• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.75-81
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• 2012

RFID is new recognition technology which can trace IC chip(built in information) with wireless frequency. The present RFID is used in parcel service, missing child potection system, bus card, and extensive areas. This paper proposes and designs a belongings position tracking system using RFID with GPS. The main features of the proposed system are as follows. First, the system can in real time track the lost belongings. Second, the system can provide lost belonging location information to the users. The performance evaluation of the proposed system is performed by using AVD(Android Virture Device).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5253-5270
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• 2016

With device-to-device (D2D) communications, an inactive user terminal can be utilized as a relay node to support multi-hop communication so that connective experience of the cell-edge user as well as the capacity of the whole system can be significantly improved. In this paper, we investigate the spectrum sharing for a cooperative relay assisted D2D communication underlying a cellular network. We formulate a joint relay selection and channel assignment problem to maximize the throughput of the system while guaranteeing the quality of service (QoS) requirements of cellular users (CUs) and D2D users (DUs). By exploiting coalition formation game theory, we propose two algorithms to solve the problem. The first algorithm is designed based on merge and split rules while the second one is developed based on single user's movement. Both of them are proved to be stable and convergent. Simulation results are presented to show the effectiveness of the proposed algorithms.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.126-127
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• 2013

In industry, Supervisory Control and Data Acquisition (SCADA) system plays critical role to ensure production is monitored and controlled rigorously and in timely manner. Having a cost saving yet still effective SCADA system would be much desired by Industry. SCADA itself is a field with constant development and research like how this paper investigates on creating an extremely low cost device, which can be adapted to many different SCADA applications through some very basic programming when combined with relevant peripherals. Much of the process in some expensive SCADA application based on smartphone application is due to specialized communication infrastructure. This paper addresses the needs by developing low cost and integrated wireless SCADA system. The system features capability on accessing the performance of remotely situated device parameter, such as temperature, control analog or digital input output on real time basis. We use existing mobile network capability through Bluetooth communication channel.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1287-1292
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• 2018

In case of fire, the information related with the fire need to be provided to fire fighters in order to extinguish the fire efficiently. However, existing fire detection systems have the problem not to provide the data of the fire to fire fighters visually. In this paper, we propose the fire spot system using a cloud server to solve this problem. In the proposed system, the sensors installed in a building collect the gas and temperature data and store them into the cloud database using a wireless network. For fire fighters in the field, the details and history of the fire spot are displayed visually on top of the blue print retrieved from the cloud database using a smart device.

• Journal of Korea Game Society
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• v.15 no.5
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• pp.119-130
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• 2015

In the recent gaming industry, the paradigm has been changed with upcoming core-platform as time goes by. Arcade, console, PC online and smart device platforms are representative ones. In recently, the platform is changed to multi-platform which connecting to smart device and other platforms. Besides, the multi-platform without PC is up-coming. This paper suggests that a kind of multi-platform which connecting from smart devices to arcade devices be aware of lack of continuous. It provides a new arcade gaming condition connecting to smart devices, then supplies online network conditions to the arcade gaming machine. The original arcade game was lack of continuous and the game platform was so simple, but now, it could be focused from players by connecting to smart devices to increase the gaming machines' continuity. Furthermore, Bluetooth communication module and wireless Wi-Fi communication module are used to adapt various communication environments. The Unity3D engine would make contents' expandability.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.83-90
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• 2009

White LEDs(Light Emitting Diode) offer advantageous properties such as high brightness, improved reliability, lower power consumption, and long lifetimes. An LED is an electronic device that converts an electrical signal into a tight signal and is used not only in Optical Communication Indoor wireless optical illuminating rooms, but also for wireless optical communication systems. Currently, studies about these white LEDs have been being progressed, and in this raper, we discuss the multiplex and the multiple access method of VLC(Visible Light Communication) systems using white LEDs. In proposed system, CDMA(Code Division Multiple Access) apples to VLC system to reduce interference of VLC system, and improve capacity. The superiority of OOK modulation is presented in analysis of results by comparing VLC-CDMA communication system using OOK(On-off keying) modulation and BPSK modulation in AWGN(Additive White Gaussian Noise) channel and Diffuse channel. And we investigate the significance of a solution of interference by multipath by comparing BER in multipath channel and AWGN channel. In the proposed system, we assume Directed LOS(Line Of Sight) and Diffuse Link, and suppose VLC-CDMA using OOC(Optical Orthogonal Code) as methods to increase efficiency of system by removing ISI(Inter Symbol Interference) caused by multiple access, optical spreading code, and also present an analysis of its performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.356-359
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• 2017

According to the plan of operation of the Ministry of Education, IWB (Interactive White Board) was distributed to one or two classrooms per school. Therefore, instead of the overhead projector (OHP) and the screen, the visual presenter and the IWB replaced the role. However, the development speed of the imaging device and the display device could not keep up, and the utilization was often lowered. In this study, we study to obtain a high resolution image using the camera of smartphone. It uses WiGig(Wireless Gigabit) technology to transmit the acquired high-resolution images to IWB or large-screen TV without delay in wireless communication. In addition, while the smartphone camera is equipped with a lens of a wide field of view(FOV), the microscope lens can be used to magnify and magnify a specific portion of a smartphone 400 times. As s result of this study it will be used as active material for real-time 400 times magnification in education and research field.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1641-1647
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• 2018

In this paper, we describe a portable potentiostat which is capable of cyclic voltammetry(CV) and amperometry for electrochemical dissolved oxygen sensor. In addition, this portable potentiostat can also transmit the measured data wirelessly to android devices such as smart phone, tablet, etc. through Bluetooth. The potentiostat system consists of three parts; a voltage generator circuit which is controlled by Arduino nano and 12-bit DAC(digital to analog converter) to generate necessary electric potential for operating the electrochemical sensor, an oxidation/reduction current measurement circuit, and a Bluetooth module to transmit data wirelessly to an android device. Once measurements are carried out with the android application, the measured data is transmitted to the android device via Bluetooth and displayed using the android app. in real time. In this paper, we report the measured reduction current with a fabricated dissolved oxygen sensor in both saturated-oxygen state and zero-oxygen states. The results of the developed portable potentiostat system are in good agreement with those of the commercial portable potentiostat (${\mu}stat200$, Dropsens inc.). The measured peak reduction currents using the developed potentiostat and the commercial ${\mu}stat200$ potentiostat were $-0.755{\mu}A$ and $-0.724{\mu}A$, respectively. The reduction currents measured at zero-oxygen state were $-0.005{\mu}A$ and $-0.004{\mu}A$. The discrepancy between those two systems seems very small, which implies successful development of a portable and wireless potentionstat.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1464-1474
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• 2012

In this paper, we propose a QoS (Quality of Service)-aware and cooperative resource reservation scheme using cross-layer link adaptation for wireless high definition video transmission through UWB (Ultra Wide Band) network with D-MAC (Distributed Medium Access Control). A wireless high definition video transmission system usually requires stable high throughput even without line-of-sight, e.g., a destination device in another room separated by a wall. Since the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme causes lots of DRP resource reservation conflicts due to failure of beacon detection in wireless channel environment, overall performances of the WiMedia D-MAC can be deteriorated. And the current WiMedia MAC standard has not considered QoS provisioning even though QoS parameters such as a range of service rates are provided to each traffic stream. Therefore, we propose Relay DRP protocol with QoS-based relay node selection criterion, which makes a relay path to avoid DRP resource reservation conflicts and guarantee QoS more stably through cross-layer link adaptation of cooperative relay transmission scheme and is compliant with the current WiMedia D-MAC protocol. Simulation results demonstrate performance improvements of the proposed method for throughput and QoS provisioning.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.25-31
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• 2015

Smart healthcare environments which merge medical and IT technology are getting ready for the third generation centering EHR from current second generation. As a basic technology for the introduction and activation of EHR systems it requires heterogeneous network interworking techniques between various wired and wireless medical devices. Interworking technology for heterogeneous network among various medical devices is needed to introduce EHR system. The heterogeneous network interworking technology is needed for construction of a reliable data system to convert each of unstructured data into structured data. Therefore, in this paper, we identify the domestic and international trends of smart medical field and analyze the characteristics of wired and wireless communication technology that is used in a heterogeneous network. and also suggest requirements needed for interworking technology and provide interworking technology based on them. we expect that proposed method which is designed for smart healthcare environments would provide a basic architecture needed for third smart medical technology generation.