• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.904-910
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• 2008

In this paper, we consider the military requirement, study the military network services and their related traffic parameters, evaluate the performance the experimental army network and then suggest the design guideline of applying VoIP to the whole military. We evaluate the performance of the delay and loss in the viewpoint of packet and call levels for the several scenarios. First, the performances of separate network service were considered and the satisfaction of the requirement was obtained. Secondly, the delays and losses of the integrated network services were calculated as the amount of the background traffic increases. Finally, based on the simulation results, we presented the design guideline which classified network configurations for applying VoIP equipment and helped estimate the number of VoIP terminals in the existing link.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.997-1002
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• 2017

Underwater communication, which is used acoustic channel of 1500[m/s] speed being different of wireless electric wave in terrestrial communication, is sensitive on water temperature and salinity and also affected from 3D underwater space. 3D underwater communication is sensitive on propagation loss of acoustic wave and underwater noise with complexity of communication space. In this paper, transmission performance with consideration of these characteristics of 3D underwater communication environments is measured and analyzed on MANET operated on 3D underwater communication environments. Some underwater MANET operation conditions will be suggested. Computer simulation with underwater simulator based on NS-2 will be used for performance measure, performance parameter like as throughput, transmission delay, packet loss rate and consumed energy will be used in simulation for performance measure.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1003-1008
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• 2017

In this paper, we studied the design and fabrication of double T Structure with CPW antenna at around 5 GHz band.. To improve of frequency properties of antenna, Double T Structure with CPW antenna was simulated by HFSS(: High Frequency Structure Simulator). A double T Structure with CPW antenna was designed and fabricated by photolithograph on an FR4 substrate (dielectric constant of 4.4 and thickness of 1.6 mm). The fabricated A double T Structure with CPW antenna showed a center frequency, the minimum return loss and impedance were 5.29GHz, -34dB, and 390MHz, $49.6{\Omega}$ respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.1-7
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• 2008

In this paper, we propose a lossy MTM transmission line unit cell and retrieve the parameter values related with radiation effects. Based on this unit cell model, we plot dispersion diagrams and analyze resonance conditions. We also discuss the input impedance or admittance behavior when we terminate the load as open or short. Then, we examine the quality factor and return loss bandwidth. We also design a very compact unit cell antenna using the provided lossy MTM-TL model. The results based on EM simulations and measurements are shown to be in good agreement with those based on circuit simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.265-271
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• 2015

In this paper, Dualband meander microstrip antenna is proposed for Wireless Body Area Network application. Designed antenna is mounted on the phantom to maintain a constant distance of the substrate, and studied the characteristics related to change in several meaningful parameters to improve performance. Characteristics of antenna, returnloss, radiation pattern, gain, bandwidth, are analyzed using Computer Simulation Technologes(CST) software. The proposed antenna operates at 4.33Ghz and 6.09GHz ~ 9.88GHz for UWB. The antenna showed that returnloss and -10dB bandwidth are -42.30dB and 410Mhz at 4.33GHz, maximum -29.11dB and 3.75GHz at 6.1GHz ~ 9.8GHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.525-529
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• 2009

In this paper, microstrip patch antenna with diagonal slotted type using RFID is designed. This microstrip patch antenna is designed by considering the properties of critical parameter like the size, the truncating dimension, position of feed power and the height of airspace. the designed microstrip patch antenna has the lowest return loss in 915MHz, and in case of the voltage standing wave ratio(VSWR) is less than 1.2 under return loss -16dB, it has bandwidth of about 26MHz. Also, the microstrip patch antenna has the gain of 6dBi on the center frequency of 915MHz band and 2.8dB in the rate of reduction.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.4
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• pp.311-317
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• 1999

In this paper, the resonant inverter of SEPP-LCC type is proposed and described the operating principle. As adding t two capacitors in the switching devices in parallel. the proposed inverter can reduce switching losses. noise and voltage s stress at Turn-on and Turn-off. The analysis of the proposed circuit are described by using the normalized parameters. The data of design are got by the characteristic values and an example of the design's method is proposed. In addition. t the justification of theoretical analysis is verified by comparing to the experimental waveforms.

• IE interfaces
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• v.7 no.1
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• pp.75-80
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• 1994

In a recent article, Leon et al. lucidly explained the ideas of the Taguchi two-stage procedure for parameter design optimization, and proposed alternative performance measures called PerMIA to the signal-to-noise ratios. On the other hand, Box proposed an empirical approach to the problem based upon monotone transformations of the performance characteristic(y). This paper develops procedures for parameter design optimization under the assumptions that the expected loss(not necessarily a mean squared error loss) is increasing with respect to the variance of the error in y, and that the mean of y satisfies certain conditions of adjustability. It turns out that the variance of the error in y can play the role of PerMIA, and it is further shown that the derived PerMIA can be adapted to the Box empirical procedure for the minimization of the expected loss in the original metric.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.208-209
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• 2019

저해상도의 홀로그램을 Bilinear및 Bicubic 등의 알고리즘을 이용하여 업 스케일링을 하는 방법도 있다. 하지만, 홀로그램 데이터의 손실이 매우 크게 발생하며, 이로 인한 화질 저하가 발생하게 된다. 본 논문에서는 기존에 요구되던 파라미터와 연산량, 메모리를 대폭 감소시키면서도 준수한 성능을 보이는 RCI 구조를 제안한다. 제안한 네트워크 구조는 준수한 성능을 보이면서도 기존 2D 이미지에 대한 SISR 네트워크보다 더 빠르고 더 적은 메모리를 사용하였다.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.189-192
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• 2000

본 논문에서는 청각 장애인의 보다 향상된 보청 환경을 조성하고자 청각손실을 심리음향 모델을 적용하여 감음 신경성 난청을 보정하는 알고리즘을 제안한다. 제안한 알고리즘에서는 난청의 유형은 내이에서부터 중추 뇌에 걸친 감음계와 신경계의 장애에서 비롯되는 감음신경성 난청(sensorineural hearing loss)으로 주파수 영역상에서 MTH(minimum hearing threshold)가 균일하지 않게 상승하게되어 가청영역이 좁아지는 문제점을 해결하기 위한 방법으로 각각의 주파수 밴드마다 멀티밴드 압축 알고리즘을 적용하였다. 그러나 이 경우 각각의 주파수 밴드에 따른 서로 다른 가청 영역의 영향에 의한 변형된 스펙트럼 모양으로 인해 spectral contrast reduction과 변형된 마스킹 특성으로 인해 음성 변별력에 제한을 가하게 된다. 이것은 주변 주파수 성분들에 의한 마스킹 효과에 의한 것으로, 신호에 대한 난청인이 느끼는 지각 영역(perceptual domain)에서의 해석과 심리음향 모델 파라미터를 통한 보청기의 개발이 이루어져야 하며, 본 논문에서 그 알고리즘을 적용하였다.