Online Error Research Articles

Using online annotations to support error correction and corrective feedback

Giving feedback on second language (L2) writing is a challenging task. This research proposed an interactive environment for error correction and corrective feedback. First, we developed an online corrective feedback and error analysis system called Online Annotator for EFL Writing. The system consisted of five facilities: Document Maker, Annotation Editor, Composer, Error Analyzer, and Viewer. With this system, teachers can mark error corrections on online documents and students can receive corrective feedback accordingly. The system also classifies and displays error types based on user query. Second, an experiment was conducted to evaluate the effectiveness of this system. Fifty EFL (English as a Foreign Language) college freshmen were randomly assigned to two groups. The experimental group received corrective feedback with the developed system whereas the control group used the paper-based error correction method. After the treatment, students in both groups conducted corrective feedback activities by correcting the same document written by an EFL student. The experimental results were encouraging in that the analysis of students’ corrective feedback revealed significantly better performance in the experimental group on recognizing writing errors. Implications for further research are discussed.

Kinematic analysis of a functional and sequential bimanual task in patients with left hemiparesis: intra-limb and interlimb coordination

Purpose. To characterise upper limb performance of each hand (intra-limb coordination) and interlimb coordination on a functional, sequential bimanual task in patients with left hemiparesis and age-matched controls.Method. Fourteen patients with left hemiparesis (age: 60.01±9.09 years) and 13 adults without neurological impairments (age: 59.14±10.59 years) were instructed to reach-to-grasp a jar with the affected/left limb and to unscrew the jar cap with the unaffected/right limb. Reaching and grasping kinematics were analysed for intra-limb coordination and bimanual synchronisation and temporal correlation for interlimb coordination.Results. The patients showed significantly less efficient, less smooth, and less forceful movement and spent significantly more time for on-line error correction with the affected hand than the healthy controls. Interlimb coordination was disrupted at movement onset but was preserved at movement end in the hemiparetic patients.Conclusions. The major deficits of the left hemiparetic patients involved heavy reliance on feedback control with the affected hand, and poor bimanual coordination at movement onset, which might be specifically retrained during stroke rehabilitation. Preservation of interlimb coordination at movement end in stroke patients suggested that they retained flexibility in response to the impaired temporal performance of the affected hand to achieve the end goal.

Transmission error analysis and avoidance for IEEE 802.15.4 wireless sensors on rotating structures

Wireless sensors are increasingly adopted in manufacturing and vehicular systems for monitoring critical components under continuous operation. Many such components move rapidly and frequently in metallic containments with challenging radio propagation characteristics. For wireless sensors mounted on rotating structures, previous experimental studies observed an eminent increase in packet transmission errors at higher rotation speeds. Such errors were found to occur at specific locations around the rotating spindle's periphery and such locations depended sensitively on sensor location and surrounding geometry. This paper analyses the expected packet error rates with different rotation speeds and error region distributions, and proposes a transmission error avoidance approach based on online error pattern inference and transmission time control for IEEE 802.15.4 compatible sensor radios. Simulation studies showed a 50% error reduction and up to 75% throughput increase; higher throughput gains are expected for applications with more frequent and larger size data transmissions.

Dorsal Medial Prefrontal Cortex Plays a Necessary Role in Rapid Error Prediction in Humans

Activity in human dorsal anterior cingulate cortex (dACC) is correlated with errors, near-misses, and response conflict. Based on these observations, this region has been cast as playing a central role in models of error processing, conflict monitoring, and cognitive control. However, clear evidence that this region of the brain is necessary for these processes has been elusive. We studied the effects of damage to this region on four different error-related measures in five patients, and 19 healthy participants. Most error-related indices were not affected by such damage: patients had intact post-error slowing, and were able to report and to correct errors after they were made with accuracies comparable with the control group. However, all five patients were notably slow to correct errors, suggesting a deficit in on-line error prediction. This slowing was associated with impairment in the conscious prediction of error likelihood before a response. This finding constitutes important converging evidence for a critical role for human dACC in error monitoring, and sheds light on the selectivity and timing of the error-related process affected by dACC damage.

The effect of cerebellar cortical degeneration on adaptive plasticity and movement control

Clinical and neuroimaging studies provide converging evidence that the cerebellum plays an important role for sensorimotor adaptation by participating in the adaptive process per se, and/or by evaluating motor performance errors as a prerequisite for adaptation. Recent experimental evidence suggests that error signals pertinent to adaptation are related to sensory prediction rather than to online corrections (Tseng et al. in J Neurophysiol 98(1):54-62, 2007). To further elucidate the role of the cerebellum, the present study uses a multiple regression approach to separate out three independent determinants of adaptive success. Seventeen patients with cerebellar atrophy but without extra-cerebellar lesions, and 17 healthy, sex- and age-matched controls participated. Both subject groups performed center-out pointing movements before, during, and after exposure to 60 degrees rotated visual feedback. From the registered data, we quantified four indicators of adaptive success (adaptive improvement, retention without feedback, intermanual transfer, and de-adaptation under normal feedback), as well as five measures of motor performance (reaction time, peak velocity, movement time, response variability, and ability for online error corrections). The variance of each adaptation indicator was then partitioned into three components, one related to subject group but not to motor performance, a second related to group and motor performance, and a third related to motor performance but not to group. In accordance with previous work, adaptation and motor performance were degraded in patients. The deficit was similar in magnitude for all four adaptation indicators, which suggests that adaptive recalibration rather than strategic control were affected in our patients. No adaptation indicator shared statistically significant variance with group alone; we therefore found no evidence for cerebellar circuitry dedicated to adaptation but not motor performance. Three indicators shared significant variance jointly with group and motor performance; this suggests that the cerebellar contribution to motor performance is related to adaptive success. All four indicators shared significant variance with motor performance alone; this indicates that extracerebellar contributions to motor performance are also related to adaptive success. In conclusion, our data support the view that neural structures inside and outside the cerebellum are processing motor performance-related signals as a prerequisite for adaptation, but provide no evidence for a cerebellar structure related exclusively to adaptation.

Shared Internal Models for Feedforward and Feedback Control

A child often learns to ride a bicycle in the driveway, free of unforeseen obstacles. Yet when she first rides in the street, we hope that if a car suddenly pulls out in front of her, she will combine her innate goal of avoiding an accident with her learned knowledge of the bicycle, and steer away or brake. In general, when we train to perform a new motor task, our learning is most robust if it updates the rules of online error correction to reflect the rules and goals of the new task. Here we provide direct evidence that, after a new feedforward motor adaptation, motor feedback responses to unanticipated errors become precisely task appropriate, even when such errors were never experienced during training. To study this ability, we asked how, if at all, do online responses to occasional, unanticipated force pulses during reaching arm movements change after adapting to altered arm dynamics? Specifically, do they change in a task-appropriate manner? In our task, subjects learned novel velocity-dependent dynamics. However, occasional force-pulse perturbations produced unanticipated changes in velocity. Therefore, after adaptation, task-appropriate responses to unanticipated pulses should compensate corresponding changes in velocity-dependent dynamics. We found that after adaptation, pulse responses precisely compensated these changes, although they were never trained to do so. These results provide evidence for a smart feedback controller which automatically produces responses specific to the learned dynamics of the current task. To accomplish this, the neural processes underlying feedback control must (1) be capable of accurate real-time state prediction for velocity via a forward model and (2) have access to recently learned changes in internal models of limb dynamics.

On-demand generation of reduced mechanisms based on hierarchically extended intrinsic low-dimensional manifolds in generalized coordinates

A new implementation scheme for reduced mechanisms based on hierarchically generated and extended intrinsic low-dimensional manifolds (ILDMs) created “on-demand” is presented. The algorithm includes the use of ILDMs in generalized coordinates and a new hierarchical concept for the extension of the ILDMs into the domain of slow chemistry. Problems of pre-calculated ILDM tables are overcome by generating ILDM cells on-demand during the flame calculation, yielding an increased efficiency of the table generation and implementation. In view of a future generation of ILDMs with adaptive dimension based on a local online error control, the presented algorithm includes the possibility to increase the ILDM dimension hierarchically after the stationary solution (solution after 104s) of the first flame calculation with an nc-dimensional ILDM is reached and to re-calculate the result of this first flame calculation using higher-dimensional manifolds with a subsequent error test. The paper presents the generation of hierarchically extended ILDMs in generalized coordinates as well as the on-demand implementation scheme. A sample free flame calculation for the syngas–air system validates the algorithms.

On-Line Error Measurement Based on CCD in Quick-Point Grinding of Curve Parts

This paper deals with an on-line mismachining error measurement for curve grinding based on digital image processing. Using CCD camera, the contour of the workpiece’s finished surface is captured and the image is preprocessed for denoising and edge detecting. The worktable is guided by the image of the finished workpiece to follow the path of the finished contour and then the real curve of the finished workpiece is measured by fitting a curve according to the moving path of the worktable. Finally, the machining error is obtained by comparing the measured curve with the theoretical curve of the workpiece. This method is applied to a CNC curve grinding machine MD9040. A measurement experiment is given. The experiment results show that the measurement method offers high detection precision and can be used in wide fields, especially for measuring the parts with complex curve.

Development of a three-degree-of-freedom laser linear encoder for error measurement of a high precision stage

In this study, a laser linear encoder with three degrees of freedom (3-DOFs) based on diffraction and interference was developed to measure the linear displacement and two angular errors of a linear moving stage. Parts of the linear motion errors induced from the two angular errors can be calculated by this prototype 3-DOF laser encoder. It was an effective method for online error calculation and compensation to improve precision stage performance. This new function was superior to other laser encoders. The verification results showed that the resolution is 20 nm. It detected displacements relative to an external grating scale with accuracy of about +/-150 nm for a measuring range of +/-1 mm, and detected the angular errors with related accuracy of about +/-1 arc sec for a measuring range of +/-100 arc sec.

High-speed digital image correlation: error estimations and applications

Among the different optical measurement techniques for full-field analysis of displacements and strains, digital image correlation (DIC) has proven to be very flexible, robust, and easy to use, covering a wide range of different applications. DIC measurement results, among others, are influenced by the systematic errors of the measurements system, a major source of which is due to imaging system calibration. We present a 3-D DIC system that provides online error information concerning diverse error sources, and even more important, the propagation of errors throughout the calculations to the resulting contours, displacements, and strains. On the basis of this system we discuss error sources, error propagation, and the impact on correlation results. Performance tests for studying the impact of calibration errors on the resulting data are shown for static and dynamic applications.

Objective Metamemory Testing Captures Awareness of Deficit in Alzheimer's Disease

For reasons that remain unknown, there is marked inter-person variability in awareness of episodic memory loss in patients with Alzheimer's disease (AD). Existing research designs, primarily subjective in nature, have been at a relative disadvantage for evaluating disordered metamemory and its relation to the clinical and neuropathological heterogeneity of AD, as well as its prognosis for various disease outcomes. The current study sought to establish an objective means of evaluating metamemory in AD by modifying traditional metacognitive paradigms in which participants are asked to make predictions regarding their own memory performance. Variables derived from this measure were analyzed in relation to clinically rated awareness for memory loss. As predicted, a range of awareness levels existed across patients with mild to moderate AD (n = 24) and clinical ratings of awareness (CRA) were significantly associated with verbal episodic memory monitoring (r = .46, p = .03). Further, patients who were rated as aware of their memory loss remained well calibrated over the course of the task whereas those rated as relatively unaware grew over-confident in their predictions [F (1, 33) = 4.19, p = .02]. Findings suggest that over-confidence may be related to impaired online error recognition and compromised use of metamemory strategies such as the Memory for Past Test (MPT) heuristic. Importantly, clinically rated awareness did not vary as a function of demographic variables, global cognition, or verbal memory. However, participants characterized as relatively unaware were impaired on a nonverbal memory task as compared to aware participants [F (1, 20) = 6.98, p = .02]. The current study provides preliminary support for the use of a recognition-based verbal episodic memory monitoring task as a quantitative measure of awareness for memory loss in AD, and offers insight into the manner in which metamemory breaks down. Discrepancies in nonverbal memory across the two awareness groups provide preliminary support for the idea that metamemory variability in AD may be related to the neuroanatomic presentation of the disease, with disordered awareness potentially reflective of a critical level of right hemisphere involvement.

A new digital measurement method for accurate curve grinding process

In this paper, an online measurement and error compensation system for curve grinding based on pattern recognition was presented and verified by experiments. The measurement system organization and its principle of operation were introduced in detail. The work piece and grinding wheel image were sampled at certain positions to avoid spark influence. In order to increase system resolution, images were sampled only at local areas of the work piece and grinding wheel. A discrimination technology based on a circular tolerance zone was proposed which can solve the problem of local image edge comparison. For image de-noising, a local threshold algorithm was applied to determine new wavelet coefficients. Furthermore, a two-step edge detection method was used to realize sub-pixel precision. Finally, a series of experiments were carried out to examine the detection precision of the image measurement system and its influencing factors. From experiments, it can be said that the proposed method in this paper is effective, and its detection precision is much better than traditional methods.

On-Line Monitoring of the Buffer Capacity of Particleboard Furnish by Near-Infrared Spectroscopy

This paper reports on a study of on-line monitoring of the buffer capacity of particleboard furnish using near-infrared (NIR) spectroscopy and multivariate analysis models (chemometrics). The buffer capacity of wood furnish is known to affect the quality of polymerization and the curing rates of urea-formaldehyde (UF) resins, which may affect the mechanical properties of manufactured panel. The first phase of the study consisted of building multivariate calibration and validation models from NIR spectroscopy data to predict the buffer capacity of particleboard furnish in a laboratory environment. During this phase, a spectrometer (Ocean Optics USB2000) operating in the 550-1100 nm spectral range was evaluated. The second phase of the study took place at a North American particleboard plant over several weeks. Several multivariate calibration models were constructed and tested on-line during a four-day test period. The on-line root mean square error of prediction (RMSEP) and the coefficient of variation (CV) for buffer capacity predictions ranged from 3.45 to 0.92 and 22.4% to 5.8%, respectively.

The Human Dorsal Premotor Cortex Generates On-Line Error Corrections during Sensorimotor Adaptation

A number of different sites in the human brain have been shown to play a role in sensorimotor adaptation. However, the specific role played by each of these structures in the learning process is poorly understood. In the present study, the contribution of the dorsal aspect of the premotor cortex was examined by disrupting activity at this site using transcranial magnetic stimulation (TMS) while subjects wearing prism goggles pointed at visual targets. This manipulation slowed down the rate of adaptation when vision of the hand was available throughout the movement and reduced the presence of on-line trajectory corrections. This was accompanied by a reduced shift in the felt position of the arm. In contrast, TMS did not cause any alteration in the performance of this task when vision of the hand was available only at the end of the movement. Thus, we infer from this pattern of results that the human dorsal premotor cortex contributes to the generation of the visually based on-line error corrections that are responsible for the remapping of arm position sense underlying sensorimotor adaptation.

Software-Based Fault Tolerant Computing

This paper describes how to design a software-based fault tolerant application using microprocessor (MP), in order to tolerate the burst errors in memory. This approach may be called a single -- version scheme (SVS). The SVS relies on a single version application program which is enhanced with self-checking code redundancy to tolerate memory burst errors that are difficult to correct during the run-time of an application. Conventionally, the other software based approaches can detect a few bit errors (in memory) only towards fail-stop kind of fault tolerance against transient bit errors. Reed Solomon codes are mainly effective for burst errors in coding of audio Compact Disks at offline only. The proposed online technique does not need multiple versions of software and multiple machines. This approach employs only two copies of the application software running on one machine only. Two copies of the enhanced version version of an application are used here for online error detection and tolerance thereof as well. This is an effective low-cost online tool for hardening a microprocessor-based industrial computing system or for on-chip DRAM applications using an affordable code and time redundancy against the burst errors in processor memory. The SVS aims to provide a non-fail-stop kind of fault tolerance against burst errors. This approach supplements the Error Correcting Codes (ECC) in memory system also, against both the transient and permanent bit errors in memory.

Technical Communication in Information Systems Development: The Use of Cognitive Mapping

Technical communicators can and should play an important role in the development of information systems to improve the usability of the systems. Besides writing user guides and training material, technical communicators can engage in four other tasks to add value to information systems development: acting as user advocate, writing online help, writing system and error messages, and providing advice on interface design. We assert that technical communicators' involvement in systems development should not be tied to a particular development methodology. Instead, they should be associated with four general tasks in systems development: system investigation, analysis, design, and implementation. We then discuss some notable human factors and their impacts on the tasks performed by technical communicators. Three cognitive mapping techniques-causal mapping, semantic mapping, and concept mapping-are introduced as a means to elicit an individual's belief system regarding a problem domain. These cognitive mapping techniques have great potential for overcoming some behavioral and cognitive problems as well as facilitating understanding among stakeholders in the development of information systems. We discuss how technical communicators can apply various cognitive mapping techniques to improve the usability of the resulting information systems. The use of these techniques is illustrated using a case study.

Vestibular Reafference Shapes Voluntary Movement

The vestibular organs in the inner ear are commonly thought of as sensors that serve balance, gaze control, and higher spatial functions such as navigation. Here, we investigate their role in the online control of voluntary movements. The central nervous system uses sensory feedback information during movement to detect and correct errors as they develop. Vestibular organs signal three-dimensional head rotations and translations and so could provide error information for body movements that transport the head in space. To test this, we electrically stimulated human vestibular nerves during a goal-directed voluntary tilt of the trunk. The stimulating current waveform was made identical to the angular velocity profile of the head in the roll plane. With this, we could proportionally increase or decrease the rate of vestibular nerve firing, as if the head were rotating faster or slower than it actually was. In comparison to movements performed without stimulation, subjects tilted their trunk faster and further or slower and less far, depending upon the polarity of the stimulus. The response was negligible when identical stimulus waveforms were replayed to stationary subjects. We conclude that the brain uses vestibular information for online error correction of planned body-movement trajectories.

Kinematic properties of on-line error corrections in the monkey

Despite the abundant experimental evidence for the irregular, multipeaked velocity profiles that often characterize rapid human limb movements, there is currently little agreement on how to interpret these phenomena. While in some studies these irregularities have been interpreted as reflecting a continuous control process, in others the irregularities are considered to be evidence for the existence of discrete movement primitives that are initiated by an intermittent controller. Here we introduce a novel "soft symmetry" method for analyzing irregular movements and decomposing them into their discrete movement primitives. We applied this method to analyze rapid pronation/supination wrist movements in monkeys during a one-dimensional tracking task. We showed that the properties of the extracted overlapping submovements (OSMs) were very similar to those of single, regular movements, despite the fact that the decomposition algorithm did not restrict the extracted submovements to a particular shape. In addition we showed that the movement primitives corrected preceding primitives and that the correction initiation time was highly variable, and thus could not be explained by the relatively fixed sensorimotor delay. These results argue against the interpretation of movement irregularities as reflecting a continuous control process and reinforce the hypothesis that movement irregularities result from an intermittent control mechanism. Demonstrating these phenomena in non-human primates will allow neurophysiological investigation of the neural mechanisms involved in these corrections.

Optimal interpolation analysis of high‐latitude ionospheric electrodynamics using empirical orthogonal functions: Estimation of dominant modes of variability and temporal scales of large‐scale electric fields

In this paper the optimal interpolation method, in conjunction with empirical orthogonal function (EOF) bases and the maximum likelihood method for online error covariance parameter estimation, is successfully implemented for the objective analysis of large‐scale high‐latitude ionospheric electrodynamic variables. This study demonstrates how this methodology can be used to extract information about the temporal and spatial coherence of the large‐scale electric field for a magnetic cloud event on 10–11 January 1997. Compared with the temporal persistence of the interplanetary magnetic field (IMF) and solar wind parameters, the timescale of the spatially coherent part of the electric field, on the spatial scale of the EOFs, is shorter. The principal components of the high‐latitude electric field are analyzed during two periods when either the IMF BY or BZ component was relatively steady while the other component varied. The first principal component, not surprisingly, generally reflects the change in the ionospheric convection pattern predicted by IMF‐dependent empirical models and thus tends to represent changes in the convection that are directly driven by solar wind–magnetosphere interactions. However, it is the second principal component that is more strongly correlated with the westward auroral electrojet, suggestive of a link to substorm phenomena.

Cone-beam-CT guided radiation therapy: A model for on-line application

Background and PurposeThis paper presents efficient and generalized processes for the clinical application of on-line X-ray volumetric cone-beam CT imaging (XVI) to improve the accuracy of patient set-up in radiation therapy. XVI image-guided therapy is illustrated by application to two contrasting sites, intra-cranial radiosurgery and prostate radiation therapy, with very different characteristics regarding organ motion, treatment precision, and imaging conditions. Patients and methodsOn-line set-up errors are determined in a two-step process. First the XVI data is registered to the planning data by matching the machine-isocenter with the planning-isocenter, respectively. The machine isocenter is defined in the XVI data during the reconstruction. The planning-isocenter is defined during the planning process in the planning CT data. Set-up errors are then determined from a second registration to remove residual displacements. The accuracy of the entire procedure for on-line set-up error correction was investigated in precision radiosurgery phantom studies. ResultsThe phantom studies showed that sub-pixel size set-up errors (down to 0.5mm) can be correctly determined and implemented in the radiosurgery environment. XVI is demonstrated to provide quality skull detail enabling precise skull based on-line alignment in radiosurgery. A ‘local XVI’ technique was found to give encouraging soft-tissue detail in the high-scatter pelvic environment, enabling on-line soft-tissue based set-up for prostate treatment. The two-step process for determination of set-up errors was found to be efficient and effective when implemented with a dedicated six panel interface enabling simultaneous visualization on the XVI and planning CT data sets. ConclusionsXVI has potential to significantly improve the accuracy of radiation treatments. Present image quality is highly encouraging and can enable bony and soft-tissue patient set-up error determination and correction. As with all image guided treatment techniques the development of efficient procedures to utilize on-line data are of paramount importance.