• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.454-459
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• 2003

We report the first demonstration of 10 Gb/s wavelength conversion in a Mach-Zehnder interferometric wavelength converter monolithically integrated with a loss-coupled DFB probe source. The integrated device is fabricated using a BRS (buried ridge stripe) structure with an undoped InP clad layer on the top of a passive waveguide to reduce high propagation loss. The device exhibited a static extinction ratio of 11 dB. Good performance at 10 Gb/s is obtained with an extinction ratio of 7 dB and a power penalty of 2.8 dB at a 10$^{-9}$ bit error rate.

• Journal of the Korean Geographical Society
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• v.37 no.5
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• pp.465-479
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• 2002

This paper seeks to Produce a typology of enterprise-support services. Drawing upon this typology, this study will attempt to identify the status quo of the government enterprise-support services system and also examine the demand for and supply of these services according to regional differences and industrial characteristics (old versus new). Based on results of the survey taken in the Seoul software industry cluster especially around the Seocho, Gangnam-Gu, the Daejeon ICT industry cluster and the Gumi electronics industry cluster, it can be said that the demand for and supply of enterprise-support services are differentiated by the nature of an industry, the characteristics of a region and the growth stage of a firm. Finally, some policy suggestions will be addressed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.9-14
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• 2004

Lightwave communication system for Wavelength division multiplexing(WDM) consists of multiplexer, demultiplexer and optical Inter. But, the existing multiplexer, demultiplexer and optical filter is difficult to minimize system and reduce weight because they are not integrated device type. In this paper, thus, we propose the OADM baed on a Mach-Zehnder interferometer(MZI) with FBG(fiber Bragg Slating) in the interferometer Ems. The OADM using FBG. and MZI is able to minimize system and reduce weight. We analyze output characteristics of OADM and present the optimum design data through the computer simulation and experimentation. Also unposed OADM fits for DWDM(Dense WDM) system because of wide bandwidth by tuning narrow linewidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1598-1603
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• 2011

This paper describes an enhancement method for a computational pickup model. The conventional computational pickup model utilizes the ray-trace model and the pinhole model. The conventional model is very useful, however, it suffers from quality degradation of reconstructed images at long distances. To overcome the problem, we propose an accurate pickup model. The proposed model includes integration of the rays incoming to a sensor that generates a pixel, resulting in robustness on the Aliasing artifact. To show the effectiveness of the proposed method, experimental results are carried out. The results indicated that the proposed method is superior to the conventional method.

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.160-163
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• 1992

유골골종(osteoid osteoma)은 특징적으로 직경 약 1cm미만의 원형 또는 타원형의 유골질제부(nidus)가 병소의 중심부에 있고, 그 주위는 반응성골질로 둘러싸여 있다. 그러므로 반응성골질 병소에서 제부의 확인은 유골골종의 진단에 매우 중요하다. 더우기 유골골종의 치료는 반드시 제부를 제거하여야 하기 때문에, 제부의 위치를 정확히 아는 것이 중요하다. 그러나, 유골골종의 제부는 단순 X-선 촬영상에서 잘 안나타나는 경우가 많아 진단에 어려움이 있다. 또한 골스캔도 유골골종의 진단에 많이 이용되고 있으나, 단순 신티그램에서 제부의 정확한 위치 파악은 어렵다. 이에 저자들은 바늘구멍조준기 골스캔을 시행하여 유골골종 제부에는 아주 진한 동위원소 집적이 보였고 주위의 반응성 골질 부위에는 제부보다 약한 동위원소 집적이 보여 특징적인 '이중 농도 집적' 소견을 얻었기에 바늘구멍조준기 골스캔이 유골골종의 진단에 매우 유용한 검사로 사료되어 보고하는 바이다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.275-281
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• 2003

A new neural oscillator has been designed and fabricated in an 0.5 ${\mu}{\textrm}{m}$ double poly CMOS technology. The proposed neural oscillator consists of a nonlinear variable resistor with negative resistance as well as simple transconductors and capacitors. The variable negative resistor which is used as a input stage of the oscillator consists of a positive feedback transconductors and a bump circuit with Gaussian-like I-V curve. The proposed neural oscillator has designed in integrated circuit with SPICE simulations. Simulations of a network of 4 oscillators which are connected with excitatory and inhibitory synapses demonstrate cooperative computation. Measurements of the fabricated oscillator chip with a $\pm$ 2.5 V power supply is shown and compared with the simulated results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.2
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• pp.81-91
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• 2002

In this paper, a high-quality integrated transformer using bondwires is proposed and fabricated. The bondwire transformer inherently has low conductor loss due to wide cross-section and small parasitic capacitance because the vertical placement of the bondwire loop separates from substrate and effectively reduces the substrate effects. It can be fabricated easily by used of the modern automatic wirebonding technology. The electrical characteristics of the fabricated transformers are compared with those of the spiral transformer It is expected that the bondwire transformer can improve the performance for RFIC and MMIC applied to a variety of application, for example, Mixer, Balanced Amplifier, VCO, and LNA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.3
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• pp.153-163
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• 1986

GaAs, one of the III-V compounding semicondnctors, has been widely employed as base materials for the fabrication of the ultra-high-speed devices in the filelds of DBS, optical communications, MMIC'S and digital IC'S. There have been some reports on 4Kx4bit SRAM by D/E MESFET'S, 4K bit SRAM by HEMT'S, and receiver front ends for X-band by MMIC technologies, respectively. This paper reviews GaAs materials, wafer fabrication processes, device applications, and design aspects, and, finally, descusses the future of the ultra-high-spped-devices.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.71-76
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• 2004

A compact embedded tapped-line combline filter with interdigital capacitors using low temperature co-fired ceramic (LTCC) technology for wireless application is proposed. Also, in-situ measurement using T-pattern microstrip resonator was performed to acquire exact knowledge of electrical properties of the LTCC substrate. The proposed filter makes it possible to realize a relatively small size, 2.7mm${\times}$2.03mm. by employing interdigital and combline structure. It shows 1.8 ㏈ insertion loss, 37.6㏈ return loss, and 280 MHz bandwidth at the center frequency of 5.09 GHz. Its small size and simple structure make it a good candidate as an integrated filter for various LTCC substrates.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.12
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• pp.77-84
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• 1998

A voltage controlled chaotic circuit has been designed in integrated circuit and fabricated by using 0.8$\mu\textrm{m}$ single poly CMOS technology. The fabricated chaotic circuit consist of sample and hold circuits, op-amps, nonlinear function generator and two phase clock generator. The test results of the chaotic circuit show that periodic state, quasi-periodic state and chaotic state can be obtained according to the input control voltage with the ${\pm}$2.5V power supply and clock rate of 20kHz. In addition, two dimensional chaotic patterns have been observed by connecting this circuit in parallel or series