An arrhythmia classification algorithm using a dedicated wavelet adapted to different subjects

<p>Abstract</p> <p>Background</p> <p>Numerous studies have been conducted regarding a heartbeat classification algorithm over the past several decades. However, many algorithms have also been studied to acquire robust performance, as biosignals have a large amount of variation among individuals. Various methods have been proposed to reduce the differences coming from personal characteristics, but these expand the differences caused by arrhythmia.</p> <p>Methods</p> <p>In this paper, an arrhythmia classification algorithm using a dedicated wavelet adapted to individual subjects is proposed. We reduced the performance variation using dedicated wavelets, as in the ECG morphologies of the subjects. The proposed algorithm utilizes morphological filtering and a continuous wavelet transform with a dedicated wavelet. A principal component analysis and linear discriminant analysis were utilized to compress the morphological data transformed by the dedicated wavelets. An extreme learning machine was used as a classifier in the proposed algorithm.</p> <p>Results</p> <p>A performance evaluation was conducted with the MIT-BIH arrhythmia database. The results showed a high sensitivity of 97.51%, specificity of 85.07%, accuracy of 97.94%, and a positive predictive value of 97.26%.</p> <p>Conclusions</p> <p>The proposed algorithm achieves better accuracy than other state-of-the-art algorithms with no intrasubject between the training and evaluation datasets. And it significantly reduces the amount of intervention needed by physicians.</p

Robust algorithm for arrhythmia classification in ECG using extreme learning machine

<p>Abstract</p> <p>Background</p> <p>Recently, extensive studies have been carried out on arrhythmia classification algorithms using artificial intelligence pattern recognition methods such as neural network. To improve practicality, many studies have focused on learning speed and the accuracy of neural networks. However, algorithms based on neural networks still have some problems concerning practical application, such as slow learning speeds and unstable performance caused by local minima.</p> <p>Methods</p> <p>In this paper we propose a novel arrhythmia classification algorithm which has a fast learning speed and high accuracy, and uses Morphology Filtering, Principal Component Analysis and Extreme Learning Machine (ELM). The proposed algorithm can classify six beat types: normal beat, left bundle branch block, right bundle branch block, premature ventricular contraction, atrial premature beat, and paced beat.</p> <p>Results</p> <p>The experimental results of the entire MIT-BIH arrhythmia database demonstrate that the performances of the proposed algorithm are 98.00% in terms of average sensitivity, 97.95% in terms of average specificity, and 98.72% in terms of average accuracy. These accuracy levels are higher than or comparable with those of existing methods. We make a comparative study of algorithm using an ELM, back propagation neural network (BPNN), radial basis function network (RBFN), or support vector machine (SVM). Concerning the aspect of learning time, the proposed algorithm using ELM is about 290, 70, and 3 times faster than an algorithm using a BPNN, RBFN, and SVM, respectively.</p> <p>Conclusion</p> <p>The proposed algorithm shows effective accuracy performance with a short learning time. In addition we ascertained the robustness of the proposed algorithm by evaluating the entire MIT-BIH arrhythmia database.</p

Pair suppression caused by mosaic-twist defects in superconducting Sr 2 RuO 4 thin-films prepared using pulsed laser deposition

Funder: IBS Institute for Basic Science in Korea Grant No. IBS-R009-D1Abstract: Sr2RuO4 (SRO214) is a prototypical unconventional superconductor. However, since the discovery of its superconductivity a quarter of a century ago, the symmetry of the bulk and surface superconducting states in single crystal SRO214 remains controversial. Solving this problem is massively impeded by the fact that superconducting SRO214 is extremely challenging to achieve in thin-films as structural defects and impurities sensitively annihilate superconductivity. Here we report a protocol for the reliable growth of superconducting SRO214 thin-films by pulsed laser deposition and identify universal materials properties that are destructive to the superconducting state. We demonstrate that careful control of the starting material is essential in order to achieve superconductivity and use a single crystal target of Sr3Ru2O7 (SRO327). By systematically varying the SRO214 film thickness, we identify mosaic twist as the key in-plane defect that suppresses superconductivity. The results are central to the development of unconventional superconductivity

Side-Payments and the Costs of Conflict

Conflict and competition often impose costs on both winners and losers, and conflicting parties may prefer to resolve the dispute before it occurs. The equilibrium of a conflict game with side-payments predicts that with binding offers, proposers make and responders accept side-payments, generating settlements that strongly favor proposers. When side-payments are non-binding, proposers offer nothing and conflicts always arise. Laboratory experiments confirm that binding side-payments reduce conflicts. However, 30 % of responders reject binding offers, and offers are more egalitarian than predicted. Surprisingly, non-binding side-payments also improve efficiency, although less than binding. With binding side-payments, 87 % of efficiency gains come from avoided conflicts. However, with non-binding side-payments, only 39 % of gains come from avoided conflicts and 61 % from reduced conflict expenditures

Essays on financial incentive mechanisms under repetition in economics experiments

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Effect of Deletion of the Circadian Gene Bmal1 in Neuromedin-S Neurons on Female Fertility

The female reproductive system is coupled with circadian rhythms, and circadian disruption is associated with decreased reproductive capacity. For example, the preovulatory luteinizing hormone (LH) surge is temporally regulated. In the hypothalamus, the suprachiasmatic nucleus (SCN) sends projections to the kisspeptin and gonadotropin-releasing hormone (GnRH) neurons to properly synchronize their endogenous clocks. Previous studies have demonstrated that the whole-body deletion of Bmal1, a critical molecular clock gene, in female mice results in no LH surge and infertility. However, the site of action of Bmal1 in the LH surge is unknown. Recently, we demonstrated that mice with a conditional Bmal1 knockout in either kisspeptin or GnRH neurons were fertile, with a normal LH surge. Therefore, we hypothesized that Bmal1 in the SCN would be critical for female reproduction. Neuromedin-S (NMS) is a neuropeptide abundantly expressed in the SCN, and in nearly all VIP and AVP expressing neurons, which send projections to GnRH and kisspeptin neurons, respectively. Bmal1 knockout in NMS neurons resulted in loss of behavioral circadian rhythm under constant darkness, verifying clock disruption in the SCN. Nevertheless, ovariectomized Bmal1fl/fl-NMSCre mice showed an LH surge at the appropriate time when given exogenous estradiol, and with kisspeptin administration. They had normal estrous cyclicity and were fertile when mated with a wildtype male. Thus, despite Bmal1fl/fl-NMSCre female mice showing arrhythmic behavior, they are fertile. However, preliminary results indicate that ovaries in constant darkness showed less numbers of corpora lutea meaning decreased ovulation. These data suggest that the reproductive neurons, the endogenous clock or SCN temporal regulation is sufficient for fertility

Effect of Deletion of the Circadian Gene Bmal1 in Neuromedin-S Neurons on Female Fertility

The female reproductive system is coupled with circadian rhythms, and circadian disruption is associated with decreased reproductive capacity. For example, the preovulatory luteinizing hormone (LH) surge is temporally regulated. In the hypothalamus, the suprachiasmatic nucleus (SCN) sends projections to the kisspeptin and gonadotropin-releasing hormone (GnRH) neurons to properly synchronize their endogenous clocks. Previous studies have demonstrated that the whole-body deletion of Bmal1, a critical molecular clock gene, in female mice results in no LH surge and infertility. However, the site of action of Bmal1 in the LH surge is unknown. Recently, we demonstrated that mice with a conditional Bmal1 knockout in either kisspeptin or GnRH neurons were fertile, with a normal LH surge. Therefore, we hypothesized that Bmal1 in the SCN would be critical for female reproduction. Neuromedin-S (NMS) is a neuropeptide abundantly expressed in the SCN, and in nearly all VIP and AVP expressing neurons, which send projections to GnRH and kisspeptin neurons, respectively. Bmal1 knockout in NMS neurons resulted in loss of behavioral circadian rhythm under constant darkness, verifying clock disruption in the SCN. Nevertheless, ovariectomized Bmal1fl/fl-NMSCre mice showed an LH surge at the appropriate time when given exogenous estradiol, and with kisspeptin administration. They had normal estrous cyclicity and were fertile when mated with a wildtype male. Thus, despite Bmal1fl/fl-NMSCre female mice showing arrhythmic behavior, they are fertile. However, preliminary results indicate that ovaries in constant darkness showed less numbers of corpora lutea meaning decreased ovulation. These data suggest that the reproductive neurons, the endogenous clock or SCN temporal regulation is sufficient for fertility

Do Subjects Separate (or Are They Sophisticated)?

In many experiments, particularly individual choice experiments, experimenters ask many questions to the subjects and use the random lottery incentive mechanism to give an incentive to the subjects. That is, the experimenter, at the end of the experiment, picks just one of the questions, plays out that question, and pays the subject on the basis of this one question. The idea is that subjects should separate the various questions and reply to each as if it were a separate question—in isolation from all the other questions in the experiment. This procedure is methodologically sound if the subjects behave in accordance with Expected Utility (EU) theory, since this theory says that the best procedure for the subjects is to separate the various questions. However, if there is any doubt as to whether the subjects obey EU theory, and particularly if the experiment is designed to test whether the behaviour of the subjects is in accordance with EU, this incentive mechanism is open to criticism. Indeed many referees use this argument against the research. The response that the subjects may not respect EU, yet still separate the various questions, is obviously open to objection and generally it is not clear whether this response is valid or not. There have been two direct tests of this separation hypothesis (by Starmer and Sugden (1991) and by Cubitt et al. (1998), which suggest that it is valid, but further evidence is required. This paper provides a further, stronger, test of this hypothesis: we confront the two stories—(1) that the subjects answer the various questions separately, and (2) that the subjects respond to the experiment as a whole—using experimental data from an experiment in which the random lottery incentive mechanism was used. Our analysis shows that it would appear that subjects do answer as if they were separating the questions. This should be considered reassuring for those experimenters who use the random lottery incentive mechanism. Copyright Springer Science + Business Media, Inc. 2005random lottery incentive mechanism, separation hypothesis, strategies, Selten’s measure of predictive success,