• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.238-244
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• 2020

The development and distribution rate of smartphones have progressed so rapidly that it is safe for the entire nation to use them in the smart age, and the use of smartphones has become an essential medium for the use of domestic media content, and many people are using various contents regardless of gender, age, or region. Recently, various media outlets have been consuming video content for online learning, indicating that learners utilize video content online for learning. In the previous research, satisfaction studies were conducted according to the type of content, and the improvement plan was necessary because no research was conducted on how to evaluate the learning content itself and provide it to learners. In this paper, we would like to propose a system through evaluation and review of learning content itself as a way to improve the way of providing video content for learning and quality learning content.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.3
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• pp.202-207
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• 2013

In the paper, we design a autonomous mobile robot for freight transportation and propose an operation method of the robot in the warehouse. In order to implement autonomous navigation, it is needed to recognize the position of the robot and track the path to the target. Previous methods are hard to change the workspace environment and need high cost to install and keep a maintenance of the system. The lifter of freight transportation robot is designed to load and unload a baggage through up and down motion. Also, ultrasonic sensor, RFID, QR-code and camera sensor is used to carry out various functions while the robot navigates in the various environment. We design an operation method of the mobile robot in order to effectively arrive a goal position and transport a freight. The proposed methods are verified through various experiments.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.56-62
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• 2013

Recently with smart phones and tablets, next generation mobile communication systems have supported various multimedia contents services. Thus, multimedia communication systems have been gradually increased compared to voice communication systems. Since the growth of multimedia services has increased users' duration on systems and decreased systems' effectiveness on power, a study on effective usage of power needs to be researched. Furthermore, radio shadow areas under heavy urban environments have generated unnecessary power consumption which reduces the usage duration of power on next generation mobile communication systems. This paper has reviewed the communication network architecture on next generation mobile communication systems and the unnecessary power consumption in radio shadow areas. This paper has also proposed the method of the effective power usage and analyzed the effective power usage on next generation mobile communication systems with simulation.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.446-451
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• 2015

Recently, researches on sensor-based U-health applications that provide personal health information such as blood pressure, body temperature, and glucose, have actively been studied. The health information obtained via sensors, however, may have accuracy problems so that they can not be used unprocessed. This paper proposes a sensor abstraction layer for enhancing the accuracy of sensor readings from biomedical sensors that interact with smart phones. This layer recognizes sensor types and converts sensor readings into a form as specified in ISO/IEEE 11073 Personal Health Standard. When necessary, not only a filtering method that eliminates outlier values from sensor readings but also a summarization method that transforms them into more suitable forms, can also be applied. An android-based development board is used for the evaluation of proposed sensor abstraction layer. The results obtained by applying filtering and summarization show improved accuracy over unprocessed sensor readings of the body temperature and heartbeat sensors.

• Journal of Advanced Navigation Technology
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• v.19 no.3
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• pp.217-223
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• 2015

This paper describes the design and implementation of a network system for UAV for multiple clients that enables long-range operation based on a commercial mobile network. A prototype data modem is developed with a commercial embedded M2M module in order to provide an access to the mobile network. A central server with a database is constructed to record all of real-time flight and video data and communicate with a ground control system. A GCS is developed for the central control, the single UAV and the smart phone version to be used for different purposes. Performance tests were progressed for data delay, video frame rate and state of clients. Flight tests were also performed to verify the reliability of the modem with respect to altitude.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.562-567
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• 2016

IoT is attracting attention as the development of the Internet and the spread of smart devices are rapidly increasing worldwide. As IoT is integrated into everyday life, the market is getting bigger. So, experts predict that IoT devices will grow to more than one trillion in a decade. Techniques related to IoT are also being developed steadily, and studies are underway to develop IoT in various fields. However, vendors launching IoT services do not interact with data from other platforms. Therefore, it is limited to growing into a big market by facing the obstacle called the silo phenomenon. To solve this problem, web technology attracts attention. Web technology can interact with data regardless of platform, and it can not only develop various services using the data, but also reduce unnecessary costs for developers. In this paper, we have studied a web - based open IoT system that can transmit data independently in real time to the IoT platform.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.881-889
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• 2004

Using the ETC Service, it is now possible to charge a vehicle for driving pass a specific toll booth electronically, without the vehicle even having to slow down. The smart card and card reader used to collect tolls electronically have a serious problem which it dose not have a standard for the ETC system. In this paper, we suggest the ETC system using mobile phone to collect tolls efficiently instead of existing system which is consist of a Interface Module to connect between a mobile phone and OEE, a mobile phone to send the information of tollgate fees and OEE to communication with RSE of roadway in the vehicle. This primary focus of this system is the IM functions and protocol to assist of the existing mobile phone and OBE.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.697-702
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• 2012

With an elevator supply and demand increases, It has been enlarged various requirements for the safety of the elevator. Elevator safety requirements can be the ability to respond to emergencies quickly. Recently, QR code was attached to all elevator for the elevator safety and it is established by law for the Elevator rescue work. And also the elevator system is seeking to utilize more secure elevator with mandatory installation of CCTV and direct call devices. However, CCTV and direct call service is operating on an individual method and it has not been proposed integrated model. In this paper, we propose the safety elevator integration model with CCTV, direct call service and remote control based on smart phone. Using the proposed model, we can be improved the efficiency of maintenance and ability of prompt action in the event of a disaster.

• Journal of Advanced Navigation Technology
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• v.17 no.4
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• pp.421-428
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• 2013

Voice over IP refers to technology that enables routing of voice conversations over the Internet or a TCP/IP network. VoIP communication costs cheaper than traditional analog phone. Phone calls can be made to anywhere / anyone: Both to VoIP numbers as well as people with normal phone numbers. VoIP protocol equipment available today follows the SIP standard. Older VoIP equipment though would follow H 323, MGCP, Megaco/H.248. A SIP server is the main component of an IP PBX, dealing with the setup of all SIP calls in the TCP/IP network. A SIP server is also referred to a Asterisk IP-PBX. A VoIP telephone, also known as a SIP phone or a softphone, allows the user to make phone calls to any softphone, mobile or PC by using App store. A VoIP telephone can be a simple software-based softphone. However, the SIP Server and the program is vulnerable to VoIP attacks. In this paper, eavesdropping attacks tested by using the Asterisk SIP server. Eavesdropping attacks and TLS security methods apply to VoIP system. TLS can be applied to determine whether the eavesdropping available for VoIP Environments.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.43-47
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• 2018

In recent years, bicycle craze has been blowing in Korea, and bicycle has become a means of transportation near. In addition, there is a lot of interest in the Internet of things, and recently there is a lot of interest in the Internet of things. However, despite the development of the bicycle market, the bicycle cradle does not have such a development, and it still has a drawback in that it requires a separate lock for the lock. In this regard, I would like to find some problems and solve them. In this paper, we have implemented a system that can control the location and use of the bicycle cradle in real time by communicating with the app and Arduino so that it can help the collection and retrieval of the bicycle which is the problem of the current bicycle cradle. n addition, we propose a method to establish a shared economic system based on Internet of things by providing shared services with acquaintances and others, and to improve user convenience by providing real - time services.