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The central challenge in building a quantum computer is error correction. Unlike classical bits, which are susceptible to only one type of error, quantum bits (qubits) are susceptible to two types of error, corresponding to flips of the qubit state about the X and Z directions. Although the Heisenberg uncertainty principle precludes simultaneous monitoring of X- and Z-flips on a single qubit, it is possible to encode quantum information in large arrays of entangled qubits that enable accurate monitoring of all errors in the system, provided that the error rate is low.sup.1. Another crucial requirement is that errors cannot be correlated. Here we characterize a superconducting multiqubit circuit and find that charge noise in the chip is highly correlated on a length scale over 600 micrometres; moreover, discrete charge jumps are accompanied by a strong transient reduction of qubit energy relaxation time across the millimetre-scale chip. The resulting correlated errors are explained in terms of the charging event and phonon-mediated quasiparticle generation associated with absorption of [gamma]-rays and cosmic-ray muons in the qubit substrate. Robust quantum error correction will require the development of mitigation strategies to protect multiqubit arrays from correlated errors due to particle impacts. Cosmic-ray particles and [gamma]-rays striking superconducting circuits can generate qubit errors that are spatially correlated across several millimetres, hampering current error-correction approaches., Author(s): C. D. Wilen [sup.1] , S. Abdullah [sup.1] , N. A. Kurinsky [sup.2] [sup.3] , C. Stanford [sup.4] , L. Cardani [sup.5] , G. D'Imperio [sup.5] , C. Tomei [...]

Eyewitness misidentification is the most common contributing factor to wrongful convictions in the United States, with eyewitness error playing a role in over 70% of the nation's DNA exoneration cases. [...]

Humans engaged in monotonous tasks are susceptible to occasional errors that may lead to serious consequences, but little is known about brain activity patterns preceding errors. Using functional MRI and applying independent component analysis followed by deconvolution of hemodynamic responses, we studied error preceding brain activity on a trial-by-trial basis. We found a set of brain regions in which the temporal evolution of activation predicted performance errors. These maladaptive brain activity changes started to evolve [approximately equal to] 30 sec before the error. In particular, a coincident decrease of deactivation in default mode regions of the brain, together with a decline of activation in regions associated with maintaining task effort, raised the probability of future errors. Our findings provide insights into the brain network dynamics preceding human performance errors and suggest that monitoring of the identified precursor states may help in avoiding human errors in critical real-world situations. deconvolution | performance monitoring | default mode | frontal lobe

Complex behavior requires a flexible system that maintains task performance in the context of specific goals, evaluating behavioral progress, adjusting behavior as needed, and adapting to changing contingencies. Generically referred [...]

This paper describes human errors and violations of end users and network administration in computer and information security. This information is summarized in a conceptual framework for examining the human and organizational factors contributing to computer and information security. This framework includes human error taxonomies to describe the work conditions that contribute adversely to computer and information security, i.e. to security vulnerabilities and breaches. The issue of human error and violation in computer and information security was explored through a series of 16 interviews with network administrators and security specialists. The interviews were audio taped, transcribed, and analyzed by coding specific themes in a node structure. The result is an expanded framework that classifies types of human error and identifies specific human and organizational factors that contribute to computer and information security. Network administrators tended to view errors created by end users as more intentional than unintentional, while errors created by network administrators as more unintentional than intentional. Organizational factors, such as communication, security culture, policy, and organizational structure, were the most frequently cited factors associated with computer and information security. Keywords: Human error; Violation; Computer security; Work system; Macroergonomic; Qualitative research

In this article, it is shown that human work can be understood as a process of creating order, and that order can be seen as a form of information. Since information can be considered as negative entropy, work is associated with energy consumption. Therefore, it is important to investigate the nature of human necessities in more detail in order to meet the desire for comfort through the efficient application of energy. Temporary increases of information cause accelerated increases in entropy. This explains the appearance of living organisms, and the historic development of increasingly complex technology. Through technical progress, repetitive human work is being replaced by automation, so that primarily creative work remains. Now the question arises of how much creative work a human can manage. In addition, one goal of automation should be the reduction of human errors, but in doing so, an optimal balance should be found between supporting the operator both during normal procedures and during unforeseen circumstances. Keywords: Turing machine; Comfort; Human error; Automation

The hypothesis is introduced that 1 source of shift costs is the strengthening of task-related associations occurring whenever an overt response is produced. The authors tested this account by examining shift effects following errors and error compensation processes. The authors predicted that following a specific type of error, called task confusion, shift benefits instead of shift costs should result. A series of 3 experiments confirmed this prediction showing that task confusions produce shift benefits in subsequent trials (Experiment 1), even when the error is detected (Experiment 2). Moreover, only post-error processes that imply an error correction response produce shift costs (Experiment 3). These results additionally suggest that error detection cannot prevent errors from affecting subsequent performance. Keywords: task shifting, error processing, response repetition

In this study, the authors sought to determine whether abnormalities exhibited by schizophrenia patients in event-related potentials associated with self-monitoring--the error-related negativity (ERN) and the correct response negativity (CRN)--persist under conditions that maximize ERN amplitude and to examine relationships between the ERN and behavior in schizophrenia. Participants performed a flanker task under 2 contingencies: one encouraging accuracy and another emphasizing speed. Compared with healthy participants, in schizophrenia patients the ERN was reduced in the accuracy condition, and the CRN was enhanced in the speed condition. The amplitude of a later ERP component, the error positivity, did not differ between groups in either task condition. Reduced self-correction and increased accuracy following errors were associated with larger ERNs in both groups. Thus, ERN generation appears to be abnormal in schizophrenia patients even under conditions demonstrated to maximize ERN amplitude; however, functional characteristics of the ERN appear to be intact. Keywords: self-monitoring, schizophrenia, error-related negativity

Educators generally agree that familiarity with students' conceptions and ways of thinking about mathematical topics are essential for teachers (e.g., Australian Education Council, 1991; Even & Tirosh, 2002; Fennema, Carpenter, […]

The central role of intention in the classification of errors into slips/lapses/mistakes is emphasized. Intention is a core concept of prospective memory theory where intention retrievals, intention persistence and output monitoring can be the contribution in the individual's possibilities for detecting error.

The purpose of this study was to evaluate a program designed to improve the work quality of employees at a food distribution warehouse. Participants (n = 23) were responsible for selecting food items to be distributed to restaurants. Selector errors were targeted using an adapted incentive program featuring tiered goals and individualized normative feedback. A pre-existing incentive program, wherein selectors forfeited money for each error, was adapted to allow the selectors the opportunity to earn back their disincentive money upon attainment of weekly goals that were increasingly demanding. The initial goal for the first two weeks was set at 2.0 errors per 1000 cases and every two weeks thereafter the new goal was reduced by 0.1 errors per 1000 cases until the final goal of 1.5 errors per 1000 cases. Weekly graphic feedback included public posting of individual error rates. The mean errors per 1000 cases for the experimental group decreased 10% from 3.16 during baseline to 2.54 during the intervention. The largest decrease in errors was observed in the mid-level performers (with baseline error rates between 2 and 3.5 errors per 1000 cases). A cost-benefit analysis revealed potential savings of $9,799.50. KEYWORDS. Incentives, employee errors, changing criterion, normative feedback

This paper studies instrumental variables (IV) estimation for an error component model with stationary and nearly nonstationary regressors. It is assumed that the numbers of cross section and time series observations are infinite. Furthermore, autoregressive disturbances are assumed for the error component model, the structure of which may vary with individuals. The estimators considered are the Within-IV-OLS, Within-IV-GLS and IV-GLS estimators. The GLS estimators use Gohberg's formula, which is particularly useful when autoregressive structures are imposed on the disturbance terms. Sequential limit theories for the estimators are derived, and it is shown that all of the estimators have normal distributions in the limit. Additionally, Wald tests for coefficient vectors are shown to have chi-square distributions in the limit. Simulation results regarding the estimator efficiency and the size of the Wald tests are also reported. The results show that the Within-IV-GLS and IV-GLS estimators are more efficient than the Within-IV-OLS estimator in most cases and that the Wald tests keep nominal size reasonably well. The relation between the trade and budget deficits of 23 OECD nations is examined using the panel IV estimators. The empirical results support the view that the budget and trade deficits move in the same direction. JEL classification: C32; C33 Keywords: Near unit roots; Panel data; Instrumental variables; Generalized least squares

INTRODUCTION To fly aircraft safely and effectively, pilots must properly use visual information about the relative positions of both stationary and moving objects in the environment. Unfortunately, making these visual […], The far-anchor effect is responsible for a motion-in-depth illusion that has only recently been recognized. When viewing conditions are limited, motions in depth of a farther target in a two-object display may readily be perceived as opposite motions in depth of the nearer target. The present studies determined whether this error could be avoided through controlled fixation or training with feedback. Under conditions of reduced visibility, participants (college students) viewed 64 two-target presentations varying in the position of the moving target and its direction of motion. Neither fixation instructions nor informational feedback about motion errors affected the occurrence of the basic illusion, nor did a vertical separation of the targets eliminate the main effect, indicating the robustness of the motion illusion under some relatively realistic variations. Such errors in judging motion in depth have significance for both midair collisions between aircraft and ground-incursion accidents under conditions o f reduced visibility. Potential applications include the elaboration of examples used in pilot training programs or in training programs for ground personnel.

Abstract: Explicit (computable) estimates for errors in some simplified two-dimensional models of the theory of elastic body are obtained. Such models are usually used if one of the characteristic sizes of a domain is significantly less than two others. In particular, the model of plane stresses is considered. To obtain estimates for the deviation of reduced solutions from exact solutions, the direct and dual variational problems are considered and the duality methods are used. Bibliography: 9 titles. Article History: Registration Date: 20/10/2004

Social scientists frequently lack methods for assessing the accuracy of survey responses about events and behaviors. And often they do not have a general framework for understanding or systematically analyzing the characteristics of experience, if any, that influence errors in reports about those events. In this validation study, structural features or characteristics of exchanging child support payments are examined to predict errors in reports about those events. The analysis compares court records about child support payments with answers from two telephone surveys that use parallel samples of divorced parents. Results show that indicators for the complexity, clarity, and affective intensity of the events predict reporting errors.

A job instruction document, or workcard, for civil aircraft maintenance produced a number of paperwork errors when used operationally. The design of the workcard was compared to the guidelines of Patel et al [1994, Applied Ergonomics, 25 (5), 286-293]. All of the errors occurred in work instructions which did not meet these guidelines, demonstrating that the design of documentation does affect operational performance.

The purpose of this study was to test competing theories regarding the relationship between true halo (actual dimensional correlations) and halo rater error (effects of raters' general impressions on specific ratee qualities) at both the individual and group level of analysis. Consistent with the prevailing general impression model of halo rater error, results at both the individual and group level analyses indicated a null (vs. positive or negative) true halo-halo rater error relationship. Results support the ideas that (a) the influence of raters' general impressions is homogeneous across rating dimensions despite wide variability in levels of true halo; (b) in assigning ratings, raters rely both on recalled observations of actual ratee behaviors and on general impressions of ratees in assigning dimensional ratings; and (c) these 2 processes occur independently of one another.

This research explores how group- and organizational-level factors affect errors in administering drugs to hospitalized patients. Findings from patient care groups in two hospitals show systematic differences not just in the frequency of errors, but also in the likelihood that errors will be detected and learned from by group members. Implications for learning in and by work in general are discussed. (Reprinted by permission of the publisher.)

The functioning of subspace-based algorithms for narrow-band direction-of-arrival (DOA) estimation when the array manifold and noise covariance are incorrect, is investigated. Multidimensional (MD) subspace-based algorithms which incorporate deterministic maximum likelihood, MD-MOSIC, weighted subspace fitting (WSF), MODE and ESPRIT are analyzed to determined their performance. A general expression for the difference in the DOA evaluates enables its application on these algorithms.

Experimental errors are inevitable in pseudodynamic testing. Some of these errors can be monitored during the test, but, due to limitations in control system, they cannot be eliminated. For example, one cannot control exactly the displacements that are actually imposed on the structure at each time step. This paper focuses on a technique to minimize the cumulative effect of such control errors. For this purpose, a posterior adjustment of the time increment from a target value Delta-t to an adjusted value Delta-t(sub n) is performed to minimize the effect of the control errors. The method is particularly for effective single-degree-of-freedom systems and systematic errors. These systematic errors can have a very detrimental effect, and they are eliminated almost completely for the single-degree-of-freedom example considered. For random errors that are probabilistically independent from one time step to the next, the method can have a deleterious effect on the error propagation characteristics, even though the control errors at each time step are reduced. However, since the effect of such random errors is small, this is not a serious draw-back. For multi-degree-of-freedom systems, posterior time step adjustment can also improve the error-propagation characteristics for certain systematic errors but its effectiveness is more limited.

This article gives theoretical reasons for the findings of a simulation study by Shaffer (1981). Two well-established procedures for multiple comparison of three normal means are compared--an F procedure and an R procedure. It turns out that for a large set of parameters the average number of rejected pairwise hypotheses is larger when the F procedure is applied. To achieve our result we have to prove a special instance of a conjecture by David, Lachenbruch, and Brandis (1972). KEY WORDS: Error rate; F test; Multiple level a; Studentized range test., 1. INTRODUCTION If we want to compare three normal populations with common variance [[sigma].sup.2] and if we have the same number, n, of independent observations for each population, then there [...]

True contact recording, where the slider interacts substantially with the disk, produces read errors in the form of shifted bits. The errors arise from velocity jitter at suspension resonance frequencies, excited by the slider/disk contact, and degrade readback performance long before the onset of tribological wear. Performance degradation is particularly apparent in high altitude/low pressure situations, which increase the amount of slider/disk interaction. Channel optimization should be revisited for low flying components.

A study is conducted to investigate the rate of citation errors in the reference lists of five social work journals. A stratified, computer-generated random sample is selected and each reference is verified against the original work for accuracy in six fields such as article title, author name, journal title, pagination, volume and year.

A control model of skilled performance is proposed to understand why prescribing errors occur at a particular rate. This model is based on control theory, which is used to explain different kinds of skilled behavior and also used as an approach to understand human error.

This paper evaluates the double-error probability (average probability of two consecutive bit errors) in digital FM for a noncoherent limiter/discriminator receiver with either integrate and dump or sample and hold (S&H) bit detection. A remarkably simple relationship is found relating the S&H double-error probability to the optimum coherent CPFSK bit error probability of Osborne and Luntz [1]. Index Terms--Communication theory, digital FM, discriminator detection, error probability.

A new expression for the average bit-error rate (BER) of differential quadrature phase-shift keying in slow frequency-nonselective Nakagami fading is derived for a space-diversity receiver having a cascade arrangement of L groups of M-branch selection combiners and an L-branch maximal-ratio combiner (MRC). This allows the use of a large number of antennas, for performance improvement, and a small number of inputs to the combiners, for low complexity. The average BER performance of the cascade receiver is investigated for different fading severity conditions characterized by the Nakagami m factor, and compared with the conventional MRC receiver. As the fading gets less severe (m increases), performance improvement over the conventional MRC scheme is only noticeable for the larger range of average signal-to-noise ratio. Index Terms--BER, DQPSK, Nakagami fading, selection diversity, maximal-ratio combining.

This paper presents the results of research on how assessment of the incidence and causes of human and organizational error in implementing processes can be utilized as a partial basis for the reengineering of organizational structures and processes. A systems integration environment was used as a site for empirical observation. A model was developed for the life cycle process of preparing a systems integration proposal involving integration of commercial-off-the-shelf (COTS) software and hardware, services, and value-added products. This model was used as a basis for analysis of errors committed during the life cycle process. From this analysis follows development of strategies for workflow and process reengineering. The identified approach can form part of a coordinated effort to reengineer vital processes within an organization with minimization of specific errors as a primary goal in efforts that involve the planning and engineering of systems. Index Terms - Human error, organizational error, systems engineering, systems management, workflow.

In the area of Human Reliability Analysis (HRA) there is a need for methods to predict the occurrence of erroneous actions. An approach for qualitative performance prediction is presented, based on the Cognitive Reliability and Error Analysis Method (CREAM). Predictions of potential erroneous actions was made for operators using alarm systems. Predictions were found to be correct in over 70% of the cases.

Suppose that the geographical and temporal resolution of the observational network could be changed on a daily basis. Of all the possible deployments of observational resources, which particular deployment would minimize expected forecast error? The ensemble transform technique answers such questions by using nonlinear ensemble forecasts to rapidly construct ensemble-based approximations to the prediction error covariance matrices associated with a wide range of different possible deployments of observational resources. From these matrices, estimates of the expected forecast error associated with each distinct deployment of observational resources are obtained. The deployment that minimizes the chosen measure of forecast error is deemed optimal. The technique may also be used to find the perturbation that evolves into the leading eigenvector or singular vector of an ensemble-based prediction error covariance matrix. This time-evolving perturbation 'explains' more of the ensemble-based prediction error variance than any other perturbation. It may be interpreted as the fastest growing perturbation on the subspace of ensemble perturbations. The ensemble-based approximations to the prediction error covariance matrices are constructed from transformation matrices derived from estimates of the analysis error covariance matrices associated with each possible deployment of observational resources. The authors prove that the ensemble transform technique would precisely recover the prediction error covariance matrices associated with each possible deployment of observational resources provided that (i) estimates of the analysis error covariance matrix were precise, (ii) the ensemble perturbations span the vector space of all possible perturbations, and (iii) the evolution of errors were linear and perfectly modeled. In the absence of such precise information, the ensemble transform technique links available information on analysis error covariances associated with different observational networks with error growth estimates contained in the ensemble forecast to estimate the optimal configuration of an adaptive observational network. Tests of the technique will be presented in subsequent publications. Here, the objective is to describe the theoretical basis of the technique and illustrate it with an example from the Fronts and Atlantic Storm Tracks Experiment (FASTEX).