• Korean Journal of Optics and Photonics
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• v.7 no.4
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• pp.428-433
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• 1996

We have demonstrated 200 km non-dispersion shifted fiber(NDSF) transmission of 10 Gb/s signal by using mid-span spectral inversion(MSSI) method as a dispersion compensation technique. We have used four-wave mixing process in dispersion shifted fiber(DSF) to generate a spectrum inverted signal. The spectral inversion efficiency of -26.7dB and signal to noise ratio of 23.0 dB have been achieved. The measured sensitivities at $10^{-9}$ bit error rates (BER) were -28.0 dBm in back to back configuration and -27.0 dBm after transmission of 200 km NDSF.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.03a
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• pp.297-303
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• 1998

본 논문에서는 게이트 길이 0.25um, 게이트 폭 150um(6 $\times$25)um 인 HEMT를 이용하여 11.7GHz~12.2GHz 대역 위성방송용 수신기의 기본회로를 설계하였다. 수신기는 저잡음증폭기, 믹서, 국부발진기, 중간주파수증폭기로 구성되어 있으며 LO 주파수는 10.75GHz 이고 IF 주파수는 0.95 ~1.45GHz 이다. 수신기의 설계목표는 전체이득 32dB 이상, 잡음지수 2.6dB 이하, 입출력 단의 반사손실은 각각 -10dB, -10dB 이하이며 저잡음증폭기, 믹서 및 중간주파수증폭기의 최소이득 및 최대잡음지수 14dB, 1dB, 믹서는 각각 0dB, 10dB, 중간주파수증폭기는 각각 18dB, 5dB 가 되게 설계하였다. 저잡음증폭기와 중간주파수증폭기는 2단으로 , 믹서는 이중 게이트구조로, 국부발진기는 반사형의 구조로 설계하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.11
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• pp.1047-1054
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• 2013

In this paper, we propose a dual-mode mixer to have multi-band radar signal receiver to be compact. The proposed mixer using a anti-parallel diode is operated as a fundamental mixer or sub-harmonic mixer with respect to a control voltage. A fundamental mixer with a control voltage show a conversion loss of -10 dB, 1dB compression point of 2 dBm at X-band. On the other hand, it is performed as a sub-harmonic mixer with a conversion loss of -10 dB, 1 dB compression point of 2 dBm at K-band.

• ETRI Journal
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• v.40 no.5
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• pp.561-569
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• 2018

Modern communication systems employ wideband antennas with circular polarization (CP) radiation. In this work, asymmetric modified bow-tie (ABT) and symmetric modified bow-tie (SBT) slotted circularly polarized single-point probe-fed circular patch antennas with dimensions of $40mm{\times}40mm$ for wideband applications are proposed. A 10 dB RL bandwidth of 350 MHz with CP, 3 dB axial ratio (AR) bandwidth of 100 MHz, peak gain of 4.9 dBic, and 10 dB RL bandwidth of 530 MHz with CP, 3 dB AR bandwidth of 140 MHz, peak gain of 5 dBic are obtained for ABT and SBT slotted circular patch antennas, respectively. The proposed SBT slotted patch is scaled up and down to $50mm{\times}50mm$ and $30mm{\times}30mm$, respectively. The proposed scaled-up version offers 10 dB RL and 3 dB AR bandwidths of 340 MHz and 80 MHz, with a peak gain of 5 dBic. The scaled-down version offers 10 dB RL and 3 dB AR bandwidths of 710 MHz and 180 MHz, with a peak gain of 5.25 dBic. These prototypes are suitable to work in IEEE 802.11a WLAN, ISM, and IEEE 802.11ac applications. The measured and simulated results are then discussed and compared.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.6-11
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• 2012

A bidirectional TDM-PON link to support 2.5 Gb/s upstream signals of 256 ONUs was considered for an extended transmission distance of 50 km. The power budget of the link was 58 dB for the upstream signal and a SOA was applied as a link extender which had a 25 dB gain. Receiver sensitivity of the upstream signal was -25 dBm for -30 dBm input power to the SOA. When the input power was -10 dBm, pulse overshooting caused by gain transient of the SOA was maximum at 45% and the signal performance degradation gave a power penalty of 1.55 dB for $10^{-12}$ BER. However the penalties diminished rapidly and became negligible as the input power went below -15 dBm. So this input power dynamic range of up to -15 dBm means that it is not positively necessary to use gain control methods for the next generation TDM-PON systems.

• Journal of Information Science Theory and Practice
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• v.10 no.spc
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• pp.96-111
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• 2022

With the rapid development of the Fourth Industrial Revolution and digital transformation, scientific and technological innovation measures are being devised to overcome Korea's low-growth, high-cost structure. Accordingly, by examining the R&D investment evaluation system of R&D PIE (R&D Platform for Investment and Evaluation), which has been promoted by the Korean government in response to the Fourth Industrial Revolution, from the perspective of R&D transformation, this study aims to explore a new path for a sustainable national science and technology innovation system following digital transformation. In particular, from the perspective of R&D PIE, a MLP (Multi-level Perspective), which had been conducted as an abstract theoretical study, was attempted with specific cases and analysis for each of the three layers: niche, landscape, and regime. In conclusion, R&D PIE was intended to elevate the abstract R&D investment evaluation system to a platform that leads innovation in the digital space of the Fourth Industrial Revolution. In addition, it was confirmed that the R&D PIE could be replaced or enhanced as a platform for innovation in response to the Fourth Industrial Revolution, thereby providing an alternative to job creation and an escape from economic crisis.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.222-235
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• 2010

After its remarkable success, "Avatar" brought another way of creating cinematic story; the stereoscopic 3-D cinema. Comparing conventional 2-D filmmaking, you need twice as much of budget and manpower in 3-D filmmaking because of the complicated process and slow production speed. The 3-D hardware like 3-D TV and 3-D projector are already showing at the retail stores while 3-D filmmaking is still in veil, and no major educational institution is yet to start 3-D related education. As 3-D movies get popular and demand more 3-D filmmaking professional crew, educating 3-D filmmaking to 2-D based film students will improve their hiring rate in the market. The successful result of the box office showing 3-D films like "Alice in Wonderland 3D" and "Titan 3D" forecasts that there will be more demand on 3-D related jobs very soon.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.571-576
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• 2016

3D printing has recently been used in various fields. Among various applications, 3D face data must be generated for 3D face printing. A laser scanner is used to acquire 3D face data, but there is a restriction that a person should not move during scanning. In this paper, we propose a 3D face modeling method based on a single image and a face transformation system to use the generated 3D face for virtual cosmetic surgery. We have defined facial feature points from the 3D face database for 3D face data generation. After extracting feature points from a single face image, 3D face of the input face image is generated corresponding to the 3D face feature points defined from the 3D face database. After 3D face modeling, 3D face modification part is applied for use such as virtual cosmetic surgery.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.129-138
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• 2006

Composite deck plate using a pre-assembled re-bar truss for slab with corrugated zinc galvanized sheet iron at manufactory, is given the improvement on design, manufacture, and performance for construction work of cast-in-place reinforced concrete slab by enabling to cast concrete directly without the form work. There are two methods in analyzing composite deck : Simplified 2D analysis and 3D analysis. Although simplified 2D analysis is being used up to date, the use of 3D analysis, allowing for the vierendeel behavior of composite deck by real configuration correlating to bar reducing, is demanded. To compare the simplified 2D analysis applied to allowable stress design with 3D analysis applied to limit state design, 8 specimen are manufactured. Main variables include the depth of slab, the length of span, the diameter of bottom bar and lattice bar, and the presence of corrugated zinc galvanized sheet iron. The comparison from the experimental result and analytical result indicates that applying of simplified 2D analysis is possible for the use of D10 with bottom bar. However, it is more reasonable to apply 3D analysis which allows to indicate vierendeel behavior considered the real configuration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.815-820
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• 2008

Recently the frequency assignment and the technical specifications of UWB systems for communications are completed. Therefore many UWB systems have been developed. In our country $3.1{\sim}4.8GHz$ and $7.2{\sim}10.2GHz$ are assigned for UWB systems for communications. When we consider RF technologies and the easy implementation of UWB systems, UWB systems used in the low band are more developed than high band systems. In this paper we design and implement a BPF for low band UWB systems by means of considering the easy implementation of UWB systems. The designed and implemented BPFs are low band filter and low band channel filters. The measured results of the low band filter show that the filter has 21.85dB and 17.91dB attenuation at 3.1GHz and 4.8GHz, 1.53GHz of -10dB bandwidth and 2dB of insertion loss. Low band can be divided into 3 channels with 500MHz of the channel bandwidth. The channel filter for channel number 1 has the characteristics of 24.85dB attenuation at 3.1GHz, 0.61GHz of -10dB bandwidth and 1.87dB of insertion loss. The filter for channel 3 in low band has 19.2dB of attenuation at 4.8GHz, 0.49GHz of -10dB bandwidth and 2.49dB of insertion loss.