SUMMARY In Web‐based social media (blogs, Internet forums, etc.), readers express their opinions by attaching reply comments to articles and understand others' perspectives by reading these comments. On Web forums, users discuss and argue with others via reply comments. Thus, a series of comments may provide new information, particularly about disputes among participants. Unfortunately, current systems for viewing reply comments are primitive; it is hard to follow disputes and their relationships by using such systems. We examine the characteristics of disputes by using reply comments and propose a novel system for automatically detecting disputes and their relationships among a large set of reply comments. This paper defines a dispute section as a series of comments where the dispute index is sufficiently high. The dispute index is determined using an exponential model with three control parameters. Next, the dispute relationship can be defined according to a pair of arguing commenters. The basic concept is to exploit the order of comment posting times and comment writer information when detecting dispute sections because the comments tend to appear in ordered pairs. The proposed system detects dispute sections and visualizes them according to dispute relationships among commenters, enabling users to appreciate the controversial structure of comments. To test the performance of our system, we constructed a dataset containing comment sequences associated with 40 articles collected from an Web forum. We constructed the set of dispute comments manually. We found that the detection accuracy of our system for disputes and their relationships were 83% and 78% on average. Copyright © 2012 John Wiley & Sons, Ltd.

This paper presents a multifunction myoelectric hand that is designed with underactuated mechanisms. The finger design allows an adaptive grasp, including adaptation between fingers and phalanges with respect to the shape of an object. In addition, a self-lock is embedded in the metacarpophalangeal joint to prevent back driving when external forces act on the fingers. The thumb design also provides adaptation between phalanges and adds an intermittent rotary motion to the carpometacarpal joint. As a result, the hand can perform versatile grasping motions using only two motors, and is capable of natural and stable grasping without complex sensor and servo systems. Moreover, the adaptive grasping capabilities reduce the requirements of electromyogram pattern recognition, as analogous motions, such as cylindrical and tip grasps, can be classified as one motion.

This paper proposes a new learning method for a Gaussian mixture model (GMM). First, a traditional maximum a posterior (MAP) parameter estimate is used to achieve regularization based on conjugate priors. Next, a model order selection criterion is derived from Bayesian-Laplace approaches such that the conjugate prior distribution can be used to measure the uncertainty in the estimated parameters. As a result, the proposed learning method avoids the possibility of convergence toward local minima in the parameter space, and is also capable of selecting the optimal order for a GMM using an additional complexity penalty for the prior distribution. The proposed method is applied to electromyogram (EMG) pattern recognition for controlling a multifunction myoelectric hand, and experiments conducted to recognize nine kinds of hand motion from EMG signals for ten subjects. In conclusion, the proposed learning method effectively estimated the change of feature vectors according to the subject and the GMM classifier demonstrated a high recognition accuracy.

A biomimetic entertainment robot called ELIRO-II(Eating Lizard RObot version 2) is proposed that includes an autonomous eating function based on the instinctual behavior of an animal that wanders around looking for food and eat food by itself. ELIRO-II is modeled on a lizard, with four legs, a 2-DOF waist-joint, eye part, mouth part and stomach part. Each component is also designed based on the natural world, i.e. eating food(=batteries) using a tongue, walking with a side to side swinging body motion, and stacking food in the stomach(=pack).

In this paper, a new gait is presented for a quadruped walking robot with waist-joint. Although various types of walking robot have already been developed, their structure and gaits are still quite distinct from the natural walking motion of an animal, and the key point is that animals have waist-joint and use their waist-joint to walk, but, on the other hand a conventional 4-legged walking robot even has single rigid body which has no waist joint. Especially in turning, most animals bend oneself on one side, which makes turn faster and more stable. Spinning gait is very important as same as straight forward/backward gait. All animals need a spinning gait to avoid obstacle or to change walking direction. Therefore, this paper proposes a discontinuous gait for a quadruped walking robot with waist-joint which divides body into the front and rear parts of the body. Firstly, we describe a kinematic relation of waist-joint, the hip, and the centre of gravity of body, and then find the optimal values of parameters to spin most stable with simulation. We implemented a waist-jointed walking robot and showed that proposed spinning gait using waist-joint is more stable than that of a conventional walking robot.

Recently, there has been a high demand for smart actuators in the field of micro-machines. However, the control accuracy of smart actuators is currently limited due to their inherent hysteresis nonlinearity. The Preisach hysteresis model has emerged as an appropriate model for the behavior of many smart actuators, e.g., a shape memory alloy (SMA). Yet it is still not easy to construct a practical model of hysteresis using the classical Preisach model. Accordingly, the current paper proposes a new simple method for modeling the hysteresis nonlinearity of an SMA. Using only the proportional relationship of the major loop of hysteresis, the proposed method makes the computation of the Preisach model much easier. The modeling accuracy is demonstrated through experimentation and a comparison between the proposed model and the classic Preisach model.

In the demining application area of a multi-legged robot, one of the important problems is to develop a gait with one or more legs missing. The paper presents a three-legged gait under the assumption that one leg of a quadruped walking robot is missing. We propose a classification scheme of postures for three-legged walking. As one of the basic and reasonable gaits for three-legged walking, the kick-and-swing gait is proposed and analyzed using a simple dynamic model. The minimum energy gait planning and an active shock-absorbing method are investigated. The validity of the proposed gait is shown by experiments using a quadruped walking robot TITAN VIII.

In this presentation we propose an algorithm for the adaptive gait control by which a quadruped walking robot can walk against external disturbances. The proposed gait mechanism makes it possible for a quadruped walking robot to change its gait pattern in response to external disturbances from various external forces acting on the body of the walking robot. More specifically, we propose a new criterion for the stability margin of a walking robot under unknown external forces by using the effective mass center based on the zero moment point. And for the solution of the adaptive gait algorithm against external disturbances, a method of altitude control and reflexive direction control is suggested. Based on the algorithmic search method, an optimal stride of the quadruped walking robot that walks from any leg configuration to the standard configuration is also proposed. To verify the efficiency of the proposed approach, some simulation results are provided.