• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.2
• /
• pp.170-178
• /
• 2011

In this paper, a research was performed to develop a wireless measurement system for bridge monitoring using MEMS sensor and bluetooth wireless communication module. First, in order to prove the suitability of MEMS sensor for the bridge measurement, its ranges of measuring acceleration and of frequency response were experimented. Also, the quality of wireless communication was tested by an experiment on long-distance communication for the knowledge of maximum communication distance, and also by an experiment on the data transmit-receive capability both inside and outside of a steel box bridge. Later, placing the wireless acceleration sensor system that had been developed in our lab on a bridge in public service, we acquired vibration data from the bridge under traffic load and analyzed its dynamic characteristics in realtime. For the analysis of the data, NExT & ERA algorithm were employed. The result of analysis was compared to the FE analysis of the same bridge, and the comparison made it possible to evaluate the performance of wireless acceleration sensor system. As a result, it was proven that the wireless acceleration sensor system developed with the use of MEMS sensor and bluetooth wireless communication module could be effectively applied to the measurement of structure whose vibration feature was low frequency like a bridge.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.4125-4130
• /
• 2015

This paper presents the communication performance for the radiation pattern reconfigurable antenna in the wearable device measuring bio signal (temperature, blood pressure, pulse etc.) of human body. The operational frequency is 2.4 - 2.5 GHz, which covers Bluetooth communication bandwidth. The maximum gain of the antennas is 1.96 dBi. The proposed antenna is efficiently transmitting and receiving signal by generating two opposite beam directions using two RF switches (PIN diode). Also, we investigated how radiation pattern changes according to three angles ($30^{\circ}$, $90^{\circ}$, $150^{\circ}$) of Top Loading. In this paper, we measured and compared the SNR (Signal-to-Noise Ratio) and BER (Bit Error Rate) performances of the proposed antennas in the condition between an ideal environment of anechoic chamber and smart house existing practical electromagnetic interferences (Universal Software Radio Peripheral, USRP). Throughout the comparing the results of the measurement of two cases, we found that the SNR is degraded over 5dB in average and BER is increased over ten times in maximum, therefore, it is confirmed that the error rate of receiving signal is increased. The measured results of SNR and BER value in this paper able to expect the performance degrading by the interference from the electromagnetic devices.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.2
• /
• pp.8-14
• /
• 2020

Recently, there was an increasing demand for an integrated access control system which is capable of user recognition, door control, and facility operations control for smart buildings automation. The market available door lock access control solutions need to be improved from the current level security of door locks operations where security is compromised when a password or digital keys are exposed to the strangers. At present, the access control system solution providers focusing on developing an automatic access control system using (RF) based technologies like bluetooth, WiFi, etc. All the existing automatic door access control technologies required an additional hardware interface and always vulnerable security threads. This paper proposes the user identification and authentication solution for automatic door lock control operations using camera based visible light communication (VLC) technology. This proposed approach use the cameras installed in building facility, user smart devices and IoT open source controller based LED light sensors installed in buildings infrastructure. The building facility installed IoT LED light sensors transmit the authorized user and facility information color grid code and the smart device camera decode the user informations and verify with stored user information then indicate the authentication status to the user and send authentication acknowledgement to facility door lock integrated camera to control the door lock operations. The camera based VLC receiver uses the artificial intelligence (AI) methods to decode VLC data to improve the VLC performance. This paper implements the testbed model using IoT open-source based LED light sensor with CCTV camera and user smartphone devices. The experiment results are verified with custom made convolutional neural network (CNN) based AI techniques for VLC deciding method on smart devices and PC based CCTV monitoring solutions. The archived experiment results confirm that proposed door access control solution is effective and robust for automatic door access control.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.8
• /
• pp.13-18
• /
• 2016

In Internet of Things (IoT) environment, a variety of smart devices are connected to Internet through various network technologies such as 4G/5G, WiBro, Bluetooth, etc. in order to provide the remote monitoring service such as smart healthcare service, etc. Most standard mobility management protocols based on IETF Mobile IP may not be suitable for Internet of Things (IoT) environments due to constrained power, constrained CPU processing and memory capacity, and large signalling overhead which are inherently accompanied by various devices in IoT environments. In this article, we propose a new mobility management protocol CoMP (CoAP-based Mobility Managemenbt Protocol) for reliable mobility management in IoT environments. The architecture and algorithm to achieve both reliability and simplicity for IoT mobility management are proposed. Finally, performance has been evaluated by both mathematical analysis and simulation.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.6
• /
• pp.1148-1153
• /
• 2016

The number of cyclists is on the steady growing for leisure and transportation with the increasing interest in health and environment. However, the number of cycling accidents is also increasing steadily due to the lack of safety awareness and regulations. Focusing on this issue, we propose and develop a smart LED bicycle helmet in order to reduce a risk of cycling accident. The main idea is to change status of the LED on the helmet based on the bicycle's movement and provide motion information of the bicycle for others. To control the LED lights on the helmet, we use the Arduino board which communicates with the LED module through serial connection. We decide motion information by using the values from acceleration and GPS sensors of the smartphone. To receive this information from the smartphone, the control board and the smartphone are connected by Bluetooth.

• Journal of the Korea Convergence Society
• /
• v.8 no.12
• /
• pp.63-69
• /
• 2017

This study is about the development of a smart bed control system to be able to detect the human position and body signal on bed. The main control board in the bed control system consists of the human sensing part, motor driving part and MCU. Here, to increase the credibility to check the human presence on bed, the human sensing part is combined with the human position part by membrane sensor and the body-signal detecting part of EMFI sensor. Also, remotely connecting the two detected signal to the application program of the app mode makes it possible to monitor human information on bed. In this paper, the remote function monitoring of the on-bed human information by bluetooth communication will be abe to make it applicable to the technical prevention method of the bed fall and absence accident in hospital and care facilities.

• Journal of Advanced Navigation Technology
• /
• v.21 no.2
• /
• pp.200-205
• /
• 2017

Modern sports are developing into sports science that incorporates science and various analytical simulation systems for improving records are being developed, and they are helping to improve actual game records. Therefore golf which is one of various sports events, has been popularized among the hobbyists and the general public and there is an increasing demand for correcting the movement attitude of the person. In response to these demands, many systems have been developed to analyze and correct golf swing postures. The golf swing accuracy analysis system analyzes the moments that can not be seen with the naked eye and guides them to understand easily. It can improve the golf swing motion through immediate feedback due to the visual effect. Using the knowledge of golf swing motion collected from golf swing video, we improved reliability. In addition, it provides the ability to visually check and analyze your golf swing video, allowing you to analyze each segment based on various golf swing classification methods.

• Convergence Security Journal
• /
• v.15 no.2
• /
• pp.11-17
• /
• 2015

According to NIA (National Information Society Agency) report, digital divide is a vicious circle which makes quality interval of human's life between people who have information and relatively not. Especially in a smart phone society, there is a big problem between disabled people and normal people. This paper suggests a braille keyboard system for the blind to solve these problems. It is designed for portable use, convenience and quick text typing based on bluetooth communication technique. In text input test, all texts (Korean, English, number) were accurately expressed and typing speed was about 22 [c/m](characters per a minute). Especially, we design text2voice function to provide more accurate key input system. Popular applications such as call, alarm, message, kakao talk, internet, music, were performed without carring problems using the proposed braille keyboard system. The proposed technique is thought to contribute to eliminating the digital divide through the expansion of smartphone users.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.10
• /
• pp.2195-2202
• /
• 2011

Recently, navigation system is used to inform users of vehicle location and driving direction, moving distance and so on. This navigation uses GPS sensor for current location determination. The GPS sensor will determinate current coordinates by using triangulation algorithm. This characteristic bring about that the GPS signal is not available in the shadow region such as tunnel and urban canyon. Moreover, Even though the signal is available, inherent positional error rate of the GPS often results in the dislocation of vehicle. To solve, these problems, a new positioning system is proposed in the paper. The System utilizes geomagnetic sensors of smartphone, speed information of CAN of vehicle though bluetooth and WiFi APs for GPS shadow area. The experimental test shadows that the proposed system using multiple data is able to determine the position of vehicle in GPS shadow areas.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.10
• /
• pp.1941-1948
• /
• 2016

The incident during commuting to school happened frequently in these days, such that the government announced the student commuting safety policy for addressing to implement the safety management system of the unsafer school commuting zone. In this paper, a commuting tracking system is proposed that notifies the location of vehicles and the boarding status of student using BLE beacon and smart phone GPS function. The commuting tracking system that gets the data from the system server of driver's smart phone GPS location and UUID of the beacon which had provided students has configured to provide notifications to parents and related administrators. It provides real-time information about whether a student boarding, boarding times and bus locations for parents and administrators. It verifies the disembarking time for each student and also provides to driver to secure if any student tries to board the wrong school bus and if any students is left behind in the bus.