2,044 research outputs found

    Generation of Explicit Knowledge from Empirical Data through Pruning of Trainable Neural Networks

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    This paper presents a generalized technology of extraction of explicit knowledge from data. The main ideas are 1) maximal reduction of network complexity (not only removal of neurons or synapses, but removal all the unnecessary elements and signals and reduction of the complexity of elements), 2) using of adjustable and flexible pruning process (the pruning sequence shouldn't be predetermined - the user should have a possibility to prune network on his own way in order to achieve a desired network structure for the purpose of extraction of rules of desired type and form), and 3) extraction of rules not in predetermined but any desired form. Some considerations and notes about network architecture and training process and applicability of currently developed pruning techniques and rule extraction algorithms are discussed. This technology, being developed by us for more than 10 years, allowed us to create dozens of knowledge-based expert systems. In this paper we present a generalized three-step technology of extraction of explicit knowledge from empirical data.Comment: 9 pages, The talk was given at the IJCNN '99 (Washington DC, July 1999

    Control the presence of students in classroom settings

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    Materials using the control system of the presence of students that gave the opportunity to identify and correct gaps in attendance, as the group's common and characteristic for each student individuallyПриведены материалы использования системы контроля присутствия студентов, что дало возможность своевременно выявлять и устранять пробелы в посещаемости, как общие для группы, так и характерные для каждого студента в отдельност

    Panic Attacks in Patients with Supraventricular Tachycardia: Problems of Differential Diagnosis and Impact on Quality of Life

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    Aim. To study the psychosomatic relationships and quality of life (QOL) of patients with paroxysmal supraventricular tachycardia (SVT) depending on the presence or absence of panic attacks (PA) in comparison with patients with heartbeat against the background of somatoform autonomic dysfunction.Material and methods. The study included patients with SVT and heart attacks due to sinus tachycardia in the context of somatoform autonomic disorder (SAD). All patients were interviewed to identify anxiety and depressive disorders (Hospital Anxiety and Depression Scale [HADS] and Hamilton's Depression Scale), QOL assessment (SF-36 questionnaire), and they were also consulted by a psychiatrist who established the presence or absence of PA. According to a visual analogue scale, in points from 0 to 6, we assessed the general state of our patients' health (0 points corresponded to complete health, and 6 points corresponded to a serious illness) and the effect of heartbeat on well-being (0 points - no arrhythmia, 6 points - arrhythmia «nterferes with life»).Results. The study included 96 patients: 60 with SVT (21 men, 39 women, average age was 51 [33; 61] years) and 36 with heart attacks caused by sinus tachycardia in the framework of somatoform autonomic disorder (10 men, 26 women, average age was 33 [27; 41] years). Panic disorder was diagnosed in the SVT group in 17 patients, accounting for 28.3%. Only 7 patients (41%) could clearly differentiate between SVT and PA attacks. The low sensitivity of the HADS questionnaire in patients with SVT determined the need to consult a psychiatrist for the diagnosis of panic disorders.Conclusion. PA is typical for 28.3% of patients with SVT. The combination of SVT with PA reduces the QOL of patients due to its mental components, including due to the more frequent occurrence of depressive symptoms. Patients with SAD subjectively perceive the heartbeat as a more significant factor affecting health, compared with patients with SVT. Difficulties in the differential diagnosis of PA and SVT paroxysms in real clinical practice often lead to the appointment of the same therapy without taking into account the differences in the genesis of heartbeats

    De Sitter space and perpetuum mobile

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    We give general arguments that any interacting non--conformal {\it classical} field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile. The arguments are based on the observation that massive free falling particles can radiate other massive particles on the classical level as seen by the free falling observer. The intensity of the radiation process is non-zero even for particles with any finite mass, i.e. with a wavelength which is within the causal domain. Hence, we conclude that either de Sitter space can not exist eternally or that one can build a perpetuum mobile.Comment: 11 pages revtex, no figures. Added discussion to strengthen conclusio

    Effectiveness of Class IC Antiarrhythmics in Patients with Paroxysmal Form of Atrial Fibrillation in Absence of Structural Heart Disease

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    Aim. To study the efficacy of class IC arrhythmic drugs (AAD) and catheter ablation (CA) for paroxysmal form of atrial fibrillation (AF) in patients with without structural heart disease.Material and methods. The study included 122 patients (44 men, 78 women, mean age 63 [55;68] years) with symptomatic AF paroxysms. Patients was divided into the lappaconitine hydrobromide group (LH group; n=26), the propafenone group (P group; n=25) – 25 patients, the diethylaminopropionylethoxycarbonylaminophenothiazine hydrochloride (DH group; n=23), the CA groups: radiofrequency ablation (RFA group; n=24) and cryoballoon ablation (CRYO group; n=24) groups each included 24 patients. The primary endpoint was the AF recurrence within 6 and 12 months from the onset of antiarrhythmic drug therapyand in RFA and CRYO groups – within 6 and 12 months after the end of the blinding period. Additionally, in AAD groups a composite endpoint was assessed: the frequency of recurrence of AF within 6 months and the frequency of side effects requiring drug withdrawal.Results. Within the 6 months AF recurrence was observed in 13 (50%) patients of the LH group, 11 (44%) patients of the P group, and 13 (56.5%) patients of the DH group (p=0.687). Side effects requiring drug withdrawal were observed in the LH group in 2 patients (7.7%), in the P group in 3 patients (12%) and in the DH group in 3 patients (13%) (p=0.801). The difference in frequency of reaching the composite endpoint was not significant (p = 0.581) and the incidence was 57.7%, 56%, 69.5%, respectively in groups LH, P and DH. The efficacy of CA was higher than class IC AADs: 77% vs 39% (that including the withdrawals of AADs due to side effects) (p˂0.001). At the same time, there was no significant difference in the effectiveness of RFA and CRYO: AF recurrences within 6 months after the end of the blinding period were registered in the RFA group in 29% of cases, in the CRYO group – in 16.7% of cases (p=0.247). The overall effectiveness of CA after 12 months was 69%, which was significantly higher than the effectiveness of AADs that was 38% (p˂0.001).Conclusion. Starting the AAD therapy with IC class in patients with paroxysmal AF in the absence of structural pathology, despite acceptable safety, one should take into account that, regardless of the initially prescribed drug, less than half of patients can achieve prevention of AF recurrence within 1 year. CA for AF can be considered as a first line therapy or can be recommended if one of IC class AADs is ineffective

    HEP Applications Evaluation of the EDG Testbed and Middleware

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    Workpackage 8 of the European Datagrid project was formed in January 2001 with representatives from the four LHC experiments, and with experiment independent people from five of the six main EDG partners. In September 2002 WP8 was strengthened by the addition of effort from BaBar and D0. The original mandate of WP8 was, following the definition of short- and long-term requirements, to port experiment software to the EDG middleware and testbed environment. A major additional activity has been testing the basic functionality and performance of this environment. This paper reviews experiences and evaluations in the areas of job submission, data management, mass storage handling, information systems and monitoring. It also comments on the problems of remote debugging, the portability of code, and scaling problems with increasing numbers of jobs, sites and nodes. Reference is made to the pioneeering work of Atlas and CMS in integrating the use of the EDG Testbed into their data challenges. A forward look is made to essential software developments within EDG and to the necessary cooperation between EDG and LCG for the LCG prototype due in mid 2003.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics Conference (CHEP03), La Jolla, CA, USA, March 2003, 7 pages. PSN THCT00

    Measurement of the CKM angle γ from a combination of B±→Dh± analyses

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    A combination of three LHCb measurements of the CKM angle γ is presented. The decays B±→D K± and B±→Dπ± are used, where D denotes an admixture of D0 and D0 mesons, decaying into K+K−, π+π−, K±π∓, K±π∓π±π∓, K0Sπ+π−, or K0S K+K− final states. All measurements use a dataset corresponding to 1.0 fb−1 of integrated luminosity. Combining results from B±→D K± decays alone a best-fit value of γ =72.0◦ is found, and confidence intervals are set γ ∈ [56.4,86.7]◦ at 68% CL, γ ∈ [42.6,99.6]◦ at 95% CL. The best-fit value of γ found from a combination of results from B±→Dπ± decays alone, is γ =18.9◦, and the confidence intervals γ ∈ [7.4,99.2]◦ ∪ [167.9,176.4]◦ at 68% CL are set, without constraint at 95% CL. The combination of results from B± → D K± and B± → Dπ± decays gives a best-fit value of γ =72.6◦ and the confidence intervals γ ∈ [55.4,82.3]◦ at 68% CL, γ ∈ [40.2,92.7]◦ at 95% CL are set. All values are expressed modulo 180◦, and are obtained taking into account the effect of D0–D0 mixing

    Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)

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    The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma and Bs0 -> phi gamma has been measured using 0.37 fb-1 of pp collisions at a centre of mass energy of sqrt(s) = 7 TeV, collected by the LHCb experiment. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.12 +/- 0.08 ^{+0.06}_{-0.04} ^{+0.09}_{-0.08}, where the first uncertainty is statistical, the second systematic and the third is associated to the ratio of fragmentation fractions fs/fd. Using the world average for BR(B0 -> K*0 gamma) = (4.33 +/- 0.15) x 10^{-5}, the branching fraction BR(Bs0 -> phi gamma) is measured to be (3.9 +/- 0.5) x 10^{-5}, which is the most precise measurement to date.Comment: 15 pages, 1 figure, 2 table

    Observation of an Excited Bc+ State

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    Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date

    Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at √s=7 TeV

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    Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the form of an enhancement of pairs of like-sign charged pions with small four-momentum difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source is investigated, determining both the correlation radius and the chaoticity parameter. The measured correlation radius is found to increase as a function of increasing charged-particle multiplicity, while the chaoticity parameter is seen to decreas
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