• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1224-1230
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• 2020

Since the spread of smart phones, interest in wearable devices has increased and diversified, and is closely related to the lives of users, and has been used as a method for providing personalized services. In this paper, we propose a method to detect the user's behavior by applying information from a 3-axis acceleration sensor and a 3-axis gyro sensor embedded in a smartphone to a convolutional neural network. Human behavior differs according to the size and range of motion, starting and ending time, including the duration of the signal data constituting the motion. Therefore, there is a performance problem for accuracy when applied to a convolutional neural network as it is. Therefore, we proposed a Time-Division Feature Fusion Convolutional Neural Network (TDFFCNN) that learns the characteristics of the sensor data segmented over time. The proposed method outperformed other classifiers such as SVM, IBk, convolutional neural network, and long-term memory circulatory neural network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.157-165
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• 2015

With the ever-improving performance of smartphone cameras and the universal dissemination of cloud services, users can now record and store the events in their daily lives more easily and conveniently. The advent of lifelogging technology has been changing the uses as well as the paradigm of internet services, and emphasizing the importance of services being personalization. As the amount of lifelog data becomes vast, it requires an efficient way to manage and store such vast information. In this paper, we propose an low power lifelog management scheme based on user movement behaviors in wireless networks. In order to reduce the power consumption of a smartphone, in our proposal, frequency of data collection and transfer can be dynamically adjusted based on a user's movement pattern. The analytical results show that our approach achieves better performance than that of the existing lifelog management scheme.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.351-357
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• 2017

The purpose of this study is to analyze the relationship between users' expectation and satisfaction through analyzing smart phone voice recognition service and surveying the situational satisfaction of voice recognition service. First, the concept and current status of speech recognition service were investigated through literature research, and the questionnaire survey was carried out through questionnaires based on the second and third principles. As a result, the user is most likely to use the smartphone voice recognition service when making a telephone call. Also, it was found that the service is the most used at home and the service is used most when the hand is not available. Through these results, various methods such as personalization service, condition recognition function, automatic emergency recognition, unlocking by voice could be derived. Based on this research, it is expected that it will be used effectively for improving smartphone voice recognition service and developing wearable device in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.39-51
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• 2016

In accordance to rapid aging of population, the accidents of elderly pedestrian and pedestrian safety are becoming very important issues. In terms of smartphone technologies, older people are increasingly looking for useful and friendly ICT services that which can add a value on their silver life. This paper introduced a new IT-based service for elderly walking assist using a smart-phone accompanied by a wearable watch. We describe the functional requirements and a systems architecture model with an interface between a smart-phone and wearable watch. Moreover, this study attempted to verify what services are needed and to estimate elderly pedestrians' WTP (willingness to pay) for IT-based walking assistance device. A total of 189 elderly pedestrians were randomly surveyed through face-to-face interviews. The questionnaire consisted of 3 categories: (1) questions pertaining to socio-economic status, (2) 12 questions regarding walking attitudes, and (3) a question to measure WTP. With this gathered data, factor analysis and path model estimating were conducted. The results identified the elderly user requirements and the use-value of new innovative products for IT-based walking assistance services by two groups(latent elderly and elderly). The modeling result shows that elderly's service preference would increase the possibilities for the commercialization of IT-based walking device with improving their walking safety.

• Healthcare Informatics Research
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• v.24 no.4
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• pp.387-393
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• 2018

Objectives: This paper describes an experience of implementing seamless service trials online and offline by adopting Internet of Things (IoT) technology based on near-field communication (NFC) tags and Bluetooth low-energy (BLE) beacons. The services were provided for both patients and health professionals. Methods: The pilot services were implemented to enhance healthcare service quality, improve patient safety, and provide an effective business process to health professionals in a tertiary hospital in Seoul, Korea. The services to enhance healthcare service quality include healing tours, cancer information/education, psychological assessments, indoor navigation, and exercise volume checking. The services to improve patient safety are monitoring of high-risk inpatients and delivery of real-time health information in emergency situations. In addition, the services to provide an effective business process to health professionals include surveys and web services for patient management. Results: Considering the sustainability of the pilot services, we decided to pause navigation and patient monitoring services until the interference problem could be completely resolved because beacon signal interference significantly influences the quality of services. On the other hand, we had to continue to provide new wearable beacons to high-risk patients because of hygiene issues, so the cost increased over time and was much higher than expected. Conclusions: To make the smart connected hospital services sustainable, technical feasibility (e.g., beacon signal interference), economic feasibility (e.g., continuous provision of new necklace beacons), and organizational commitment and support (e.g., renewal of new alternative medical devices and infrastructure) are required.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.2008-2016
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• 2014

With the increased attention about health care and management of heart diseases, ubiquitous healthcare services and related devices have been actively developed recently. In this paper we developed a mobile healthcare system which consists of smartphone and patch-type ECG measuring device. This system is capable of monitoring, storing, and sending bio signals such as ECG, heart rate, heart rate variability as well as exercise management functions through heart rate zones. With monitoring bio signal continuously by mobile healthcare system and wearable device like us, people can prevent chronic disease and maintain good health. Here we report our implementation results on real platforms.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.311-320
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• 2022

Objective: To investigate the reliability and validity of static balance measurements using an acceleration sensor and a gyroscope sensor in smart phone inertial sensors. Design: Equivalent control group pretest-posttest. Methods: Subjects were forty five healthy adults aged twenty to fifty-years-old who had no disease that could affect the experiment. After pre-test, all participants wore a waist band with smart phone, and conducted six static balance measurements on the force plate twice for 35 seconds each. To investigate the test-retest reliability of both smart phone inertial sensors, we compared the intra-correlation coefficient (ICC 3, 1) between primary and secondary measurements with the calculated root mean scale-total data. To determine the validity of the two sensors, it was measured simultaneously with force plate, and the comparision was done by Pearson's correlation. Results: The test-retest reliability showed excellent correlation for acceleration sensor, and it also showed excellent to good correlation for gyroscope sensor(p<0.05). The concurrent validity of smartphone inertial sensors showed a mostly poor to fair correlation for tandem-stance and one-leg-stance (p<0.05) and unacceptable correlation for the other postures (p>0.05). The gyroscope sensor showed a fair correlation for most of the RMS-Total data, and the other data also showed poor to fair correlation (p<0.05). Conclusions: The result indicates that both acceleration sensor and gyroscope sensor has good reliability, and that compared to force plate, acceleration sensor has unacceptable or poor correlation, and gyroscope sensor has mostly fair correlation.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.433-440
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• 2022

Recently, owing to global warming, average summer temperatures are increasing and the number of hot days is increasing is increasing, which leads to an increase in heat stroke. In particular, outdoor workers directly exposed to the heat are at higher risk of heat stroke; therefore, preventing heat-related illnesses and managing safety have become important. Although various wearable devices have been developed to prevent heat stroke for outdoor workers, applying various sensors to the safety helmets that workers must wear is an excellent alternative. In this study, we developed a smart helmet that measures various vital signs of the wearer such as body temperature, heart rate, and sweat rate; external environmental signals such as temperature and humidity; and movement signals of the wearer such as roll and pitch angles. The smart helmet can acquire the various data by connecting with a smartphone application. Environmental data can check the status of heat wave advisory, and the individual vital signs can monitor the health of workers. In addition, we developed an algorithm that classifies the risk of heat-related illness as normal and abnormal by inputting a set of vital signs of the wearer using a support vector machine technique, which is a machine learning technique that allows for rapid binary classification with high reliability. Furthermore, the classified results suggest that the safety manager can supervise the prevention of heat stroke by receiving feedback from the control system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.507-514
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• 2015

The Internet of Things era is approaching where all the things are equipped with smart sensors and communicate through internet. The three core technologies of the Internet of Things are 'detection technology' to get information from things and the environment, 'wired and wireless communications and network infrastructure skills' that support to connect things to the internet, and 'service interface technology' that processes the information appropriate to various services. Smart sensor application can expand to smartphone, smart cars, smart home systems, wearable electronic devices, telemedicine systems, and environmental monitoring systems, etc. In particular, technologies that mimic the five human senses. This study reviews the biological principles of the human senses and the principles of operation, research & development status, technology trends and market analysis of the sensors.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.1
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• pp.20-29
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• 2021

This study developed a smartwatch and a wind speed system in accordance with the necessity of a device that provides the information required in marine leisure. Based on a marine leisure smartwatch with a multi-sensor, a gyro box, and a wind speed system, external data such as GPS, motion, humidity, temperature, air pressure, and heart rate can be collected. In addition, the collected external environment data can be managed through an application on a smartphone, which is an Android-based mobile device. The developed smartwatch and wind speed system are expected to contribute to increasing accessibility and revitalization of the marine leisure industry. In addition, in terms of safety and education, the need for a device that provides marine information is large, so it is expected to increase the possibility of entering the high value-added market and improve the product localization rate.