• Title/Summary/Keyword: WI-Fi

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Study on the Positioning Method using BLE for Location based AIoT Service (위치 기반 지능형 사물인터넷 서비스를 위한 BLE 측위 방법에 관한 연구)

  • Ho-Deok Jang
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.17 no.1
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    • pp.25-30
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    • 2024
  • Smart City, a key application area of the AIoT (Artificial Intelligence of Things), provides various services in safety, security, and healthcare sectors through location tracking and location-based services. an IPS (Indoor Positioning System) is required to implement location-based services, and wireless communication technologies such as WiFi, UWB (Ultra-wideband), and BLE (Bluetooth Low Energy) are being applied. BLE, which enables data transmission and reception with low power consumption, can be applied to various IoT devices such as sensors and beacons at a low cost, making it one of the most suitable wireless communication technologies for indoor positioning. BLE utilizes the RSSI (Received Signal Strength Indicator) to estimate the distance, but due to the influence of multipath fading, which causes variations in signal strength, it results in an error of several meters. In this paper, we conducted research on a path loss model that can be applied to BLE IPS for proximity services, and confirmed that optimizing the free space propagation loss coefficient can reduce the distance error between the Tx and Rx devices.

Design and Implementation of Convenience System Based on IoT (IoT를 기반한 편의 시스템 설계 및 구현)

  • Ui-Do Kim;Seung-Jin Yu;Jae-Won Lee;Seok-Tae Cho;Jae-Wook Kim
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.1
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    • pp.165-172
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    • 2024
  • In this paper, we designed a smart home system that can be used intuitively and easily in everyday life, such as sending text messages to users, providing various information and scheduling using smart AI, and providing lighting and atmosphere suitable for the atmosphere in situations such as listening to music using neopixels, as well as using ESP32, RFID, and Google Cloude Console using raspberry pie. As a result of the experiment, it was confirmed that security characters were normally sent to users when RFID was recognized on ESP32 connected to Wi-Fi even if the power was reconnected, and smart AI using Neopixel lighting, Raspberry Pie, and voice recognition, which calculated frequency, also changed the recognition rate over distance, but it worked.

Research on convergence data pre-processing technology for indoor positioning - based on crowdsourcing - (실내 측위를 위한 융합데이터 전처리기술 연구 - 크라우드 소싱 기반 -)

  • Seungyeob Lee;Byunghoon Jeon
    • Journal of Platform Technology
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    • v.11 no.5
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    • pp.97-103
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    • 2023
  • Unlike GPS, which is an outdoor positioning technology that is universally and uniformly used all over the world, various technologies are still being developed in the field of indoor positioning technology. In order to acquire accurate indoor location information, a standard of representative indoor positioning technology is required. Recently, indoor positioning technology is expanding into the Real Time Location Service (RTLS) area based on high-precision location data. Accordingly, a new type of indoor positioning technology is being proposed. Thanks to the development of artificial intelligence, artificial intelligence-based indoor positioning technology using wireless signal data of a smartphone is rapidly developing. At this time, in the process of collecting data necessary for artificial intelligence learning, data that is distorted or inappropriate for learning may be included, resulting in lower indoor positioning accuracy. In this study, we propose a data preprocessing technology for artificial intelligence learning to obtain improved indoor positioning results through the refinement process of the collected data.

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Experiments for Efficiency of a Wireless Communication in a Buffer Material and Conceptual Design of THM Integrated Sensor System (완충재 내 무선 통신 효율 실험 및 THM 통합 센서 시스템 개념 설계)

  • Chang-Ho Hong;Jiwook Choi;Jin-Seop Kim;Sinhang Kang
    • Tunnel and Underground Space
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    • v.34 no.4
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    • pp.267-282
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    • 2024
  • This study aims to develop a wireless communication system for long-term monitoring of high-level radioactive waste disposal facilities. Conventional wired sensors can lead to a deterioration in buffer quality and management difficulties due to the use of cables for power supply and data transmission. This study proposes the adoption of a wireless communication system and compares the received signal strengths within bentonite using modules such as WiFi, ZigBee, and LoRa. Increases in dry density of bentonite and distance between transceivers led to reduced received signal strength. Additionally, using the low-frequency band exhibited less signal attenuation. Based on these findings, a conceptual design for a wireless network-based THM integrated sensor system was proposed. Results of this study can be used as foundational data for long-term monitoring of disposal facility.

Provision of a Novel Unlicensed Access Relay Station in IEEE 802.16-based Broadband Wireless Access Networks (IEEE 802.16 기반의 무선 액세스 망에서 Unlicensed 대역 액세스 릴레이에 대한 설계)

  • Choi, W.;Shon, T.S.;Choi, H.H.;Lee, Y.
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.10
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    • pp.169-177
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    • 2007
  • Existing wireless access (mobile) routers are based commonly on the network address and port translation (NAPT) technique which permits simultaneously sharing a subscriber's connection to the network with multiple users. However, the NAPT architecturally makes the users invisible on the network side, thus becoming a user-oriented connection technique. In this paper, we propose a novel service provider-oriented unlicensed nomadic access relay station (WiNNERS) for helping wireless broadband network service providers to make their business more lucrative by accommdating unlicensed band users as subscribers into their network. The WiNNERS offers service providers the capability to directly manage each of the unlicensed band users at the network side. This direct management allows the service providers to flexibly and simply handle QoS, access control, and billing for each user. In order to distinguish each of the unlicensed band users the WiNNERS constructs a virtual tunnel from each user's terminal to the network access router using connection identifiers which is defined for service flow management within the WiBro system, Consequently, our proposed service provider-oriented relay station can be included into the WiBro network system with minimum modifications.

The Individual Discrimination Location Tracking Technology for Multimodal Interaction at the Exhibition (전시 공간에서 다중 인터랙션을 위한 개인식별 위치 측위 기술 연구)

  • Jung, Hyun-Chul;Kim, Nam-Jin;Choi, Lee-Kwon
    • Journal of Intelligence and Information Systems
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    • v.18 no.2
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    • pp.19-28
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    • 2012
  • After the internet era, we are moving to the ubiquitous society. Nowadays the people are interested in the multimodal interaction technology, which enables audience to naturally interact with the computing environment at the exhibitions such as gallery, museum, and park. Also, there are other attempts to provide additional service based on the location information of the audience, or to improve and deploy interaction between subjects and audience by analyzing the using pattern of the people. In order to provide multimodal interaction service to the audience at the exhibition, it is important to distinguish the individuals and trace their location and route. For the location tracking on the outside, GPS is widely used nowadays. GPS is able to get the real time location of the subjects moving fast, so this is one of the important technologies in the field requiring location tracking service. However, as GPS uses the location tracking method using satellites, the service cannot be used on the inside, because it cannot catch the satellite signal. For this reason, the studies about inside location tracking are going on using very short range communication service such as ZigBee, UWB, RFID, as well as using mobile communication network and wireless lan service. However these technologies have shortcomings in that the audience needs to use additional sensor device and it becomes difficult and expensive as the density of the target area gets higher. In addition, the usual exhibition environment has many obstacles for the network, which makes the performance of the system to fall. Above all these things, the biggest problem is that the interaction method using the devices based on the old technologies cannot provide natural service to the users. Plus the system uses sensor recognition method, so multiple users should equip the devices. Therefore, there is the limitation in the number of the users that can use the system simultaneously. In order to make up for these shortcomings, in this study we suggest a technology that gets the exact location information of the users through the location mapping technology using Wi-Fi and 3d camera of the smartphones. We applied the signal amplitude of access point using wireless lan, to develop inside location tracking system with lower price. AP is cheaper than other devices used in other tracking techniques, and by installing the software to the user's mobile device it can be directly used as the tracking system device. We used the Microsoft Kinect sensor for the 3D Camera. Kinect is equippedwith the function discriminating the depth and human information inside the shooting area. Therefore it is appropriate to extract user's body, vector, and acceleration information with low price. We confirm the location of the audience using the cell ID obtained from the Wi-Fi signal. By using smartphones as the basic device for the location service, we solve the problems of additional tagging device and provide environment that multiple users can get the interaction service simultaneously. 3d cameras located at each cell areas get the exact location and status information of the users. The 3d cameras are connected to the Camera Client, calculate the mapping information aligned to each cells, get the exact information of the users, and get the status and pattern information of the audience. The location mapping technique of Camera Client decreases the error rate that occurs on the inside location service, increases accuracy of individual discrimination in the area through the individual discrimination based on body information, and establishes the foundation of the multimodal interaction technology at the exhibition. Calculated data and information enables the users to get the appropriate interaction service through the main server.

Development of Micro Thermal Image Acquisition System (마이크로 열화상 계측 시스템의 IOT 모듈화 개발)

  • Lee, Jun-Yeob;Oh, Jong-woo;Lee, DongHoon
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2017.04a
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    • pp.169-169
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    • 2017
  • 스마트 돈사 내의 열환경 분석에 필수적으로 고려되어야 인자는 가축의 복사 에너지 변화로 볼 수 있다. 열환경 제어의 대상이기도 하지만 회귀적으로 열환경 변화의 인자이기도 하다. 이러한 가축의 복사 에너지 분석을 위하여 시설 내에 용이하게 배포가 가능한 열화상 계측 시스템을 개발하였다. 초소형 마이크로 열화상 계측 시스템에 부가적으로 IOT(Internet of Thing) 기반 기술을 이용한 모듈화 개발을 병행하였다. 열화상 계측 센서로 LWIR(Longwave infrared)영역에 해당하는 $8{\mu}m{\sim}4{\mu}m$의 영역에서 $0.05^{\circ}C$의 분해능을 보이는 $Lepton^{TM}$ (500-0690-00, FLIR, Goleta, CA)모델을 사용하였다. SPI(Serial Peripheral Interface) 속도 2 Mhz로 마이크로프로세서(NanoPi NEO Air, FrendlyArm, CA, USA)와 고속 통신을 수행하여 9 Hz의 계측이 가능하다. 열화상 센서와 마이컴으로 구성되는 단위 계측 시스템의 통신 기능 확장을 위하여 다음과 같이 세 단계의 정보 전달 시나리오를 설계하였다. 1) 단독적으로 열화상을 계측 하고 내장된 메모리에 저장하는 형식 2) 인접한 사용자 인터페이스에서 1번 단독 모듈에 접속하여 열화상을 실시간으로 전송하여 화면에 도시하는 형식 3) 2번 사용자 도시모듈과 병행적으로 Local WI-FI 통신을 이용한 모바일 기기에 화면을 도시하는 형식. 이와 같은 계층적이며 모듈화된 계측 시스템을 구성하기 위해서 1번 모듈에 공개 소프트웨어인 Hostapd 2.5(http://w1.fi/hostapd)버전을 설치하였다. 외부 인터넷 환경이 없는 상황에 1번 모듈 단독으로 AP(Access Point) 기능을 제공하여 지근 거리에 있는 2번 모듈과 3번 모바일 기기의 접속을 관리할 수 있다. 2번 모듈의 경우 화면 다수의 1번 모듈에 접속을 교차적으로 수행하는 방식과 2번 모듈 자체가 AP가 되어 1번 모듈의 접속을 허용하는 형태로 구성되어 있다. 계측 시스템의 계측 매트릭스 구성에 따라 선택적으로 결정할 수 있다. 1번 2번 모듈 공통적으로 TCP/IP Listener와 Client 서비스를 병렬적으로 수행할 수 있도록 개발을 하였다. 3번 모바일 기기에서 사용자 인터페이스 구현을 위하여 범용 Android 기반 GUI 프로그램과 Socket 통신을 연동시켰다. 1개의 열화상 Frame의 전송량은 9,600 Byte ($=80{\times}60{\times}2Byte$) 로 WI-FI 통신 전송 시 2회 ~ 6회 정도 내외로 가변적인 통신 수행 횟수를 나타내었다. 센서 계측 시스템과 정보 전송 시스템을 병렬적으로 구성한 모듈화 된 계측시스템의 전 요소에서 센서에서 제공하는 최대 계측 주기인 9 Hz 구현이 일반적으로 가능하였다. 이를 이용한 추후 연구를 통해 가축 객체의 열복사 정보와 돈사 내 열환경 간의 역학성을 연구할 것이다.

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Ground Radiation Antenna for Mobile Devices Using Controlled Endless Metal Rim Mode

  • Jeon, Jihwan;Qu, Longyue;Lee, Hongkoo;Kim, Hyeongdong
    • ETRI Journal
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    • v.40 no.2
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    • pp.180-187
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    • 2018
  • In this paper, we introduce a ground radiation antenna that uses controlled endless metal rim modes. In the proposed technique, the metal rim mode is tuned and excited as a one-wavelength radiator by a small ground radiation antenna. The proposed antenna occupies a clearance of $1mm{\times}4mm$ in a $30mm{\times}20mm$ ground plane. A metal rim with dimensions of $34mm{\times}24mm$ surrounds the ground plane, and the metal rim is separated from the ground plane by a gap of 2 mm. In addition, a lumped capacitor is inserted between the metal rim and the ground plane to control the characteristic mode of the metal rim such that the resonance of the metal rim is tuned to be equal to the operating frequency. By performing simulations and measurements, we compare the performance of the proposed antenna with that of a reference antenna that does not have an inserted capacitor between the metal rim and the ground plane. The results show that a significant improvement of the radiation performance is obtained by employing the proposed technique.

Compact and Flexible Monopole Antenna for Ultra-Wideband Applications Deploying Fractal Geometry

  • Geetha, G;Palaniswamy, Sandeep Kumar;Alsath, M. Gulam Nabi;Kanagasabai, Malathi;Rao, T. Rama
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.400-405
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    • 2018
  • This paper presents a compact ultra-wideband (UWB) flexible monopole antenna design on a paper substrate. The proposed antenna is made of iterations of a circular slot inside an octagonal metallic patch. This fractal-based geometry has been deployed to achieve compactness along with improved bandwidth, measured reflection coefficient -10 dB bandwidth ranging from 2.7 to 15.8 GHz. The overall size of the antenna is $26mm{\times}19mm{\times}0.5mm$, which makes it a compact one. The substrate used is paper and the main features like environment friendly, flexibility, green electronics applications and low cost of fabrication are the key factors for the proposed antenna. The aforementioned UWB prototype is suitable for many wireless communication systems such as WiMAX, WiFi, RFID and WSN applications. Antenna has been tested for the effect of bending by placing it over a curved surface of a very small radius of 10 mm.

An Efficient Mode Selection Method for OFDM Based Multi-System Wireless Communication Systems (OFDM 기반 다중 무선 통신 환경에서의 효과적인 모드 선택 기법)

  • Park, Jong-Min;Kang, Min-Soo;Cho, Sung-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.2
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    • pp.19-25
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    • 2008
  • When there are numerous wireless communication systems co-existing in the limited available frequency resource, an unexpected time delay can be caused during the system switching. So, in order to reduce this time delay, a mode selection method is required. In this paper, we propose a mode selection method to minimize the time delay for multi-system wireless communication systems. For the sake of efficiency, the mode selection method is designed by analyzing the preamble characteristics of different standards. Instead of performing a full search, we propose the preamble partial search to reduce the time delay to a minimum. Simulated with Matlab in an additive white Gaussian noise(AWGN) environment with a signal to noise ratio(SNR) of 10dB and bit error rate(BER) of $10^{-6}$, we evaluated and showed the performance improvement gained by using our proposed mode selection method.