• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.435-435
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• 2022

디지털 필터 기반의 기저유출 분리 기법은 하천유량으로부터 기저유량을 분리하는 기법으로서 적절한 분석을 위해서는 필터 매개변수에 대한 추정이 요구된다. 이 연구에서는 비교적 간단한 방법으로 기저유출을 분리할 수 있는 단일 매개변수를 가진 디지털 필터 기반의 기저유출 분리 기법에 대하여 민감도 분석을 수행하였으며, 민감도 분석 결과를 바탕으로 적정 매개변수 범위를 결정하였다. 적용된 디지털 필터 기반의 기저유출 분리 기법은 Lyne-Hollick(LH), Chapman, Chapman-Maxwell(CM), EWMA 기법이다. 분석 대상 지점은 낙동강 지류 하천 중 8년이상 연속된 유량측정 기록이 존재하는 25개 수위관측소이다. 민감도 분석을 위한 기저유출 분리 기법별 매개변수 범위는 과거 연구 사례에 근거하여 LH, Chapman, CM 기법의 경우 0.9 ~ 0.99, EWMA 기법은 0.003 ~ 0.015로 선정하였다. 기저유출 분리 기법별 민감도 분석 결과, EWMA 기법이 매개변수 변화에 따른 기저유출 지표의 변화가 가장 적은 것으로 분석되었으며, LH 기법이 민감도가 가장 큰 것으로 분석되었다. 또한, LH 기법과 EWMA 기법은 수위관측소에 따라 산정된 기저유출 지수가 큰 차이를 보였으며, 이는 각 수위관측소의 유황곡선에서 10%와 90%에 해당하는 유량의 무차원 변동량에 기인한 것으로 분석되었다. 각 기저유출 분리 기법별 적용성 검토 결과, Chapman과 CM 기법은 기저유출만 존재하는 비 강우 기간에서 기저유출을 분리하는 오류가 확인됨에 따라, 비교적 유량 변동이 큰 우리나라의 유출 특성상 Chapman과 CM 기법의 적용은 부적절한 것으로 판단된다. LH 기법과 EWMA 기법은 홍수 수문곡선 상승부에 대한 기저유출의 비율, 비 강우 기간에 대한 기저유출 분리 오류 등을 검토하여, EWMA 기법은 0.012 ~ 0.015, LH 기법은 0.950 ~ 0.975로 선정하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.48-52
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• 2008

In this paper, we propose a new selective subspace projection method in order to recognize the occlusive face image effectively. The conventional subspace projection method is project to basis image using a full image of face. The face recognition rate has reduced because the face characteristic is easy to be distorted by occlusion. To overcome this problem, the proposed method first decide to occlusion. If it hasn't an occlusion, we get the feature vectors with total basis projection using the conventional subspace projection method. If it has an occlusion, we get one with partial basis projection. We get better recognition rate than conventional PCA and NMF using AR face database with occlusive face images.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.192-192
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• 2022

하천유량은 기저유량과 직접유량으로 구성되어 있으며 기저유량은 갈수기 하천유량의 대부분을 차지하므로 직접유출과 기저유출의 분리는 중요하다. 또한, T-N, T-P는 기저유출에 영향을 많이 받는 수질 항목으로 기저유출과 직접유출에 의한 오염부하량을 정확히 분석해야한다. 따라서, 기저유출의 오염부하량 산정을 위해 기존의 WAPLE 2의 단점을 개선한 WAPLE 3가 개발되었으며, WAPLE 3는 유량 곡선의 하강부 변곡점에 붙는 특성을 가지고 있는 Baseflow filter program(BFlow) pass 1값을 사용하여 기저유량을 분리해 기저유출 오염부하량을 산정한다. WAPLE 3는 하천유량 중 기저유출을 어느 정도 분리하는지 결정하는 filter parameter 값을 Nathan과 McMahon가 제시한 최적값인 0.925를 사용하였다. 그러나 지형과 강우량 등에 따라 하천 유량에서의 기저유출 비율은 달라지기 때문에 이러한 한계점을 극복하기 위해 WAPLE 4를 개발하였다. WAPLE 4는 filter parameter 값을 사용자가 변경할 수 있게 개발하여 강우에 의한 유량변동 특정이 고려된 기저유량 및 오염부하를 산정하여 결과에 대한 정확도를 높였다. 또한, WAPLE 4는 강우시 오염부하량 산정에 탁월한 Numeric Integration(NI) 방법을 사용하여 직접유량, 기저유량의 오염부하량 및 유량가중평균농도(FWMC) 산정이 가능하도록 하였다. 본 연구의 결과는 오염총량제 및 기저유량 관리를 통한 유량 관련 정책 수립 시 기초자료로 활용될 수 있을 것으로 판단된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.1023-1026
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• 2005

본 논문에서는 SDR(Software Defined Radio) 시스템을 위한 Digital IF(Intermediate Frequency) Up/Down 변환기를 설계하고 성능을 평가하였다. 설계한 시스템은 AD 변환부, DA 변환부 및 Up-Down conversion 기능을 수행하는 FPGA로 구성된다. AD 변환부는 Analog Device 사의 AD6645를 사용하였으며, DA 변환부는 Analog Device 사의 AD9775를 사용하였다. Up-Down conversion 기능을 수행하는 FPGA부는 샘플된 IF 입력을 혼합기와 NCO에 의해 기저대역(DC)으로 다운 시키는 역할을 하며, 14bit의 기저대역(DC) 신호를 혼합기와 NCO에 의해 IF 출력으로 올려주는 역할을 한다. 이러한 설계는 기존의 아날로그 헤테로다인 방식에 비하여 높은 유연성 및 우수한 성능 향상을 보여준다.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.565-568
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• 2001

이 논문에서는 미디언 필터의 선형 조합을 통해 임의의 주파수 특성을 갖는 필터 구조와 그 설계 방법을 제안한다. Linear-phase FIR 저대역통과 필터의 홀수번째 필터 계수의 부호를 바꾸면 FIR 고대역 통과 필터를 얻을 수 있는데, 이것은 필터 계수의 부호가 모두 양수인 두 개의 부분 필터의 차와 같은 모양을 가진다. 이 과정을 일반화하여 비선형 필터에 적용하면 LCWM(linear combination of median filter)필터는 가중 미디언 부필터(sub-filter)의 선형 조합으로 구성된다. 이는 선형 대수학에서 어떤 공간상의 임의의 벡터가 그 공간의 기저 (basls) 벡터들의 선형 조합으로 표현된다는 사실과 유사하다. 따라서 부필터의 필터 계수를 기저 벡터로이용하여 얻어지는 기저 행렬과 필터의 주파수 특성을 조절하는 계수 벡터를 구함으로써 LCWM 필터를 설계할 수 있다. 제안된 필터 설계 방법을 이용하면 특정 주파수 특성을 가지는 FIR 필터와 유사한 특성을 갖는 비선형 필터 구조를 만들 수 있다. LCWM 필터는 고대역 통과, 저대역 통과, BP(band-pass), BS(band-stop)의 임의의 주파수 특성을 가지는 필터로 설계될 수 있음이 실험을 통해 확인되었다.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.102-109
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• 2009

Purpose: Flash 3D (pixon(R) method; 3D OSEM) was developed as a software program to shorten exam time and improve image quality through reconstruction, it is an image processing method that usefully be applied to nuclear medicine tomography. If perfoming brain diamox perfusion scan by reconstructing subtracted images by Flash 3D with shortened image acquisition time, there was a problem that SNR of subtracted image is lower than basal image. To increase SNR of subtracted image, we use LEAP collimators, and we emphasized on sensitivity of vessel dilatation than resolution of brain vessel. In this study, our purpose is to confirm possibility of application of LEAP collimators at brain diamox perfusion tomography, identify proper reconstruction factors by using Flash 3D. Materials and methods: (1) The evaluation of phantom: We used Hoffman 3D Brain Phantom with $^{99m}Tc$. We obtained images by LEAP and LEHR collimators (diamox image) and after 6 hours (the half life of $^{99m}Tc$: 6 hours), we use obtained second image (basal image) by same method. Also, we acquired SNR and ratio of white matters/gray matters of each basal image and subtracted image. (2) The evaluation of patient's image: We quantitatively analyzed patients who were examined by LEAP collimators then was classified as a normal group and who were examined by LEHR collimators then was classified as a normal group from 2008. 05 to 2009. 01. We evaluate the results from phantom by substituting factors. We used one-day protocol and injected $^{99m}Tc$-ECD 925 MBq at both basal image acquisition and diamox image acquisition. Results: (1) The evaluation of phantom: After measuring counts from each detector, at basal image 41~46 kcount, stress image 79~90 kcount, subtraction image 40~47 kcount were detected. LEAP was about 102~113 kcount at basal image, 188~210 kcount at stress image and 94~103 at subtraction image kcount were detected. The SNR of LEHR subtraction image was decreased than LEHR basal image about 37%, the SNR of LEAP subtraction image was decreased than LEAP basal image about 17%. The ratio of gray matter versus white matter is 2.2:1 at LEHR basal image and 1.9:1 at subtraction, and at LEAP basal image was 2.4:1 and subtraction image was 2:1. (2) The evaluation of patient's image: the counts acquired by LEHR collimators are about 40~60 kcounts at basal image, and 80~100 kcount at stress image. It was proper to set FWHM as 7 mm at basal and stress image and 11mm at subtraction image. LEAP was about 80~100 kcount at basal image and 180~200 kcount at stress image. LEAP images could reduce blurring by setting FWHM as 5 mm at basal and stress images and 7 mm at subtraction image. At basal and stress image, LEHR image was superior than LEAP image. But in case of subtraction image like a phantom experiment, it showed rough image because SNR of LEHR image was decreased. On the other hand, in case of subtraction LEAP image was better than LEHR image in SNR and sensitivity. In all LEHR and LEAP collimator images, proper subset and iteration frequency was 8 times. Conclusions: We could archive more clear and high SNR subtraction image by using proper filter with LEAP collimator. In case of applying one day protocol and reconstructing by Flash 3D, we could consider application of LEAP collimator to acquire better subtraction image.

• Applied Microscopy
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• v.31 no.4
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• pp.355-365
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• 2001

This study was performed to investigate the distribution and differentiation on the immunoreacted cells of the ChAT (choline acetyltransferase) at the Meynert basal nucleus of the forebrains in the growth periods of rat, using the immunohistochemistric method. According to the cell shape and the ratio of long axis vs short axis of cell soma, the ChAT antibody reacted nerve cells in the Meynert basal nucleus of the rats were classified into six types. In the adult rats, the FD (frequency distributions) of round, oval and elongated cells were maximum. The FD of these types were shown to be progressively decreased during the postnatal development. In addition, the FD of elongated nerve cells in were observed in the adult rats respectively. This was thought to be the same phenomenon as those in the round and oval cells . The total mean volume of ChAT antibody reacted cell somata was lowest in the PND (postnatal days) 7 rats and was highest in the PND 21 rats. But, those were decreased to the adult. These results suggest that ChAT antibody reacted nerve cells grow up to PND 21 and then, differentiate into the various types by neurites outgrowing. On the electron micrography, the adult rat forebrain cells were obtained to be well developed ribosomes, polysomes , rough endoplasmic reticula and mitochondria. The immunreactivities were observed in ribosomes, polysomes, rough endoplasmic reticula and outer membrane of mitochondria. Golgi complexes were poorly developed and not showed jmmunreactivity. The ribosomes , polysomes and endoplasmic reticula are considered to be closely related to the inter cellular localization and biosynthesis of the ChAT but not Golgi complex. According to the results in the present study, it is considered that the ChAT-immunoreacted nerve cells in the Meynert basal nucleus of the rat forebrains are differentiated throughout the postnatal development with following processes of changes; 1) the cholinergic nerve cells develop postnatally 2) cell soma volumes gradually increase during the early postnatal days 3) and then, cells differentiate into the various types by projecting the neurites to the appropriate area after PND 21.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.117-123
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• 2014

This paper proposes the constructing method of effective multiplier using basis transformation. Th proposed multiplier is composed of the standard-dual basis transformation circuit module to change one input into dual basis the operation module to generate from bm to bm+k by the m degree irreducible polynomial, and the polynomial multiplicative module to consist of $m^2$ AND and m(m-1) EX-OR gates. Also, the dual-standard basis transformation circuit module to change the output part to be shown as a dual basis into standard basis is composed. The operation modules to need in each operational part are defined.

• Applied Microscopy
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• v.34 no.3
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• pp.199-209
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• 2004

The migut epitheluim of the last instar larva in the mosquito larvae, Anopheles sinensis was observed with electron microscopes. The midgut epitheluim of the mosquito larva is composed of a single-layered columnar absorptive cells, regenerative cells and secretory granular cells. The free surface of the columnar absorptive cells has a regular array of microvilli 'brush border', while cell membranes close to the basal lamina are extrmely infolded and a lot of mitochondria are concentrated in those processes. The columnar absorptive cells also contain cell organelles expected to be found in absorptive cell. Midgut regenerative cells which are positioned basally in the epithelium form the groups, which are called 'nidi', composed of 1 or $2{\sim}3$ cells, they show darker appearance than the columnar absoptive cells. The secretory granular cells contain numerous electron dense granules, $200{\sim}400$ nm in diameter. The cone shaped secretory granular cells are located in the basal portion of the midgut epitheluim. The epithelium is surrounded by the subepithelial space and muscle bundles. The subepithelial space, which is filled with fibrous connective tissue, is innervated by many axon cells and tracheoles.

• Applied Microscopy
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• v.29 no.4
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• pp.479-491
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• 1999

This study was performed to investigate the distribution and differentiation of choline acetyltransferase (ChAT)-immunoreactive cells in the basal nucleus of Meynert of the postnatal and adult rat forebrains, utilizing techniques of immunocytochemistry. According to the cell shape and the ratio of long axis vs short axis of cell soma, the ChAT-immunoreactive nerve cells in the basal nucleus of Meynert of the adult rat were classified into six types. In the adult rat, the frequency distributions (FD) of round, oval, elongated, fusiform, triangular and polygonal cells were 9.4%, 35.5%, 32.1%, 5.9%, 9.1% and 8.0%, respectively. The FD of oval and round nerve cells on the postnatal day (PND) 14 were observed to be 18.7% and 51.5%, respectively. Those were shown to be progressively decreased during developmental process to the adult. Also, those of elongated and triangular nerve cells on the PND 21 were observed to be 30.4% and 10.1%, respectively. Those were shown to be same phenomenon a,1 those in the round and oval cells. Meanwhile, those of the triangular and polygonal nerve cells were progressively increased from the early postnatal stage to the adult. The total mean volumes of ChAT-immunoreactive cell somata in the PND 7 rat were the lowest $(1,083{\mu}m^3)$ and those in the PND 21 rat were shown to be the highest $(5,045{\mu}m^3)$. But in the adult, those were decreased to $(2,731{\mu}m^3)$. Those in the PND 21 rat were shown to be about 84.7% larger than those in the adult. On the electron micrography, the cell organelles such as ribosomes, polysomes, rough endoplasmic reticula (RER) and mitochondria were well developed in the PND 21 rat forebrains, but Golgi complexes were shown to be proliferating phase. Especially, ribosomes, polysomes and RER were immunoreactive in the tissues treated with 0.05% triton X-100. According to the observations in the present study, it is considered that the ChAT-immunoreactive nerve cells in the basal nucleus of Meynert of the rat forebrains are differentiated throughout the following processes of changes during the postnatal development: 1) increase of cell soma volumes with the differentiation of tell organelles and neurites, 2) increase in the FD of differentiated tell types and 3) cell schrinkage without cell loss. The ribosomes, polysomes and RER are considered to be closely related to the intracellular localization and biosynthesis of the ChAT but not Colgi complex.