to 12 min a maximum of three times. The control group receives no instructor feedback. Both groups receive the automated feedback generated by the virtual reality simulator. The study follows the CONSORT Statement for randomized trials. Main outcome measures are time and repetitions to reach the predefined proficiency level on the simulator. We include focus on potential sex differences, computer gaming experience and self-perception. The findings will contribute to a better understanding of optimal training methods in surgical education. NCT01497782.

Modeling and simulation of Indus-2 RF feedback control system

International Nuclear Information System (INIS)

Sharma, D.; Bagduwal, P.S.; Tiwari, N.; Lad, M.; Hannurkar, P.R.

2012-01-01

Indus-2 synchrotron radiation source has four RF stations along with their feedback control systems. For higher beam energy and current operation amplitude and phase feedback control systems of Indus-2 are being upgraded. To understand the behaviour of amplitude and phase control loop under different operating conditions, modelling and simulation of RF feedback control system is done. RF cavity baseband I/Q model has been created due to its close correspondence with actual implementation and better computational efficiency which makes the simulation faster. Correspondence between cavity baseband and RF model is confirmed by comparing their simulation results. Low Level RF (LLRF) feedback control system simulation is done using the same cavity baseband I/Q model. Error signals are intentionally generated and response of the closed loop system is observed. Simulation will help us in optimizing parameters of upgraded LLRF system for higher beam energy and current operation. (author)

Intra-operative cone beam computed tomography can help avoid reinterventions and reduce CT follow up after infrarenal EVAR.

Science.gov (United States)

Törnqvist, P; Dias, N; Sonesson, B; Kristmundsson, T; Resch, T

2015-04-01

Re-interventions after endovascular abdominal aortic aneurysm repair (EVAR) are common and therefore a strict imaging follow up protocol is required. The purpose of this study was to evaluate whether cone beam computed tomography (CBCT) can detect intra-operative complications and to compare this with angiography and the 1 month CT follow up (computed tomography angiography [CTA]). Fifty-one patients (44 men) were enrolled in a prospective trial. Patients underwent completion angiography and CBCT during infrarenal EVAR. Contrast was used except when pre-operative renal insufficiency was present or if the maximum contrast dose threshold was reached. CBCT reconstruction included the top of the stent graft to the iliac bifurcation. Endoleaks, kinks, or compressions were recorded. CBCT was technically successful in all patients. Twelve endoleaks were detected on completion digital subtraction angiography (CA). CBCT detected 4/5 type 1 endoleaks, but only one type 2 endoleak. CTA identified eight type 2 endoleaks and one residual type I endoleak. Two cases of stent compression were seen on CA. CBCT revealed five stent compressions and one kink, which resulted in four intra-operative adjunctive manoeuvres. CTA identified all cases of kinks or compressions that were left untreated. Two of them were corrected later. No additional kinks/compressions were found on CTA. Groin closure consisted of 78 fascia sutures, nine cut downs, and 11 percutaneous sutures. Seven femoral artery pseudoaneurysms (<1 cm) were detected on CTA, but no intervention was needed. CA is better than CBCT in detecting and categorizing endoleaks but CBCT (with or without contrast) is better than CA for detection of kinks or stentgraft compression. CTA plus CBCT identified all significant complications noted on the 1 month follow up CTA. The use of intra-operative CA and CBCT could replace early CTA after standard EVAR thus reducing overall radiation and contrast use. Technical development might further

Stabilization of synchrotron radiation x-ray beam by MOSTAB

CERN Document Server

Kudo, T P; Tanida, H; Furukawa, Y; Hirono, T; Ishikawa, T; Nishino, Y

2003-01-01

Monochromator stabilization (MOSTAB) is a feedback control system to stabilize an x-ray beam of synchrotron radiation. It applies a feedback voltage to a piezo electric transducer attached to a double-crystal monochromator. We developed MOSTAB modules and examined their performances using SPring-8 beamlines. The x-ray beam position stabilization using MOSTAB was realized simultaneously with the x-ray beam intensity stabilization. As an example of its application, we performed EXAFS measurement with MOSTAB. (author)

SuperB Bunch-By-Bunch Feedback R&D

Energy Technology Data Exchange (ETDEWEB)

Drago, A.; Beretta, M.; /Frascati; Bertsche, K.; Novokhatski, A.; /SLAC; Migliorati, M.; /Rome U.

2011-08-12

The SuperB project has the goal to build in Italy, in the Frascati or Tor Vergata area, an asymmetric e{sup +}/e{sup -} Super Flavor Factory to achieve a peak luminosity > 10**36 cm{sup -2} s{sup -1}. The SuperB design is based on collisions with extremely low vertical emittance beams and high beam currents. A source of emittance growth comes from the bunch by bunch feedback systems producing high power correction signals to damp the beams. To limit any undesirable effect, a large R&D program is in progress, partially funded by the INFN Fifth National Scientific Committee through the SFEED (SuperB Feedback) project approved within the 2010 budget. The SuperB project [1] has the goal to build in Italy, in the Frascati or Tor Vergata area, an asymmetric e{sup +}/e{sup -} Super Flavor Factory to achieve a peak luminosity > 10**36 cm{sup -2} s{sup -1}. In the last and current years, the machine layout has been deeply modified, in particular the main rings are now shorter and an option with high currents has been foreseen. In the fig.1 the new SuperB layout is shown. From bunch-by-bunch feedback point of view, the simultaneous presence in the machine parameters, of very low emittance, of the order of 5-10 pm in the vertical plane, and very high currents, at level of 4 Ampere for the Low Energy Ring, asks for designing very carefully the bunch-by-bunch feedback systems. The parameter list is presented in Fig. 2. The bunch-by-bunch feedback design must take care of the risky and exciting challenges proposed in the SuperB specifications, but it should consider also some other important aspects: flexibility in terms of being able to cope to unexpected beam behaviours [2], [3] legacy of previous version experience [4], [5] and internal powerful diagnostics [6] as in the systems previously used in PEP-II and DAFNE [7].

Software feedback for monochromator tuning at UNICAT (abstract)

Science.gov (United States)

Jemian, Pete R.

2002-03-01

Automatic tuning of double-crystal monochromators presents an interesting challenge in software. The goal is to either maximize, or hold constant, the throughput of the monochromator. An additional goal of the software feedback is to disable itself when there is no beam and then, at the user's discretion, re-enable itself when the beam returns. These and other routine goals, such as adherence to limits of travel for positioners, are maintained by software controls. Many solutions exist to lock in and maintain a fixed throughput. Among these include a hardware solution involving a wave form generator, and a lock-in amplifier to autocorrelate the movement of a piezoelectric transducer (PZT) providing fine adjustment of the second crystal Bragg angle. This solution does not work when the positioner is a slow acting device such as a stepping motor. Proportional integral differential (PID) loops have been used to provide feedback through software but additional controls must be provided to maximize the monochromator throughput. Presented here is a software variation of the PID loop which meets the above goals. By using two floating point variables as inputs, representing the intensity of x rays measured before and after the monochromator, it attempts to maximize (or hold constant) the ratio of these two inputs by adjusting an output floating point variable. These floating point variables are connected to hardware channels corresponding to detectors and positioners. When the inputs go out of range, the software will stop making adjustments to the control output. Not limited to monochromator feedback, the software could be used, with beam steering positioners, to maintain a measure of beam position. Advantages of this software feedback are the flexibility of its various components. It has been used with stepping motors and PZTs as positioners. Various devices such as ion chambers, scintillation counters, photodiodes, and photoelectron collectors have been used as

Effectiveness of instruction and video feedback on staff's use of prompts and children's adaptive responses during one-to-one training in children with severe to profound intellectual disability

NARCIS (Netherlands)

Vonderen, A.M.H. van; Swart, C.C.W. de; Didden, H.C.M.

2010-01-01

Although relatively many studies have addressed staff training and its effect on trainer behavior, the effects of staff training on trainee's adaptive behaviors have seldomly been examined. We therefore assessed effectiveness of staff training, consisting of instruction and video feedback, on (a)

Intra- and interobserver analysis in the morphological assessment of early stage embryos during an IVF procedure: a multicentre study

Directory of Open Access Journals (Sweden)

Devroe Johanna

2011-09-01

Full Text Available Abstract Background Quality control programs are necessary to maintain good clinical practice. Embryo grading has been described as one of the external quality assurance schemes. Although the evaluation of embryos is based on the assessment of morphological characteristics, considerable intra- and inter-observer variability has been described. In this multicentre study, the variability in the embryo evaluation has been evaluated using morphological characteristics on day 1, day 2 and day 3 of embryo development. Methods Five embryologists of four different IVF centers participated in this study. Multilevel images of embryos were presented on a website at different time points to evaluate intra-and inter-observer agreement in the assessment of embryo morphology. The embryos were evaluated on day 1, day 2 and day 3 of their development and each embryologist had to decide if the embryo had to be transferred, cryopreserved or discarded. Results Both intra-observer agreement and inter-observer agreement were good to excellent for the position of the pronuclei on day 1, the number of blastomeres on day 2 and day 3 and the clinical decision (transfer, cryopreservation, discard. For all other characteristics (size of pronuclei, presence of cytoplasomic halo, degree of fragmentation and size of blastomeres the intra- and inter-observer agreement was moderate to very poor. Conclusions Mono- or multicentre quality control on embryo scoring by morphological assessment can easily be performed through the design of a simple website. In the future the website design can be adapted to generate statistical feedback upon scoring and can even include a training module.

Dynamic imperfections and optimized feedback design in the Compact Linear Collider main linac

CERN Document Server

Eliasson, Peder

2008-01-01

The Compact Linear Collider (CLIC) main linac is sensitive to dynamic imperfections such as element jitter, injected beam jitter, and ground motion. These effects cause emittance growth that, in case of ground motion, has to be counteracted by a trajectory feedback system. The feedback system itself will, due to jitter effects and imperfect beam position monitors (BPMs), indirectly cause emittance growth. Fast and accurate simulations of both the direct and indirect effects are desirable, but due to the many elements of the CLIC main linac, simulations may become very time consuming. In this paper, an efficient way of simulating linear (or nearly linear) dynamic effects is described. The method is also shown to facilitate the analytic determination of emittance growth caused by the different dynamic imperfections while using a trajectory feedback system. Emittance growth expressions are derived for quadrupole, accelerating structure, and beam jitter, for ground motion, and for noise in the feedback BPMs. Fina...

The Most Common Feedback Themes in Communication Skills Training in an Internal Medicine Residency Program: Lessons from the Resident Audio-Recording Project.

Science.gov (United States)

Han, Heeyoung; Papireddy, Muralidhar Reddy; Hingle, Susan T; Ferguson, Jacqueline Anne; Koschmann, Timothy; Sandstrom, Steve

2018-07-01

Individualized structured feedback is an integral part of a resident's learning in communication skills. However, it is not clear what feedback residents receive for their communication skills development in real patient care. We will identify the most common feedback topics given to residents regarding communication skills during Internal Medicine residency training. We analyzed Resident Audio-recording Project feedback data from 2008 to 2013 by using a content analysis approach. Using open coding and an iterative categorization process, we identified 15 emerging themes for both positive and negative feedback. The most recurrent feedback topics were Patient education, Thoroughness, Organization, Questioning strategy, and Management. The residents were guided to improve their communication skills regarding Patient education, Thoroughness, Management, and Holistic exploration of patient's problem. Thoroughness and Communication intelligibility were newly identified themes that were rarely discussed in existing frameworks. Assessment rubrics serve as a lens through which we assess the adequacy of the residents' communication skills. Rather than sticking to a specific rubric, we chose to let the rubric evolve through our experience.

A Virtual Emergency Telemedicine Serious Game in Medical Training: A Quantitative, Professional Feedback-Informed Evaluation Study.

Science.gov (United States)

Nicolaidou, Iolie; Antoniades, Athos; Constantinou, Riana; Marangos, Charis; Kyriacou, Efthyvoulos; Bamidis, Panagiotis; Dafli, Eleni; Pattichis, Constantinos S

2015-06-17

Serious games involving virtual patients in medical education can provide a controlled setting within which players can learn in an engaging way, while avoiding the risks associated with real patients. Moreover, serious games align with medical students' preferred learning styles. The Virtual Emergency TeleMedicine (VETM) game is a simulation-based game that was developed in collaboration with the mEducator Best Practice network in response to calls to integrate serious games in medical education and training. The VETM game makes use of data from an electrocardiogram to train practicing doctors, nurses, or medical students for problem-solving in real-life clinical scenarios through a telemedicine system and virtual patients. The study responds to two gaps: the limited number of games in emergency cardiology and the lack of evaluations by professionals. The objective of this study is a quantitative, professional feedback-informed evaluation of one scenario of VETM, involving cardiovascular complications. The study has the following research question: "What are professionals' perceptions of the potential of the Virtual Emergency Telemedicine game for training people involved in the assessment and management of emergency cases?" The evaluation of the VETM game was conducted with 90 professional ambulance crew nursing personnel specializing in the assessment and management of emergency cases. After collaboratively trying out one VETM scenario, participants individually completed an evaluation of the game (36 questions on a 5-point Likert scale) and provided written and verbal comments. The instrument assessed six dimensions of the game: (1) user interface, (2) difficulty level, (3) feedback, (4) educational value, (5) user engagement, and (6) terminology. Data sources of the study were 90 questionnaires, including written comments from 51 participants, 24 interviews with 55 participants, and 379 log files of their interaction with the game. Overall, the results were

Survey of Digital Feedback Systems in High Current Storage Rings

International Nuclear Information System (INIS)

Teytelman, Dmitry

2003-01-01

In the last decade demand for brightness in synchrotron light sources and luminosity in circular colliders led to construction of multiple high current storage rings. Many of these new machines require feedback systems to achieve design stored beam currents. In the same time frame the rapid advances in the technology of digital signal processing allowed the implementation of these complex feedback systems. In this paper I concentrate on three applications of feedback to storage rings: orbit control in light sources, coupled-bunch instability control, and low-level RF control. Each of these applications is challenging in areas of processing bandwidth, algorithm complexity, and control of time-varying beam and system dynamics. I will review existing implementations as well as comment on promising future directions

Dynamic imperfections and optimized feedback design in the Compact Linear Collider main linac

Directory of Open Access Journals (Sweden)

Peder Eliasson

2008-05-01

Full Text Available The Compact Linear Collider (CLIC main linac is sensitive to dynamic imperfections such as element jitter, injected beam jitter, and ground motion. These effects cause emittance growth that, in case of ground motion, has to be counteracted by a trajectory feedback system. The feedback system itself will, due to jitter effects and imperfect beam position monitors (BPMs, indirectly cause emittance growth. Fast and accurate simulations of both the direct and indirect effects are desirable, but due to the many elements of the CLIC main linac, simulations may become very time consuming. In this paper, an efficient way of simulating linear (or nearly linear dynamic effects is described. The method is also shown to facilitate the analytic determination of emittance growth caused by the different dynamic imperfections while using a trajectory feedback system. Emittance growth expressions are derived for quadrupole, accelerating structure, and beam jitter, for ground motion, and for noise in the feedback BPMs. Finally, it is shown how the method can be used to design a feedback system that is optimized for the optics of the machine and the ground motion spectrum of the particular site. This feedback system gives an emittance growth rate that is approximately 10 times lower than that of traditional trajectory feedbacks. The robustness of the optimized feedback system is studied for a number of additional imperfections, e.g., dipole corrector imperfections and faulty knowledge about the machine optics, with promising results.

Dynamic imperfections and optimized feedback design in the Compact Linear Collider main linac

Science.gov (United States)

Eliasson, Peder

2008-05-01

The Compact Linear Collider (CLIC) main linac is sensitive to dynamic imperfections such as element jitter, injected beam jitter, and ground motion. These effects cause emittance growth that, in case of ground motion, has to be counteracted by a trajectory feedback system. The feedback system itself will, due to jitter effects and imperfect beam position monitors (BPMs), indirectly cause emittance growth. Fast and accurate simulations of both the direct and indirect effects are desirable, but due to the many elements of the CLIC main linac, simulations may become very time consuming. In this paper, an efficient way of simulating linear (or nearly linear) dynamic effects is described. The method is also shown to facilitate the analytic determination of emittance growth caused by the different dynamic imperfections while using a trajectory feedback system. Emittance growth expressions are derived for quadrupole, accelerating structure, and beam jitter, for ground motion, and for noise in the feedback BPMs. Finally, it is shown how the method can be used to design a feedback system that is optimized for the optics of the machine and the ground motion spectrum of the particular site. This feedback system gives an emittance growth rate that is approximately 10 times lower than that of traditional trajectory feedbacks. The robustness of the optimized feedback system is studied for a number of additional imperfections, e.g., dipole corrector imperfections and faulty knowledge about the machine optics, with promising results.

The Effect of Communication Skills Training by Video Feedback Method on Clinical Skills of Interns of Isfahan University of Medical Sciences Compared to Didactic Methods

Science.gov (United States)

Managheb, S. E.; Zamani, A.; Shams, B.; Farajzadegan, Z.

2012-01-01

Background: Effective communication is essential to the practice of high-quality medicine. There are methodological challenges in communication skills training. This study was performed in order to assess the educational benefits of communication skills training by video feedback method versus traditional formats such as lectures on clinical…

Beam Loss in Linacs

CERN Document Server

Plum, M.A.

2016-01-01

Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

Assembly and evaluation of a training module and dataset with feedback for improved interpretation of digital breast tomosynthesis examinations

Science.gov (United States)

Gur, David; Zuley, Margarita L.; Sumkin, Jules H.; Hakim, Christiane M.; Chough, Denise M.; Lovy, Linda; Sobran, Cynthia; Logue, Durwin; Zheng, Bin; Klym, Amy H.

2012-02-01

The FDA recently approved Digital Breast Tomosynthesis (DBT) for use in screening for the early detection of breast cancer. However, MQSA qualification for interpreting DBT through training was noted as important. Performance issues related to training are largely unknown. Therefore, we assembled a unique computerized training module to assess radiologists' performances before and after using the training module. Seventy-one actual baseline mammograms (no priors) with FFDM and DBT images were assembled to be read before and after training with the developed module. Fifty examinations of FFDM and DBT images enriched with positive findings were assembled for the training module. Depicted findings were carefully reviewed, summarized, and entered into a specially designed training database where findings were identified by case number and synchronized to the display of the related FFDM plus DBT examinations on a clinical workstation. Readers reported any findings using screening BIRADS (0, 1, or 2) followed by instantaneous feedback of the verified truth. Six radiologists participated in the study and reader average sensitivity and specificity were compared before and after training. Average sensitivity improved and specificity remained relatively the same after training. Performance changes may be affected by disease prevalence in the training set.

Generation of “gigantic” ultra-short microwave pulses based on passive mode-locking effect in electron oscillators with saturable absorber in the feedback loop

International Nuclear Information System (INIS)

Ginzburg, N. S.; Denisov, G. G.; Vilkov, M. N.; Zotova, I. V.; Sergeev, A. S.

2016-01-01

A periodic train of powerful ultrashort microwave pulses can be generated in electron oscillators with a non-linear saturable absorber installed in the feedback loop. This method of pulse formation resembles the passive mode-locking widely used in laser physics. Nevertheless, there is a specific feature in the mechanism of pulse amplification when consecutive energy extraction from different fractions of a stationary electron beam takes place due to pulse slippage over the beam caused by the difference between the wave group velocity and the electron axial velocity. As a result, the peak power of generated “gigantic” pulses can exceed not only the level of steady-state generation but also, in the optimal case, the power of the driving electron beam.

Beam diagnostics based on time-domain bunch-by-bunch data

International Nuclear Information System (INIS)

Teytelman, D.; Fox, J.; Hindi, H.; Limborg, C.; Linscott, I.; Prabhakar, S.; Sebek, J.; Young, A.; Drago, A.; Serio, M.; Barry, W.; Stover, G.

1998-01-01

A bunch-by-bunch longitudinal feedback system has been used to control coupled-bunch longitudinal motion and study the behavior of the beam at ALS, SPEAR, PEP-II, and DAΦNE. Each of these machines presents unique challenges to feedback control of unstable motion and data analysis. Here we present techniques developed to adapt this feedback system to operating conditions at these accelerators. A diverse array of techniques has been developed to extract information on different aspects of beam behavior from the time-domain data captured by the feedback system. These include measurements of growth and damping rates of coupled-bunch modes, bunch-by-bunch current monitoring, measurements of bunch-by-bunch synchronous phases and longitudinal tunes, and beam noise spectra. A technique is presented which uses the longitudinal feedback system to measure transverse growth and damping rates. Techniques are illustrated with data acquired at all of the four above-mentioned machines

Beam diagnostics based on time-domain bunch-by-bunch data

International Nuclear Information System (INIS)

Teytelman, D.; Fox, J.; Hindi, H.; Limborg, C.; Linscott, I.; Prabhakar, S.; Sebek, J.; Young, A.; Drago, A.; Serio, M.; Barry, W.; Stover, G.

1998-01-01

A bunch-by-bunch longitudinal feedback system has been used to control coupled-bunch longitudinal motion and study the behavior of the beam at ALS, SPEAR, PEP-II, and DAΦNE. Each of these machines presents unique challenges to feedback control of unstable motion and data analysis. Here we present techniques developed to adapt this feedback system to operating conditions at these accelerators. A diverse array of techniques has been developed to extract information on different aspects of beam behavior from the time-domain data captured by the feedback system. These include measurements of growth and damping rates of coupled-bunch modes, bunch-by-bunch current monitoring, measurements of bunch-by-bunch synchronous phases and longitudinal tunes, and beam noise spectra. A technique is presented which uses the longitudinal feedback system to measure transverse growth and damping rates. Techniques are illustrated with data acquired at all of the four above-mentioned machines. copyright 1998 American Institute of Physics

Smith-Purcell Distributed Feedback Laser

CERN Document Server

Kipnis, D; Gover, A

2005-01-01

Smith-Purcell radiation is the emission of electromagnetic radiation by an electron beam passing next to an optical grating. Recently measurement of relatively intense power of such radiation was observed in the THz-regime [1]. To explain the high intensity and the super-linear dependence on current beyond a threshold it was suggested that the radiating device operated in the high gain regime, amplifying spontaneous emission (ASE) [1,2]. We contest this interpretation and suggest an alternative mechanism. According to our interpretation the device operates as a distributed feedback (DFB) laser oscillator, in which a forward going surface wave, excited by the beam on the grating surface, is coupled to a backward going surface wave by a second order Bragg reflection process. This feedback process produces a saturated oscillator. We present theoretical analysis of the proposed process, which fits the reported experimental results, and enables better design of the radiation device, operating as a Smith-Purcell DF...

Task-irrelevant auditory feedback facilitates motor performance in musicians

Directory of Open Access Journals (Sweden)

Virginia eConde

2012-05-01

Full Text Available An efficient and fast auditory–motor network is a basic resource for trained musicians due to the importance of motor anticipation of sound production in musical performance. When playing an instrument, motor performance always goes along with the production of sounds and the integration between both modalities plays an essential role in the course of musical training. The aim of the present study was to investigate the role of task-irrelevant auditory feedback during motor performance in musicians using a serial reaction time task (SRTT. Our hypothesis was that musicians, due to their extensive auditory–motor practice routine during musical training, have a superior performance and learning capabilities when receiving auditory feedback during SRTT relative to musicians performing the SRTT without any auditory feedback. Here we provide novel evidence that task-irrelevant auditory feedback is capable to reinforce SRTT performance but not learning, a finding that might provide further insight into auditory-motor integration in musicians on a behavioral level.

Use of the learning conversation improves instructor confidence in life support training: An open randomised controlled cross-over trial comparing teaching feedback mechanisms.

Science.gov (United States)

Baldwin, Lydia J L; Jones, Christopher M; Hulme, Jonathan; Owen, Andrew

2015-11-01

Feedback is vital for the effective delivery of skills-based education. We sought to compare the sandwich technique and learning conversation structured methods of feedback delivery in competency-based basic life support (BLS) training. Open randomised crossover study undertaken between October 2014 and March 2015 at the University of Birmingham, United Kingdom. Six-hundred and forty healthcare students undertaking a European Resuscitation Council (ERC) BLS course were enrolled, each of whom was randomised to receive teaching using either the sandwich technique or the learning conversation. Fifty-eight instructors were randomised to initially teach using either the learning conversation or sandwich technique, prior to crossing-over and teaching with the alternative technique after a pre-defined time period. Outcome measures included skill acquisition as measured by an end-of-course competency assessment, instructors' perception of teaching with each feedback technique and candidates' perception of the feedback they were provided with. Scores assigned to use of the learning conversation by instructors were significantly more favourable than for the sandwich technique across all but two assessed domains relating to instructor perception of the feedback technique, including all skills-based domains. No difference was seen in either assessment pass rates (80.9% sandwich technique vs. 77.2% learning conversation; OR 1.2, 95% CI 0.85-1.84; p=0.29) or any domain relating to candidates' perception of their teaching technique. This is the first direct comparison of two feedback techniques in clinical medical education using both quantitative and qualitative methodology. The learning conversation is preferred by instructors providing competency-based life support training and is perceived to favour skills acquisition. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

INTRA graphical package - INTRA-Graph 1.0

International Nuclear Information System (INIS)

Hofman, D.; Edlund, O.

2001-04-01

INTRA-Graph 1.0 has been developed at Studsvik Eco and Safety AB in the frame of the European Fusion Technology Programme for application in the safety analysis using the INTRA code. INTRA-Graph 1.0 is a graphical package producing 2-dimensional plots of results generated by the INTRA code. INTRA-Graph 1.0 has been developed by extending the Grace package source code, distributed under the terms of GNU General Public License. The changes in the Grace source files are limited to provide easy updates of the INTRA-Graph when a new version of Grace will be released. The INTRA-related functionality has been implemented in new source files. The present report describes and gives complete listing of these files. The changes in the Grace source files are also described and the listing of the changed parts of the files is presented. The report gives detailed explanations and examples of files required for installation and configuration of INTRA-Graph on the different types of Unix workstations

Does a web-based feedback training program result in improved reliability in clinicians' ratings of the Global Assessment of Functioning (GAF) Scale?

Science.gov (United States)

Støre-Valen, Jakob; Ryum, Truls; Pedersen, Geir A F; Pripp, Are H; Jose, Paul E; Karterud, Sigmund

2015-09-01

The Global Assessment of Functioning (GAF) Scale is used in routine clinical practice and research to estimate symptom and functional severity and longitudinal change. Concerns about poor interrater reliability have been raised, and the present study evaluated the effect of a Web-based GAF training program designed to improve interrater reliability in routine clinical practice. Clinicians rated up to 20 vignettes online, and received deviation scores as immediate feedback (i.e., own scores compared with expert raters) after each rating. Growth curves of absolute SD scores across the vignettes were modeled. A linear mixed effects model, using the clinician's deviation scores from expert raters as the dependent variable, indicated an improvement in reliability during training. Moderation by content of scale (symptoms; functioning), scale range (average; extreme), previous experience with GAF rating, profession, and postgraduate training were assessed. Training reduced deviation scores for inexperienced GAF raters, for individuals in clinical professions other than nursing and medicine, and for individuals with no postgraduate specialization. In addition, training was most beneficial for cases with average severity of symptoms compared with cases with extreme severity. The results support the use of Web-based training with feedback routines as a means to improve the reliability of GAF ratings performed by clinicians in mental health practice. These results especially pertain to clinicians in mental health practice who do not have a masters or doctoral degree. (c) 2015 APA, all rights reserved.

Mirror Visual Feedback Training Improves Intermanual Transfer in a Sport-Specific Task: A Comparison between Different Skill Levels

Directory of Open Access Journals (Sweden)

Fabian Steinberg

2016-01-01

Full Text Available Mirror training therapy is a promising tool to initiate neural plasticity and facilitate the recovery process of motor skills after diseases such as stroke or hemiparesis by improving the intermanual transfer of fine motor skills in healthy people as well as in patients. This study evaluated whether these augmented performance improvements by mirror visual feedback (MVF could be used for learning a sport-specific skill and if the effects are modulated by skill level. A sample of 39 young, healthy, and experienced basketball and handball players and 41 novices performed a stationary basketball dribble task at a mirror box in a standing position and received either MVF or direct feedback. After four training days using only the right hand, performance of both hands improved from pre- to posttest measurements. Only the left hand (untrained performance of the experienced participants receiving MVF was more pronounced than for the control group. This indicates that intermanual motor transfer can be improved by MVF in a sport-specific task. However, this effect cannot be generalized to motor learning per se since it is modulated by individuals’ skill level, a factor that might be considered in mirror therapy research.

Object discrimination using electrotactile feedback.

Science.gov (United States)

Arakeri, Tapas J; Hasse, Brady A; Fuglevand, Andrew J

2018-04-09

A variety of bioengineering systems are being developed to restore tactile sensations in individuals who have lost somatosensory feedback because of spinal cord injury, stroke, or amputation. These systems typically detect tactile force with sensors placed on an insensate hand (or prosthetic hand in the case of amputees) and deliver touch information by electrically or mechanically stimulating sensate skin above the site of injury. Successful object manipulation, however, also requires proprioceptive feedback representing the configuration and movements of the hand and digits. Therefore, we developed a simple system that simultaneously provides information about tactile grip force and hand aperture using current amplitude-modulated electrotactile feedback. We evaluated the utility of this system by testing the ability of eight healthy human subjects to distinguish among 27 objects of varying sizes, weights, and compliances based entirely on electrotactile feedback. The feedback was modulated by grip-force and hand-aperture sensors placed on the hand of an experimenter (not visible to the subject) grasping and lifting the test objects. We were also interested to determine the degree to which subjects could learn to use such feedback when tested over five consecutive sessions. The average percentage correct identifications on day 1 (28.5%  ±  8.2% correct) was well above chance (3.7%) and increased significantly with training to 49.2%  ±  10.6% on day 5. Furthermore, this training transferred reasonably well to a set of novel objects. These results suggest that simple, non-invasive methods can provide useful multisensory feedback that might prove beneficial in improving the control over prosthetic limbs.

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized educational trial

Directory of Open Access Journals (Sweden)

Oestergaard Jeanett

2012-02-01

Full Text Available Abstract Background Several studies have found a positive effect on the learning curve as well as the improvement of basic psychomotor skills in the operating room after virtual reality training. Despite this, the majority of surgical and gynecological departments encounter hurdles when implementing this form of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational tasks on a virtual reality simulator. Methods/Design The study population consists of medical students on their 4th to 6th year without prior laparoscopic experience. The study is conducted in a skills laboratory at a centralized university hospital. Based on a sample size estimation 98 participants will be randomized to an intervention group or a control group. Both groups have to achieve a predefined proficiency level when conducting a laparoscopic salpingectomy using a surgical virtual reality simulator. The intervention group receives standardized instructor feedback of 10 to 12 min a maximum of three times. The control group receives no instructor feedback. Both groups receive the automated feedback generated by the virtual reality simulator. The study follows the CONSORT Statement for randomized trials. Main outcome measures are time and repetitions to reach the predefined proficiency level on the simulator. We include focus on potential sex differences, computer gaming experience and self-perception. Discussion The findings will contribute to a better understanding of optimal training methods in surgical education. Trial Registration NCT01497782

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized educational trial

Science.gov (United States)

2012-01-01

Abstract Background Several studies have found a positive effect on the learning curve as well as the improvement of basic psychomotor skills in the operating room after virtual reality training. Despite this, the majority of surgical and gynecological departments encounter hurdles when implementing this form of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational tasks on a virtual reality simulator. Methods/Design The study population consists of medical students on their 4th to 6th year without prior laparoscopic experience. The study is conducted in a skills laboratory at a centralized university hospital. Based on a sample size estimation 98 participants will be randomized to an intervention group or a control group. Both groups have to achieve a predefined proficiency level when conducting a laparoscopic salpingectomy using a surgical virtual reality simulator. The intervention group receives standardized instructor feedback of 10 to 12 min a maximum of three times. The control group receives no instructor feedback. Both groups receive the automated feedback generated by the virtual reality simulator. The study follows the CONSORT Statement for randomized trials. Main outcome measures are time and repetitions to reach the predefined proficiency level on the simulator. We include focus on potential sex differences, computer gaming experience and self-perception. Discussion The findings will contribute to a better understanding of optimal training methods in surgical education. Trial Registration NCT01497782 PMID:22373062

Autogenic-feedback training as a treatment for airsickness in high-performance military aircraft: Two case studies

Science.gov (United States)

Cowings, Patricia S.; Toscano, William B.; Miller, Neal E.; Reynoso, Samuel

1994-01-01

The purpose of this paper is to present a detailed description of the physiological and performance responses of two military pilots undergoing a treatment for motion sickness. The treatment used, Autogenic-Feedback Training (AFT), is an operant conditioning procedure where subjects are taught to control several of their autonomic responses and thereby suppress their motion sickness symptoms. Two male, active duty military pilots (U.S. Navy and U. S. Marine Corps), ages 30 and 35, were each given twelve 30-minute training sessions. The primary criterion for success of training was the subject's ability to tolerate rotating chair motion sickness tests for progressively longer periods of time and at higher rotational velocities. A standardized diagnostic scale was used during motion sickness to assess changes in the subject's perceived malaise. Physiological data were obtained from one pilot during tactical maneuvers in an F-18 aircraft after completion of his training. A significant increase in tolerance to laboratory-induced motion sickness tests and a reduction in autonomic nervous system (ANS) response variability was observed for both subjects after training. Both pilots were successful in applying AFT for controlling their airsickness during subsequent qualification tests on F-18 and T-38 aircraft and were returned to active duty flight status.

Direct atomic fabrication and dopant positioning in Si using electron beams with active real-time image-based feedback

Science.gov (United States)

Jesse, Stephen; Hudak, Bethany M.; Zarkadoula, Eva; Song, Jiaming; Maksov, Artem; Fuentes-Cabrera, Miguel; Ganesh, Panchapakesan; Kravchenko, Ivan; Snijders, Panchapakesan C.; Lupini, Andrew R.; Borisevich, Albina Y.; Kalinin, Sergei V.

2018-06-01

Semiconductor fabrication is a mainstay of modern civilization, enabling the myriad applications and technologies that underpin everyday life. However, while sub-10 nanometer devices are already entering the mainstream, the end of the Moore’s law roadmap still lacks tools capable of bulk semiconductor fabrication on sub-nanometer and atomic levels, with probe-based manipulation being explored as the only known pathway. Here we demonstrate that the atomic-sized focused beam of a scanning transmission electron microscope can be used to manipulate semiconductors such as Si on the atomic level, inducing growth of crystalline Si from the amorphous phase, reentrant amorphization, milling, and dopant front motion. These phenomena are visualized in real-time with atomic resolution. We further implement active feedback control based on real-time image analytics to automatically control the e-beam motion, enabling shape control and providing a pathway for atom-by-atom correction of fabricated structures in the near future. These observations open a new epoch for atom-by-atom manufacturing in bulk, the long-held dream of nanotechnology.

Direct atomic fabrication and dopant positioning in Si using electron beams with active real-time image-based feedback.

Science.gov (United States)

Jesse, Stephen; Hudak, Bethany M; Zarkadoula, Eva; Song, Jiaming; Maksov, Artem; Fuentes-Cabrera, Miguel; Ganesh, Panchapakesan; Kravchenko, Ivan; Snijders, Panchapakesan C; Lupini, Andrew R; Borisevich, Albina Y; Kalinin, Sergei V

2018-06-22

Semiconductor fabrication is a mainstay of modern civilization, enabling the myriad applications and technologies that underpin everyday life. However, while sub-10 nanometer devices are already entering the mainstream, the end of the Moore's law roadmap still lacks tools capable of bulk semiconductor fabrication on sub-nanometer and atomic levels, with probe-based manipulation being explored as the only known pathway. Here we demonstrate that the atomic-sized focused beam of a scanning transmission electron microscope can be used to manipulate semiconductors such as Si on the atomic level, inducing growth of crystalline Si from the amorphous phase, reentrant amorphization, milling, and dopant front motion. These phenomena are visualized in real-time with atomic resolution. We further implement active feedback control based on real-time image analytics to automatically control the e-beam motion, enabling shape control and providing a pathway for atom-by-atom correction of fabricated structures in the near future. These observations open a new epoch for atom-by-atom manufacturing in bulk, the long-held dream of nanotechnology.

Undergraduate Research and Training in Ion-Beam Analysis of Environmental Materials

Science.gov (United States)

Vineyard, Michael F.; Chalise, Sajju; Clark, Morgan L.; LaBrake, Scott M.; McCalmont, Andrew M.; McGuire, Brendan C.; Mendez, Iseinie I.; Watson, Heather C.; Yoskowitz, Joshua T.

We have an active undergraduate research program at the Union College Ion-Beam Analysis Laboratory (UCIBAL) focused on the study of environmental materials. Accelerator-based ion-beam analysis (IBA) is a powerful tool for the study of environmental pollution because it can provide information on a broad range of elements with high sensitivity and low detection limits, is non-destructive, and requires little or no sample preparation. It also provides excellent training for the next generation of environmental scientists. Beams of protons and alpha particles with energies of a few MeV from the 1.1-MV tandem Pelletron accelerator (NEC Model 3SDH) in the UCIBAL are used to characterize environmental samples using IBA techniques such as proton-induced X-ray emission, Rutherford back-scattering, and proton-induced gamma-ray emission. Recent projects include the characterization of atmospheric aerosols in the Adirondack Mountains of upstate New York, the study of heavy metal pollutants in river sediment, measurements of Pb diffusion in sulfide minerals to help constrain the determination of the age of iron meteorites, and the search for heavy metals and toxins in artificial turf.

Effectiveness of Instruction and Video Feedback on Staff's Use of Prompts and Children's Adaptive Responses during One-to-One Training in Children with Severe to Profound Intellectual Disability

Science.gov (United States)

van Vonderen, Annemarie; de Swart, Charlotte; Didden, Robert

2010-01-01

Although relatively many studies have addressed staff training and its effect on trainer behavior, the effects of staff training on trainee's adaptive behaviors have seldomly been examined. We therefore assessed effectiveness of staff training, consisting of instruction and video feedback, on (a) staff's response prompting, and (b) staff's trainer…

Status of Digital Orbit Feedback for SPEAR

International Nuclear Information System (INIS)

Hettel, Robert

2003-01-01

The present global orbit feedback system for SPEAR can adjust the electron beam position with a cycle time of 5 s. In addition, 50 Hz analog local servos stabilize the vertical photon beam position at monitors situated in the ten SSRL beamlines. The global and local systems will soon be merged into a single unified system operating from a dedicated DSP board. The goal is to acquire orbits, process the data, and correct beam position in a 1-2 ms interval to achieve a 30-50 Hz closed-loop bandwidth

Application of integral-separated PID algorithm in orbit feedback

International Nuclear Information System (INIS)

Xuan, K.; Bao, X.; Li, C.; Li, W.; Liu, G.; Wang, J.; Wang, L.

2012-01-01

The algorithm in the feedback system has important influence on the performance of the beam orbit. PID (Proportion Integration Differentiation) algorithm is widely used in the beam orbit feedback system; however, the deficiency of PID algorithm is a big overshooting in strong perturbations. In order to overcome the deficiencies, the integral-separated PID algorithm is developed. When the closed orbit distortion is too large, it cancels integration action until the closed orbit distortion is lower than the separation threshold value. The implementation of integral-separated PID algorithm with MATLAB is described in this paper. The simulation results show that this algorithm can improve the control precision. (authors)

Prevailing Trends in Haptic Feedback Simulation for Minimally Invasive Surgery.

Science.gov (United States)

Pinzon, David; Byrns, Simon; Zheng, Bin

2016-08-01

Background The amount of direct hand-tool-tissue interaction and feedback in minimally invasive surgery varies from being attenuated in laparoscopy to being completely absent in robotic minimally invasive surgery. The role of haptic feedback during surgical skill acquisition and its emphasis in training have been a constant source of controversy. This review discusses the major developments in haptic simulation as they relate to surgical performance and the current research questions that remain unanswered. Search Strategy An in-depth review of the literature was performed using PubMed. Results A total of 198 abstracts were returned based on our search criteria. Three major areas of research were identified, including advancements in 1 of the 4 components of haptic systems, evaluating the effectiveness of haptic integration in simulators, and improvements to haptic feedback in robotic surgery. Conclusions Force feedback is the best method for tissue identification in minimally invasive surgery and haptic feedback provides the greatest benefit to surgical novices in the early stages of their training. New technology has improved our ability to capture, playback and enhance to utility of haptic cues in simulated surgery. Future research should focus on deciphering how haptic training in surgical education can increase performance, safety, and improve training efficiency. © The Author(s) 2016.

The continuation training of operators and feedback of operational experience in the Royal Navy's nuclear submarine programme

International Nuclear Information System (INIS)

Manson, R.P.

1983-01-01

Naval continuation training has relied heavily on the use of realistic simulators for over ten years, and this has been proved to be a cost-effective and efficient method of training. The type of simulator used, the selection and qualification of simulator instructors, and the method of training experienced operators is described. Also, the assessment of operator performance, the use of simulators during the final stages of operator qualification, and their use for training operators on plant operation whilst shut-down are covered. The Navy also pays great attention to the feedback of operating experience from sea into both continuation and basic training. This is accomplished using Incident Reports, which are rendered whenever the plant is operated outside the approved Operating Documentation, or when any other unusual circumstance arises. Each Report is individually assessed and replied to by a qualified operator, and those incidents of more general interest are published in a wider circulation document available to all plant operators. In addition, each crew is given an annual lecture on recent operating experiences. Important lessons are fed forward into new plant design, and the incident reports are also used as a source of information for plant reliability data. (author)

Decorrelation of Neural-Network Activity by Inhibitory Feedback

Science.gov (United States)

Einevoll, Gaute T.; Diesmann, Markus

2012-01-01

Correlations in spike-train ensembles can seriously impair the encoding of information by their spatio-temporal structure. An inevitable source of correlation in finite neural networks is common presynaptic input to pairs of neurons. Recent studies demonstrate that spike correlations in recurrent neural networks are considerably smaller than expected based on the amount of shared presynaptic input. Here, we explain this observation by means of a linear network model and simulations of networks of leaky integrate-and-fire neurons. We show that inhibitory feedback efficiently suppresses pairwise correlations and, hence, population-rate fluctuations, thereby assigning inhibitory neurons the new role of active decorrelation. We quantify this decorrelation by comparing the responses of the intact recurrent network (feedback system) and systems where the statistics of the feedback channel is perturbed (feedforward system). Manipulations of the feedback statistics can lead to a significant increase in the power and coherence of the population response. In particular, neglecting correlations within the ensemble of feedback channels or between the external stimulus and the feedback amplifies population-rate fluctuations by orders of magnitude. The fluctuation suppression in homogeneous inhibitory networks is explained by a negative feedback loop in the one-dimensional dynamics of the compound activity. Similarly, a change of coordinates exposes an effective negative feedback loop in the compound dynamics of stable excitatory-inhibitory networks. The suppression of input correlations in finite networks is explained by the population averaged correlations in the linear network model: In purely inhibitory networks, shared-input correlations are canceled by negative spike-train correlations. In excitatory-inhibitory networks, spike-train correlations are typically positive. Here, the suppression of input correlations is not a result of the mere existence of correlations between