• Electronics and Telecommunications Trends
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• v.34 no.5
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• pp.26-35
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• 2019

Modern imaging technologies utilizing electromagnetic waves are indispensable in our daily lives. Applications, such as television and smartphone screens, radar imaging for weather forecast, and medical imaging, can be attributed to technology developments in various electromagnetic regions. Terahertz (THz) waves, electromagnetic (EM) waves located between far infrared and microwave regions, had left unexplored EM waves. Recent advances in technology have led to various two-dimensional and three-dimensional THz imaging techniques. In this article, we explain THz imaging techniques as well as the experimental results from our laboratory. Additionally, we introduce commercial THz cameras developed worldwide. Finally, we present the applications of THz imaging techniques.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.4
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• pp.85-96
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• 2022

Personalized recommendation technology is one of the most important technologies in electronic commerce environment. It helps users overcome information overload by suggesting information that match user's interests. In e-commerce environment, both mobile device users and smart device users have risen dramatically. It creates new challenges. Our method suggests product information that match user's device interests beyond only user's interests. We propose a device-centered personalized recommendation method. Our method uses both purchase and share behavior for user's devices interests. Moreover, it considers data type preference for each device. This paper presents a new recommendation method and algorithm. Then, an e-commerce scenario with a computer, a smartphone and an AI-speaker are described. The scenario shows our work is better than previous researches.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.98-105
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• 2021

As the average life expectancy is rising, the population is aging and the number of chronic diseases is increasing. This has increased the importance of healthy life and health management, and interest in mobile health services is on the rise thanks to the development of ICT(Information and communication technologies) and the smartphone use expansion. In order to meet these interests, many mobile services related to daily health are being launched in the market. Therefore, in this study, the characteristics of users who actually use mobile health services were analyzed and a predictive model applied with machine learning modeling was developed. As a result of the study, we developed a prediction model to which the decision tree and ensemble methods were applied. And it was found that the mobile health service users' continued use can be induced by providing features that require frequent visit, suggesting achievable activity missions, and guiding the sensor connection for user's activity measurement.

• Journal of Auto-vehicle Safety Association
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• v.8 no.2
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• pp.30-36
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• 2016

According to revolutionary developments in automobile technologies, various electronically controlled components of vehicles are rapidly increasing. A variety of advanced vehicles (hybrid vehicle, hydrogen fuel-cell vehicle, electric vehicle, etc.) using electrical energy source are increasing, too. The electromagnetic compatibility is getting more important for development of a vehicle because those advanced vehicles are equipped with more new electronic systems. In general, electromagnetic compatibility tests consist of an electromagnetic interference (EMI) test and an electromagnetic susceptibility (EMS) test. In this paper, in order to investigate the electromagnetic interference in the cabin of vehicle by various electric and electronic components of vehicles, a series of narrowband electromagnetic emission tests are conducted. For comparison, the several digital home appliances (smartphone under charging, laptop compuer and digital camera), which are used a lot in daily lives, are tested.

• Journal of Digital Convergence
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• v.10 no.10
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• pp.439-445
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• 2012

The aim of the work that is presented in this paper is to develop the new prior educational materials which use the field trip and to present educational possibilities. The QR codes were used to develop the prior materials. The developed materials applied to elementary students who attended to filed trips in 2012. This was practically achieved by the use of smartphone which enhance the learning experience of a physical visit by providing personalized information with QR codes. The results demonstrate the technology supported physical field trips provides significantly improved learning outcomes, increases students curiosity. Furthermore the findings of the study demonstrate that the application of the specific emerging technologies could facilitate the development of advanced learning experiences in field trips, increasing at a significant level the learning outcomes and the motivation of the participating students.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.3
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• pp.46-55
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• 2012

Recently, the concept of PES(Personal Environment Service) is being widely discussed on various standardization organizations such as ITU-R, ETSI, 3GPP, TTA and etc. The purpose of PES is to introduce the services which can dynamically, automatically and intelligently reconfigures the electronic, electrical, and mechanical equipment surrounding the user according to the user preferences included in a user's profile by using a smartphone embedding WPAN radio technologies such as bluetooth and WiFi. This research introduces an Android Platform-based PES system which consists of a PES app, PES devices and a PES server. A smartphone platform is Android 2.2(Froyo) version and 4 simulated PES devices were implemented by using Galaxy Tab. It has shown that the PES would be a killer application of M2M(Machine-to-Machine) or D2D(Device-to-Device) in the future and it would need to study how to update a user's profile based on analyzing user's behaviour for enhancing the PES user's satisfaction.

• The Journal of the Convergence on Culture Technology
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• v.4 no.2
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• pp.185-189
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• 2018

Today, the incidence of illnesses due to a lack of exercise, such as lack of exercise in the 20s and 30s, 40s menstrual period, and 50s in the fifties, is increasing every year, because of the introduction of new technologies such as smartphone development,And the pattern of life according to it changes conveniently and the amount of activity decreases, and the lack of momentum has a great influence. I would like to study new mixed reality healthcare service products by merging the existing human smartphone with mixed reality. This is not merely showing the numerical value of the momentum by attaching to the human body like the existing healthcare product,And to measure and analyze the amount of exercise to help people to manage their health.

• 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.

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.141-148
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• 2018

Currently, the user authentication technology used by users to access multiple applications within an organization is being applied with ID/PW-based SSO technology. These user authentication methods have the fundamental disadvantages of ID/PW and SSO. This means that security vulnerabilities in ID/PW can lead to periodic changes in PWs and limits on the number of incorrect PW inputs, and SSO adds high cost of the SSO server, which centrally stores the authentication information, etc. There is also a fundamental vulnerability that allows others to freely use other people's applications when they leave the portal application screen with SSO. In this paper, we proposed an app-based 2-channel authentication scheme to fundamentally eliminate problems with existing ID/PW-based SSO user authentication technologies. To this end, it distributed centralized user authentication information that is stored on SSO server to each individual's smartphone. In addition, when users access a particular application, they are required to be authenticated through their own smartphone apps.

• 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.