• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.7
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• pp.372-379
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• 2014

When a hand-held device with limited battery transmits and receives data using short-range wireless communication systems, such as WLAN(Wireless Local Area Network) or high speed WPAN(Wireless Personal Area Network), instead of mobile communication systems, the device is able to reduce the power consumption due to the reduced transmission distance. However, if there are many WLAN or high speed WPAN systems around the device, non-negligible power may be consumed by receiving and decoding the packets which have nothing to do with the device. In this paper, we propose a scheme reducing the power consumption by including physical-layer ID in WLAN or WPAN packets and avoiding unnecessary packet receptions. Also, we describe a method to determine the optimum number of physical-layer IDs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.83-88
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• 2016

We treat device-to-device direct communication (D2D) by reusing cellular uplink resources in LTE-Advanced systems. Conventional schemes assume that D2D transmitter employs SC-FDMA scheme for the date transmission. In the conventional schemes, however, it is very difficult to reduce the interference between the users, D2D communication cannot be used when the interference caused by cellular uplink signal is high. In this paper, we propose D2D transmission scheme which employes MC-CDMA technology and D2D detection scheme which uses MMSE algorithm to reduce interference from the cellular uplink signal. Therefore, in the proposed scheme the D2D communication becomes possible even in the high interference scenario. Through simulation, we show that the proposed scheme has better BER performance than the conventional scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.1
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• pp.91-107
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• 2014

Device-to-device (D2D) communication is an excellent technology to improve the system capacity by sharing the spectrum resources of cellular networks. Multicast service is considered as an effective transmission mode for the future mobile social contact services. Therefore, multicast based on D2D technology can exactly improve the spectrum resource efficiency. How to apply D2D technology to support multicast service is a new issue. In this paper, a resource allocation scheme based on cognitive radio (CR) for D2D underlay multicast communication (CR-DUM) is proposed to improve system performance. In the cognitive cellular system, the D2D users as secondary users employing multicast service form a group and reuse the cellular resources to accomplish a multicast transmission. The proposed scheme includes two steps. First, a channel allocation rule aiming to reduce the interference from cellular networks to receivers in D2D multicast group is proposed. Next, to maximize the total system throughput under the condition of interference and noise impairment, we formulate an optimal transmission power allocation jointly for the cellular and D2D multicast communications. Based on the channel allocation, optimal power solution is in a closed form and achieved by searching from a finite set and the interference between cellular and D2D multicast communication is coordinated. The simulation results show that the proposed method can not only ensure the quality of services (QoS), but also improve the system throughput.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.129-135
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• 2016

There are many visual enhancement devices for people with low vision. However, almost conventional devices have been simple magnifying and high cost. The symptoms of people with low vision are very variety. It needs to control of image magnifying, brightness, and contrast to improve the visuality. We developed a portable microdisplay driver and device for visual enhancement. This device based on our suggested four methods such as image magnifying, specific color control, BLU brightness control, and visual axis control using a prism. The basic clinical experiments of the proposed Head Mounted Visual Enhancement Device (HMVED) have been performed. The results show beneficiary effects compared with conventional devices, and improve the life quality on people with low vision on account of low weight, low cost, and easy portability.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.2
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• pp.271-284
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• 2021

This study presents the educational utility of blended learning by analyzing the effectiveness of learning after class by blending team project learning and smart device app-based learning methods. Qualitative analysis and survey analysis were conducted and the results were as follows. First, team project activities based on task resolution were conducted freely through detailed activities such as sharing roles, planning meetings, and coordinating opinions. Team activities were carried out with respect and consideration, team member bonding, and a sense of responsibility. Second, the smart device app is recognized as a medium for work and communication, and fast feedback has been made, making it highly impactful on classroom activities. Third, in terms of learning satisfaction, most learners showed an interest in the course and were satisfied with the project results. The smart device app was used as a learning and communication medium for personal and team activities and was analyzed as a blended method applicable to classes that conduct practical activities as an efficient tool to further activate project activities.

• International journal of advanced smart convergence
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• v.6 no.2
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• pp.82-88
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• 2017

The data generated by the BSN sensor attached to the human body is mostly mobile. Accordingly, in a mobile cloud environment that processes BSN data, the service should not be fixed in a specific area but be able to support it according to the move. The mobile device must be able to process, filter and transmit the collected BSN data. The cloud server must be able to collect the data processed by the mobile device and provide it as a service. And the transfer of data requires standardized transfer between each device. In this paper, we propose a data delivery method through standard schema when mobile device processes data and provides service in cloud system and a data processing method according to the movement of the mobile device.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1483-1490
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• 2003

In existent industry spot, device administrators should be ever-ready for monitor and control of devices. Thus, it is inefficient because there are much human strength waste and time loss. To solve these problem, we develop a real time device management system based on wire and wireless internet. If any device brutes down, this system senses breakdown automatically and notify it to device administrators via mobile phones. Then the administrator does emergency measures for breakdown device though wire and wireless internet. For the purpose, we develop each local device control system. device management system, mobile system, and web system.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1255-1261
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• 2010

An operating information and fault recode of train is very important information for safety driving and maintenance. And these information is increased and need high speed as the number of trains is increased. Wireless LAN or CDMA network is efficient to report more complicated and various information from vehicle to server in control center. Existing wireless transmission system has weakness due to transmission system is separated with TDCS and standalone. At first, standalone system needs space to be installed and cost is increased. And data transmission capacity and speed is limited by complicated structure that transmission system receive data thru serial communication like RS232 and then data transmission system send data to server in control center. This article is study to develop embedded & wireless fault code transmission device to be installed in TDCS to overcome weakness of space and to have more cost effective and simple structure. It is adapted 802.11b/g WiFi for wireless communication and OS is used embedded Linux that can easily implement wireless communication environment and ensure TCP/IP communication’s security. We also implement simple server to test wireless communication between embedded & wireless fault code transmission device and server in control center.

• Journal of electromagnetic engineering and science
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• v.15 no.3
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• pp.158-166
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• 2015

The early detection of breast cancer is very important. The final goal of this study is to develop an inexpensive portable device for simply detecting the existence of breast cancer using microwaves. In this study, we proposed a detection algorithm and the system configuration of such a device. The feasibility of the proposed method was investigated by numerical simulation and actual measurement. A prototype sensing module was fabricated, and the measurement results for tumor phantoms were presented. The measurement results showed that the prototype sensing module worked well, and the simulation results revealed that the detection rate of the device could be about 60% for a 4 mm tumor and almost 100% for a 6 mm tumor. The proposed device can be used for the self-diagnosis of breast cancer. Further study is required to reduce the size of the sensing module.

• International journal of advanced smart convergence
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• v.1 no.1
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• pp.38-42
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• 2012

Automobilist in South Korea in order to provide car driving information to the insurance company uses 'car driving information device'. They provide car driving information of device to insurers for their premium discount. Currently these devices are used in Korea has inconvenience that this device Installation and the process for send this information to insurance companies. In this paper, Korean smart car driving information system designed using Smart phone and local-range network as a basis the 'Certification Regulations of Driving Information Check Device' of the Korea Insurance Development Institute.