• Journal of Digital Contents Society
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• v.15 no.1
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• pp.93-99
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• 2014

Recently Wireless communication among short-distance devices has come to notice due to smart phone generalization recently. However, instead of setting up additional H/W, communication technology providing wireless communication based on S/W is in need due to limited availability of NFC's use. Accordingly, short-distance wireless communication technology that makes great use of mike and speaker which installed in every device draws attention. Our thesis suggests improvement of acoustic transmission speed by applying multi-channel parallel transmission and advancement of transmission rate that differed from each mike's own characteristics through optimizing adaptive threshold. The study is not only just applied in specific and limited conditions such as promoting corporation and payments system but also fast and convenient data transmit system general users-oriented.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.2
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• pp.141-152
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• 2022

As a method to understand the ecological habits around the artificial reef, various reports such as fishing gear survey, diving, sound survey, underwater CCTV and camera, etc. are reported. Among them, the sound survey method is carried out by installing an acoustic system on the ship and can be investigated regardless of the marine environment such as time constraints and turbidity. Such method, however, takes a lot of manpower and time as the ship travels at a constant speed. Investigations around artificial reefs are being conducted in an artificial way, and a lot of time and labor are consumed as such. Maritime buoys have been operated for various purposes such as route signs, weather observation, marine environment monitoring and defense monitoring for navigation safety in the past, but studies on monitoring systems for ecological habits and distribution of fish using marine buoys are remarkably insufficient. Therefore, this study aims to develop a system that allows users to directly monitor fish group detector data by estimating the distribution of fish groups around artificial reefs and using wireless communication at sea. In order to confirm the suitability of the maritime buoy used in this study, it was operated to compare data using LTE-equipped buoys capable of wireless communication and a data logger-type system buoy. Data transmission of buoys capable of LTE communication was carried out in a 10-minute ON, 10-minute OFF method due to the limitation of the power supply capacity, and data of the data logger-type buoy received full data. We compared and analyzed the data received from the two fish detectors. It is expected that real-time monitoring of the wireless buoy detection device using LTE will be possible through future research.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.223-232
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• 2019

With the development of the information communication industry, the size of the communication device has been reduced to a system that generates a large amount of heat. Therefore, since the amount of heat generated by the wireless equipment is large in the wireless base station, the energy consumption is continuously consumed and the failure of the wireless base station may occur. Therefore, in this study, The study was analyzed. As a research method, we performed base station with a lot of calorific value and electric charge. We selected 25 base stations and obtained data for two weeks. To ensure reliability, the room temperature was kept constant at $27^{\circ}C$, and the control system was installed and equiped for two weeks to obtain the date analysis. In order to calculate the test results in the study method, the instrument was used with a computer, a digital thermometer, and dust measurement. For the date analysis, we conducted a research study on 25 wireless basestations before and after the installation of Control Sysetm.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.1-7
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• 2004

In addition to wired communication technology, wireless communication technology has been driving communication revolution nowadays. Bluetooth technology carries out data/voice communication making pico-net and the various application services are supported by access network connected to public network. This paper presents educational software development of bluetooth protocol stack including HCI, L2CAP, RFCOMM, SDP and profiles including GAP, SPP, GEOP, FTP. This software which supports programming environment of these protocol monitoring and emulation is implemented basically step by step for education based on H connected to the bluetooth device through RS-232-C, UART or USB cable. Application program coded by Visual C is operated over the firmware loaded on the bluetooth device connected to the PC. Additionally ftp and chatting function are developed to enhance educational efficiency.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1446-1459
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• 2008

In an infrastructure-based wireless network, an access point is used for all communications among mobile devices. However, when a mobile device moves into a dead Bone, a connectivity disruption between the mobile device and the access point occurs. Such connectivity disruption consequently leads to another connectivity disruption between the mobile device moving toward the dead zone and other wireless-enabled devices located within the area of the infrastructure-based wireless network. To cope with the connectivity disruption in the infrastructure-based wireless network the ad hoc network that dynamically forms a network without any preexisting communication infrastructure needs to be set up to provide seamless connections among mobile devices. In this paper, we propose the DNSQ-MAC (Dynamic Network State aware QoS-Medium Access Control) technique that meets the deadlines of MAC frames forwarded over hop-by-hop multipaths and guarantees the QoS performance of an ad hoc-based wireless network. Mobile devices incorporating the DNSQ-MAC technique are capable of adjusting to the new dynamic network status in order to enhance the QoS performance in the ad hoc-based wireless network. A case study which exploits the Qualnet simulator shows that the proposed DNSQ-MAC technique can guarantee the deadlines of MAC frames forwarded over hop-by-hop multipaths and enhance the QoS performance of various routing protocols and packet schedulers running on the network layer above the MAC layer.

• Journal of the Korea Society of Computer and Information
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• v.23 no.9
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• pp.113-122
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• 2018

In this paper, IoT(Internet of things) technology, which is the core of the 4th industrial revolution, was applied to the study of reduction of consumption current. The IoT is a sensor that collects data, a sensor communication, a gateway that processes and stores the collected data. Data application of IoT technology is applied to smart home, smart city, healthcare, smart factory, etc. and it needs to be applied to various industrial fields. By sensing the location of the sensor device, the specific functions of the gateway and the platform are turned ON and OFF to reduce the consumption current of the equipment during the OFF period. When the sensor device accesses the gateway, the specific function of the gateway is turned ON and When the device is separated from the gateway, it senses the sensitivity of the wireless signal and automatically turns off the certain functions. As a resurt, it has reduced the consumption of current. In this paper, we propose a novel system for detecting the location of sensor devices by applying IoT technology. The system implementation is realized by software based, and defines the requirements for the implementation of the sensor device gateway. The gateway automatically detects the location, movement of the device and performs necessary functions. Finally verifies the automatic detection performance of the gateway according to the location of the device. It will contribute greatly to the development of the smart city and office.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.920-930
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• 2012

In this paper, we designed and built a wired temperature controller system which is based on ASIC for a wireless temperature controller system based on FPGA. FPGA devices and wireless controller systems are growing quickly especially for industrial systems for sensing temperature and humidity. FPGA can set up a desired system and a CPU, and directly set up or change a peripheral device based on an IP quickly for an affordable price. This wireless system is easy to install in the field where there are lots of changes and the system is complex. It also has advantages for maintenance. In this study, we are using a 32 bit RISC CPU based on MicroBlaze, with a touch interface, peripheral device, and porting the embedded Linux. Also, we added wireless communication using ZigBee. With this system we provide remote monitoring and control through the web by adding a web server. Compared to the original system, we say not only a performance improvement, but also more efficient development and cheaper costs. In this study, we focused especially on building a better development environment and a more effective user interface.

• The KIPS Transactions:PartB
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• v.10B no.4
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• pp.411-418
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• 2003

The proposed system in this paper uses a camera attached to a mobile device in order to inquire a car and track its location anywhere. To do this, the system recognizes and verifies license plates on the front and back of a cu. The plates are scanned by the camera attached to a mobile device. The technology enables us to detect a car registration number and to transmit the number along with the location of the device to a server through a wireless communication network. The information of a car obtained through the terminal is encoded and transmitted to a server in a remote place through a wireless communication network also. The car registration number and its location information are decoded and transmitted as a text to the server in a remote place. In order to track a user´s location through spatial relative distance estimated in real-time, the server uses the spatial and attribute information which are the most prior to the desired data value. With this property information, the right location can be calculated.

• The Journal of the Korea Contents Association
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• v.6 no.12
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• pp.169-176
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• 2006

Since home network system is usually set up based on the built-in system inside home at the time of construction, it has a difficulty in being compatible with new devices after construction. In this paper, we propose DBS(Dynamic Binding System) that can make links effectively among the devices located in inside and outside of home networks. Implementation of the DBS is based on the ZigBee's binding in WPAN(Wireless Personal Area Network). For this research, we constructed the system consisting of home server that contains proxy server and location server, devices inside home in which tinyOS is embedded, and mobile device that is an emulator. The communication inside home is done by IEEE 802.15.4 protocol and the communication between servers and mobile devices outside home is done by TCP/IP protocol. Regardless of device's address format, the DBS facilitates a link among the devices located inside and outside of home networks. And, introducing a new device into home network can be recognized easily by exchanging messages between devices.

• Journal of Korea Multimedia Society
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• v.10 no.5
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• pp.612-622
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• 2007

As compared with wired network environment, mobile VOD service in wireless network environment is difficult to guarantee the quality of VOD service due to the limitation of the system resources. Moreover, the wireless network has small bandwidth resources and short access range so that has limitations for providing the service to a large number of mobile clients. The limited battery capacity of a mobile device becomes an obstacle to mobile clients for enjoying VOD service for a long time. Therefore, these drawbacks should be considered in developing mobile VOD applications. This paper proposes a new technique for improving QoS of mobile VOD service by jointly use of broadcasting technique, which can provide VOD service to a large number of mobile clients simultaneously, and bursty communication technique, which can reduce the power consumption of a mobile device. With having these two techniques, streaming data are divided into segments, each of which is grouped into a particular packet and then transmitted at a time in the busty communication manner. In the performance evaluation, the power consumption on WNIC of a mobile device can be reduced by over 80%, and the initial service delay can be reduced in proportion to the number of channels compared with the existing staggered broadcasting technique.