• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.233-240
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• 2017

Due to a recent rise in use of a wireless keyboard and mouse, attacks which take user's input information or control user's computer remotely exploiting the physical vulnerability in the wireless communication have been reported. Especially, MouseJack, announced by Bastille Network, attacks 2.4 GHz wireless keyboards and mice through exploiting vulnerability of each manufacturer's receiver. Unlike other attacks that have been revealed, this allows to attack AES wireless keyboards. Nonetheless, there is only a brief overview of the attack but no detailed information on this attacking method. Therefore, in this paper we will analyze the Microsoft 2.4 GHz wireless mouse packet and propose a way to set the packet configuration for HID packet injection simulating a wireless mouse. We also develop a system with 2.4 GHz AES wireless keyboard HID packet injection using the proposed packet and demonstrate via experiment that HID packet injection is possible through the system we built.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.41-50
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• 2008

In this study, an improved scheme for distance-based registration (DBR) is proposed and its performance is analyzed. In the DBR, when a mobile station (MS) enters a new cell, it calculates the distance between last registered cell and current cell and registers its location if the distance reaches reference distance D. In this study, two-location DBR (TDBR) is proposed to improve the performance of the DBR. In the TDBR, an MS stores not only last registered location area (LA) but also previously registered LA, and then no registration is needed when the MS crosses two LAs stored already. However, since the TDBR may increase paging cost, trade-off is necessary between decreased registration cost and increased paging cost. In this study, the performances of two schemes are analyzed and compared using 2-dimensional random walk mobility model in hexagonal cell configuration. We show that our mathematical analysis is accurate by comparing with simulation. From the numerical results for various circumstances, it is shown that our proposed TDBR outperforms current DBR in most cases.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.481-488
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• 2016

This study is about comparing the mobile user experience of Facebook and Instagram which are most often used among the recent SNSs by the people in their 30s and under. This study analyzed the user experience level after dividing the user experience factors through the Creating Pleasurable Interfaces model, and suggested the mean analysis as well as the result of Wilcoxon rank test which is a nonparametric statistics method. As a result of study, the Display information visually factor in functional factor and the configuration of the main page in convenient factor were a statistically significant difference in the mobile user experience of Facebook and Instagram. It is expected that this study may help seeking the user experience factors to be promoted preferentially in a competitive situation through the statistical comparative evaluation of the experience of two SNS users.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1055-1057
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• 2013

Routers currently used in homes and institutions have a function of multiple computers to connect to the Internet with a single IP address. It is possible only through setting or establishing a separate operation in a used PC or server to function as a web/printer server, web hard, and P2P. In this paper, by utilizing the OpenWRT Linux-based through the construction of the Web server through a router OpenWRT of (Open Wireless Router) base, to build a server simple compact, low power consumption, low cost, to operate by reliability to provide Internet telephony and multimedia services high securely over the server security, which is based on the setting of policy and various firewall at the same time the configuration of the network utilizing OpenWRT router that can be enhanced, to construct a Web server through a router multi functional can receive the provision of services using the program PC and mobile APP.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.611-620
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• 2011

A planar monopole antenna that was developed for WLAN/WiMAX application is presented in this paper. The proposed antenna with three strips, an asymmetrical ground plane, and a rectangular slit in the ground is designed to cover the popular frequency spectrum of WLAN (wireless local area network) bands and WiMAX (Worldwide Interoperability for Microwave Access) bands. The proposed antenna, which is capable of wideband operation, is fed by a strip line and fabricated on an FR-4 substrate. The obtained numerical results agree well with the experiment data. It was validated that the configuration can meet the demands for the WLAN/WiMAX systems and effectively enhanced the impedance bandwidth to 9.95% for the lower band and 76.05% for the upper band for VSWR < 1 : 2. This paper also presents and discusses the 2D radiation patterns and 3D gains according to the results of the experiment.

• Journal of electromagnetic engineering and science
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• v.11 no.4
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• pp.282-289
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• 2011

GHz electromagnetic interference (EMI) characteristics are analyzed for a 3dimensional (3D) stacked chip power distribution network (PDN) with through silicon via (TSV) connections. The EMI problem is mostly raised by P/G (power/ground) noise due to high switching current magnitudes and high PDN impedances. The 3D stacked chip PDN is decomposed into P/G TSVs and vertically stacked capacitive chip PDNs. The TSV inductances combine with the chip PDN capacitances produce resonances and increase the PDN impedance level in the GHz frequency range. These effects depend on stacking configurations and P/G TSV designs and are analyzed using the P/G TSV model and chip PDN model. When a small size chip PDN and a large size chip PDN are stacked, the small one's impedance is more seriously affected by TSV effects and shows higher levels. As a P/G TSV location is moved to a corner of the chip PDNs, larger PDN impedances appear. When P/G TSV numbers are enlarged, the TSV effects push the resonances to a higher frequency range. As a small size chip PDN is located closer to the center of a large size chip PDN, the TSV effects are enhanced.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.336-342
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• 2007

Industrial HMI(Human Machine Interface) system is the main element among the factory automation processes and have been used to monitor and control operation and status of machine in factory with PLC. This HMI often brings heavy loads to the system development and difficult decreasing the system because it tends to use a specific system per each manufacturer. Therefore, in this thesis, we have developed an embedded linux-based embedded industrial HMI software modules which can be used for touch panel embedded system to solve these problem. In this module, we have used the Qt/Embedded software component because it can be used by all systems which support C++ compiler without modifying the existing codes. We can design more flexible system and network configuration because we have used the wireless communication module. In this thesis, we implement linux-based HMI software modules which are capable of wireless communication as well as bringing the mobility to the overall system and finally decreasing the system development loads by using the general purpose OS with competitive price.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1588-1596
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• 2004

Recently, many WMS(Web Mapping Services) and POI(Point of Interest) service on to be in service on the Internet using Web CIS(Geographic Information System) as information Technology and computer HW are evolved faster in its speed, network bandwidth and features. The Web GIS is, however, limited and constrained on the specification of its system configuration, the service class provided and the presentation methodology of a map. As the mobile Internet becomes popular in mobile service, Web GIS service on mobile environment is strongly required and to be provided by LBS(Location Based Service) on a mobile client such as PDA with location information of the user. In this paper, we made an effort to design and implement a GIS computing environment by thin client for mobile web mapping service. For implementing the thin client GIS computing environment, we were using NGII's(National Geographic Information Institute's) DXF map, representing the map by SVG(Scalable Vector Graphics) recommended by OGC(OpenGis Consortium), and adapting standard XML web service to provide the thin client GIS service on PDA by applying the location information of the user in realtime with GPS on mobile environment.

• The Transactions of the Korea Information Processing Society
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• v.4 no.3
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• pp.811-820
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• 1997

Disk arrays are using to enhance data trandfer rate and I/O performance in multimedia applications which need a high-performance storage device with large storage capacity and high-speed network.As performance varies with configuration and data layout scheme,disk array characteristic variables must be approrpriately deter-mined in desibning disk array archetecture for a speciffic applicatoin. In this paper,in order to design a disk array architecturte as a storage server of a small-scale VOD system,we evaluate performance of a disk array to chose the number of disks in the array,disk array cinfiguration,a degree of declustering for a given data block size of continous media file system and I/D request size through simulation.Simulation result shows that RAID level 5 with 5 disks ios a suitable candidate for the disk array architecture which privides MPEG-2 files with a rate of 6 Mbps,Moreover,we whow that stripe unit is 64 KB and a layout scheme is contigous placement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4B
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• pp.200-207
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• 2007

Many P2P systems which are designed to implement large-scale data sharing have been introduced in internet recently. They exhibit interesting features like sell-configuration, sell-healing and complete decentralization, which make them appealing for deployment in ad hoc environments as well. This paper proposes an Gnutella-based P2P system that can operate efficiently in ad hoc networks. The objectives of this paper are to extend the overall system lifetime, to reduce overheads, and to provide enhanced performance. The proposed system uses an ultrapeer election scheme based on metric values and proactive distribution of ultrapeer information. According to the simulation results, the proposed system can provide better performance than Gnutella in terms of query success rate, query response time, overhead and residual battery power by utilizing network resources efficiently.