• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.922-929
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• 2005

This paper proposes an adaptive pilot beacon equipment for mobile communication systems based on direct spread spectrum technology which generates the pilot channel for handoff between base stations by using the information acquired from the downstream wireless signal regarding the overhead channel information. Such an adaptive pilot beacon equipment will enable low power operation since among the wireless signals, only the pilot channel will be generated and transmitted. The pilot channel in the downstream link of the CDMA receiver is used to acquire time and frequency synchronization and this is used to calibrate the offset for the beacon, which implies that time synchronization using GPS is not required and any location where forward receive signal can be received can be used as the installation site. The downstream link pilot signal searching within the CDMA receiver is performed by FPGA and DSP. The FPGA is used to perform the initial synchronization for the pilot searcher and DSP is used to perform the offset correction between beacon clock and base station clock. The CDMA transmitter the adaptive pilot beacon equipment will use the timing offset information in the pilot channel acquired from the CDMA receiver and generate the downstream link pilot signal synchronized to the base station. The intermediate frequency signal is passed through the FIR filter and subsequently upconverted and amplified before being radiated through the antenna.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.75-82
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• 2016

Visible light communication (VLC) using LED lamps is suitable for implementing an indoor positioning system in an indoor environment where the global positioning system (GPS) signal does not reach. In this paper, we present an indoor positioning system for mobile robots using a VLC beacon and fuzzy rules. This system consists of an autonomous mobile robot, VLC modules, and device application software. Fuzzy rules are applied to plan the global and local paths along which the mobile robot navigates indoors. The VLC transmitter modules are attached to the wall or the ceiling as beacons to transmit their own location information. The variable pulse position modulation (VPPM) algorithm is used to transmit data, which is a new modulation scheme for VLC providing a dimming control mechanism for flicker-free optical communication. The mobile robot has a receiver module to receive the location information while performing its mission in the environment where VLC transmitters are deployed.

• Journal of Digital Contents Society
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• v.19 no.9
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• pp.1689-1697
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• 2018

This paper explored how to design amobile application for Korea's traditional markets based on O2O service and data science technologies. In order to cover a broader scope of customers, diversify the ways to sell products, and increase the profits of Korea's traditional markets, the application bridges online customers with offline stores at traditional markets and augments both convenience and accessibility. Beyond the typical face-to-face interactions between customers and sellers at traditional markets, this application offers mobile payments and personalized recommendations of nearby stores and preferable products using Beacon and datascience technologies. Moreover, it offers multi-language support for foreign customers who are not familiar with Korea's traditional markets and the products sold there. In conclusion, using O2O service, which is a rising trend among prevalent platform technologies, this study proposed a new e-commerce model for Korea's traditional markets to promote market expansion.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.60-65
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• 2010

This paper describes the results of 2D mapping, feature detection and matching to create the surrounding environment in the mounted stereo camera on Mobile robot. Extract method of image's feature in real-time processing for quick operation uses the edge detection and Sum of Absolute Difference(SAD), stereo matching technique can be obtained through the correlation coefficient. To estimate the location of a mobile robot using ZigBee beacon and encoders mounted on the robot is estimated by Kalman filter. In addition, the merged gyro scope to measure compass is possible to generate map during mobile robot is moving. The Simultaneous Localization and Mapping (SLAM) of mobile robot technology with an intelligent robot can be applied efficiently in human life would be based.

• Convergence Security Journal
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• v.12 no.1
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• pp.55-61
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• 2012

Owing to the development of wireless infrastructure and mobile communication technology, There is growing interest in smart phone using it. The resulting popularity of smart phone has increased the Mobile Malicious AP-related security threat and the access to the wireless AP(Access Point) using Wi-Fi. mobile AP mechanism is the use of a mobile device with Internet access such as 3G cellular service to serve as an Internet gateway or access point for other devices. Within the enterprise, the use of mobile AP mechanism made corporate information management difficult owing to use wireless system that is impossible to wire packet monitoring. In this thesis, we propose mobile AP mechanism-based mobile malicious AP detection and prevention mechanism in radius authentication server network. Detection approach detects mobile AP mechanism-based mobile malicious AP by sniffing the beacon frame and analyzing the difference between an authorized AP and a mobile AP mechanism-based mobile malicious AP detection.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.31-36
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• 2020

The LTE-R system is a system consisting of a packet network that provides all IP-based services. Continuous failures related to the platform safety gate and subsequent safety accidents related to passengers and safety gate workers continue. The secondary damage caused by the failure of the platform safety door and the related human life damage have emerged as a major social issue.. By linking the beacon system to the Long Term Evoluton-Railway (LTE-R) network, an LTE-based railway wireless network currently in operation or being installed, it precisely locates trains and provides standardized fault alerts to train crews. When entering into the station, ultimately we will decelerate the train and reduce the accidents of metropolitabn railroad traffic by securing safe driving.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.288-290
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• 2017

Recently, interest and demand of Augmented Reality(AR) contents are increasing as an application field of AR. Generally, when the AR contents are served in the outdoor environment, the position information using the GPS signal is used to control the display of the object on the AR screen, or a marker based on the image of the object is used. However, there is a problem that location information can not be used in an indoor environment. If the service is provided using only the marker, there is a problem that the recognition of the marker due to the moving obstacle in the vicinity is unstable. and there is a problem that information displayed on the AR screen is not displayed in a fixed state at a specific position, it moves according to the movement of the camera. In this paper, we have studied the object control method for displaying the object to be displayed on the AR screen by using iBeacon using indoor location recognition and specific markers.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.242-247
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• 2008

As an absolute positioning system, iGS is designed based on ultrasonic signals whose speed can be formulated clearly in terms of time and room temperature, which is utilized for a mobile robot localization. The iGS is composed of an RFID receiver and an ultra-sonic transmitter, where an RFID is designated to synchronize the transmitter and receiver of the ultrasonic signal. The traveling time of the ultrasonic signal has been used to calculate the distance between the iGS system and a beacon which is located at a pre-determined location. This paper suggests an effective operation method of iGS to estimate position of the mobile robot working in unstructured environment. To expand recognition range and to improve accuracy of the system, two strategies are proposed: utilization of beacons belonging to neighboring blocks and removal of the environment-reflected ultrasonic signals. As the results, the ubiquitous localization system based on iGS as a pseudo-satellite system has been developed successfully with a low cost, a high update rate, and relatively high precision.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.1060-1073
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• 2013

In this paper, we present a cluster-based routing scheme for efficiently delivering data to group mobile users by extracting and clustering mobile user group simply from beacon message information in wireless ad-hoc networks. First, we propose an online-clustering mechanism that uses a local neighbor table on each node by recursively transmitting to neighbor nodes, and forms a group table where a set of listed nodes are classified as group members, without incurring much overhead. A node that appears the most frequently from neighbor tables throughout the network is selected as the cluster-head node, serving as a data gateway for the intra-cluster. Second, we design an inter-cluster routing that delivers data from stationary data sources to the selected cluster-head node, and a intra-cluster routing to deliver from the cluster-head node to users. Simulation results based on ns-2 in the ad-hoc networks consisting of 518 stationary nodes and 20 mobile nodes show that our proposed clustering mechanism achieves high clustering accuracy of 96 % on average. Regarding routing performance, our cluster-based routing scheme outperforms a naive one-to-one routing scheme without any clustering by reducing routing cost up to 1/20. Also, our intra-cluster routing utilizing a selected cluster-head node reduces routing cost in half as opposed to a counterpart of the intra-cluster routing through a randomly-selected internal group member.

• Healthcare Informatics Research
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• v.24 no.4
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• pp.387-393
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• 2018

Objectives: This paper describes an experience of implementing seamless service trials online and offline by adopting Internet of Things (IoT) technology based on near-field communication (NFC) tags and Bluetooth low-energy (BLE) beacons. The services were provided for both patients and health professionals. Methods: The pilot services were implemented to enhance healthcare service quality, improve patient safety, and provide an effective business process to health professionals in a tertiary hospital in Seoul, Korea. The services to enhance healthcare service quality include healing tours, cancer information/education, psychological assessments, indoor navigation, and exercise volume checking. The services to improve patient safety are monitoring of high-risk inpatients and delivery of real-time health information in emergency situations. In addition, the services to provide an effective business process to health professionals include surveys and web services for patient management. Results: Considering the sustainability of the pilot services, we decided to pause navigation and patient monitoring services until the interference problem could be completely resolved because beacon signal interference significantly influences the quality of services. On the other hand, we had to continue to provide new wearable beacons to high-risk patients because of hygiene issues, so the cost increased over time and was much higher than expected. Conclusions: To make the smart connected hospital services sustainable, technical feasibility (e.g., beacon signal interference), economic feasibility (e.g., continuous provision of new necklace beacons), and organizational commitment and support (e.g., renewal of new alternative medical devices and infrastructure) are required.