Adaptive state construction for reinforcement learning and its application to robot navigation problems

This paper applies our state construction method by ART neural network to robot navigation problems. Agents in this paper consist of ART neural network and contradiction resolution mechanism. The ART neural network serves as a mean of state recognition which maps stimulus inputs to a certain state and state construction which creates a new state when a current stimulus input cannot be categorized into any known states. On the other hand, the contradiction resolution mechanism (CRM) uses agents' state transition table to detect inconsistency among constructed states. In the proposed method, two kinds of inconsistency for the CRM are introduced: &#34;Different results caused by the same states and the same actions&#34; and &#34;Contradiction due to ambiguous states.&#34; The simulation results on the robot navigation problems confirm the effectiveness of the proposed method</p

Prediction Of Lateral Vibration Behavior Of Integrally Geared Centrifugal Compressor During Synchronous Motor Startup By Transient Torsional-Lateral Coupled Analysis

LectureStartup transients of both torsional and lateral vibration behaviors of an integrally geared centrifugal compressor driven by a synchronous motor are examined by transient torsional-lateral coupled analyses, and the numerical calculation results are evaluated using the field measurements as a benchmark. Since linear bearing coefficients are employed in the numerical simulation instead of more sophisticated nonlinear bearing model, bilinear stiffness is additionally considered to reflect the effects of the rotor confinement within the bearing clearance. Moreover, temporary teeth separation of the gear meshing and engagement at the backside during torque reversal is also considered in the numerical calculation. The transient lateral vibration behavior of the pinion rotor during the synchronous motor’s startup is successfully replicated. Both (a) bilinear stiffness of the pinion rotor bearings due to rotor restraint within the bearing clearance, and (b) effect of temporary teeth separation within the backlash and engagement at the backside because of torque reversal, are found to strongly influence the numerical predictions

An incremental state-segmentation method for reinforcement learning using ART neural network

In this paper, we propose a new incremental state segmentation method by utilizing information of the agents' state transition table which consists of a tuple of (state; action, state) in order to reduce the effort of designers and which is generated using the ART neural network. In the proposed method, if an inconsistent situation in the state transition table is observed, agents refine their map from perceptual inputs to states such that inconsistency is resolved. We introduce two kinds of inconsistency, i.e., different results caused by the same states and the same actions, and contradiction due to ambiguous states. Several computational simulations on cart-pole problems confirm the effectiveness of the proposed method</p

Effects of nicorandil, a potassium channel opener, on idiopathic ventricular tachycardia

AbstractObjectives. We assessed the effects of the adenosine triphosphate (ATP)–sensitive potassium channel opener, nicorandil, on ATP- and verapamil-responsive ventricular tachycardias (VTs).Background. Adenosine- or ATP-sensitive VTs are thought to be due to a nonreentrant mechanism, presumably delayed afterdepolarization. We suggest that this potassium channel opener may suppress ATP- and verapamil-sensitive VTs.Methods. The subjects included 13 patients with idiopathic VTs, 7 of whom had sustained VT and 6 of whom had nonsustained VT. We evaluated the effects of ATP, nicorandil and verapamil on VTs.Results. Sustained VT: Verapamil had preventive effects on seven VTs. Four VTs were terminated by ATP, and of these, nicorandil terminated two and prevented exercise-induced VT in the two others. Three ATP-insensitive VTs, which were determined to be due to a reentry by an electrophysiologic study, were not terminated by nicorandil. Nonsustained VT: All six VTs were inhibited by ATP, and five of these were suppressed by nicorandil. Verapamil inhibited four of the five VTs. QT intervals and the corrected QT intervals were significantly shortened by nicorandil.Conclusions. Nicorandil suppresses ATP- and verapamil-responsive VTs. One of the mechanisms of suppression by nicorandil might be related to a reduction of calcium in the myocardium, because it reduces the action potential duration