• Title/Summary/Keyword: Short-range wireless communication

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Development of a Framework for Improvement of Sensor Data Quality from Weather Buoys (해양기상부표의 센서 데이터 품질 향상을 위한 프레임워크 개발)

  • Ju-Yong Lee;Jae-Young Lee;Jiwoo Lee;Sangmun Shin;Jun-hyuk Jang;Jun-Hee Han
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.46 no.3
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    • pp.186-197
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    • 2023
  • In this study, we focus on the improvement of data quality transmitted from a weather buoy that guides a route of ships. The buoy has an Internet-of-Thing (IoT) including sensors to collect meteorological data and the buoy's status, and it also has a wireless communication device to send them to the central database in a ground control center and ships nearby. The time interval of data collected by the sensor is irregular, and fault data is often detected. Therefore, this study provides a framework to improve data quality using machine learning models. The normal data pattern is trained by machine learning models, and the trained models detect the fault data from the collected data set of the sensor and adjust them. For determining fault data, interquartile range (IQR) removes the value outside the outlier, and an NGBoost algorithm removes the data above the upper bound and below the lower bound. The removed data is interpolated using NGBoost or long-short term memory (LSTM) algorithm. The performance of the suggested process is evaluated by actual weather buoy data from Korea to improve the quality of 'AIR_TEMPERATURE' data by using other data from the same buoy. The performance of our proposed framework has been validated through computational experiments based on real-world data, confirming its suitability for practical applications in real-world scenarios.

A Frequency-Sharing Method to Use Frequency Resources Efficiently (효율적인 주파수 이용을 위한 주파수 공유 방법)

  • Kang, Sang-Gee;Hwang, Taek-Jin
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.8
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    • pp.1349-1355
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    • 2008
  • Recently many short-range transceiver systems, such as ZigBee, Bluetooth and RFID(Radio Frequency Identification), have been developed. These systems are mostly low-power transceivers. In the near future many more low-power transceivers are appeared for WPAN(Wireless Personal Area Network) and interference mitigation technologies are necessary to the low-power transceivers for using frequency resources efficiently. In this paper we consider two methods for sharing frequency resources. The first case is that a frequency band previously assigned fer a certain system is shared and the second case is that the white frequency band is shared. We study the method and conditions for sharing frequency resources in the above two cases. When a frequency band is shared with ZigBee, RFID, DCP (Digital Cordless Phone) and Bluetooth as an example for the first case, the sharing conditions are investigated and the results are presented. We propose a balancing factor to maintain an equal transmitting conditions between systems having a different interference mitigation technique. In the interference simulation we use FH(Frequency Hopping) as a reference system and 0.9 of a balancing factor for LBT(Listen Before Talk) and 0.8 for DS(Direct Spreading). From the simulation results we know that a balancing factor reduces interference probability therefore many more systems can be operated in the same frequency bands compared with the case without using a balancing factor.

Beacon Signal Strength Analysis for Efficient Indoor Positioning (효율적인 실내 위치 측위를 위한 비콘 신호세기 분석)

  • Hwang, Hyun-seo;Park, Jin-tae;Yun, Jun-soo;Phyo, Gyung-soo;Moon, Il-young;Lee, Jong-sung
    • Journal of Advanced Navigation Technology
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    • v.19 no.6
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    • pp.552-557
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    • 2015
  • Recent performed by recognizing a user's location, various services have been tailored focus on short-range wireless communication technology. A beacon in which is attracting attention as next-generation technology. Beacon is a terminal by utilizing the frequency of the non-audible area can not be bluetooth and human sending and receiving terminals and information, Apple recently iBeacon like a low-power Bluetooth (BLE; bluetooth low energy) based beacon showing a tendency to rise into the mainstream there. Services using a beacon is basically installs the terminal in a certain place indoor. It is characterized by providing the user the services to catch the user's position, even automatically take a separate action. Various types of location-based service provided by the target interior space began to attract attention. A variety of location-based services are provided in the interior space in order to be successfully deployed and provide guidance to the interior space, the movement route and the like are essentially required to build various types of information. In this paper, for efficient indoor positioning by varying the signal strength of the beacon in such areas were measured and analyzed.

An Automatic Access Registration System using Beacon and Deep Learning Technology (비콘과 딥러닝 기술을 활용한 전자출입명부 자동등록시스템)

  • Huh, Ji-Won;Ohm, Seong-Yong
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.4
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    • pp.807-812
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    • 2020
  • In order to prevent the national wide spread of the COVID-19 virus, the government enforces to use an electronic access registration system for public facilities to effectively track and manage the spread. Initially, there was a lot of hassle to write a directory, but recently a system for creating an electronic access list using QR codes, what is called KI-Pass, is mainly used. However, the procedure for generating a QR code is somewhat cumbersome. In this paper, we propose a new electronic access registration system that does not require QR code. This system effectively controls the suspicious visitor by using a mask wearing discriminator which has been implemented using deep learning technology, and a non-contact thermometer package. In addition, by linking the beacon, a short-range wireless communication technology, and the visitor's smartphone application, basic information of the facility visitor is automatically registered to KDCA through the server. On the other hand, the user access information registered in the server is encrypted and stored, and is automatically destroyed after up to 4 weeks. This system is expected to be very effective in preventing the spread of other new infectious diseases as well as responding to the coronavirus which is recording a high spread worldwide.

Implementation of Real-time Sedentary Posture Correction Cushion Using Capacitive Pressure Sensor Based on Conductive Textile

  • Kim, HoonKi;Park, HyungSoo;Oh, JiWon
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.2
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    • pp.153-161
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    • 2022
  • Physical activities are decreasing and sitting time is increasing due to the automation, smartization, and intelligence of necessary household items throughout daily life. Recent healthcare studies have reported that the likelihood of obesity, diabetes, cardiovascular disease, and early death increases in proportion to sitting time. In this paper, we develop a sitting posture correction cushion in real time using capacitive pressure sensor based on conductive textile. It develops a pressure sensor using conductive textile, a key component of the posture correction cushion, and develops a low power-based pressure measurement circuit. It provides a function to transmit sensor values measured in real time to smartphones using BLE short-range wireless communication on the posture correction cushion, and develops a mobile application to check the condition of the sitting posture through these sensor values. In the mobile app, you can visualize your sitting posture and check it in real time, and if you keep it in the wrong posture for a certain period of time, you can notify it through an alarm. In addition, it is possible to visualize the sitting time and posture accuracy in a graph. Through the correction cushion in this paper, we experiment with how effective it is to correct the user's posture by recognizing the user's sitting posture, and present differentiation and excellence compared to other product.

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.