• KIPS Transactions on Computer and Communication Systems
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• v.4 no.8
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• pp.253-258
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• 2015

From the point of view of u-healthcare, heart rate is so useful for both illness for taking care of patients and wellness for improving the level of health and wellbeing. It is because heart rate is a significant clinical variable for all kinds of diseases as well as an indicator of the intensity of exercise. Recently, a number of various wearable heart rate monitors have been released to check people's status in the body by monitoring their heart rates. In addition, a number of smartphone applications have been released to conveniently monitor the status of exercise by using heart rate monitors. However, all of these applications are limited to a personal usage. In this paper, we will design a system to simultaneously monitor heart rates coming from multiple users in a real-time, and develop an Android application to apply the system. The application mainly features a simultaneous monitoring of heart rates coming from multiple users, allowing to be effectively applied to fitness centers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.81-87
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• 2016

With the rapid growth of the up-to-date smartphone and wireless network technologies, huge and various types of smart applications using these technologies are actively developed recently. Especially, multiplex types of smart applications using smartphone are developed and diffused with the rapid development of the ubiquitous sensor network technology using various sensors and the mobile computing technology that enables us to get network services at any time in any places. In this paper, we design a smart application that can accurately diagnose and process the current state of the local environment, objects, and persons remotely based on the context information such as local ecology, circumstances, medical or healthcare records and realtime sound or motion pictures using up-to-date samrtphone technology on the USN based mobile computing environment.

• Journal of IKEEE
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• v.22 no.1
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• pp.29-37
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• 2018

In recent years, there have been increasing interests in the mobile crowdsourcing that exploits multiple sensors, communication and user interfaces, and the computation power of widespread smartphones. In this paper, we present a novel mobile crowdsourcing-based driver assistance systems (MC-DAS) that crowdsource the sensor data of smartphone app having already passed a road segment, generate its profile information through a massive data processing, and forward this profile to the smartphone app of vehicle entering the road segment. Based on the MC-DAS platform, we also design and implement a new navigation system that advices the vehicle speed depending on the speedbump and on the road curvature profile. We expect that the proposed MC-DAS platform will be used as a platform for emerging new mobile crowdsourcing applications.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.147-152
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• 2020

The purpose of this study was to develop an auxiliary device useful for promoting continued participation in the golf among young golfers and female beginner-level golfers who were gradually increasing in number but often losing interest in the golf and gave up playing golf due to difficulty with posture, boredom from golf itself, slow improvement of skill, etc., in the process of learning the golf. For that, a hardware device fitted with various sensors was attached to the lower part of golf club grip to develop a platform capable of collecting and transmitting the data on each golfer's swing posture, driving distance, etc. If a smartphone app, which can analyze and store those data, is developed and synchronized, each golfer's postures can be identified and golfers can correct the posture on their own. Moreover, the smartphone app provides the contents for self-comparison and comparison with others and will be able to infuse the beginner-level golfers with internal motivation for continued participation in the golfing exercise if the game-type elements are added.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.837-845
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• 2016

Providing a customer with tailored location-based services (LBSs) is a fundamental problem. For location-estimation techniques with radio-based measurements, LBS applications are widely available for mobile devices (MDs), such as smartphones, enabling users to run multi-task applications. LBS information not only enables obtaining the current location of an MD but also provides real-time push-pull communication service. For indoor environments, localization technologies based on radio frequency (RF) pattern-matching approaches are accurate and commonly used. However, to survey radio information for pattern-matching approaches, a considerable amount of time and work is spent in indoor environments. Consequently, in order to reduce the system-deployment cost and computing complexity, this article proposes an indoor positioning approach, which involves using Asus Xtion to facilitate capturing RF signals during an offline site survey. The depth information obtained using Asus Xtion is utilized to estimate the locations and predict the received signal strength (RF information) at uncertain locations. The proposed approach effectively reduces not only the time and work costs but also the computing complexity involved in determining the orientation and RF during the online positioning phase by estimating the user's location by using a smartphone. The experimental results demonstrated that more than 78% of time was saved, and the number of samples acquired using the proposed method during the offline phase was twice as much as that acquired using the conventional method. For the online phase, the location estimates have error distances of less than 2.67 m. Therefore, the proposed approach is beneficial for use in various LBS applications.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.155-161
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• 2015

In the paper, we developed the mobile based rehabilitation system for patients with upper extremity hemiplegia after stroke and evaluated clinical usefulness and effectiveness of the system. The sensors built in the smartphone were used to track patients' upper limb motion and the movements was transferred to the tablet PC through bluetooth connection so that the game contents could be interact with the movements. The rehabilitation game contents was based on Brunnstrom stage(B-stage), and was designed to lead accurate movement of upper limb. For the clinical evaluation of the effectiveness, 11 patients were recruited and make them perform an exercise of their wrist, shoulder, and forearm using the system for two weeks. The change of upper limb motor function was measured using fugl-meyer assessment(FMA), Brunnstrom stage(B-stage). And the change of quality of life was measured using EuroQoL-5 Dimension(EQ-5D), Beck Depression Inventory(BDI). The results showed significant improvement in upper limb function but not in quality of life. We verified mobile based rehabilitation program could be useful and effective for the clinical use.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7187-7192
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• 2014

Recently, theservice field based on the location while expanding into a variety of business areas and have generated significant revenue. In particular, the map service provides a variety of information in conjunction with such public transport directions. Therefore, this study evaluated the map service, as one of the key technologies, StreetView and LoadView photographs of panoramic photograph-support service-modules that can be supported on smart phones. For this, purpose sensors were provided to allow smart phone users to easily publish panoramic photographs. The unnecessary parts could be removed from several photos and pictures using the design technology, and the naturalness of the connection could be maintained by applying the algorithm to handle a single photograph. Finally, a system to work with smartphone panoramic photographs was configured and designed to operate a smartphone application panoramic photograph for 6 months.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.7
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• pp.610-617
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• 2017

In the recent weapon system trend, it is required to develop small and low cost guidance missile to track and strike the enemy target effectively. Controling the such small drone typed weapon demands a integrated electronic device that equipped with not only a wireless network interface, a high resolution camera, various sensors for target tracking, and position and attitude control but also a high performance processor that integrates and processes those sensor outputs in real-time. In this paper, we propose the android smartphone as a solution for that and implement the guidance and control application of the missile. Furthermore, the performance of the implemented guidance and control application is analyzed through the simulation.

• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.65-71
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• 2015

In this paper, we present binocular augmented reality system with smartphones. With improvements of performance and resolution of recent smartphones, various virtual reality devices using smartphones and applications are appearing in the market. But the augmented reality system with smartphones are not that popular because of the lack of required technologies. In our work, we discuss about 3D mapping and tracking using computer vision. Also, we provide hybrid tracking using sensors in the smartphone which can handle the computer vision failure cases. Bare hand 3D interaction method in our system will be also presented.

• Journal of Korea Game Society
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• v.14 no.2
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• pp.67-76
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• 2014

Recently there have been many interests on tangible sport games that can recognize the motions of players. In this paper, we propose essential technologies required for tangible games, which are methods for swing motion recognition and the calculation of shuttle cock's trajectory. When a user carries out a badminton swing while holding a smartphone with his hand, the motion signal generated by smartphone-embedded acceleration sensors is transformed into a feature vector through a Daubechies filter, and then its swing type is recognized using a k-NN based method. The method for swing motion presented herein provides an advantage in a way that a player can enjoy tangible games without purchasing a commercial motion controller. Since a badminton shuttle cock has a particular flight trajectory due to the nature of its shape, it is not easy to calculate the trajectory of the shuttle cock using simple physics rules about force and velocity. In this paper, we propose a method for calculating the flight trajectory of a badminton shuttle cock in which the wind effect is considered.