• 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 Industrial Technology
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• v.20 no.B
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• pp.227-232
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• 2000

ISDN AO/DI provides efficient communication. It dynamically allocates channels for bandwidth, which is key component for packet data communication. In this paper, we analyze performance improvement of ISDN AO/DI system with buffering scheme and compare with AO/DI system without buffering scheme. From the simulation of AO/DI with buffering scheme, we see that the required bandwidth is less than of the AO/DI system without buffering scheme.

• Journal of electromagnetic engineering and science
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• v.3 no.1
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• pp.50-56
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• 2003

This paper proposes a coding scheme of control channel for mobile packet communication to maximize the minimum Hamming distance, which is based on shifting of basis vectors of Reed Muller code with optimized dynamic puncturing and/or(partial) sequence repetition. Since the maximum likelihood decoding can be performed using the extremely simple FHT(Fast Hadamard Transformation), it is suitable for real time optimum decoding of control channel information with very little complexity. We show applications of the proposed coding method to TFCI(Transport Format Combination Indicator) code in split and normal modes of 3GPP W-CDMA system. We also discuss how this method can reduce rate indication error over AWGN(Additive White Gaussian Noise) as well as fading channels when the proposed coding scheme is applied to 1xEV-DV system of $3^{rd}$TEX> generation partnership project 2(3GPP2) to indicate the data rate transmitted on the reverse traffic channel by a Mobile Station(MS).

• Journal of IKEEE
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• v.13 no.3
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• pp.87-94
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• 2009

TETRA(TErrestrial Trunked RAdio) is the wireless communication system generally adopted to public network and backbone network, as the technology of Trunked Radio System specified by ETSI(European Telecommunications Standards Institute) and currently adopted to the Electric Power IT Backbone Network in Korea. IEC 61850 is the protocol proposed for SAS(Substation Automation System) of SCADA(Supervisory Control And Data Acquisition) system. In this paper, IEC 61850 Server and Client simulator are used based on Linux operating system. The multi-functional gateway, which transforms the communication based on TCP/IP between IEC 61850 Server Simulator and Client Simulator to the one based on TETRA Packet Data Service, is developed such that IEC 61850 SCADA system is constructed based on TETRA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.652-663
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• 1996

In this paper, we analyze the blocking probability of a call in a PC communication network. In a PC communication network, a call generated from the PSTN (public switched telephone network) requests the connection to the ICPS(information communication processing system) which interconnects the the PSTN and the PSDN(packet switched data network). Then, as a second step, a packet call is requested to the specific service database attached in the PSDN. The call blocking probabilies are analyzed for these two interface points, the PSTN interface ports of the ICPS and the PSDN interface link of the database. We also present some numerical results to show the effects of the system parameters on the performance of the network. The results show the effects of the capacity of each interface point on the performance point.

• IE interfaces
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• v.4 no.1
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• pp.63-69
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• 1991

In this paper, the Go-Back-N ARQ protocol with decoding in communication network is considered. The time delay and throughput are respectively analyzed as a function of window size and decoding time out. Packets arrive continuously at the decoder, and are stored in a buffer if the decoder is busy upon its arrival. The decoder devotes no more than a time-out period of predetermined length to the decoding of any single packet. If packet decoding is completed within that period, the packet leaves the system. Otherwise, it is retransimitted and its decoding starts anew. The time delay and throughput are obtained using recursive formula and difference equation. An appropriate time out and window size that satisfies the grade of service can be determined.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.43-46
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• 2006

IEEE 802.16 WirelessMAN aiming to broadband wireless access (BWA) is evolving to 4G mobile communication system through the standardization of IEEE 802.16e supporting mobility on existing fixed WirelessMAN system. It is necessary for hand-over to provide seamless data service while MS (Mobile Station) moves to another BS (Base Station). Because the performance of handover affects packet loss or delay of any communications, it must consider low latency handover mechanism in packet based network. In this paper, we describes handover scheme of IEEE 802.16e with the cell edge interference problem and shows the way to solve the problem in frequency reuse one deployment. Our scheme reduces the handover latency and packet loss probability.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.509-512
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• 2002

We propose a control method for mobile robot system using the bluetooth. The control packet is defined and used for control of the mobile robot. The control packet is composed of behavior components and has reserved packets for future working. The control packet has to be simple and provide commands to the mobile robot, since the bluetooth has a limited bandwidth. The data transmission rate and the distance, which can control the mobile robot in various circumstances, for example, corridor, yard, and room are measured by some experiments.

• Journal of Communications and Networks
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• v.14 no.2
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• pp.140-150
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• 2012

In this paper, we investigate the optimal packet scheduling problem in a two-user multiple access communication system, where the transmitters are able to harvest energy from the nature. Under a deterministic system setting, we assume that the energy harvesting times and harvested energy amounts are known before the transmission starts. For the packet arrivals, we assume that packets have already arrived and are ready to be transmitted at the transmitter before the transmission starts. Our goal is to minimize the time by which all packets from both users are delivered to the destination through controlling the transmission powers and transmission rates of both users. We first develop a generalized iterative backward waterfilling algorithm to characterize the maximum departure region of the transmitters for any given deadline T. Then, based on the sequence of maximum departure regions at energy arrival instants, we decompose the transmission completion time minimization problem into convex optimization problems and solve the overall problem efficiently.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.552-557
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• 2017

Wire, wireless digital broadcasting has sharply expanded with the birth of high definition TV since 2010, the use of duplex contents as well as simplex contents has rapidly increased. Currently, our satellite communications system adopted DVB by European digital broadcasting standardization organization as a standard of domestic data broadcasting, the method how to use selective contents has been studied variously according to the development of IPTV. Digital broadcasting utilizes the method using Transport Stream Packet(TSP) by the way of multiplexing of information in order to send multimedia information such as video, audio and data of MPEG-2, this streams include detail information on TV guide and program as well as video and audio information. In order to understand these data broadcasting system, this study realized TS analyzer that divides transport stream (TS) by packet in Linux environment, analyzes and prints by function, it can help the understanding of TS, the enhancement of stream parsing ability.