Gwan Kim

Tactile Substitution System for Transmitting a Few Words to a Prosthetic Hand User

This paper describes an efficient system for transmitting a few words (verbal information) to a prosthetic hand user by using a two-channel electrotactile stimulation capable of generating apparent movements, which is applied to the upper arm area of the left hand via surface concentric electrodes. If the prosthetic hand user gets verbal information about interaction between the prosthesis and the environment, e.g., the prosthetic hand just touched a doorknob, he/she will be able to open or close the door even in the darkness, and also to handle an object on the top of a shelf out of his/her view. In this study, verbal information was provided regarding which finger touches the object (three states), and the fingers angle (two states). Consequently, six states of verbal information could be sent. We therefore designed five stimulation patterns (duration 600 - 800 ms) comprising several burst profiles in which each burst was composed of several pulses (interval of biphasic pulses, 2.85 ms) modulated in amplitude. The recognition experiments using 10 healthy subjects showed that the mean percentage of recognition was about 94% (standard deviation: 3.9). These results suggested the possible applicability of the proposed system to assist prosthetic hand users

Sound Information Notification System by Two-Channel Electrotactile Stimulation for Hearing Impaired Persons

Hearing impaired persons (HIPs) are afraid of walking along a street and living a life alone. If they can successfully get sound information via some machine interface, dangerous situations outdoors will be avoided, and their quality of life indoors will be improved. This paper describes a notification system for transmitting sound information to HIPs with two-channel electrotactile stimulation, assuming that it is used both outdoors and indoors. The proposed system consists of two subsystems: one is a block which detects sound information and another one is to transmit the detected sound information with electrotactile stimulation. In the system developed, sound information is provided with the attention arousal, notifying the direction of the sound source (four states) and the sound category (seven states). Thus, 28 states of sound information are sent. We adopted 12 stimulation patterns comprising several burst profiles, each burst composed of several pulses modulated in amplitude. In the first subsystem, recognition ratio of the direction was 90 % and detection ratio of the sound category was 80 %. In the second subsystem, recognition experiments for the direction of the sound source and the sound category performed for four healthy subjects showed that the average percentages of correct recognition were 91 % and 89 %, and the reaction times 1.21 seconds and 1.62 seconds. These results suggested the possible applicability of the proposed system to assist HIPs.

Sensory substitution system of two-channel electrotactile stimulation for transmitting verbal information

We have aimed at developing a sensory substitution system for transmitting verbal information. In this work, we propose a basic two-channel electrotactile stimulation system and examine the usefulness of the system. The verbal information to be provided consists of two items: one is the object and another is the location (direction) of the object in the surrounding of the subject Three objects and three directions are utilized in this work. Each of the nine possibilities was transmitted to the subject as a skin stimulus consisting of two consecutive stimulation patterns; the first pattern represents the direction and the second the object. Stimulation pattern for each item was generated by two-channel voltage-pulse trains, which elicited a movement impression on the subjects skin. The electrical stimulus was delivered on the dorsal carpal area of the left hand. High percentage of recognition (average: 92%, standard deviation: 4.2) was obtained. Recognition percentages were improved by giving the subject a prior explanation about each stimulation pattern and increasing the stimulus intensity up to 95 % of the pain threshold.

A Regional Model for the Distribution of Industrial Activities

Abstract This paper describes a regional model which is constructed to forecast industrial activities in a highly-disaggregated region. As the divided subregions are very close, mutual influences among them cannot be ignored in forecasting the future of the subregions. In this paper, taking the industrial activities in each subregion as state variables, their changes are described by using the state equation. It can be shown that the state equation can be simplified to a linear equation with respect to unknown parameters by introducing the potential defined by W. Isard, if we postulate some reasonable assumptions. For the puspose of making a positive study, Kansai Region, which is divided into 120 zones, is taken as an objective region. First, a submodel is constructed to estimate time distances between zones which are necessary to calculate the value of various potentials in each zone. Second, taking employment by industries as the state variable, unknown parameters of the linearlized state equation for each of 31 industries are identified, and an employment submodel is constructed. Then, these two submodels are used to constitute a comprehensive regional model, together with the other two submodels of population and land use submodel which are developed concurrently. The final test of the regional model is performed by using the data from 1970 through 1980, and it is confirmed that the constructed model has sufficient validity.

AN INTEGRATED REGIONAL SIMULATION MODEL BASED ON LARGE SCALE DATABASE — EXPERIENCE IN THE KANSAI REGION OF JAPAN

Abstract The effects of various socio-economic policies at the national level must be evaluated by considering the effects of these policies on each region of a nation and also by examining the consistency of these policies. From this point of view, it is indispensable to have an integrated model which simulates the socio-economic activities of regional level. In this study, a large scale, integrated socio-economic database is constructed for the Kansai region of Japan with population of over 20 million. The main part of the database is composed of population and employment data such as the number of employees by 31 categories of industry and population by age and sex, for each of more than 400 cities, towns and villages, but it also contains data of land use and road and railway networks. By utilizing the database, an integrated socio-economic simulation model (Osaka University Regional Simulation Model - OURS Model) has been constructed which forecasts above-mentioned various socio-economic indicators for each subregion. The model contains a macro economic model and the following three submodels, i.e., population, industry (employment) and land use, each of which has rather simple structural equation whose coefficients are determined by carefully analyzing the collected data. The change in the transportation network is modeled in a separate submodel as the change in the journey time between the subregions. OURS Model has made it possible to simulate the socio-economic activities of each of the 120 zones in the Kansai region, and it allows us to see in detail the effects of various policies on each zone over the entire region.

An Integrated Regional Simulation Model Based on Large Scale Database — Experience in the Kansai Region of Japan

Abstract The effects of various socio-economic policies at the national level must be evaluated by considering the effects of these policies on each region of a nation and also by examining the consistency of these policies. From this point of view, it is indispensable to have an integrated model which simulates the socio-economic activities of regional level. In this study, a large scale, integrated socio-economic database is constructed for the Kansai region of Japan with population of over 20 million. The main part of the database is composed of population and employment data such as the number of employees by 31 categories of industry and population by age and sex, for each of more than 400 cities, towns and villages, but it also contains data of land use and road and railway networks. By utilizing the database, an integrated socio-economic simulation model (Osaka University Regional Simulation Model - OURS Model) has been constructed which forecasts above-mentioned various socio-economic indicators for each subregion. The model contains a macro economic model and the following three submodels, i.e., population, industry (employment) and land use, each of which has rather simple structural equation whose coefficients are determined by carefully analyzing the collected data. The change in the transportation network is modeled in a separate submodel as the change in the journey time between the subregions. OURS Model has made it possible to simulate the socio-economic activities of each of the 120 zones in the Kansai region, and it allows us to see in detail the effects of various policies on each zone over the entire region.

Long Range Electric Demand Forecasts for Osaka City by Modeling Socio-Economic Structural Changes

Abstract This paper describes the results of long range forecasts of power demand for the city of Osaka. The modeling is based on the analyses of past records relevant to electric power consumption. In the model constructed, the power demand estimation is carried out by four sectors, i.e., household, business and commercial, manufacturing and miscellaneous, taking into account the difference in consumption patterns in each sector. The model which is capable of describing the future socio-ecnomic structure in each tract in Osaka Area, is used in order to forecast various socio-economic indicators. Hence the estimation model can forecast the distribution of power demand over the city. The simulation results show that the power demand for the entire city in the year 2005 is forecasted to be 2.2 times that of 1980 with annual rate of increase of 3.2% in Case 3 in which the power demand is forecasted to be the largest, and 2.4% in Case 2 of standard case, compared with 5.0% during the past 15 years.