• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.175-177
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• 2007

This paper is concerned with a performance analysis using a wired/wireless gateway based on DeviceNet. For the performance analysis, the data transmission time between DeviceNet and the wireless devices is investigated and analyzed. The experimental results show the perfom1ance in terms of the polling/COS service time and end-to-end delay.

• 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.

• 정보보호학회논문지
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• 제23권2호
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• pp.169-179
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• 2013

최근 스마트 폰, 스마트 패드와 같은 모바일 디바이스의 발전과 무선 네트워크 및 이동통신 네트워크의 발전으로 모바일 디바이스를 이용하는 서비스는 증가하고 있다. 그러나 무선 네트워크는 유선 네트워크에 비해 보안에 취약하므로 보다 강한 보안의 적용이 필요한 반면 배터리 기반의 모바일 디바이스는 낮은 계산 능력과 메모리 공간의 제약 및 무선통신에 사용되는 비용이 높기 때문에 보안의 적용은 효율적이어야 한다. 따라서 본 논문에서는 모바일 디바이스를 이용한 서비스에서 요구되는 보안 요구사항을 충족시키고 모바일 환경에 적합한 티켓 기반의 인증 기법을 제안한다.

• 한국군사과학기술학회지
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• 제20권6호
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• pp.813-821
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• 2017

This paper presents the study result on a realization of wireless umbilical device for missile systems. In general, a missile system is connected to a fire control equipment via an umbilical connector to get the electrical power for its internal equipment and communicate with each other. And these connectors inherently have many problems of mis-contact between pin and socket, and mis-separation during missile firing, etc. A wireless umbilical device using LC resonance is devised to solve these problems of the current technology. For hundreds of watts power transmission under the missile system environment of restricted space, we designed and made a prototype of wireless umbilical device. And we tested this wireless umbilical device with an aluminum cylinder having cutout windows which simulate missiles. We realized that the wireless technology can be used as a substitute for the conventional umbilical connectors, and EMI and environment tests should be followed further.

• 한국콘텐츠학회논문지
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• 제13권5호
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• pp.19-27
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• 2013

본 논문에서는 마스터 장치와 슬레이브 장치로 구성된 대기 전력 제어 시스템을 구현한다. 마스터 장치의 RFID 카드의 인증여부에 따라 슬레이브 장치의 릴레이를 제어한 후에 전원 공급을 차단함으로써 대기전력이 관리된다. 마스터 장치는 RFID 인터페이스 및 무선 통신 모듈을 내장하고 있고, 마스터 장치 1개에 대해 n개의 슬레이브 장치가 무선으로 연계되며 각각의 슬레이브 장치는 전력제어에 필요한 동작을 독립적으로 수행한다. 슬레이브 장치에 수동으로 전력을 on/off 할 수 있는 기능과 스위치 조작을 통해 마스터 장치에 사용자 ID를 등록하는 기능을 구현했다. 또한, 본 시스템은 무선으로 양방향 통신이 가능하고 TinyOS 상에서 실행된다. 실험 결과, 본 시스템은 마스터 장치에서 사용자 여부를 인식하고, 이에 대한 인식 정보를 무선 통신으로 슬레이브 장치에 전송함으로써, 릴레이를 제어하여 대기 전력이 차단된 것을 보여 주었다. 본 시스템을 건물이나 사무실에 설치할 경우 전력 절감을 기할 수 있다.

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.19-25
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• 2015

In this time, as an industrial society developed to a welfare society, more and more people want their quality of lives upgraded and specially customized service by mass production/mass consumption. And it leads to an increase of requiring service. There're active developments and studies on various IT equipment as the requirement made IT devices used in service. In this paper, we try to design and realize radio paging DID by using smart device to be used as a receiver of a radio pager which is broadly used at face to face service. Firstly, we used MCU to design and implement Wireless Calling Gateway which change radio calling signal of ISM band to smart device. A receiver of wireless caller used original receiver module. Also it used bluetooth module to communicate with smart device. It was possible to have satisfactory communication since radio paging signal converter and smart device were linked in 3M. Secondly, to indicate various paging information delivered from a radio pager, we realized DID application program by using Smart PAD. As a result, we could indicate various information compared to an original receiver which only could indicate letters or numeric data. Secondly, we implemented the DID app for wireless calls that can display a variety of information sent from a wireless pager. Was implemented using the Smart Pad. As a result, it is shown that can display a variety of information than the existing receiver.

• 한국군사과학기술학회지
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• 제22권4호
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• pp.501-508
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• 2019

In this paper, a study on a wireless check-up method of test equipment for captive flight test(CFT) was conducted. For CFT, test equipment is mounted on a POD, and check-up is carried on the test equipment's. For check-up the POD wirelessly, battery, power distribution unit, wireless communication devices were designed within the POD, and a check-up device is designed outside of the POD. Once the external check-up device sends a 'start signal' to the POD, it performs the overall check-up procedures and transmits the 'end signal' to the external check-up device. Detailed check-up results are stored in an internal storage device, and are possible to read from external check-up device if necessary, thereby improving the reliability of the wireless check-up. By implementing and applying these wireless check-up system, the reliability of the check-up was enhanced by dynamical and movable check-up, and safety is guaranteed as the check-up was carried without access to the aircraft.

• ETRI Journal
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• 제37권4호
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• pp.707-716
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• 2015

The purpose of a localization system is to estimate the coordinates of the geographic location of a mobile device. The accuracy of wireless localization is influenced by nonline-of-sight (NLOS) errors in wireless sensor networks. In this paper, we present an improved time of arrival (TOA)-based localization method for wireless sensor networks. TOA-based localization estimates the geographic location of a mobile device using the distances between a mobile station (MS) and three or more base stations (BSs). However, each of the NLOS errors along a distance measured from an MS (device) to a BS (device) is different because of dissimilar obstacles in the direct signal path between the two devices. To accurately estimate the geographic location of a mobile device in TOA-based localization, we propose an optimized localization method with a BS selection scheme that selects three measured distances that contain a relatively small number of NLOS errors, in this paper. Performance evaluations are presented, and the experimental results are validated through comparisons of various localization methods with the proposed method.

• 한국정보통신학회논문지
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• 제21권11호
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• pp.2015-2021
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• 2017

최근, 사물인터넷이 초연결사회에 다가서는 발판으로 많은 관심을 받으면서 비면허 대역을 사용하는 비면허 무선기기의 수가 증가하고 있다. 따라서 본 논문은 효율적인 주파수 사용을 위해서 900 MHz 대역에서 802.11ah 기반 비면허 무선기기가 주면허 무선기기인 LTE 단말기(UE, User Equipment)에 미치는 전파 간섭 영향을 분석하였다. 간섭 분석 방법으로는 최소결합손실(Minimum Coupling Loss) 방법과 몬테카를로(Monte Carlo) 방법을 사용했다. 최악의 상황을 가정한 최소결합손실 방법으로 단일 간섭원일 때 희생원에 간섭이 없음을 보장하기 위한 간섭원과 희생원 사이의 최소이격거리는 약 22 m로 계산되었고, 통계 기법을 기반으로 한 몬테카를로 방법을 통해 희생원의 셀 반경 내에서 간섭 확률 5% 이하를 만족하는 최대 간섭원의 수는 약 3000개로 산출됐다. 본 논문에서 제시한 간섭 분석 방법 및 결과는 향후 비면허 무선기기와 주면허 무선기기의 공유 방안으로 유용하게 활용될 것으로 기대된다.

• 대한의용생체공학회:의공학회지
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• 제29권4호
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• pp.295-301
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• 2008

A wireless 3 channel ECG monitoring system was developed so that it could monitor the health and movement state during subject's daily life. The developed system consists of a wireless biomedical signal acquisition device, a personal healthcare server, and a remote medical server. Three experiments were performed to evaluate the accuracy, reliability and operability, applicability during daily life of the developed device. First, ECG signals were measured using the developed device and commercial reference device during sitting and marking time and compared to verify the accuracy of R-R intervals. Second, the reliable data transmission to remote server was verified on two types of simulated emergency event using patient simulator. Third, during five types of motion in daily life, the accuracy of data transmission to remote server using CDMA network was verified on two types of event occurring. By acquiring and comparing subject's biomedical signal and motion signal, the accuracy, reliability and operability, applicability during daily life of the developed device were verified. In addition, PDA-phone based wireless system enabled subject to be monitored without any constraints. Therefore, the developed system is expected to be applicable for monitoring the aged and chronic diseased people and giving first-aid in emergency.