• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.226-231
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• 2014

Because of development of information communication and multimedia technology, the focus of M2M(Machine to Machine) intelligent network, multimedia collaboration environment, and transportation safety service is increased. This paper describes a multimedia replicated architecture based on Shepherd environment for transportation safety service. The relationship of information collection and utility is relationship of man to man, but is developed object to object by information communication and control system. This paper suggests a design of multimedia cyber collaboration environment based on M2M. This structure can make multimedia collaboration environment and fault tolerance, so on easily. Because M2M system does not affected to all system in spite of occurring to fault to a node or resource, it has a good condition for design of transportation safety service running on M2M.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.1-8
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• 1994

In this paper, a model of trellis-coded M-ary PSK (TCM/M-PSK) for digital land mobile communication is realized. Bit error rate(BER) of TCM/M-PSK is calculated theoretically in time selective fading environment due to Doppler spread in the presence of AWGN. cochannel interference. These analyses are employed the receiver with post detection diversity and the direct sequence to improve the BER performance of TCM-MPSK system. It is shown that the CNR required by the diversity reception and the direct sequece(process gain=20dB) TCM-4PSK system is reduced to about 25 dB.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.938-940
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• 2011

IT 기술의 발전으로 전 세계적으로 M2M시장이 급부상 하고 있는 가운데 언제 어디서나 이용할 수 있도록 정보통신기술을 토대로 제공되는 보건의료 서비스인 U-헬스케어 서비스에 대한 관심이 급증하고 있다. 그와 더불어 국내외 적으로 U-헬스케어 시장의 확산에도 불구하고 U-헬스케어 장치에 대한 보안 시스템의 구축은 아직 미흡한 편이다. 이에 본 논문에서는 U-헬스케어 서비스의 새로운 비즈니스 모델과 정보를 주고받는 네트워크상의 문제점과 해결방안을 제시하고자 한다.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.35-41
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• 2007

An alternative solution to the problem of obtaining acceptable performances on a fading channel is the diversity technique, which is widely used to combat the fading effects of time-variant channels. The symbol error probability of M-ary DPSK (MDPSK), PSK (MPSK) and QAM (MQAM) systems using 2 branches from the branch with the largest signal-to-noise ratio(SNR) at the output of L-branch selection combining(SC), i.e., SC2 in frequency-nonselective slow Nakagami fading channels with an additive white Gaussian noise(AWGN) is derived theoretically. These performance evaluations allow designers to determine M-ary modulation methods against Nakagami fading channels.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.272-281
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• 2013

This paper presents low power frequency shift keying (FSK) transmitter using all digital PLL (ADPLL) for smart utility network (SUN). In order to operate at low-power and to integrate a small die area, the ADPLL is adopted in transmitter. The phase noise of the ADPLL is improved by using a fine resolution time to digital converter (TDC) and digitally controlled oscillator (DCO). The FSK transmitter is implemented in $0.18{\mu}m$ 1-poly 6-metal CMOS technology. The die area of the transmitter including ADPLL is $3.5mm^2$. The power consumption of the ADPLL is 12.43 mW. And, the power consumptions of the transmitter are 35.36 mW and 65.57 mW when the output power levels are -1.6 dBm and +12 dBm, respectively. Both of them are supplied by 1.8 V voltage source. The frequency resolution of the TDC is 2.7 ps. The effective DCO frequency resolution with the differential MOS varactor and sigma-delta modulator is 2.5 Hz. The phase noise of the ADPLL output at 1.8 GHz is -121.17 dBc/Hz with a 1 MHz offset.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.1
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• pp.18-22
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• 2015

The relationship of information collection and utility is relationship of man to man, but is developed object to object by information communication and control system. This paper suggests a multimedia collaboration environment based on M2M(Machine to machine). We propose a study on reliability for application QoS in distributed multimedia. When it recovers, the characteristic of this system is to use the same method to get back again it as it creates a session.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.85-90
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• 2019

This paper related with the M-CMA adaptive equalization algorithm which is possible to improve the residual isi and robustness performance compare to the current MMA algorithm that is reduce the intersymbol interference occurs in channel when transmitting the QAM signal. The current MMA algorithm depend on the cost function and error function using fixed signal dispersion constant, but the M-CMA algorithm depend on the new proposed cost function and error function using multiple dispersion constant. By this, it is possible to having robustness of the CMA and simultaneous compensation of amplitude and phase of MMA. The computer simulation was performed in the same channel and noise environment for compare the proposed M-CMA and current MMA algorithm. The equalizer output signal constellation, residual isi, MD, MSE learning courves and SER, represents the robustness were used for performance index. As a result of simulation, the M-CMA has more superior to the MMA in robustness and other performance index.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.2
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• pp.115-123
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• 1987

It is known that conventional spread spectrum communication systems have a characteristics of non-synchronous multiple access. However, because the system has a interchannel interference, the number of channels that can communicate at the same time is small as compared with TDM. This paper presents a new synchronous sprea spectrum mulitple access communication system using a modified M sequence as a spread sequence. The system was constructed and through experiment we confirmed that a modified M sequence is superior to a M sequence in the area of interchannel interference, And we also confirmed that received waveforms are better with a increase of transmission bandwidth.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.53-62
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• 2020

In the end-user domain of an IoT environment, there are more and more intelligent M2M devices that provide resources to create and share application services. Therefore, it can be very useful to manage trust by transferring the role of the existing centralized service provider to end users in a P2P environment. However, in a decentralized M2M computing environment where end users independently provide or consume services, mutual trust building is the most important factor. This is because malicious users trying to build malfunctioning services can cause security problems in M2M computing environments such as IoT. In this paper, we provide an integrated analysis and approach for trust evaluation of M2M application services, and an optimized trust evaluation model that can guarantee reliability among users of the M2M community.

• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.242-253
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• 2022

When the source waveform is unknown, the Green's function can be estimated by Ray-based Blind Deconvolution (RBD) based on the simple array signal processing. In previous papers, RBD was successfully demonstrated using simulation and experiments in shallow water environment. In this paper, we investigate the applicability of RBD for a long-range communication (e.g., 30 km, 60 km, and 90 km) in a deep water environment (1,000 m ~), using experimental data conducted in the east of Pohang, South Korea, in October 2018. Data results are presented to demonstrate Green's function estimation of a communication signal (2.2 kHz ~ 2.9 kHz) using a 16-element, 42-m long vertical array. The results show that the Green's function estimated from RBD is comparable to that of matched filter result. Additional communication performance at a maximum range of 90 km will be also presented.