• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.766-777
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• 2021

This paper presents an improved scheme for detection of the physical broadcast channel (PBCH) in long-term evolution (LTE)-based fifth-generation (5G) multimedia broadcast and multicast services (MBMS) and 5G new radio (NR) for cellular broadcast. In the time domain, by combining the correlations between the received signal and primary synchronization signal (PSS) within all SS/PBCH blocks, the frame synchronization and the start position of the SS/PBCH blocks can be obtained. In this paper, to improve the detection performance of PBCH for 5G NR, a combining scheme of PBCH signals within a frame is proposed. In addition, the performance of the proposed detection scheme is evaluated and the performance is compared with the conventional scheme for PBCH detection of LTE-based 5G MBMS. The simulation results show that the detection performance of PBCH for 5G NR is improved by combining the PBCH signals and outperforms LTE-based 5G MBMS under the additive white Gaussian noise (AWGN), fixed, and mobile environments.

• Journal of the Korea Society of Computer and Information
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• v.17 no.10
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• pp.137-143
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• 2012

The learners using learning content through the smart devices can access to the Internet from anytime and anywhere. However, with the rapid increase of learning content on the Web, it will be time-consuming for learners to find contents they really want to and need to study. Therefore, e-learning systems should not only provide flexible content delivery, but support adaptive harmonizing fusion content. The harmonizing fusion content it is a very important in fusion e-learning service. The representative method to provide synchronization between fusion content is a provide absolute time value between of the contents. However, this method is occurs a problem transferring time delay. Also, to enter an absolute time value for the duration of the each content is several problems arise. In this paper introduces a new smart e-smart service support the harmonizing media based technology to create synchronized learning presentation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8C
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• pp.806-813
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• 2009

This paper presents a modem chip design for high-speed wireless communications. Among the high-speed communication technologies, we design the UWB (Ultra-Wideband) modem SoC (System-on-Chip) Chip based on a MB-OFDM scheme which uses wide frequency band and gives low frequency interference to other communication services. The baseband system of the modem SoC chip is designed according to the standard document published by WiMedia. The SoC chip consists of FFT/IFFT (Fast Fourier Transform/Inverse Fast Fourier Transform), transmitter, receiver, symbol synchronizer, frequency offset estimator, Viterbi decoder, and other receiving parts. The chip is designed using 90nm CMOS (Complementary Metal-Oxide-Semiconductor) procedure. The chip size is about 5mm x 5mm and was fab-out in July 20th, 2009.

• The Journal of Society for e-Business Studies
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• v.8 no.3
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• pp.165-176
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• 2003

Instead of existing cell phones, PDAs are observed as leading wireless Internet devices recently Numerous applications are developed by extended usage of PDAs and it should be installed appropriately according to devices. Furthermore, when battery is discharged, all data stored in RAM(Random Access Memory) becomes obsolete. So it should be recovered or reinstalled from flash memory, backup media or something. In this paper, we present an automatic application installation system(PAIS : PDA Automatic Installation System) to solve problems that users have to install applications by themselves whenever it is necessary. With this system, users feel comfortable by saving time and effort to install each applications and application development companies save cost needed to make materials illustrating installation process. Consequently PAIS may flourish wireless Internet business.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.31-34
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• 2008

양방향 중계 채널(two-way relay channel)은 2명의 사용자가 중계기(relay)의 도움을 받아 서로 정보를 주고받는 통신 채널이다. 중계기에서는 각각의 사용자로부터 독립적으로 수신한 두 데이터 패킷에 네트워크 코딩 기법을 적용하고, 이를 통해 만든 패킷을 두 사용자에게 동시에 전송한다. 따라서 양방향 중계 채널에서는 기존의 협력 통신에 비해 보다 효율적인 자원의 사용이 가능하다. 한편, 다중 중계기 환경에서의 중계기 선택 기반 전송 방식은 시스템의 전력 제한(power constraint), 전송 패킷의 동기화(synchronization) 문제 등을 고려할 때 다중 중계기 기반 전송 방식보다 우수한 성능을 얻을 수 있다. 본 논문에서는 양방향 다중 중계기 채널에서 중계기 선택 기법을 제안한다. 양방향 중계 채널에서는 수신한 두 신호의 결합을 위해 중계기에서 네트워크 코딩 기법을 적용함으로써 중계기의 부담이 보다 증가하는 특징이 있다. 또한, 중계기는 신호 전송 시 두 사용자 모두에게 전송하게 되고 이로 인해 두 수신지와의 채널 조건을 모두 고려하여야 한다. 따라서 중계기 선택은 데이터 패킷의 전송이 시작되기 전에 분산된 방식(distributed method)으로 이루어지며, 각각의 사용자와 중계기 간 일시적(instantaneous) 채널 이득을 바탕으로 사용자-사용자 간(end-to-end) 경로 조건의 최대값을 계산하는 메트릭(metric)을 중계기 선택 기준으로 사용한다. 모의실험을 통해 제안된 중계기 선택 기법이 중계기의 개수에 해당하는 다이버시티 이득을 얻을수 있음을 보여준다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.457-462
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• 2006

In UMTS (Universal Mobile Telecommunication System), a protocol called UMTS AKA is used to authenticate MSs (Mobile Stations). When an MS is in a foreign network, the serving network contacts the AuC (Authentication Center) located at the home network of the MS to authenticate it. To reduce this cost, AuC sends n AVs(Authentication Vectors) to the serving network. Although the use of AVs allows the serving network to authenticate an MS without contacting the AuC each time, there are also shortcomings such as synchronization problem. Subsequently, a set of protocols adopting the same or similar method have been proposed. In this paper, we analyze and compare authentication protocols for UMTS with respect to the use of AVs and its alternatives. We conclude that using Kerberos-like ticket key overcomes some of the drawbacks of using AVs, whereas AVs provide much better security.

• Journal of Broadcast Engineering
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• v.4 no.2
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• pp.176-186
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• 1999

In order to produce an image that lends realism to audience in the virtual studio system. it is important to synchronize precisely between foreground objects and background image provided by computer graphics. In this paper, we propose a method of camera parameter extraction for the synchronization by tracking the pose of TV camera. We derive an equation for extracting camera parameters from inverse perspective equations for tracking the pose of the camera and 3-D transformation between base coordinates and estimated coordinates. We show the validity of the proposed method in terms of the accuracy ratio between the parameters computed from the equation and the real parameters that applied to a TV camera.

• Journal of Broadcast Engineering
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• v.7 no.1
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• pp.28-36
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• 2002

In this paper. we propose an interactive broadcasting system based on MPEG-4 to provide Interactive services in digital TV broadcast. The proposed system is designed to support various functionalities such as authoringof MPEG-4. encapsulation of MPEG-4 Into MPEG-2 TS (Transport Stream) protocol, synchronization of MPEG-4 with MPEG-2 program. demultiplexing of MPEG-4 from MPEG-2 TS. decoding/rendering of MPEG-4 and interactivity through IP network on ATSC (Advanced Television Systems Committee) platform. The interactive broadcasting system based on MPEG-4 Is used to provide interactive functionality In full for user. and it has a particular advantage of substitution for the ATSC or DVB platform. as well.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.4
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• pp.1076-1089
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• 2012

Home automation networks are good environments for merging sensor networks and consumer electronics technologies. It is very important to reduce the energy consumption of each sensor node because sensor nodes operate with limited power based on a battery that cannot be easily replaced. One of the primary mechanisms for achieving low energy operation in energy-constrained wireless sensor networks is the duty-cycle operation, but this operation has several problems. For example, unnecessary energy consumption occurs during synchronization between transmission schedules and sleep schedules. In addition, a low duty-cycle usually causes more performance degradation, if the network becomes congested. Therefore, an appropriate control scheme is required to solve these problems. In this paper, we propose UDC (Unsynchronized Duty-cycle Control), which prevents energy waste caused by unnecessary preamble transmission and avoids congestion using duty-cycle adjustment. In addition, the scheme adjusts the starting point of the duty-cycle in order to reduce sleep delay. Our simulation results show that UDC improves the reliability and energy efficiency while reducing the end-to-end delay of the unsynchronized duty-cycled MAC (Media Access Control) protocol in sensor-based home automation networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1640-1645
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• 2010

There exists an inconvenience that players of each instrument pass musical score in orchestra recital. In this paper, we implement the electronic musical score transmitting system that possible to hand sheet music automatically, using Mini - ITX and LCD Panel. We made them unite with a sheet music pair, and it was made and a message and data transmission were embodied using reliable TCP/IP socket communication. In this paper, the client hands sheet music automatic, and server implemented the manual function to manage each clients individually. Because one band can be managed by one Access file all together, it is easy to manage each band. Along with this, this system selects TCP/IP as the reliable transfer protocol that protect loss and errors.