1,284 research outputs found

    Torque Ripple Minimization in a Switched Reluctance Drive by Neuro-Fuzzy Compensation

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    Simple power electronic drive circuit and fault tolerance of converter are specific advantages of SRM drives, but excessive torque ripple has limited its use to special applications. It is well known that controlling the current shape adequately can minimize the torque ripple. This paper presents a new method for shaping the motor currents to minimize the torque ripple, using a neuro-fuzzy compensator. In the proposed method, a compensating signal is added to the output of a PI controller, in a current-regulated speed control loop. Numerical results are presented in this paper, with an analysis of the effects of changing the form of the membership function of the neuro-fuzzy compensator.Comment: To be published in IEEE Trans. on Magnetics, 200

    Investigation of the effect of articulatory-based second language production learning on speech perception

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    International audienceThe effect of second language production training on perception has been previously explored, but it remains unclear whether such training by itself influences the perception of speech sounds. In previous work participants heard the correct pronunciation of the target while simultaneously undergoing production training, making it unclear what component of improvement was due to the production training alone. In the current study we have therefore modified our electromagnetic articulometer-based training system, which provides estimates of learner-specific head-corrected tongue positions for a target utterance in real time, to eliminate simultaneous presentation of audio stimuli. Japanese learners of the American English vowel /ae/ performed ABX perceptual testing on this vowel before and after the visually presented articulatory-based pronunciation training. We examined whether or not the production-driven pronunciation improvement also induces a change in the perception of the second language sounds

    <症例>マムシ (Agkistrodon halys Blomhoffii) 咬傷における少量抗毒素血清投与の経験 : 43症例の検討

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    Forty-three consecutive patients of venomous snakebite by the Japanese viper (Agkistrodon halys Blomhoffii, "Mamushi" in Japanese) were treated with an uniformly scheduled therapy from 1990 and 1994. The therapy was mainly composed of minimal dose of antivenin, methylprednisolon and cepharanthin. There were two clinical courses, i.e., the minimal envenomation course (Group A, n=14) and the severe one (Group B, n=29). Our treatment was so satisfactory that all patients of both groups fully recovered activities of daily living with neither organic disorders nor sequelae of the bitten extremities. The high appearance ratio of atypical lymphocytes (P < 0. 05) and the increased ratio of lymphocyte count to White blood cell count (P<0. 02) could be indicators that predict hich clinical courses the patients take.1990年から1994年までの5年間に当院で治療したマムシ咬傷43例について検討した. 当院では原則として抗毒素血清, ステロイド, セファランチンの投与を行っているが, 死亡例はなく, 咬傷部の機能障害を示した症例もなかった. 4例(9. 3%)に即効型過敏反応が認められた. 1例は anaphylaxy shock を呈したが治療により即時改善をみた. 遅延型血清病は入院期間中観察されなかった. McCollough らの分類により軽症例(n=14)と重症例(n=29)に分け予後因子を検討した. 治療開始前の WBC, CPK, LDH, BUN, Cr はいずれも重症化指標とはなりえなかったが, 白血球中のリンパ球比率(P<0. 02), 異型リンパ球出現率(P<0. 05)が高い程, 重症化することが示唆された. 死亡報告が散見されるマムシ咬傷に対し受傷早期の抗毒素血清投与は有用であり, 即効型過敏反応に即座に対応すれば比較的安全に投与できるものと考えられた. しかし, 軽症例に対しての抗毒素血清投与には疑問が残り, 今後は重症化が危倶される症例を的確に選択する必要があると思われた

    Somatosensory and Visual Deprivation Each Decrease the Density of Parvalbumin Neurons and Their Synapse Terminals in the Prefrontal Cortex and Hippocampus of Mice

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    In the phenomenon known as cross-modal plasticity, the loss of one sensory system is followed by improved functioning of other intact sensory systems. MRI and functional MRI studies suggested a role of the prefrontal cortex and the temporal lobe in cross-modal plasticity. We used a mouse model to examine the effects of sensory deprivation achieved by whisker trimming and visual deprivation achieved by dark rearing in neonatal mice on the appearance of parvalbumin (PV) neurons and the formation of glutamic acid decarboxylase 67 (GAD67)-positive puncta around pyramidal neurons in the prefrontal cortex and hippocampus. Whisker trimming, but not dark rearing, decreased the density of PV neurons in the hippocampus at postnatal day 28 (P28). In the prefrontal cortex, whisker trimming and dark rearing decreased the density of PV neurons in layer 5/6 (L5/6) at P28 and in L2/3 at P56, respectively, whereas dark rearing increased the density of PV neurons in L5/6 at P56. Whisker trimming decreased the density of GAD67-positive puncta in CA1 of the hippocampus at both P28 and P56 and in L5/6 of the prefrontal cortex at P28. Dark rearing decreased the density of GAD67-positive puncta in CA1 of the hippocampus and in both L2/3 and L5/6 of the prefrontal cortex at P28, and in L2/3 of the prefrontal cortex at P56. These results demonstrate that somatosensory or visual deprivation causes changes in the PV-interneuronal network in the mouse prefrontal cortex and hippocampus. The results also suggest that the alteration of the PV-interneuronal network, especially in the prefrontal cortex, may contribute to cross-modal plasticity

    A real-time articulatory visual feedback approach with target presentation for second language pronunciation learning

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    International audienceArticulatory information can support learning or remediating pronunciation of a second language (L2). This paper describes an electromagnetic articulometer-based visual-feedback approach using an articulatory target presented in real-time to facilitate L2 pronunciation learning. This approach trains learners to adjust articulatory positions to match targets for a L2 vowel estimated from productions of vowels that overlap in both L1 and L2. Training of Japanese learners for the American English vowel /ae/ that included visual training improved its pronunciation regardless of whether audio training was also included. Articulatory visual feedback is shown to be an effective method for facilitating L2 pronunciation learning

    Attenuated Sensory Deprivation-induced Changes of Parvalbumin Neuron Density in the Barrel Cortex of FcγRllB-deficient Mice

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    Recent studies have demonstrated the important role of immune molecules in the development of neuronal circuitry and synaptic plasticity. We have detected the presence of FcγRllB protein in parvalbumin- containing inhibitory interneurons (PV neurons). In the present study, we examined the appearance of PV neurons in the barrel cortex and the effect of sensory deprivation in FcγRllB-deficient mice (FcγRllB-/-) and wild-type mice. There was no substantial difference in the appearance of PV neurons in the developing barrel cortex between FcγRllB-/- and wild-type mice. Sensory deprivation from immediately after birth (P0) or P7 to P12-P14 induced an increase in PV neurons. In contrast, sensory deprivation from P7 or P14 to P28, but not from P21 to P28, decreased PV neurons in wild-type mice. However, sensory deprivation from P0 or P7 to P12-P14 did not increase PV neurons and sensory deprivation from P7 or P14 to P28 did not decrease or only modestly decreased PV neurons in FcγRllB-/- mice. The results indicate that expression of PV is regulated by sensory experience and the second and third postnatal weeks are a sensitive period for sensory deprivation, and suggest that FcγRllB contributes to sensory experience-regulated expression of PV
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