• Journal of Digital Convergence
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• v.12 no.1
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• pp.379-388
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• 2014

We noted that substituting hard disk with high-performance storage device on SAN did not immediately result in getting high performance. Investigating the reason behind this leaded us to propose optimization schemes for high-performance storage system. We first got rid of the latency in the I/O process which is unsuitable for the high-performance storage device, added parallelism on the storage server, and applied temporal merge to Superhigh speed network protocol for improving the performance with small random I/O. The proposed scheme was implemented on the SAN with high-performance storage device and we verified that there were about 30% reduction on the I/O delay latency and 200% improvement on the storage bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1100-1105
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• 2017

In this paper, we propose a power control technique for D2D communication in the heterogenous network consisting of cellular and D2D communication systems. Although the transmit signal of D2D communication degrades the performance of cellular system by interfering the signal reception at CU in the conventional heterogenous networks without eavesdroppers, it can be utilized as jamming signal for preventing other devices from recovering the transmitted information if there are eavesdroppers in the network. The proposed power control technique maximizes the achievable rate of D2D communication while ensuring the target security performance of cellular communication system. Through simulation results, we validate the analysis results and compare the performance with the conventional D2D communication scheme that utilizes its full transmit power for maximizing the achievable rate regardless of the performance of cellular system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.720-740
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• 2011

Wi-Fi-enabled portable devices have recently been introduced into the consumer electronics market. These devices download or upload content, from or to a host machine, such as a personal computer, a laptop, a home gateway, or a media server. This paper investigates the fairness among multiple Wi-Fi-enabled portable devices in a home network when they are simultaneously communicated with the host machine. First, we present that, a simple IEEE 802.11-based home network suffers from unfairness, and the fairness is exaggerated by the wireless link errors. This unfairness is due to the asymmetric response of the TCP to data-packet loss and to acknowledgment-packet loss, and the wireless link errors that occur in the proximity of any node; the errors affect other wireless devices through the interaction at the interface queue of the home gateway. We propose a QoS-provisioning framework in order to achieve per-device fairness and service differentiation. For this purpose, we introduce the medium access price, which denotes an aggregate value of network-wide traffic load, per-device link usage, and per-device link error rate. We implemented the proposed framework in the ns-2 simulator, and carried out a simulation study to evaluate its performance with respect to fairness, service differentiation, loss and delay. The simulation results indicate that the proposed method enforces the per-device fairness, regardless of the number of devices present and regardless of the level of wireless link errors; furthermore it achieves high link utilization with only a small amount of frame losses.

• 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 Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.295-307
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• 2002

The IEEE 1394 protocol is a de facto standard in multimedia digital home network. It supports several advanced features such as hot plugging, dynamic network reconfiguration, isochronous transmission and so on. Since the IEEE 1394 was adapted in the field of multimedia service with QoS guarantee, back bone network protocol with reel-time digital instrumentation and control sub networks, and physical layer protocol for real-time middleware such as real-time CORBA, the additional real-time features has been required in device driver implementation because of the necessity of the predictability enhancement. To guarantee the real-time features, the device driver of the IEEE 1394 should support the priority based packet processing and also need a isochronous buffer management mechanism to deal with the periodic isochronous communication. In this paper, we proposed a new software architecture of the IEEE 1394 device driver for supporting the real-time characteristics such as priority based packet processing, priority based scheduling and so on.

• Journal of Convergence Society for SMB
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• v.6 no.3
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• pp.29-35
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• 2016

This paper presents the design of a user authentication system (DCIAS) using the device constant information. Defined design a new password using the access device constant information to be used for user authentication during system access on the network, and design a new concept the user authentication system so that it can cope with the threat required from passive replay attacks to re-use the password obtained in other applications offer. In addition, by storing a password defined by the design of the encrypted random locations in the server and designed to neutralize the illegal access to the system through the network. Therefore proposed using the present system, even if access to the system through any of the network can not know whether any where the password is stored, and if all right even stored information is not easy to crack's encrypted to neutralize any replay attacks on the network to that has strong security features.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.540-542
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• 2014

The Universal Plug and Play (UPnP) specification permits networked devices to discover each other and to provide diverse services in the home network environment. Recently, new paradigms such as mobile connected computing, cloud-based service delivery, smart device content sharing, and Internet of Things (IoT) have emerged, but the home network based UPnP shows functional limitations in supporting such paradigms. To support them, the UPnP Forum has recently extended the capabilities of the existing UPnP, calling it UPnP+. In this paper, the UPnP Device Architecture V2.0 (UDA 2.0), which forms the basis of UPnP+, is presented. We present how UDA 2.0 enables the expansion of the home network to wide-area networks and non-IP device domains.

• Journal of Broadcast Engineering
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• v.27 no.6
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• pp.914-922
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• 2022

In this paper, we construct a commercial 4K UHD(Ultra High Definition) streaming device that utilizes a 5G mobile communication network as a transport channel and conduct a streaming performance test. It uses RTP(Realtime Transport Protocol) which has transmission quality monitoring capability as a transmission protocol to apply adaptive streaming. In addition, it provides the function to adjust the encoding rate of the video signal so that encoding can be optimized for the change in the bandwidth of the transmission channel. Through the performance test, it is confirmed that the H.265 encoding rate for 4K UHD signal is 48.69Mbps, the average glass-to-glass delay time is 293.60ms, and the average time difference between video and audio for lip sync is 120ms. With the result of performance test, it is shown that the streaming device is applied to 4K UHD Streaming device over 5G mobile communication network.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.129-136
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• 2012

Temperature of fresh concrete can be effectively used to predict the strength of concrete being cured and make an informed decision for stripping the molds. A hygrothermograph and thermo-couple sensors that require an extensive wiring have been applied to measure a temperature of concrete at the early stage of the curing process on site. However, these methods have limits to provide the temperature data in real time due to harsh working environment including frequent cutting of wires. Therefore, this study is aiming at developing a device based on wireless sensor network to measure the temperature of concrete being cured in formwork. The result showed that the wireless sensor with probe type thermistor which is developed had the same temperature data compared to the existed wire type thermistor, and we confirmed the temperature history of concrete in real time for 28 days throughout the gateway by wireless network that collects the temperature data measured from specimens in laboratory. Also, the network device for transmission can be easily separated from the probe sensor part and reused consistently. If the wireless sensor network device developed uses in the field, the temperature management of concrete will be systematically conducted from at the early stage of the curing, and especially be effective for cold weather concrete construction. In addition, it will contribute to the establishment of advanced quality control system for concrete and productivity of supervisors on site will be increased in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.745-748
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• 2006

With a home network, a device can dynamically join a home network, obtain an IP address, convey its capabilities, and learn about the presence and capabilities of other devices. Devices can subsequently communicate with each other directly. Device discovery protocol defines how network services can be discovered on the network. In this paper, we propose the secure discovery method of devices that uses mutual authentication with symmetric key between devices. This method that we present distributes symmetric-key to home network devices by the home server. Using this key, mutual authentication is performed between home appliances. It enables any appliance under any middleware's control to securely communicate any other appliances.