• 전자공학회논문지B
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• 제28B권10호
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• pp.799-806
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• 1991

Utilizing dual basis, normal basis, and subfield representation, three different finite field multipliers are presented in this paper. First, we propose an extended dual basis multiplier based on Berlekamp's bit-serial multiplication algorithm. Second, a detailed explanation and design of the Massey-Omura multiplier based on a normal basis representation is described. Third, the multiplication algorithm over GF(($2^{n}$) utilizing subfield is proposed. Especially, three different multipliers are designed over the finite field GF(($2^{4}$) and the complexity of each multiplier is compared with that of others. As a result of comparison, we recognize that the extendd dual basis multiplier requires the smallest number of gates, whereas the subfield multiplier, due to its regularity, simplicity, and modularlity, is easier to implement than the others with respect to higher($m{\ge}8$) order and m/2 subfield order.

• 통합자연과학논문집
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• 제11권3호
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• pp.139-147
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• 2018

Hippocampal atrophy is a well-established imaging biomarker of Alzheimer disease (AD). However, hippocampus is a non-homogenous structure with cytoarchitecturally and functionally distinct sub-regions or subfield, with each region performing distinct functions. Certain regions of the subfield have shown selective vulnerability to AD. Here, we are interested in studying the effects of normal aging and mild cognitive impairment on these sub-regional volumes. With a reliable automated segmentation technique, we segmented these subregions of the hippocampus in 101 cognitively normal (CN), 135 early mild cognitive impairment (EMCI), 67 late mild cognitive impairment (LMCI) and 48 AD subjects. Thereby, dividing the hippocampus into hippocampal tail (tail), subiculum (SUB), cornu ammonis 1 (CA1), hippocampal fissure (fissure), presubiculum (PSUB), parasubiculum (ParaSUB), molecular layer (ML), granule cells/molecular layer/dentate gyrus (GCMLDG), cornu ammonis 3(CA3), cornu ammonis 4(CA4), fimbria and hippocampal-amygdala transition area (HATA). In this cross sectional study of 351 ADNI subjects, no differences in terms of age, gender, and years of education were observed among the groups. Though, the groups had statistically significant differences (p < 0.05 after the multiple comparison correction) in the Mini-Mental State Examination (MMSE) scores. There was asymmetrical volume loss in the early stages of AD with the left hemisphere showing volume loss in regions that were unaffected in the right hemisphere. Bilateral parasubiculum, right cornu ammonis 1, 3 and 4, right fimbria and right HATA regions did not show any volume loss till the late MCI stages. Our findings suggest that the hippocampal subfield regions are selectively vulnerable to AD and also that these vulnerabilities are asymmetrical especially during the early stages of AD.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.109-112
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• 2005

본 논문에서는 초기화 구간에서의 시간단축과 높은 암실 명암비를 얻을 수 있는 새로운 초기화 파형을 제시한다. 새로운 초기화 파형에서 첫 번째 subfield는 기존의 conventional 구동파형과 마찬가지로 초기화 구간에서 ramp-up구간과 ramp-down구간이 필요하지만, 두 번째 subfield부터는 단지 ramp-up구간만이 적용된다. 한 frame에 8개의 subfield를 적용할 경우, 기존의 구동파형의 배경광이 $0.40cd/m^2$로 측정되는 반면, 새로운 초기화파형을 패널에 적용할 경우 배경광이 측정되지 않는다. 이러하여 우리는 새로운 초기화파형에서 무한대의 암실 명암비를 얻을 수 있다. 또한 새로운 초기화파형에서는 ramp-down구간을 없앰으로써 첫 번째 subfield를 제외하고는 초기화 시간을 165us로 시간을 줄일 수 있다.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.1004-1008
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• 2012

The effect of address discharge characteristics by selective reset method is investigated to prevent the weakness of address discharge in the middle of a TV-field without increase of the black luminance. To reduce black luminance in AC PDP usually, the first subfield during one TV frame adopted the conventional rising ramp-reset waveform, whereas the other subfields adopted the subsidiary reset waveform without rising ramp type. As the wall charge for the address discharge was accumulated by only the rising ramp waveform during the first reset period, the wall charge on three electrodes was disappeared as time passed and the address discharge would be weakened in the rear subfields. To prevent a reduction of the address discharge characteristics without decrease the black luminance, the modified rising ramp reset waveform was adopted only in the sixth subfield. As a result, a modified driving method could improve the address discharge characteristics compared with selective reset driving scheme with almost the same black luminance.

• 대한전자공학회논문지TC
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• 제44권3호
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• pp.61-67
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• 2007

리드솔로몬 복호기에서 4중 오류 이상의 오류치와 위치를 발견해 정정시는 보통 치엔탐색기를 사용한다. 이때 기존의 방법은 회로량이 많고 지연시간이 길어 비효율적이었다. 본 논문에서는 갈로이스 부분장을 이용 이 탐색기를 속도도 빠르고 회로량도 대폭 줄인 새로운 효율적 탐색기회로 설계법을 제시한다. 본 논문에서는 4중 오류위치를 정확히 추출함을 보였으나, 이새 설계된 탐색기회로는 5중이상의 오류위치도 정확히 찾을 수 있는 설계이다. 새로운 회로는 정확히 오류위치를 발견할 수 있음이 예를 통해 검증되었다.

• 한국정보통신학회논문지
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• 제16권8호
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• pp.1686-1692
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• 2012

확산수열(spreading sequence)은 다중 반송파 대역확산(multi-carrier spectrum) 통신시스템과 CDMA와 같은 무선통신에서 중요한 역할을 한다. 이러한 통신 시스템에서 낮은 상호상관관계를 갖는 확산수열은 다중접속 충돌을 최소화하고, 시스템의 보안수준을 가능한 높일 수 있다. 수열을 설계하는 데 있어 상호상관관계를 분석한는 것을 반드시 필요한 절차이다. 상호상관관계를 분석하기 위해서는 많은 계산 시간이 요구된다. 본 논문에서는 비선형 이진수열의 상호상관관계를 실제적으로 계산하는 과정에서 부분체를 이용하여 효과적으로 구하는 방법을 제안한다.

• 대한수의학회지
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• 제41권4호
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• pp.467-475
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• 2001

Cardiac arrest, hypoxia, shock or seizure has been known to induce cerebral ischemia. This study was designed to investigate the effect of ischemia on hippocampal pyramidal layer induced by transient bilateral occlusion of the common carotid arteries. Mature Mongolian gerbils were sacrificed at days 2, 4, and 7 after carotid occlusion for 10 minutes. Sham-operated gerbils of control group were subjected to the same protocol except for carotid occlusion. During operation for ischemia, body temperature was maintained $37{\pm}0.5^{\circ}C$ in all gerbils. Paraffin-embedded brain tissue blocks were cut into coronal slices and stained with H-E stain or immunostain by TUNEL method. Neurons with the oval and prominent nucleus and without the eosinophilic cytoplasm in the subfield of hippocamapal pyramidal layer were calculated as to be viable neurons. Their chromatins were condensed or clumped. Their nuclei appeared multiangular or irregularly shrinked. The width of the pyramidal layer was reduced due to the loss of nuclei. At day 2 after reperfusion, some neurons in the CA1 subfield were slightly eosinophilic. But most neurons in the CA2 subfield were strongly eosinophilic. At day 4 day, most neurons in the CA1 subfield were severely damaged and at day 7 day, only a few survived neurons were observed. Survived neurons per longitudinal 1mm sector in the CA1, CA2, CA3, and CA4 subfields of pyramidal layer were investigated. At day 2, the mean numbers of pyramidal neurons in CA1, CA2, CA3, and CA4 subfiedls were 104.5/mm (54.3%), 51.0/mm (33.8%), 105.5/mm (85.6%), and 124.3/mm (93.5%) compared to the nonischemic control group, respectively. At day 4, the mean numbers of pyramidal neurons in CA1, CA2, CA3, and CA4 subfields were 3.2/mm (1.7%), 51.5/mm(34.2%), 95.3/mm (77.4%), and 112.5/mm (84.6%), respectively. At day 7, the mean numbers of pyramidal neurons in CA1, CA2, CA3, and CA4 subfiedls were 0.8/mm (0.4%), 5.7/mm(3.8%), 9.8/mm (8.0%), and 5.0/mm (3.7%), respectively. The mean numbers of apoptotic positive neurons in the CA1 subfield at day 2, 4, and 7 after reperfusion were 67.8/mm, 153.2/mm and 123.7/mm, respectively. These results suggest that the transient cerebral ischemia cause severe damages in most neurons at day 7 and that the prosminent apoptotic positive neurons in hippocampal pyramidal layer are the delayed neuronal death induced by ischemia.

• 대한수학회보
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• 제45권2호
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• pp.375-384
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• 2008

Let $k={\mathbb{F}}_q(T)$ and ${\mathbb{A}}={\mathbb{F}}_q[T]$. Fix a prime divisor ${\ell}$ q-1. In this paper, we consider a ${\ell}$-cyclic real function field $k(\sqrt[{\ell}]P)$ as a subfield of the imaginary bicyclic function field K = $k(\sqrt[{\ell}]P,\;(\sqrt[{\ell}]{-Q})$, which is a composite field of $k(\sqrt[{\ell}]P)$ wit a ${\ell}$-cyclic totally imaginary function field $k(\sqrt[{\ell}]{-Q})$ of class number one. und give various conditions for the class number of $k(\sqrt[{\ell}]{P})$ to be one by using invariants of the relatively cyclic unramified extensions $K/F_i$ over ${\ell}$-cyclic totally imaginary function field $F_i=k(\sqrt[{\ell}]{-P^iQ})$ for $1{\leq}i{\leq}{\ell}-1$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.327-328
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• 2007

A contour shape matching based pixel motion estimation is proposed. The pixel motion information is very useful to compensate the motion artifact generated at the specific gray level contours in the moving image for subfield gray-scale display devices. In this motion estimation method, the gray level boundary contours are extracted from the input image. Then using contour shape matching, the most similar contour in next frame is found, and the contour is divided into segment unit. The pixel motion vector is estimated from the displacement of the each segment in the contour by segment matching. From this method, more precise motion vector can be estimated and this method is more robust to image motion with rotation or from illumination variations.

• 한국컴퓨터정보학회논문지
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• 제6권3호
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• pp.56-63
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• 2001

본 논문에서는 부분체(24)를 갖는 유한체 GF(216)의 곱셈기를 설계하였다. 이런 설계는 부분체를 이용한 비트 병렬 곱셈기를 사용한 순차 논리 곱셈기를 만들기 위해 사용된다. 부분체 상의 병렬연산기를 사용하여 유한체 GF(216)의 직렬 곱셈기를 설계하면 기존의 직렬 곱셈기보다는 짧은 지연시간을 얻을 수 있으며, 병렬 곱셈기보다는 적은 하드웨어로 구현할 수 있다. 이러한 설계는 유용한 특징을 갖는다. 여기서는 회로 복잡도와 지연시간의 특징을 비교하고 C언어를 이용하여 시뮬레이션 결과를 보였다.