• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.688-691
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• 2004

In this study, we synthesized a new red emitting material of a Red225 doped into $Alq_3$ (tris(8-quinolinolato)aluminum (III)) and fabricated white organic light-emitting diodes (OLEDs) with a simple device structure. With a blue emitting material of DPVBi (4,4'-bis(2,2'-diphenylvinyl)1,1'-biphenyl) that can transfer effectively both a hole and an electron, OLEDs with a narrow emission layer could be possible without a hole-blocking layer. Consequently, the driving voltage and stability of devices have been improved. The devices show the Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.36, 0.35) at luminance of 2000 cd/$m^2$. The luminous efficiency is about 3.5 cd/A, luminance is about 12000 cd/$m^2$ and current density is about 350 mA/$cm^2$ at 12 V, respectively.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.2
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• pp.27-32
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• 2016

Several sensor devices have been developed for monitoring individual's health and status information and services which visualize customized information by associating applications running on smartphones with sensor devices also have been emerged. Though these applications provide similar information to a user, each sensor device has its own application caused by non-standardized packet formats. In this paper, we propose a sensor device identification for dynamic interworking between a smartphone and personal sensor devices. In the proposed scheme, we can use the same application which plays role of a client on the smartphone as changing sensor devices because server stores packet information of sensor devices.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.3356-3374
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• 2018

The healthcare and fitness wearable-device market is considered as the driving force of the entire wearable device market. However, there are concerns with respect to information privacy because wearable devices constantly collect sensitive data such as individuals' health information. Thus, there is a need for a comprehensive understanding from the perspective of information privacy concerns and related behavior. This study investigates factors considered in the privacy calculus of wearable fitness devices, and verifies differences obtained by the privacy calculus process according to the frequency of exercise. The results obtained from a survey of 248 undergraduate students in Korea revealed that service providers should consider users' interests and exercise characteristics in order to mitigate their privacy concerns and encourage continuous use of wearable devices. This study provides useful insights pertaining to users of wearable fitness devices, and targets researchers and practitioners.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.2
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• pp.55-62
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• 2012

Convergence of information technology (IT) and medical devices enables people to measure health-related information ubiquitously, such as measuring blood glucose at home and checking cardiac signals during exercise and it allows us to access to medical care anywhere and anytime. Nowadays, the market for U-healthcare medical devices is growing rapidly, but guidelines for the evaluation of safety and effectiveness of such devices remain to be formulated. We performed a study on the development of safety and performance evaluation method for portable, hand-held, U-healthcare medical devices. We reviewed current guidelines and standards for home-health devices from the Korea Food and Drug Administration (KFDA) and related international committees such as the ISO/IEEE and CE. We summarized the test methods and items for the evaluation of safety and performance related to U-healthcare medical devices from the above guidelines and standards. We defined requirements for a U-healthcare medical device to demonstrate good performance. In conclusion, we propose an evaluation method for U-healthcare medical devices, which will help improve the safety and reliability of these devices.

• International Journal of Contents
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• v.3 no.3
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• pp.38-42
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• 2007

In this paper, we propose a new storage system architecture called as U-Storage (ubiquitous storage system). U-Storage allows a user to access an on-line storage with any type of information devices that are able to connect to internet. The on-line storage is virtualized to the user's information devices as a local hard disk or a memory card by our U-Storage. With devices supporting U-Storage, users can read and write their data anytime and anywhere without downloading and uploading operation.

• Journal of the Korea Society of Computer and Information
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• v.22 no.2
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• pp.9-19
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• 2017

Useful continuous sensing applications are increasingly emerging as a new class of mobile applications. Meanwhile, open, multi-use sensor devices are newly adopted beyond smartphones, and provide huge opportunities to expand potential application categories. In this upcoming environment, uncoordinated use of sensor devices would cause severe imbalance in power consumption of devices, and thus result in early shutdown of some sensing applications depending on power-hungry devices. In this paper, we propose EnergyCordy, a novel inter-device energy use coordination system; with a system-wide holistic view, it coordinates the energy use of concurrent sensing applications over multiple sensor devices. As its key approach, we propose a relaxed sensor association; it decouples the energy use of an application from specific sensor devices leveraging multiple context inference alternatives, allowing flexible energy coordination at runtime. We demonstrated the effectiveness of EnergyCordy by developing multiple example applications over custom-designed wearable senor devices. We show that EnergyCordy effectively coordinates the power usage of concurrent sensing applications over multiple devices and prevent undesired early shutdown of applications.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.3
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• pp.191-211
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• 2020

The main purpose of this research is to identify limitations and problems in access to information using reading aids devices for the visually impaired and to suggest ways to activate the use of alternative materials using reading aids devices. A survey was conducted on adults with visual impairment in order to identify the factors of limitation in using reading aids devices. The analysis resulted in six aspects of limiting factors in activating the use of reading aids devices. The approaches for activating the use of reading aids devices were proposed by dividing them into policy and operational aspects, focusing on the limiting factors derived. Policy aspects suggested developing low-cost reading aids devices, increasing awareness of the devices, and complying with Web standard guidelines for improving the applicability of the devices, while operational aspects suggested reinforcing hearing-use functions, expanding information services related to reading aids devices, and enhancing portability of the devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1313-1316
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• 2005

In the present paper, it was investigated that adhesion layer on gate insulator could affect the electrical characteristics for the organic thin film transistors (OTFTs). The polyimide (PI) as organic adhesion layer was fabricated by using the vapor deposition polymerization (VDP) processing . It was found that electrical characteristics improved comparing OTFTs using adhesion layer to another. We researched adhesion layer as a function of thickness. For inverted-staggered top contact structure, field effect mobility, threshold voltage, and on-off current ratio of OTFTs using adhesion layer of PI 15 nm thickness on the gate insulator with a thickness of 0.2 ${\mu}m$ were about 0.5 $cm^2/Vs$, -0.8 V, and $10^6$, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1399-1402
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• 2007

We have demonstrated efficient white WOLEDs by using three emissive materials for primary colors (red, green, and blue). The characteristics of WOLEDs showed the maximum luminance of $37600\;cd/m^2$ at 13V, the maximum luminous efficiency of 20.6 cd/A, and the $CIE_{xy}$ coordinates of (x = 0.33, y = 0.33) at 10V.

• Journal of Information Processing Systems
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• v.15 no.6
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• pp.1406-1421
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• 2019

The Internet-of-Things (IoT) has been deployed in almost every facet of our day to day activities. This is made possible because sensing and data collection devices have been given computing and communication capabilities. The devices implement System-on-Chips (SoCs) that incorporate a lot of functionalities, yet they are severely constrained in terms of memory capacitance, hardware area, and power consumption. With the increase in the functionalities of sensing devices, there is a need for low-cost synthesizable processors to handle control, interfacing, and error processing. The first step in selecting a synthesizable processor core for low-cost devices is to examine the hardware resource utilization to make sure that it fulfills the requirements of the device. This paper gives an analysis of the hardware resource usage of ten synthesizable processors that implement the Reduced Instruction Set Computer Five (RISC-V) Instruction Set Architecture (ISA). All the ten processors are synthesized using Vivado v2018.02. The maximum frequency, area, and power reports are extracted and a comparison is made to determine which processor is ideal for low-cost hardware devices.