• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.800-802
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• 1999

본 논문에서는 기존의 알고리즘에서 벗어나 새로이 제안된 유전자 알고리즘을 이용하여 디지털 필터를 설계하는데 목적이 있다. 이 방법은 아날로그 필터에서 디지털 필터로의 전환이 불필요하며, 기존의 디지털 필터 설계방법과는 달리 저역통과(low-pass), 고역통과(high-pass), 대역통과(band-pass), 대역소거(band-stop) 필터와 같은 주파수 선택별 필터를 각각 독립적으로 설계 가능하게 하고, 이에 따른 계산 손실을 줄일 수 있다. 유전자 알고리즘을 사용하는데 있어 적합도 함수는 주파수 응답 크기를 이용한다. 실제로 주파수 응답특성과 디지털 필터의 계수와는 밀접한 관계가 있으므로, 원하는 필터의 주파수응답특성을 통해, 디지털 필터의 계수를 최적화 한다. 또한 필터계수 최적화 과정에 있어, 선택, 교배, 돌연변이와 같은 유전 연산자 적용시 필터의 계수들은 각각 안정도가 보장되어지는 범위내에서 선택되게 한다. 디지털 필터를 설계한 후 기존의 방법과 새로이 제안된 방법의 성능을 비교 평가 한다.

• 한국광학회지
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• 제14권5호
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• pp.515-520
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• 2003

수 KHz의 반복율로 발진하는 레이저광을 증폭하는 증폭기를 제작하고, 특성을 조사하였다. 증폭기로는 연속 방전하는 섬광등으로 펌핑되는 Nd:YAG 헤드를 사용하였고, 레이저 매질에서 발생하는 열 복굴절을 보상하여 이중통과 증폭기를 구성한 경우, 복굴절에 의한 레이저광 손실을 5%로 감소시켰다. 4 중통과 증폭기를 구성을 하였을 때, 반복율 5-10 KHz에서 이득은 약 3.2이었고, 펄스폭은 40 ns에서 48 ns로. 20%증가하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.864-867
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• 2005

In this paper we introduce a design of parallel architecture for wavelet transformation on FPGA. We implement wavelet transforms though lifting scheme and apply Daubechies4 transform equations. This technique has an advantage that we can obtain perfect reconstruction of the data. We divide our process to high pass filter and low pass filter. With this division, we can find coefficients from low and high pass filters simultaneously using parallel processing properties of FPGA to reduce processing time. From the equations, we have to design real number computation module, referred to IEEE754 standard. We choose 32 bit computation that is fine enough to reconstruct data. After that we arrange the real number module according to Daubechies4 transform though lifting scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1621-1623
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• 2005

The input chattering in the sliding mode control (SMC) is alleviated through a low pass filter. When the low pass filter is added to the original system, the overall system including the low pass filter dynamics can not satisfy the matching condition. So the integral SMC is applied for a main controller. A sliding surfaces are designed carefully to make the overall dynamics same with the nominal control system.

• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.462-466
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• 2007

This paper proposes an automatic bandwidth control method for the performance improvement of Binary Amplitude Shift Keying (BASK) system for Giga-Bit Modem in millimeter band. In order to improve the performance of the BASK system with a fixed bandwidth, the proposed method is to adjust a bandwidth of low pass filter in receiver using the fuzzy system. The BASK system consists of a high speed shutter of the transmitter and a counter and a repeater of receiver. The repeater consists of four stage converters, and a converter is constructed with a low pass filter and a limiter. The inputs to the fuzzy system are the reminder and integral of remainder of counter, and output is a bandwidth. We used a Viterbi algorithm to find the optimum detection from the output of the counter. Simulation results showed that the proposed system improves the performance compared to the fixed bandwidth.

• 소성∙가공
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• 제16권5호통권95호
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• pp.386-390
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• 2007

In order to, simultaneously, synthesize and control the size of microstructure of amorphous/crystalline composites, a repeated extrusion process was performed using the gas atomized $Cu_{54}Ni_6Zr_{22}Ti_{18}$ metallic glass powders and the crystalline brasses. The size of microstructure in the resultant composites was varied depending on the pass of extrusion as well as on the area reduction ratio. The microstructure could be estimated using an equation of $r_n=r_{n-1}/R^{1/2}$, where R is reduction ratio and $r_n$ is the resultant radius of the extruded bar after n pass. Theory of microstructural refinement as well as the relationship between the resultant microstructures and mechanical properties was discussed.

• 한국군사과학기술학회지
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• 제12권2호
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• pp.236-247
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• 2009

In Korea, the driving system restriction criteria is strictly applied(gross weight 400kN, axial load 100kN). Especially after the Seoungsu Bridge accident, safety factor has been strictly applied. The Safety factor is applied to the cumulative results for each steps like design, construction, maintenance of the Bridge. Because of it, the bridge is undervalued compared to its capacity. So, this generates loss for both private and military sector(eg. logistical delays, structural damage, etc.). But analyzing data from many existing researches we have confirmed that the military heavy vehicle may pass through the first class bridges. In consequence, this study have focused on determining whether HETS vehicles can pass over the first class bridge, without safety issues, using MIDAS structural analysis program. The results have confirmed that the military heavy vehicle may pass over the bridge.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.676-680
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• 2006

Many collapse of road cut slope consisted of representative granite of korea peninsula is happened by weathering progress. Chose hangye pass consisted of korea peninsula's representative granite style for this study. Purpose of this study is that consider suitable reinforcement of cut slope consisted of granite by analyzing characteristic of hangye pass vicinity road cut slope.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.134-137
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• 2001

A variable bandwidth filter (VBF) is proposed for cleaning signals with known instantaneous bandwidth (IB). Also, the behaviors and the characteristics of the VBF are examined in time-frequency domain (TFD). The proposed VBF clips a noisy signal along the boundaries of IB and rejects noise in the outside of the IB of the signal in TFD. It is possible to construct four kinds of VBF that are low-pass VBF, high-pass VBF, band-pass VBF and band-stop VBF.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.138-141
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• 2001

In this paper, a VBF(variable bandwidth filter) is suggested and analyzed in time-frequency domain. There are four kinds of VBF, which are low-pass VBF, high-pass VBF, band-pass VBF and band-stop VBF. The proposed VBF can extract the components of signals within variable instantaneous bandwidth at a specific time instant. Instantaneous bandwidth is estimated in time-frequency domain. The VBF is represented by rational form in extended Fourier frequency domain.