• 대한임베디드공학회논문지
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• 제7권2호
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• pp.95-101
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• 2012

In order to supply emotion service depending on user's emotional change in a mobile environment, various researches have been carried. This paper discusses a protocol for wireless charging and an embedded platform of the mobile emotional sensing device which supports that. Wireless charging process relieves user's vexatious task to charge the emotional sensing device. To support wireless charging, there are one basestation and several mobile devices. Basestation coordinates and controls the devices over wireless communication, as well as supplies energy. For 1:N communication we defines the network whose superframe is classified into four categories: a network join superframe, a charging request superframe, a charging superframe and an inactive superframe. Physical layer provides how to supply energy to the devices and communicate physically. Mobile device is equipped with energy charged circuits, which correspond with the defined energy supplying method, as well as bidirectional communication circuits. Mobile device monitors and analyzes its own battery status, and is able to send a request packet to basestation. Therefore, it can be charged before its battery is exhausted without user's perception.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1633-1637
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• 2003

Existing input devices for desktop computers are not suitable for wearable computers because they are neither easy to carry nor convenient to use in a mobile working environment. Different input devices for wearable computers must be developed. In this paper, a wireless glove-based input device for wearable computers is proposed. The proposed input device consists of a pair of chording gloves. Its keys are mounted on the fingers and their chording methods are similar to those of a Braille keyboard. RF (Radio Frequency) and IrDA (Infrared Data Association) modules are used to make the proposed input device wireless. Since the Braille representation for numbers and characters is efficient and has been well established for many languages in the world, the proposed input device may be one of good input devices to computers. Furthermore, since the Braille has been used for visually impaired people, the proposed one can be easily used as an input device to computers for them.

• Educational Technology International
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• 제18권1호
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• pp.27-47
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• 2017

Smart devices have a variety of affordances to foster meaningful learning in elementary school. For the design of smart learning environments, more research is needed to understand students' smart device usage and their perception of learning with smart devices. In order to capture smart device usage profiles among elementary school students in South Korea, this study carried out Latent Profile Analysis with three constructs: information search, communication, and study. Participants (n=253), who ranged from the fourth to the sixth grade students, were classified into three profiles of smart device usage: low-activity, communication, and high-activity groups. The smart device usage profiles varied depending on smartphone usage experience, and the profiles were significantly related with smart device addiction, not with smart device usage ability. Perceptions of smart education were also significantly associated with the profiles. The high-activity group showed more positive attitudes toward smart education than the others, but no significant difference was found in regard to negative attitudes. Based on the findings, this study discussed implications for the use of smart devices in elementary school.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.203-228
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• 2012

It is expected that device-to-device (D2D) communication is allowed to underlay future cellular networks such as IMT-Advanced for spectrum efficiency. This article studies the mechanisms of D2D communication and interference avoidance when the D2D subsystem reuses uplink resources and downlink spectrums with a cellular system, respectively. We firstly propose an effective scheme to establish and maintain D2D communication. Moreover, a novel method to deal with the resource allocation and interference avoidance issues by utilizing the network peculiarity of a hybrid network to share the uplink resource is proposed. Most research focuses on reusing the uplink spectrums, but how to share the downlink frequency bands is seldom addressed. To share the downlink spectrums and avoid the interference to the primary cellular devices, a labeled time slots based mechanism is proposed. Implementation details are described in a real cellular system and simulation results prove that satisfying performance can be achieved by using the proposed mechanisms.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.385-385
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• 2012

A two terminal N+/P/N+ junction device to replace the conventional selective transistor was studied as a bilateral switching device for spin transfer torque (STT) MRAM based on 3D device simulation. An N+/P/N+ junction structure with $30{\times}30nm$ area requires bi-directional current flow enough to write a data by a drain induced barrier lowering (DIBL) under a reverse bias at N+/P (or P/N+ junction), and high current on/off ratio of 106. The SiGe materials are widely used in hetero-junction bipolar transistors, bipolar compensation metal-oxide semiconductors (BiCMOS) since the band gap of SiGe materials can be controlled by changing the fraction and the strain epilayers, and the drift mobility is increased with the increasing Ge content. In this work, N+/P/N+ SiGe material based junction provides that drive current is increased from 40 to $130{\mu}A$ by increased Ge content from 10~80%. When Ge content is about 20%, the drive current density of SiGe device substantially increased to 2~3 times better than Si-based junction device in case of 28 nm P length, which is sufficient current to operation of STT-MRAM.

• 한국위성정보통신학회논문지
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• 제12권1호
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• pp.125-131
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• 2017

본 논문에서는 이동통신, 무인기 통신, 차량 간 통신 등에 이용될 수 있는 효율적인 단말 간 직접통신 (D2D: device-to-device)을 위한 동기 프리앰블 (preamble) 구조를 제안하고 성능을 비교한다. 단말 간 직접 통신을 위해서는 향상된 주파수 및 시간 동기 요구 성능을 만족 시킬 수 있어야 하며, 본 논문에서는 이를 위한 프리앰블 구조를 제안한다. 주파수 영역에서 하나 걸러 하나씩의 부반송파에는 신호를 전송하지 않는 대신, 나머지 부반송파에서는 심볼 당 에너지를 2배로 전송하는 제안하는 구조가 기존 LTE D2D 프리앰블 구조에 비해 주파수 옵셋 추정 성능은 유지하면서도 시간 옵셋 추정 성능을 크게 향상시킴을 확인하였다.

• 정보처리학회논문지C
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• 제16C권6호
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• pp.691-698
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• 2009

휴대용 통신 단말은 스마트 폰이나 PDA와 같은 통신 서비스를 제공하는 작은 크기의 휴대용 컴퓨터이다. 현재 휴대용 통신 단말의 발전을 가로막는 가장 큰 장벽중의 하나가 바로 보안이다. 비록 휴대용 통신 단말을 보호할 수 있는 다양한 보안기술들은 있지만, 휴대용 통신 단말은 데스크톱 컴퓨터에 비해 컴퓨팅 자원이 빈약하고 사용자 인터페이스가 불편하여 그 보안기술 모두를 휴대용 통신 단말에 운용할 수 없기 때문이다. 본 논문에서는 휴대용 통신 단말의 보안을 효과적으로 관리할 수 있는 상황인지형 보안재구성 기법을 제안하고 설계한다. 본 보안재구성 기법은 휴대용 통신 단말의 현재 보안 상황에 가장 적합한 최적의 보안 서비스를 자동으로 제공할 수 있다. 본 제안하는 기법의 구현과 실험을 통하여 본 기법이 보안수준을 떨어뜨리는 것 없이 자원 효율성과 사용자 편의성에서 우수하다는 것을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제24권2호
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• pp.103-109
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• 2019

Recently, as the number of families raising dogs has increased, cases of lost dogs have frequently occurred. According to US statistics, 5% of the total dogs are reported to be alive, with only 18% reporting to their owners. Therefore, a device for preventing the loss of dogs is needed, and the demand for the market is rapidly growing. Therefore, it is necessary to develop a lost device for dogs. In this paper, we developed a loss prevention device that combines low-power broadband wireless communication technology, LoRa communication method, and GPS positioning technology. The result of this study is expected to prevent the loss of dogs. It is also expected that social problems will reduce the problem of lost dogs.

• Journal of Communications and Networks
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• 제18권3호
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• pp.429-438
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• 2016

In this paper, we investigate an interference mitigation scheme by antenna selection in device-to-device (D2D) communication underlaying downlink cellular networks. We first present the closed-form expression of the system achievable rate and its asymptotic behaviors at high signal-to-noise ratio (SNR) and the large antenna number scenarios. It is shown that the high SNR approximation increases with more antennas and higher ratio between the transmit SNR at the base station (BS) and the D2D transmitter. In addition, a tight approximation is derived for the rate and we reveal two thresholds for both the distance of the D2D link and the transmit SNR at the BS above which the underlaid D2D communication will degrade the system rate. We then particularize on the small cell setting where all users are closely located. In the small cell scenario, we show that the relationship between the distance of the D2D transmitting link and that of the D2D interfering link to the cellular user determines whether the D2D communication can enhance the system achievable rate. Numerical results are provided to verify these results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2206-2208
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• 2002

In this paper, using the communication port between PC(Personal Computer) and DC/STEP MOTOR DEVICE that movement and measurement of motor. Communication port used serial port and movement order transmits by communication port. Consequence of motor device movement displays to tile DC/STEP MOTOR DEVICE APPLICATION. This connection is using the serial port instead of parallel port faster than response time And this application is easier than existing application.