User-Adaptive A Posteriori Restoration for Incorrectly Segmented Utterances in Spoken Dialogue Systems

Ideally, the users of spoken dialogue systems should be able to speak at their own tempo. Thus, the systems needs to interpret utterances from various users correctly, even when the utterances contain pauses. In response to this issue, we propose an approach based on a posteriori restoration for incorrectly segmented utterances. A crucial part of this approach is to determine whether restoration is required. We use a classification-based approach, adapted to each user. We focus on each user’s dialogue tempo, which can be obtained during the dialogue, and determine the correlation between each user’s tempo and the appropriate thresholds for classification. A linear regression function used to convert the tempos into thresholds is also derived. Experimental results show that the proposed user adaptation approach applied to two restoration classification methods, thresholding and decision trees, improves classification accuracies by 3.0% and 7.4%, respectively, in cross validation

Usefulness of Real-Time 4D Ultrasonography during Radiofrequency Ablation in a Case of Hepatocellular Carcinoma

We report a case of hepatocellular carcinoma (HCC) with chronic hepatitis C virus infection successfully treated with percutaneous radiofrequency ablation (RFA) under live four-dimensional (4D) echo guidance. A 65-year-old Japanese man had a HCC nodule in the liver S5 region 2.0 cm in diameter. We performed real-time 4D ultrasonography during RFA therapy with a LeVeen needle electrode. The echo guidance facilitated an accurate approach for the needle puncture. The guidance was also useful for confirming whether an adequate safety margin for the nodule had been obtained. Thus real-time 4D ultrasonography echo technique appears to provide safe guidance of RFA needles via accurate targeting of HCC nodules, thereby allowing real-time visualization when combined with echo contrast. Furthermore the position of the needle in a still image was confirmed in every area using a multiview procedure

A noise-driven attractor switching device

Problems with artificial neural networks originate from their deterministic nature and inevitable prior learnings, resulting in inadequate adaptability against unpredictable, abrupt environmental change. Here we show that a stochastically excitable threshold unit can be utilized by these systems to partially overcome the environmental change. Using an excitable threshold system, attractors were created that represent quasi-equilibrium states into which a system settles until disrupted by environmental change. Furthermore, noise-driven attractor stabilization and switching were embodied by inhibitory connections. Noise works as a power source to stabilize and switch attractors, and endows the system with hysteresis behavior that resembles that of stereopsis and binocular rivalry in the human visual cortex. A canonical model of the ring network with inhibitory connections composed of class 1 neurons also shows properties that are similar to the simple threshold system.Comment: 9 pages, 2 tables, and 6 figures. will appear in Phy.Rev.E, vol.79, issue

Cooperative Dynamics of an Artificial Stochastic Resonant System

We have investigated cooperative dynamics of an artificial stochastic resonant system, which is a recurrent ring connection of neuron-like signal transducers (NST) based on stochastic resonance (SR), using electronic circuit experiments. The ring showed quasi-periodic, tunable oscillation driven by only noise. An oscillation coherently amplified by noise demonstrated that SR may lead to unusual oscillation features. Furthermore, we found that the ring showed synchronized oscillation in a chain network composed of multiple rings. Our results suggest that basic functions (oscillation and synchronization) that may be used in the central pattern generator of biological system are induced by collective integration of the NST element.Comment: 13 pages, 4 figure

Hepatocellular Carcinoma 11 and a Half Years after the Resolution of Chronic Hepatitis C Virus Infection Successfully Treated with Interferon

A 41-year-old Japanese man had received successful interferon (IFN) therapy against chronic hepatitis C in 1994. Since then, serum hepatitis C virus (HCV) RNA had been negative, and aminotransferase levels had been continuously normal. He had abstained from alcohol. However, his serum aminotransferase levels showed slight elevation as his body weight increased gradually. He was diagnosed as having fatty liver and diabetes mellitus. In January 2006, 11 and a half years after the resolution of HCV infection, he was found to have a hepatic nodule 4.0 cm in diameter at liver S4/8 region by plain abdominal CT at an annual follow-up examination. He was diagnosed as having hepatocellular carcinoma (HCC) by angiography. The tumor was curatively resected and its histological diagnosis was moderately differentiated HCC. Noncancerous lesion of the liver revealed fibrosis of stage F2 and mild inflammation of grade A1 with mild steatosis. This case suggests that all patients with chronic HCV infection should be followed as long as possible for the potential development of HCC even after clearance of the virus

Aldose reductase inhibition ameliorates pupillary light reflex and F-wave latency in patients with mild diabetic neuropathy

WSTĘP. Zbadanie wpływu inhibitora reduktazy aldozy, epalrestatu, na wczesną fazę neuropatii autonomicznej i somatycznej u chorych na cukrzycę typu 2 przez ocenę odruchu źrenicznego na światło oraz minimalnej latencji fali F. MATERIAŁ I METODY. Badanie objęło 30 chorych na cukrzycę z podkliniczną lub łagodną neuropatią cukrzycową, których losowo przydzielono do grupy kontrolnej (n = 15) lub do grupy leczonej epalrestatem (150 mg/d., n = 15). Po 24 tygodniach przeprowadzono badanie odruchu źrenicznego na światło, testy włókien autonomicznych układu sercowo-naczyniowego oraz badanie przewodzenia nerwowego. WYNIKI. Korzystny wpływ epalrestatu na odruch źreniczny na światło zaobserwowano w odniesieniu do minimalnej średnicy po bodźcu świetlnym (p = 0,044), wskaźnika zwężenia (p = 0,014) oraz maksymalnej szybkości zwężania (p = 0,008). Spośród testów autonomicznych układu sercowo-naczyniowego leczenie epalrestatem spowodowało poprawę wskaźnika najdłuższego odstępu RR podczas wydechu do najkrótszego odstępu RR w czasie wdechu obserwowanego podczas testu głębokiego oddychania (p = 0,037). Minimalna latencja fali F nerwów pośrodkowego oraz piszczelowego uległa istotnemu skróceniu w grupie chorych leczonych epalrestatem (odpowiednio p = 0,002 oraz p = 0,001); nie stwierdzono jednak istotnego wpływu na prędkość przewodzenia nerwowego w nerwach czuciowych oraz ruchowych. WNIOSKI. Powyższe obserwacje sugerują, że epalrestat może korzystnie działać we wczesnej fazie neuropatii cukrzycowej oraz że odruch źreniczny na światło i minimalna latencja fali F mogą stanowić przydatne wskaźniki neuropatii cukrzycowej.INTRODUCTION. The present study was conducted to investigate the effect of an aldose reductase inhibitor, epalrestat, on autonomic and somatic neuropathy at an early stage in type 2 diabetic patients by assessing the pupillary light reflex and minimum latency of the F-wave. MATERIAL AND METHODS. A total of 30 diabetic patients with subclinical or mild diabetic neuropathy were randomly allocated to a control group (n = 15) and epalrestat (150 mg/day) group (n = 15). After 24 weeks, the pupillary light reflex test, cardiovascular autonomic function tests, and nerve conduction study were performed. RESULTS. The beneficial effect of epalrestat on the pupillary light reflex was observed in the minimum diameter after light stimuli (P = 0.044), constriction ratio (P = 0.014), and maximum velocity of constriction (P = 0.008). Among cardiovascular autonomic nerve functions, the ratio of the longest expiratory R-R interval to the shortest inspiratory R-R interval during deep breathing was significantly improved by epalrestat (P = 0.037). Minimum latencies of F-wave of median and tibial motor nerves were significantly shortened by epalrestat (P = 0.002 and P = 0.001, respectively); however, no significant effects were observed in motor or sensory nerve conduction velocity. CONCLUSIONS. These observations suggest that epalrestat may have therapeutic value at the early stage of diabetic neuropathy and that the pupillary light reflex and minimum latency of F-wave may be useful indicators of diabetic neuropathy