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Disjointed Multipath Routing for Real-time Multimedia Data Transmission in Wireless Sensor Networks (무선 센서 네트워크 환경에서 실시간 멀티미디어 데이터 전송을 위한 비-중첩 다중 경로 라우팅)

  • Jo, Mi-Rim;Seong, Dong-Ook;Park, Jun-Ho;Yoo, Jae-Soo
    • The Journal of the Korea Contents Association
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    • v.11 no.12
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    • pp.78-87
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    • 2011
  • A variety of intelligent application using the sensor network system is being studied. In general, the sensor network consists of nodes which equipped with a variety of sensing module and is utilized to collect environment information. Recently, the demands of multimedia data are increasing due to the demands of more detailed environmental monitoring or high-quality data. In this paper, we overcome the limitations of low bandwidth in Zigbee-based sensor networks and propose a routing algorithm for real-time multimedia data transmission. In the previously proposed algorithm for multimedia data transmission occurs delay time of routing setup phase and has a low data transmission speed due to bandwidth limitations of Zigbee. In this paper, we propose the hybrid routing algorithm that consist of Zigbee and Bluetooth and solve the bandwidth problem of existing algorithm. We also propose the disjointed multipath setup algorithm based on competition that overcome delay time of routing setup phase in existing algorithm. To evaluate the superiority of the proposed algorithm, we compare it with the existing algorithm. Our experimental results show that the latency was reduced by approximately 78% and the communication speed is increased by approximately 6.9-fold.

Development of Wireless Ambulatory Measurement System based on Inertial Sensors for Gait Analysis and its Application for Diagnosis on Elderly People with Diabetes Mellitus (관성센서 기반의 무선보행측정시스템 개발 및 노인 당뇨 환자 보행 진단에의 응용)

  • Jung, Ji-Yong;Yang, Yoon-Seok;Won, Yong-Gwan;Kim, Jung-Ja
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.48 no.2
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    • pp.38-46
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    • 2011
  • 3D motion analysis system which is currently widely used for walking analysis has limitations due to both necessity of wide space for many cameras for measurement, high cost, and complicated preparation procedure, which results in low accessability in use and application for clinical diagnosis. To resolve this problem, we developed 3-dimensional wireless ambulatory measurement system based on inertial sensor which can be easily applicable for clinical diagnosis for lower extremity deformity and developed system was evaluated by applying for 10 elderly people with diabetes mellitus. Developed system was composed of wireless ambulatory measurement module that consists of inertial measurement unit (IMU) which measures the gait characteristics, microcontroller which collects and precesses the inertial data, bluetooth device which transfers the measured data to PC and Window's application for storing and processing and analyzing received data. This system will utilize not only to measure lower extremity (foot) problem conveniently in clinical medicine but also to analyze 3D motion of human in other areas as sports science, rehabilitation.

The Development of Real-time Feedback Vibration Control System Using Wireless Sensor Networks (무선 센서 네트워크를 이용한 실시간 Feedback 진동제어 시스템 개발)

  • Heo, Gwang Hee;Kim, Chung Gil;Ahn, Ui Jong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.3
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    • pp.60-66
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    • 2012
  • This paper aims to constitute a feedback vibration control system using wireless sensor networks and experiment it on a model structure to verify its effectiveness. For the purpose, we set up a feedback vibration control system composed of a wireless input/output(I/O) sensor node based on bluetooth, a home-made shear type MR damper, a shaker which generates a constant size of sine wave, and a simple beam model structure. The vibration control experiment was performed by shaking the 1/4 point of beam with a shaker. At the moment of shaking, we controled the vibration with MR damper which was placed vertically on the center of beam. Simultaneously, by acquiring acceleration response at the 2/4 point of beam, we evaluated the effectiveness of control capability. The control command was set to send a voltage signal to MR damper when the acceleration response, acquired from the wireless I/O sensor node placed at the center of beam, was more than a certain amount. Although the realtime feedback vibration control system constituted in this paper is effective only within a limited command system, it has been proven that the system was able to effectively decrease the vibration of structure by generating a control command aimed for realtime purpose. The system also showed a possibility to be used as a structural response control system adapting a variety of semi-active control algorithm.

Real-time Feedback Vibration Control of Structures Using Wireless Acceleration Sensor System - System Design and Basic Performance Evaluation - (무선 가속도센서 시스템을 이용한 건축물의 실시간 피드백 진동제어 - 시스템 구축 및 기초성능 평가 -)

  • Jeon, Joon Ryong;Park, Ki Tae;Lee, Chin Ok;Heo, Gwang Hee;Lee, Woo Sang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.2
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    • pp.21-32
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    • 2013
  • This is a preliminary study for the real-time feedback vibration control of building structures. The study developed a wireless acceleration sensor system based on authentic technology capacities, to integrate with the Prototype AMD system and ultimately construct the feedback vibration control system. These systems were used to evaluate the basic performance levels of the control systems within model building structures. For this purpose, the study first developed a wireless acceleration sensor unit that integrates an MEMS sensor device and bluetooth communication module. Also, the study developed an operating program that enables control output based on real-time acceleration response measurement and control law. Furthermore, the Prototype AMD and motor driver system were constructed to be maneuvered by the AC servo-motor. Eventually, all these compositions were used to evaluate the real-time feedback vibration control system of a 2-story model building, and qualitatively measure the extent of vibrational reduction of the target structure within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within 1st and 2nd resonance frequency as well as the random frequency of the model building structure. Ultimately, this study confirmed the potential of its wireless acceleration sensor system and AMD system as an effective tool that can be applied to the active vibration control of other structures.

TEM 도파관을 이용한 전자파 장해 측정 연구 및 표준화 동향

  • 권종화
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.1
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    • pp.51-62
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    • 2002
  • EMI/EMS 측정을 위해서는 주변 전자파 잡음(background noise)이 낮은 야외시험장(Open Area Test Site)이 가장 바람직하나, 근래 전자(전기 기기 사용의 증가와 방송.무선통신 시스템의 다양화로 인한 인공잡음(artificial noise)의 증대로 조건에 부합된 부지 선정이 어렵고, 설치 비용이 매우 크며 날씨 변화에 따라 시험 계획이 변경 될 수도 있는 단점이 있다. 전자파 분-무반사실(Semi Anechoic Chamber)은 대부분의 환경 잡음을 감쇠시키므로 야외시험장처럼 장소의 구애를 받지 않아 도시나 혹은 제품 생산지 가까이에 설치 운용이 가능하다. 그러나 큰 설치 공간과 많은 시설 유지 비용을 필요로 하며, 저주파 대역에서는 반사에 의한 공진을 완전히 제거할 수 없어 성능이 떨어진다. 또한, 최근 컴퓨터 CPU의 동작주파수가 급속하게 높아지고 PCS, IMT-2000 등과 같은 이동전화의 사용주파수도 계속해서 높아짐에 다라 미연방통신위원회(Federal Communication Commission)에서는 5㎓까지의 복사 방출 시험을 요구하고 있다. IEC 61000-4-3 복사 내성 시험규격도 휴대폰 주파수인 2㎓까지 확장되었으며 IMT-2000, Bluetooth 등 새로운 이동통신서비스가 속속 개발됨에 따라 18㎓ 까지 시험 주파수가 확장되는 추세이다. 그러나, 현재 국내 각 연구실에서 보유하고 있는 야외시험장이나 전자파 반-무반사실의 경우 1㎓이상에서의 시험이 곤란하여 수 ㎓주파수대역에서 시험이 가능한 복사 및 내성시험 시설이 필요하게 되었다. 이러한 문제점들을 해결하기 위해 고안된 대용 측정 시설 중 대표적인 것이 TEM 셀이나 GTEM셀과 같은 TEM 도파관(waveguide) 형태의 장비들이다. 이들은 본래 EMS 측정을 위한 장비이지만 협소한 공간이나 외부와의 전자파 간섭의 우려가 없고, 설치가 비교적 자유로워 여러 연구기관에서 도파관 원리를 이용한 측정 방식을 연구(개발하여 범용적인 전자파 적합성 측정 장비로서 활용하고 있다. 야외시험장과 무반사실 등이 안테나에 의한 피시험기기 주변 공간에서의 1점 측정으로 인해 시험 시간이 많아 소요되는 공통적인 단점이 있는 반면, TEM 도파관에 의한 측정은 일단 피시험기기의 모델링 정보만 얻어지면 계산에 의해 EMI 측정을 바로 할 수 있다. <표 1>에서 현재 상용화되어 사용되고 있는 TEM/GTEM 셀, 야외 시험장 및 전자파 무반사실에 대해 EMI 측정과 관련된 몇 가지 사안에 대해 비교하였다. 본 문서에서는 야외시험장이나 전자파 반-무반사실 등과 같은 기존 EMI/EMS 측정 시설의 단점을 보완하고, 광대역 특성을 갖는 대용 측정 시설로서의 TEM 도파관에 대해 소개하고 야외시험장 결과와의 상관관계 알고리즘 및 표준화 동향에 대해 기술하였다. 2절에서는 대표적인 TEM 도파관 구조의 측정 시설인 TEM 셀과 GTEM 셀의 전기적.구조적 특징에 대해 간단히 기술하고, 3절에서는 TEM 셀과 GTEM 셀에서이 측정결과를 이용하여 야외 시험장 결과를 얻어내는 상관관계 알고리즘에 대해 기술하였다. 4절에서는 IEC/CISPR와 TC77에서의 표준화 활동을 중심으로 현재 진행중인 TEM 도파관 관련 표준화 동향과 내용에 대해 기술하고자 한다.

IoT Based Intelligent Position and Posture Control of Home Wellness Robots (홈 웰니스 로봇의 사물인터넷 기반 지능형 자기 위치 및 자세 제어)

  • Lee, Byoungsu;Hyun, Chang-Ho;Kim, Seungwoo
    • Journal of IKEEE
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    • v.18 no.4
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    • pp.636-644
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    • 2014
  • This paper is to technically implement the sensing platform for Home-Wellness Robot. First, self-localization technique is based on a smart home and object in a home environment, and IOT(Internet of Thing) between Home Wellness Robots. RF tag is set in a smart home and the absolute coordinate information is acquired by a object included RF reader. Then bluetooth communication between object and home wellness robot provides the absolute coordinate information to home wellness robot. After that, the relative coordinate of home wellness robot is found and self-localization through a stereo camera in a home wellness robot. Second, this paper proposed fuzzy control methode based on a vision sensor for approach object of home wellness robot. Based on a stereo camera equipped with face of home wellness robot, depth information to the object is extracted. Then figure out the angle difference between the object and home wellness robot by calculating a warped angle based on the center of the image. The obtained information is written Look-Up table and makes the attitude control for approaching object. Through the experimental with home wellness robot and the smart home environment, confirm performance about the proposed self-localization and posture control method respectively.

Mobile Robot Control using Smart Phone for internet of Things (사물인터넷 구축을 위한 스마트폰을 이용한 이동로봇의 제어)

  • Yu, Je-Hun;Ahn, Seong-In;Lee, Sung-Won;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.26 no.5
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    • pp.396-401
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    • 2016
  • Owing to developments in the internet of things, many products have developed and various researches have processed. Smart home systems in Internet of things area are receiving attention from many people than the other areas. Autonomous mobile robots perform various parts in many industries. In this paper, a smart housekeeping robot was implemented using internet of things and an autonomous mobile robot. In order to make a smart housekeeping robot, Raspberry Pi, wireless USB camera, and uBrain robot of Huins Corp. is used. To control the robot, cell-phone connected with IP of Raspberry Pi, and then Raspberry Pi connected with uBrain robot using Bluetooth. a smart housekeeping robot was controlled using commands of a cell-phone application. If some user wants to move a robot automatically, we implemented that a robot can be chosen an autonomous driving mode from the user. In addition, we checked a realtime video using a cell-phone and computer. This smart housekeeping robot can help user check their own homes in real time.

A Study on Indoor Position-Tracking System Using RSSI Characteristics of Beacon (비콘의 RSSI 특성을 이용한 실내 위치 추적 시스템에 관한 연구)

  • Kim, Ji-seong;Kim, Yong-kab;Hoang, Geun-chang
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.5
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    • pp.85-90
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    • 2017
  • Indoor location-based services have been developed based on the Internet of Things technologies which measure and analyze users who are moving in their daily lives. These various indoor positioning technologies require separate hardware and have several disadvantages, such as a communication protocol which becomes complicated. Based on the fact that a reduction in signal strength occurs according to the distance due to the physical characteristics of the transmitted signal, RSSI technology that uses the received signal strength of the wireless signal used in this paper measures the strength of the transmitted signal and the intensity of the attenuated received signal and then calculates the distance between a transmitter and a receiver, which requires no separate costs and makes to implement simple measurements. It was applied calculating the value for the average RSSI and the RSSI filtering feedback. Filtering is used to reduce the error of the RSSI values that are measured at long distance.It was confirmed that the RSSI values through the average filtering and the RSSI values measured by setting the coefficient value of the feedback filtering to 0.5 were ranged from -61 dBm to - 52.5 dBm, which shows irregular and high values decrease slightly as much as about -2 dBm to -6 dBm as compared to general measurements.

A Survey on the Multi-device Media Usage of Millennials (밀레니얼 세대의 멀티 디바이스 미디어 이용에 대한 조사 및 분석)

  • Lee, Mingyu;Kwahk, Jiyoung;Han, Sung H.;Jeong, Dawoon;Park, Kyudong;Kim, Ju Hwan;Oh, Seokmin;Chae, Gunho
    • Journal of the Ergonomics Society of Korea
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    • v.36 no.6
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    • pp.645-663
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    • 2017
  • Objective: The aim of this study is to understand the multi-device media usage behaviors of the 'Millennial' generation, focusing particularly on music, photo, and videos. Background: Millennials are generally defined as those who were born between early 1980's and early 2000's, and they are known to be familiar with various digital devices since childhood. Since they constitute more than 30% of the global population, they now became the most important target users for most companies. Therefore, identifying the characteristics of the millennials and reflecting them in product development is now essential to be successful in the market. Although many studies have been conducted to understand the characteristics of the millennials, they focus on the common characteristics of millennials as a whole. Method: In this study, an online survey was conducted with a total 360 millennial users. Participants responded to survey questions including the degree of interest in media and media devices, degree of media usage, types of media devices in use, goals and purposes of media usage, and the pain points of using media in a multi-device environment. Results: The results showed that the millennials were generally interested in new media devices or services and that they were willing to utilize a variety of functions to enrich their media life. Different from our expectations, however, not all of them were so active in investing money to purchase numerous media devices or services. In a multi-device environment, the millennials were consuming media using a variety of wireless devices, such as smartphones, digital camera, tablet PC, and Bluetooth speakers or headphones, but were having difficulty in using them. Conclusion & Application: This study investigated the media usage of the millennial users. The results of this study are expected to help designers to better understand the media-related characteristics of this emerging generation in more precision and to offer devices and services that millennials love.

Design and Implement a Smart Control System of Door Security Guard (도어 안전고리 스마트 제어시스템 설계 및 구현)

  • Lee, Hyo Seung;Oh, Jae Chul
    • Smart Media Journal
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    • v.6 no.1
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    • pp.61-67
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    • 2017
  • A large number of people living in modern times prefer remaining unmarried or living alone independently for the reason of their own will or another person's will. This is because they dislike being interfered with by other persons or because there is a financial problem. This behavior has become mainstream in persons working for professional jobs, persons having a strong disposition toward individual activity or college students. In particular, career women pursuing their own comfortable life have the tendency to prefer single life. However, sometimes, they become a target of crime that targets and makes bad use of this point. For these reasons. Consequently, sometimes, they additionally install and use a security system such as door security guard at front door and so on. It is not so difficult to lock the door security guard at the front door. However, it is apt to be forgotten. And when they are on the bedspread before falling asleep, in case they should check whether the door security guard is locked or in case they should lock it, they should get up, go to the entrance, and check and lock the door security guard. They often don't lock the door security guard due to their feeling that it is all right because of annoyance and inconvenience. This paper is intended to work for safety from crime such as illegal housebreaking by more conveniently using the door security guard after designing and implementing a system that can remotely control the door security guard, using a smartphone as a method of resolving this annoyance and keeping life more safe.