• Journal of the Korea Convergence Society
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• v.8 no.1
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• pp.13-18
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• 2017

As the convergence technology is developing rapidly and the portable mobile devices are spreading in ubiquitous smart healthcare, users were able to get medical information easily through the smart health platform. According to such rapid industrialization, wellness care, aging society, information society, changes in disease aspects and life style, user-centered healthcare, and health promotion contents are being offered. In this study, we proposed the mining based mental health and blood pressure management service for the smart health. The proposed method provides the mental health management service and the blood pressure management service for chronic disease patients within the mining based smart health platform. Users receive optimized healthcare services regardless of time and place in the PHR based smart health platform. For the performance evaluation of the proposed mining based mental health and blood pressure management service, F-measure verification are conducted.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.551-555
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• 2010

Electrowetting is a versatile tool to handle tiny droplets and forms a backbone of digital microfluidics. Numerical analysis is necessary to fully understand the dynamics of electrowetting, especially in designing electrowetting-based devices, such as liquid lenses and reflective displays. We developed a numerical method to analyze the general contact-line problems, incorporating dynamic contact angle models. The method is based on the conservative level set method to capture the interface of two fluids without loss of mass. We applied the method to the analysis of spreading process of a sessile droplet for step input voltages and oscillation of the droplet for alternating input voltages in electrowetting. The result was compared with experimental data. It is shown that contact line friction significantly affects the contact line motion and the oscillation amplitude. The pinning process of contact line was well represented by including the hysteresis effect in the contact angle models. In level set method, in the mean time, material properties are made to change smoothly across an interface of two materials with different properties by introducing an interpolation or smoothing scheme. So far, the weighted arithmetic mean (WAM) method has been exclusively adopted in level set method, without complete assessment for its validity. We viscosity, thermal conductivity, electrical conductivity, and permittivity, can be an alternative. I.e., the WHM gives more accurate results than the WAM method in certain circumstances. The interpolation scheme should be selected considering various characteristics including type of property, ratio of property of two fluids, geometry of interface, and so on.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.327-334
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• 2020

Recently, mobile and smart devices are rapidly spreading. As a result, real estate services, which were formerly face-to-face, have now been replaced by mobile environments. This study focuses on the real estate app service and 261 samples were used for the empirical analysis. The results of the hypotheses test using structural equation model are summarized as follows. First, performance expectancy, facilitating conditions, security and aesthetic perceived by users of real estate services have positively influence on positive attitude, but effort expectancy and social influence do not. Second, positive attitude of real estate services have positive effects on service Acceptance. Third, involvement moderated the relationship between positive attitude and service Acceptance. Based on the results of the analysis, it provided meaningful implications for practitioners and researchers in related fields.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.110-117
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• 2012

As the demand for underwater systems providing pollution monitoring, marine ecosystem observation, surveillance monitoring is increased, acoustic modem for short-range underwater communication is spotlighted as one of significant research topics. Typically, in shallow water, it is so hard to analyze acoustic wave which undergoes spreading, absorption, reflection and scattering through transmission that there are limited advanced results. Furthermore, in order for the modem to be loaded in a fixed node or a moving vehicle in shallow water, its size should be small enough. In this paper, we address underwater acoustic channel model and design and implement an efficient micro acoustic modem which is adequate for short-range underwater communication. The developed modem is verified in a lake by varying working range and data rate up to 500 meters and 2 kbps, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1943-1949
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• 2017

In recent years, the maker culture has realized the concept of 'making' itself through the latest technology of high technology. It is rapidly spreading as a maker's movement by sharing the production methods and information of individuals through the Internet. Countries that are leading the makers' movement expect the maker's movement to be the driving force for new value creation and economic growth from the point of view of things and the Internet. We are developing various types of open IoT platforms that can register various Internet devices and services manufactured and developed through DIY and realize interoperable services. Typical open IoT platforms require specialized API analysis capabilities and difficult access to general users due to difficult platform registration conditions and procedures. In this paper, we try to construct an open IoT platform that can be operated as a real service by creating a simple Internet application device and service application from a general manufacturer's point of view.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.411-413
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• 2012

It is noticeable that the number of newly registered Android applications increases rapidly. Such a recent trend indicates the Android platform is spreading globally. The ongoing platform upgrade might be one of the main reasons of the popularity of the Android mobile platform. Android platform 4.0 or later provides WiFi-Direct APIs that allow smart devices to communicate with each other without intermediate media. In this paper, we propose design and implementation techniques for small-scale impromptu meeting applications based on WiFi-Direct. The proposed meeting application can be used in a situation when one is difficult to connect the Internet. It also provides meeting data sharing capabilities, noting functionality, real-time remote screen control, and grouping of meeting participants. Our development results have demonstrated that the Android WiFi-Direct APIs can be effectively applied to impromptu conferencing mobile applications.

• Journal of Information Processing Systems
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• v.12 no.4
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• pp.612-630
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• 2016

As mobile augmented reality technologies are spreading these days, many users want to produce augmented reality (AR) contents what they need by themselves. To keep pace with such needs, we have developed a mobile AR contents builder (hereafter referred to as MARB) that enables the user to easily connect a natural marker and a virtual object with various interaction events that are used to manipulate the virtual object in a mobile environment so that users can simply produce an AR content using natural photos and virtual objects that they select. MARB consists of five major modules-target manger, virtual object manager, AR accessory manager, AR content manager, and AR viewer. The target manager, virtual object manager and AR accessory manager register and manage natural target markers, various virtual objects and content accessories (such as various decorating images), respectively. The AR content manger defines a connection between a target and a virtual object with enabling various interactions for the desired functions such as translation/rotation/scaling of the virtual object, playing of a music, etc. AR viewer augments various virtual objects (such as 2D images, 3D models and video clips) on the pertinent target. MARB has been developed in a mobile application (app) format in order to create AR contents simply using mobile smart devices without switching to a PC environment for authoring the content. In this paper, we present the detail organizations and applications of MARB. It is expected that MARB will enable ordinary users to produce diverse mobile AR contents for various purposes with ease and contribute to expanding the mobile AR market based on spread of a variety of AR contents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2707-2716
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• 2013

The purpose of this paper is to focus on the analysis of organizational members' psychological reactance factors on IT governance control in various types of organizations by the use spreading of individual devices. For this, a model was made based on previous researches related to IT governance control, the scale of organizational members' psychological reactance and the expectancy theory. The statistical significance of organizational members' psychological reactance factors and attitude on IT governance control was tested by the Hong's psychological reactance scale, the level of reward according to expectancy theory, the position in organization and organization size. This study shows controls for achieving the managerial goal of company and an analytical framework generated by analyzing systematically organizational members' psychological reactance factors by IT governance and managerial implications on IT governance control are also presented.

• Korean Journal of Materials Research
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• v.12 no.3
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• pp.200-204
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• 2002

We fabricated TMR devices which have double oxidized tunnel barrier using plasma oxidation method to form homogeneously oxidized AlO tunnel barrier. We sputtered 10 $\AA$-bottom Al layer and oxidized it by varying oxidation time for 5, 10, 20 sec. Subsequent sputtering of 13 $\AA$ - Al was performed and the matallic layer was oxidized for 120 sec. The electrical resistance changed from 700$\Omega$ to 2700$\Omega$ with increase of oxidation time, while variation of MR ratio was little spreading 27~31% which is larger than that of TMR device of ordinary single tunnel barrier. We calculated effective barrier height and width by measuring I-V curves, from which we found the barrier height was 1.3~1.5 eV, sufficient for tunnel barrier, and the barrier width(<16.2 $\AA$) was smaller than that of directly measured value by the tunneling electron microscopy. Our results may be caused by insufficient oxidation of Al precursor into $Al_2O_3$. However, double oxidized tunnel barriers were superior to conventional single tunnel barrier in uniformity and density. We found that the external magnetic field to switch spin direction of ferromagnetic layer of pinned layer breaking ferro-antiferro exchange coupling was increased as bottom layer oxidation time increased. Our results imply that we were able to improve MR ratio and tune switching field by employing double oxidized tunnel barrier process.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.41-48
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• 2020

Recently, the spreading business of AMI (Advanced Metering Infrastructure) remote metering systems in various regions of the country has been activated, and it provides various metering functions such as two-way communication and security plan functions for power demand management. Current AMI system is difficult to analyze based on the existing RDB(Relational Database) due to the increase in the size of new internal IoT devices and networks. This study proposes a new GDB(Graph Database) based failure analysis method that utilizes existing RDB data. It analyzes the correlation of new failure patterns through accumulated data such as internal thresholds and status values. As a result of GDB-based simulation, it was confirmed that RDB can predict to a new obstacle pattern that was difficult to analyze.