Infrequent Errors Research Articles

A-7 Extending the Quantified Process Approach - Application of Nonlinear Models Toward the Understanding of Neurocognitive Decline Across the Lifespan

Abstract Objective: In this presentation, I will extend the Reliability Theory of Cognitive Decline and examine the emergence of infrequent errors on neurocognitive tests following cognitive decline or brain insult. Data Selection: Unpublished, meta norms (Figure 1), data published by Poreh (2020) (Figure 2), and cognitive/genetic data collected by the National Alzheimer’s Coordinating Center (NACC) will be used to illustrate the validity and utility of the model. Data Synthesis: Nonlinear models will be presented to show how performance on various neuropsychological tests declines across the life span and how the threshold and rate of decline are impacted by education and genetics (Figures 3a and 3b). Next, a new theoretical model will be used to explain how task-specific neurocognitive systems (neural networks) fail. The “time to failure” curve-fitting hazard model (Figure 4) will be used to illustrate how this process occurs and how this method can be applied to the development of age-based norms for such errors on neuropsychological tests. Conclusions: This cohesive empirical model extends on the Quantified Process Approach using cross-sectional and longitudinal neuropsychological data. This model allows clinicians to understand the effect of education on cognition decline (also known as “brain reserve capacity”), genetic predisposition, and heuristic biases regarding cognitive aging.

Domain-Shift Conditioning Using Adaptable Filtering Via Hierarchical Embeddings for Robust Chinese Spell Check

Spell check is a useful application which processes noisy human-generated text. Spell check for Chinese poses unresolved problems due to the large number of characters, the sparse distribution of errors, and the dearth of resources with sufficient coverage of heterogeneous and shifting error domains. For Chinese spell check, filtering using confusion sets narrows the search space and makes finding corrections easier. However, most, if not all, confusion sets used to date are fixed and thus do not include new, shifting error domains. We propose a scalable adaptable filter that exploits hierarchical character embeddings to (1) obviate the need to handcraft confusion sets, and (2) resolve sparsity problems related to infrequent errors. Our approach compares favorably with competitive baselines and obtains SOTA results on the 2014 and 2015 Chinese Spelling Check Bake-off datasets.

Inhibiting responses to difficult choices.

The stop-signal paradigm is a widely used procedure to study response inhibition. It consists of a 2-choice response-time task (a "go" task) that is occasionally interrupted by a stop signal instructing participants to withhold their responses. The paradigm owes its popularity to the underlying race model that enables estimation of the otherwise unobservable latency of stopping. As the race model assumes a single go runner that produces the response unless it is beaten by an inhibitory stop runner, it cannot account for errors on the go task. We propose a parametric framework that extends the standard 2-runner race model to account for go errors, and hence expand the scope of the stop-signal paradigm to the study of response inhibition in the context of difficult choices. We combine our treatment of go errors with the ability to address 2 common contaminants in stop-signal data: failure to trigger the go or the stop runner. We show with simulations that applying 2-runner parametric race models to difficult choices can severely bias conclusions about response inhibition. Notably, we also show that even infrequent errors, which have been common in previous stop-signal studies, can result in underestimation of stopping latencies. We demonstrate that our framework enables researchers to study difficult-choice inhibition even in relatively small samples by applying it to novel stop-signal data with high error rates and a manipulation of task difficulty, showing that it provides an accurate characterization of behavior and precise stop estimates. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Types and frequency of non-conformances in an IVF laboratory.

How many non-conformances occur in an ART laboratory and how often do they occur? The limited data to date demonstrate that IVF laboratories have a very low non-conformance rate compared with reported non-conformances in other medical laboratories, especially when one considers the high-complexity of procedures performed. ART involves a series of very complex patient and laboratory procedures. Although it is assumed that strict measures control ART laboratories, there is very little published data on non-conformances. In accordance with the ISO 9001:2008 standard, Boston IVF has created an electronic database to record non-conformances in the IVF laboratory. We reviewed the non-conformances reported between March 2003 and December 2015. The non-conformances were categorized into four grades largely based upon their impact on the outcome or continuation of an IVF treatment cycle: None/Minimal (not measurably decreasing the likelihood of success), Moderate (a negative impact but not loss of a cycle), Significant (loss of a cycle or majority of gametes or embryos) and Major (infrequent errors that have an extreme impact on a patient or patients such as a confirmed pregnancy or birth involving misidentification of sperm, egg or embryo, or an extreme equipment or documentation failure that affects numerous patients). The category of problem or error associated with the Non-conformance Report was also noted. Retrospective analysis of an electronic database registering non-conformances at a large IVF laboratory. During the study period, a total of 36 654 IVF treatment cycles (fresh and frozen embryo transfer cycles) were conducted which involved a total of 181 899 individual laboratory procedures encompassing egg retrievals, sperm preparations, inseminations, embryo transfers, etc. When combining both moderate and significant non-conformances, 99.96% of procedures and 99.77% of cycles proceeded with no non-conformances. No Major grade non-conformances were reported. A comparison of non-conformances between IVF clinics is difficult because of different classifications. Errors are inevitable and it is incumbent on all IVF centers to be honest and transparent, both within the organization and with patients when errors occur. Robust systems for identifying, documenting, analyzing and implementing improvements should be established and maintained. No external funding was used for this study. The authors have no conflicts of interest.

Missing the Target: the Neural Processing Underlying the Omission Error.

The omissions are infrequent errors consisting in missing responses to the target stimuli. This is the first study aimed at investigating the brain activities associated with omissions in a decision-making task. We recorded event-related potentials (ERPs) in 12 subjects which reported a suitable number of omissions in a visual go/no-go task. We investigated both the pre- and post-stimulus brain activities associated with correct and omitted trials. The electrical neuroimaging technique (BESA) was adopted to extract the anterior insula (aIns) activity associated with the prefrontal P2 component (pP2) peaking about 300ms after the stimulus and reflecting the stimulus-response mapping process. We found that omissions were predicted by a delayed onset (about half a second) of two pre-stimulus components, i.e. the prefrontal negativity (pN) and the Bereitschaftspotential (BP) associated with the top-down control and the motor preparation, respectively. Further, at the post-stimulus stage the omission trials were characterized by the suppression of the pP2 (and the aIns activity as measured by BESA). No differences between omission and correct trials were detected at the level of the P1 and N1 visual components, as well as the P3. These findings would suggest that omissions are attentional lapsebased errors, as indicated by the delayed brain preparation before the stimulus onset. The reduced cortical activity during the preparation phase did not affect the visual processing; in contrast the stimulus categorization process at the level of the anterior insula did not start at all, resulting in the inability to reach a decision.

An Investigation of Native and Non-Native English-Speaking Teachers' Cognitions about Oral Corrective Feedback

The present study sought to compare and contrast the perception of native and non-native speakers and experienced and less experienced teachers about CF and to examine controversial issues, such as frequency of CF, timing of CF, types of oral errors that should be corrected, its methods, and the person who should do the correcting. Ninety-nine English language teachers teaching in the preparatory year at Ha’il University participated in the study completed a questionnaire and involved in a semi structured interview. The findings showed that teachers in general have a strong positive perception of oral CF. Although teachers preferred to correct serious errors and frequent errors most frequently, they tended to delay correction until after a student finishes speaking rather than immediately. Moreover, results indicated that elicitation, implicit and repetition were the most frequently used feedback across all types of teachers. The students preferred the CF provided by the teachers. Classmates or peers were the least popular. Further, the results did not show significant differences between types of teachers, except for ‘frequent errors, and infrequent errors’ where native speakers tended to correct them more than non-native speakers. Additionally, less experienced teachers had more frequent use of CF and used the metalinguistic feedback method more compared to experienced teachers. Implication for teaching speaking are also discussed.

Orienting to errors with and without immediate feedback

A slow-down in reaction time (RT) after committing an error is a well-known effect. Recently, Notebaert and colleagues (Notebaert et al., 2009; Núñez Castellar, Kuhn, Fias, & Notebaert, 2010) suggested that posterror slowing is a reaction to the infrequent nature of errors. After infrequent errors, posterror slowing was observed but after infrequent correct trials, postcorrect slowing was observed. These data were obtained in a paradigm with trial-by-trial feedback. In this study we tested whether posterror slowing was similar with and without immediate feedback. We manipulated the overall accuracy parametrically per condition (50%, 70%, and 90% accuracy) and predicted an increase in posterror slowing as the accuracy increased. This linear effect was observed with and without immediate feedback. The data are interpreted in terms of an orienting response towards unexpected events.

Phonological mean length of utterance in specific language impairment: a multi-case study of children acquiring Finnish

This study assesses the phonological development of four Finnish-speaking children (ages 4;8, 4;9, 4;9 and 5;5) with specific language impairment (SLI) and dyspractic features in speech. The analysis is performed using the phonological mean length of utterance (pMLU) method. Moreover, the children's phonological abilities are evaluated qualitatively in relation to segments, phonotactics and word structure. The results are compared with those obtained from four age-matched typically developing peers and with the data from an earlier study using the pMLU method on younger, typically developing Finnish children. In the pMLU analysis, the children with SLI performed roughly at the level of typically developing 2-year-old children. The qualitative analyses revealed that children with SLI had difficulties in producing word-medial clusters and word-initial consonants and that they exhibited frequent consonant assimilations, infrequent errors and vowel errors. The pMLU method did differentiate between children with SLI and typically developing children. However, qualitative analyses revealed some weaknesses of the pMLU method when assessing Finnish children with SLI.

Age Effects Shrink when Motor Learning is Predominantly Supported by Nondeclarative, Automatic Memory Processes: Evidence from Golf Putting

Can motor learning be equivalent in younger and older adults? To address this question, 48 younger (M = 23.5 years) and 48 older (M = 65.0 years) participants learned to perform a golf-putting task in two different motor learning situations: one that resulted in infrequent errors or one that resulted in frequent errors. The results demonstrated that infrequent-error learning predominantly relied on nondeclarative, automatic memory processes whereas frequent-error learning predominantly relied on declarative, effortful memory processes: After learning, infrequent-error learners verbalized fewer strategies than frequent-error learners; at transfer, a concurrent, attention-demanding secondary task (tone counting) left motor performance of infrequent-error learners unaffected but impaired that of frequent-error learners. The results showed age-equivalent motor performance in infrequent-error learning but age deficits in frequent-error learning. Motor performance of frequent-error learners required more attention with age, as evidenced by an age deficit on the attention-demanding secondary task. The disappearance of age effects when nondeclarative, automatic memory processes predominated suggests that these processes are preserved with age and are available even early in motor learning.

An adaptive tit-for-tat strategy for IEEE 802.11 CSMA/CA protocol

In non-cooperative environments, selfish nodes can take advantage of the mechanisms in place to obtain unfair shares of the network resources. Unfortunately, they may impact the performance of the other nodes. Our objective is to propose a novel IEEE 802.11 medium access control protocol, which can fairly share the resources among cooperative nodes but can retaliate if some selfish ones are present. We first show that the classical jamming method is inappropriate. We then present a novel game theoretical strategy designed to cope with the short-term unfairness of resource sharing. Our reputation-based tit-for-tat mechanism is immune to infrequent misclassification errors and motivates rational selfish nodes to cooperate. It depends on the observation of the nodes' behaviour. If any node misbehaves, the monitoring nodes should adapt and behave themselves selfishly. Thus, rational nodes should not have any other choice than to follow the legitimate behaviour in order to maximise their payoff.

Remote sensing meets psychology: a concept for operator performance assessment

An often undervalued but inevitable component in remote sensing image analysis is human perception and interpretation. Human intervention is a requisite for visual image interpretation, where the interpreter actually performs the analysis. Although image processing became more and more automated, human screening and interpretation remained indispensable at certain stages. One particular stage where the operator plays a crucial role is in the development of reference maps. This is often done by a visual interpretation of an image by an operator. Although the result is crucial for adequately assessing automated systems' performance, the work of the human operator is rarely questioned. No variability is considered and the possibility of errors is not mentioned. This is an implicit assumption that operator performance approaches perfection and that infrequent errors are randomly distributed across time, operators and image types. Given that the existence of operator variability has been proven in several other related domains, for example, screening of medical images, this assumption may be questioned. This letter brings the issue to the attention of the remote sensing community and introduces a new concept quantifying operator variability. As the WAVARS project (web-based assessment of operator performance variability within remote sensing image interpretation tasks) will gain from a high amount of data, we kindly invite interested researchers to access the website http://wavars.ugent.be and take part in the test.

Aberrant Single Exon Skipping is not Altered by Age in Exons of NF1, RABAC1, AATF or PCGF2 in Human Blood Cells and Fibroblasts

In human pre-mRNA splicing, infrequent errors occur resulting in erroneous splice products as shown in a genome-wide approach. One characteristic subgroup consists of products lacking one cassette exon. The noise in the splicing process, represented by those misspliced products, can be increased by cold shock treatment or by inhibiting the nonsense mediated decay. Here, we investigated whether the splicing noise frequency increases with age in vivo in peripheral bloods cells or in vitro in cultured and aged fibroblasts from healthy donors. Splicing noise frequency was measured for four erroneously skipped NF1 exons and one exon of RABAC1, AATF and PCGF2 by RT-qPCR. Measurements were validated in cultured fibroblasts treated with cold shock or puromycin. Intragenic but not interpersonal differences were detected in splicing noise frequencies in vivo in peripheral blood cells of 11 healthy donors (15 y–85 y) and in in vitro senescent fibroblasts from three further donors. No correlation to the age of the donors was found in the splicing noise frequencies. Our data demonstrates that splicing error frequencies are not altered by age in peripheral blood cells or in vitro aged fibroblasts in the tested exons of the four investigated genes, indicating a high importance of correct splicing in these proliferating aged cells.

Orienting towards unexpected action outcomes

Event Abstract Back to Event Orienting towards unexpected action outcomes Wim Notebaert1* 1 Experimental Psychology, Ghent University, Belgium Recently we proposed the orienting account for post-error slowing, stating that RT slowing after errors is related to attentional capture by infrequent errors. In this presentation I will discuss several new studies that have confirmed various predictions of this account. We have demonstrated that the P3 (ERP component related to orienting) predicts post-error slowing, that schizophrenic patients (known to be more distractible) show increased post-error slowing compared to controls when the intertrial interval is short, and that post-error slowing is an a-specific effect that transfers over tasks. We also investigated post-error slowing in an experiment without external feedback. We showed that post-error slowing also increases as the likelihood of an error decreases, suggesting that orienting to unexpected action outcomes does not require external feedback. Finally, when manipulating the saliency of an error, we demonstrated more post-error slowing after more salient errors. Importantly, while these empirical data were predicted by the orienting account, more traditional strategic accounts for error monitoring have difficulties in explaining these observations. Keywords: Attention, P3 Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Symposium: Oral Presentation Topic: Symposium 23: Regulating access to consciousness: Cortical mechanisms of attention Citation: Notebaert W (2011). Orienting towards unexpected action outcomes. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00602 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 14 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Prof. Wim Notebaert, Experimental Psychology, Ghent University, Ghent, Belgium, wim.notebaert@ugent.be Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Wim Notebaert Google Wim Notebaert Google Scholar Wim Notebaert PubMed Wim Notebaert Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Neural correlates of bimanual anti-phase and in-phase movements in Parkinson's disease

Patients with Parkinson's disease have great difficulty in performing bimanual movements; this problem is more obvious when they perform bimanual anti-phase movements. The underlying mechanism of this problem remains unclear. In the current study, we used functional magnetic resonance imaging to study the bimanual coordination associated changes of brain activity and inter-regional interactions in Parkinson's disease. Subjects were asked to perform right-handed, bimanual in-phase and bimanual anti-phase movements. After practice, normal subjects performed all tasks correctly. Patients with Parkinson's disease performed in-phase movements correctly. However, some patients still made infrequent errors during anti-phase movements; they tended to revert to in-phase movement. Functional magnetic resonance imaging results showed that the supplementary motor area was more activated during anti-phase movement than in-phase movement in controls, but not in patients. In performing anti-phase movements, patients with Parkinson's disease showed less activity in the basal ganglia and supplementary motor area, and had more activation in the primary motor cortex, premotor cortex, inferior frontal gyrus, precuneus and cerebellum compared with normal subjects. The basal ganglia and dorsolateral prefrontal cortex were less connected with the supplementary motor area, whereas the primary motor cortex, parietal cortex, precuneus and cerebellum were more strongly connected with the supplementary motor area in patients with Parkinson's disease than in controls. Our findings suggest that dysfunction of the supplementary motor area and basal ganglia, abnormal interactions of brain networks and disrupted attentional networks are probably important reasons contributing to the difficulty of the patients in performing bimanual anti-phase movements. The patients require more brain activity and stronger connectivity in some brain regions to compensate for dysfunction of the supplementary motor area and basal ganglia in order to perform bimanual movements correctly.

Post-error slowing: An orienting account

It is generally assumed that slowing after errors is a cognitive control effect reflecting more careful response strategies after errors. However, clinical data are not compatible with this explanation. We therefore consider two alternative explanations, one referring to the possibility of a persisting underlying problem and one on the basis of the low frequency of errors (orienting account). This latter hypothesis argues that infrequent events orient attention away from the task. Support for the orienting account was obtained in two experiments. Using a new experimental procedure, Experiment 1 demonstrated post-error slowing after infrequent errors and post-correct slowing after infrequent correct trials. In Experiment 2, slowing was observed following infrequent irrelevant tones replacing the feedback signals.

Are neurologic examination abnormalities heritable? A preliminary study

Background Neurologic examination abnormalities (NEA) are more prevalent among patients with schizophrenia as well as their unaffected relatives when compared with healthy controls, suggesting that NEA may be endophenotypes for schizophrenia. We estimated the heritability of NEA in moderately sized pedigrees. We also evaluated correlations between NEA and cognitive performance in order to examine their construct validity. Methods Members of eight extended families, each consisting of two first degree relatives with schizophrenia/schizoaffective disorders, as well as available first- to fifth-degree relatives were examined ( n = 96 participants). A modification of the Neurological Evaluation Scale (NES) was employed, augmented with localizing signs. Where feasible, we used untransformed data such as error counts and completion time, rather than ordinal measures. Heritability was estimated using the variance component method, implemented in SOLAR. Results Statistically significant heritability ( h 2) estimates were obtained for several measures ( p < 0.05, h 2 ± standard error: rapid alternating movements, right-sided completion time, 0.99 ± 0.19; alternating fist–palm test, completion time, 0.77 ± 0.19 s, errors, 0.70 ± 0.32; fist–ring test, right-sided completion time, 0.53 ± 0.23 s, left-sided completion time, 0.70 ± 0.21 s; go–no go task, correct responses, 0.93 ± 0.33; audio–visual integration, correct responses, 0.79 ± 0.54). For most items, heritability analysis was hampered by insufficient data variability (infrequent errors). Correlational analyses show some degree of divergence among types of NEA, repetitive motor tasks being associated with most domains of cognitive functioning other than executive functioning, and cognitive–perceptual tasks being associated with memory and executive functioning. Conclusions Significant familial influences on certain aspects of neurologic performance were detected. These heritable measures were also correlated with heritable neurocognitive measures.

The Life and Thought of Siger of Brabant, Thirteenth-Century Parisian Philosopher: An Examination of His Views on the Relationship of Philosophy and Theology by Tony Dodd

666 BOOK REVIEWS prayer for things to have already happened) is in no way to diminish the praise that is due for a fine book, well-researched historically and cogently argued philosophically. Fordham University Bronx, New York JOSEPH W. KOTERSKI, S.J. The Life and Thought of Siger of Brabant, Thirteenth-Century Parisian Philosopher: An Examination of His Views on the Relationship of Philosophy and Theology. By TONY DODD. Lewiston, N.Y.: The Edwin Mellen Press, 1998. Pp. 531. $119.95 (doth). ISBN 0-7734-8477-9. The standard full-length studiesofthe foremost thirteenth-centuryAverroist philosopher, Siger of Brabant, have been, faute de mieux, those of Pierre Mandonnet, O.P. (1898; 1908, 1911) and of le feu Chanoine Fernand van Steenberghen (1939, 1942). Now we have a new full-length study, by Professor Tony Dodd of the University of Exeter. It is practically no less flawed, unfortunately, than its predecessors. Nevertheless, it contains extensive, nearly complete bibliographies and other useful information about Siger. Dodd covers four well-chosen, specific subjects in Siger: the intellect, determinism and free will, divine providence, and the {past) eternity of the world. Before attacking those four, however, Dodd makes a number of general observations about Siger and his times. Some of these contain factual errors. For example, he mentions the "flatness of the world" as part of the medieval world view. In fact, medieval scientists knew very well, primarily from observation of lunar eclipses, that our earth is "round." He speaks of "Alexander of Hales' own Summa theologiae" as if it had been written by Alexander (it was not). In a most serious error, he confuses the Golden Age of Scholasticism (the time of Siger and Thomas Aquinas) with the baroque Scholasticism of recent centuries: he says, "All formal argument and discussion were officially undertaken in syllogistic form." The typical form of thirteenthcentury philosophico-theological writing or discourse was not the syllogism but the question (quaestio). Amore solid knowledge of the background of medieval thought might have helped Dodd in an important respect: namely, to show how and why Siger is a thoroughly medieval man. His book fails to do that, and thereby fails to give a complete portrait of Siger as philosopher. In general, Dodd's treatment of the intellect in Siger is accurate and helpful, drawing on many pertinent texts and providing good translations (with very infrequent errors; e.g., rendering a "cum clause" as causal where it must be BOOK REVIEWS 667 concessive). He provides useful information about Siger's being influenced by St. Thomas, and emphasizes, quite rightly, that Siger disagreed with Averroes on the intellect by the time he wrote what is probably his last surviving work, the Commentary on the Liberde causis. Nevertheless, on certain points Dodd's presentation distorts Siger's relation both to Aristotle and to Thomas. Not far into his treatment of Siger and the human intellect Dodd writes, "Aristotle's metaphysics ... demands that, since matter is the principle of individuation, there can ... be [only] one unique intellect if it is truly spiritual." Agrave problem: how has he failed to consider Aristotle's "separate movers"? According to Aristotle there are either more than forty or more than fifty of them (depending on how many celestial motions the astronomers will decide that there are). Of course they are distinct from each other, individuated. Yet they have no matter at all; they are pure intellect, or we may say, purely spiritual. Missing that last point leads implicitly to the conclusion that Aristotle must not have believed that individual humans have their own intellect. Averroes did believe that Aristotle actually taught that there is only one intellect, a separate being after the manner of the separate movers, for all mankind; however, this is not because of an idea that matter is indispensable for individuation, but because of his interpretation of a famous, difficult passage at the beginning of book 3, chapter 4 of Aristotle's De anima (a mysterious question on the kind of separateness of the human intellect). Dodd speculates that Siger's change of his view on the oneness of the intellect was influenced by fear of the censors. The simpler explanation is that Siger has been...

Self-stabilizing multi-token rings

A distributed system consists of a set of loosely connected machines that do not share a global memory. The system is self-stabilizing if it can be started in any global state and achieves consistency all by itself. This also means that the system can deal with infrequent errors. This paper presents self-stabilizing multi-token rings. A multitoken ring is a generalization of a (one-)token ring. The algorithms presented are generalizations of a self-stabilizing mutual exclusion algorithm by Dijkstra [5] which can also be viewed as a token ring. We develop the algorithms in a stepwise manner, to show how and why we arrived at the final multi-token rings. The final parameterized algorithm represents a set of algorithms, one for each choice of the parameter. This enables one to select the algorithm with an optimal trade-off in desired flexibility versus memory requirements and stabilization time.

Two-state self-stabilizing algorithms for token rings

A self-stabilizing system is a network of processors, which, when started from an arbitrary (and possibly illegal) initial state, always returns to a legal state in a finite number of steps. This implies that the system can automatically deal with infrequent errors. One issue in designing self-stabilizing algorithms is the number of states required by each machine. This paper presents mutual exclusion algorithms which will be self-stabilizing while only requiring each machine in the network to have two states. The concept of a randomized central demon is also introduced in this paper. The first algorithm is a starting point where no randomization is needed (the randomized central demon is not necessary). The other two algorithms require randomization. The second algorithm builds on the first algorithm and reduces the number of network connections required. Finally, the number of necessary connections is again reduced yielding the final two-state, probabilistic algorithm for an asynchronous, unidirectional ring of processes. >

The awful German language

I was recently made aware of the decision to rename the Klinische Wochenschrift as The Clinical Investigator and to publish the journal exclusively in English. As a German-speaking American physician now working full-time in Germany, I view the decision to rename the journal with marked reservation. Further, I feel that the complete abandonment of the German language will alter the journal's character and role as forum for clinical medicine and clinical research in Germany. The Klinische Wochenschrift has been a distinguished journal, which is recognized internationally as an important forum for German clinical research. The fact that three-quarters of the articles and all the abstracts are published in English, has resulted in its wide distribution in English-speaking countries, while the basic German tenor of the journal was unmistakable. In that way, the journal was in a position to serve a role similar to the New England Journal and the JAMA in the United States and the Lancet and British Medical Journal in Great Britain. By abandoning the journal's German name, this potential function becomes blurred or lost completely. It is true that English has become the international scientific language, a role that German once served. I continue to be amazed at the excellent command of English exhibited by my German colleagues. However, the stilted style and syntax, coupled with not infrequent grammatical errors observed in English-language articles in the journal would lead one to conclude that an article in well-written, crisp German would be far superior to one written in tedious, awkward English. Moreover, some potential authors may become discouragedat having to continuously prepare their papers in English. I for one believe that it is premature to abandon the German language in favor of English. Despite Mark Twain's misgivings (,,The Awful German Language") German has served philosophers, scientists, playwrites, poets, and even lovers, in conveying their innermost thoughts. German is enjoying a revival .in English-speaking countries. American colleges and universities report a resurgence in demand for courses in German. Our English-speaking colleagues can discern a paper's content with help from the English abstract, the tables and the figures. Let's let them slog through an English-German dictionary for a change! I feel that the journal has narrowed its scope by virtue of the recent changes in language and title. Furthermore, the journal has abrogated a certain portion of its obligations to the readership by virtue of these changes. I would welcome a reconsideration of these decisions. Finally, I would be very interested in the views of other readers.