Keitaro Naruse

Three-dimensional lifting-up motion analysis for wearable power assist device of lower back support

The objective of this research is to develop a wearable power assist device which helps a person to lift up a heavy object. The device is designed to support him by holding his upper body weight and reducing his inner force. It turns to the reduction of a compression force of his lower back discs, which is a major factor of a lower back injury. In a lifting-up motion, he twists and bends his body, which means three-dimensional motion analysis is necessary for the compression force analysis. However, most of related works on the compression force analysis have been carried out in a vertical plane. For understanding the characteristics of a lifting-up motion better, this paper presents three-dimensional analysis of it. Using a motion capture system, we measured a sequence of body positions with and without the power assist device in different object location and mass, as well as surface EMG (electro-myogram) signals. The compression force of the lower back discs is estimated by a three-dimensional biomechanical human body model utilizing the position data. The results show that the range of the twist angle of his body is about 30 degree in maximum and the compression force increases about 10% due to the twist angle. With respect to the effect of the power assist device, the magnitude of the surface EMG signals of spine muscles is decreased when wearing the power assist device. It means the proposed power assist device gives a good support to him.

The possibility of an epidemic meme analogy for web community population analysis

The aim of this paper is to discuss the possibility of understanding human social interaction in web communities by analogy with a disease propagation model from epidemiology. When an article is submitted by an individual to a social web service, it is potentially influenced by other participants. The submission sometimes starts a long and argumentative chain of articles, but often does not. This complex behavior makes management of server resources difficult and a more theoretical methodology is required. This paper tries to express these complex human dynamics by analogy with infection by a virus. In this first report, by fitting an epidemiological model to Bulletin Board System (BBS) logs in terms of a numerical triple, we show that the analogy is reasonable and beneficial because the analogy can estimate the community size despite the submitters information alone being observable.

A mining method for linked Web pages using associated keyword space

We propose a novel method for mining knowledge from linked Web pages. Unlike most conventional methods for extracting knowledge from linked data, which are based on graph theory, the proposed method is based on our associated keyword space (ASKS), which is a nonlinear version of linear multidimensional scaling (MDS), such as quantification method type IV (Q-IV). We constructed a three-dimensional ASKS space using linked HTML data from the World Wide Web. Experimental results confirm that the performance of ASKS is superior to that of Q-IV for discriminating clusters in the space obtained. We also demonstrate a mining procedure realized by 1) finding subspaces obtained in terms of logical calculations between subspaces in an ASKS space and 2) detecting emerging spatial patterns with geometrical features

Development of small weeding robots for rice fields

The objective of this paper is to develop a robotic weeding system for a rice field. We took the approach of moving a large number of robots around in a field, thereby preventing weed seeds from sprouting. This paper presents the developed robotic system, in particular the robot hardware and radio communication network, and verification of the system use in an actual rice field.

Feasibility study of weeding robots in rice fields inspired by natural ducks

The objective of this research project is to develop a robotic weeding system for rice fields that will enable chemical-free rice farming, giving us safer and more valuable rice. We take the approach of moving a large number of robots around the field, which prevents weed seeds from sprouting. This is inspired by an existing rice farming method that utilizes natural ducks. One of the major research issues is to develop a robot body and locomotion method that will have sufficient weeding ability when working in the field. This paper reports on the results of a feasibility study of our artificial duck robots in an actual rice field, in which the robots demonstrate sufficient mobility for successful weeding.

Word Space: A New Approach to Describe Word Meanings

The purpose of this research is to acquire new knowledge about the meanings of words by arranging the words in space. We allocated the words and displayed their relationship with each other in a three-dimensional space with a method called Associated Keyword Space (ASKS). In the experiment, the data obtained by ASKS were compared with Thesaurus.com and WordNet, conventional methods of meaning description. The result of the experiment showed two important points. First, the strength of each meaning of a verb with polysemy was expressed by the visual relationship with and distance to associated words. Second, polysemy of the verb was expressed by the extension of the synonyms

Speech and Song Search on the Web: System Design and Implementation

This paper proposes a novel search system for speech and song segments. The amount of accumulated video data in the World Wide Web is expanding and its content is varied. Video content includes natural voices and singing voices, and these differ in their phoneme lengths. Our system uses frame-wise phoneme recognition and continuous dynamic programming (CDP). First, each target and query waveform is divided into fixed short-time frames; second, each frame of the waveform is used to estimate a phoneme label using Bayes estimation; third, the query sequences of phoneme labels are searched from target sequences by time-robustness CDP; and, finally, this system gets candidate answers. This method is robust along the time dimension, and thus has a great advantage for natural voice as well as song. This paper also introduces an implementation of this system, which is published on the Web, as a secondary search engine for Youtube data.

Muscle-like control of entertainment robot over internet

The robot technology is extending to social activities such as community work, home-use and entertainment. By combining the robot technology with the popularized public Internet, it is anticipated a new application field will come out. However, Internet, as its nature, does not permit real-time communication among robots and other systems including human operators and computers. A different approach is necessary regarding communication protocols and robot control schemes. This paper proposes the combination of the Web services technology and the autonomous robot motion generation is the proper approach. For the motion generation, we introduce the muscle-like control method, which can be applied to any kinds of robots easily with proving a variety of creature-like motions. The method is applied to gait generation of a simulated four-legged robot, and the results show that it can transit from a motion to another one smoothly. In addition, the simulated robot is controlled by the Web services over Internet for investigating the feasibility of the proposed control scheme in a real network circumstance. The result shows that the proposed method provides us smooth control of the robot, even we have overhead of Web service processes and delayed communication

Unsmooth field sweeping by Balistic random walk of multiple robots in unsmooth terrain

The major goal of this paper is to develop a robotic weeding system for a rice field by multiple robots. The task of the robots is to move around a given field for preventing sprouting of weed seeds. In other words, a key issue is to sweep or cover the given filed by robot trajectories. Since the motions of the robots are affected disturbances from an unsmooth and soft ground, we cannot apply a conventional path planning strategy. In this paper, we introduce a random walk into a path planning system for the robustness to the disturbances and we investigate the relation between a time period of robot operations and swept area.

Visualization of spread of topic words on Twitter using stream graphs and relational graphs

In this paper, we examine occurrences, cooccurrences, and characteristics for influence and meaning of words by visualizing large amounts of data from Twitter. We classified words using morphological analysis of tweets and developed a stream graph by finding the frequency of each word. We analyzed the co-occurrence of words using quantification methods of the fourth type to find relationships and showed distances between words in a similarity graph. We present examples of the relationships found by our analysis.