• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.109-112
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• 2001

기존의 K-means 알고리즘은 학습벡터가 단일군집에 할당되는 방법이 crisp 이므로 다른 군집에 할당될 확률을 무시하게 된다. 따라서 군집화 작업과 관련하여 반복적인 코드북 설계 과정에서 각 학습벡터를 다중 군집으로 할당하는 Fuzzy c-means를 사용한다. 또한 Fuzzy c-means 알고리즘의 학습과정에서 구해지는 각 클래스 의 프로토타입에 가중치를 곱하여 다음 학습의 프로토타입으로 사용함으로써 Fuzzy c-means 알고리즘 적용 결과 얻어지는 코트북의 성능을 기존 알고리즘과 비교하여 개선된 Fuzzy c-means 알고리즘을 찾기 위한 근거를 마련한다.

• Tuberculosis and Respiratory Diseases
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• 제43권2호
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• pp.123-127
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• 1996

Secretion of surfactant phospholipid can be stimulated by a variety of agonists acting via at least three different signal transduction mechanisms. These include the adenylate cyclase system with activation of cAMP-dependent protein kinase; activation of protein kinase C either directly or subsequent to activation of phosphoinositide-specific phospholipase C and generation of diacylglycerols and inositol trisphosphate; and a third mechanism that involves incresed $Ca^{2+}$ levels and a calmodulin-dependent step. ATP stimulates secretion via all three mechanisms. The protein kinase C pathway is also coupled to phopholipase D which, acting on relatively abundant cellular phospholipids, generates diacylglycerols that further activate protein kinase C. Sustained protein kinase C activation can maintain phosphatidylcholine secretion for a prolonged period of time. It is likely that interactions between the different signaling pathways have an important role in the overall physiological regulation of surfactant secretion.

• 생명과학회지
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• 제8권1호
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• pp.102-108
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• 1998

Gltcosylphosphatidylinositol (GPI)에 의해 고정된 단백질의 초기 형태는 골지체에서의 직접적인 processing을 수행하기 위한 아미노와 카르 복시 말단의 hydrophobic signal sequence를 소유하고 있다. 앞서, mouse 임파구로부터 NAD;arginine ADP-ribosyltransferase (Yac-1)가 클로닝되었으며 Yac-1 transferase의 아미노산 배열을 추정해 본 결과, hydrophobic 아미노와 카르복시 말단을 포함하고 있었으며 이는 GPI-anchroed 단백질들의 알려진 signal sequence와 일치하였다. 미 transferase는 야생형의 cDNA로 transfection된 NMU (rat mammary adenocarcinoma) cell의 표면에 존재하였으며 phosphoatidylinosotol-specific phospholipase C에 의해 방출되어졌다. 카르복시 말단의 hydrophobic sequence가 없는 돌연변이체는 수용성이며 분비성인 transferase를 생산하였다. 이러한 사실은 카르복시 말단의 sequence가 없는 돌연변이체는 수용성이며 분비성인 transferase를 생산하였다. 이러한 사실은 카르복시 말단의 sequence가 GPI의 부착에 중요함을 나타내준다.

• 한국항행학회논문지
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• 제26권2호
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• pp.78-84
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• 2022

본 논문에서는 다중 신호원이 존재하는 경우에 닫힌 형태 기반의 3차원 위치 추정 기법을 제안한다. TDOA나 AOA, FDOA와 같은 일반적인 위치 추정 기술은 단일 신호원이 존재하는 경우에 위치를 추정할 수 있으며, 미상의 다중 신호원이 존재하는 경우에 이를 구분하여 위치를 추정하는데 한계가 있다. 제안된 기법은 배열 안테나를 갖는 센서에 수신된 신호의 상호상관 벡터를 계산하고, 상호상관 값으로부터 TDOA값과 AOA값을 추정한다. 그리고 기준 센서의 위치를 이용하여 좌표 변환을 수행하고, 변환된 좌표에 대해 추정된 AOA값을 이용하여 좌표 회전을 수행한 후 각 신호원에 대한 3차원 위치를 추정한다. 제안된 기법은 컴퓨터 모의실험을 통해 그 성능을 검증한다.

• Investigative Magnetic Resonance Imaging
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• 제26권2호
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• pp.125-134
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• 2022

Purpose: The aim of this study was to investigate the change in signal sensitivity over different acquisition start times and optimize the scanning window to provide the maximal signal sensitivity of [1-¹³C]pyruvate and its metabolic products, lactate and alanine, using spatially localized hyperpolarized 3D ¹³C magnetic resonance spectroscopic imaging (MRSI). Materials and Methods: We acquired 3D ¹³C MRSI data from the brain (n = 3), kidney (n = 3), and liver (n = 3) of rats using a 3T clinical scanner and a custom RF coil after the injection of hyperpolarized [1-¹³C]pyruvate. For each organ, we obtained three consecutive 3D ¹³C MRSI datasets with different acquisition start times per animal from a total of three animals. The mean signal-to-noise ratios (SNRs) of pyruvate, lactate, and alanine were calculated and compared between different acquisition start times. Based on the SNRs of lactate and alanine, we identified the optimal acquisition start timing for each organ. Results: For the brain, the acquisition start time of 18 s provided the highest mean SNR of lactate. At 18 s, however, the lactate signal predominantly originated from not the brain, but the blood vessels; therefore, the acquisition start time of 22 s was recommended for 3D ¹³C MRSI of the rat brain. For the kidney, all three metabolites demonstrated the highest mean SNR at the acquisition start time of 32 s. Similarly, the acquisition start time of 22 s provided the highest SNRs for all three metabolites in the liver. Conclusion: In this study, the acquisition start timing was optimized in an attempt to maximize metabolic signals in hyperpolarized 3D ¹³C MRSI examination with [1-¹³C] pyruvate as a substrate. We investigated the changes in metabolic signal sensitivity in the brain, kidney, and liver of rats to establish the optimal acquisition start time for each organ. We expect the results from this study to be of help in future studies.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2006년도 High Temperature Superconductivity Vol.XVI
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• pp.45-45
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• 2006

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권4호
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• pp.166-171
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• 2006

In this paper, we have studied for analysis of the partial discharge(PD) signal in underground transmission line. The PD signal has estimated as detected signal accumulation of a PRPDA method by using Labview, and analyzed with fuzzy algorithm. In our algorithm, we developed system configuration that detected accumulating PD signal using by Labview and programmed fuzzy algorithm can be analyzed the PD signal using with Matlab. With practical PD logic implementation of theoretical detected system and hardware implementation, the device for Hipotronics Company's 50kV setup has generated and then has applied with $15k{\sim}17kV$ with 1:1 time probe. It's also used the LDPE 0.27mmt (scratch error 0.05mmt) to sample for making PD. In conclusion, Our new class of PD detected algorithm has also compared with previous PRPDA or Fuzzy algorithm. which has diagnose more conveniently by adding numerical values.

• 동력기계공학회지
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• 제14권6호
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• pp.41-46
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• 2010

Acoustic emission (AE) technique is a well-known non-destructive test technique. Fatigue crack growth test was performed using SM53C to check up the AE signal occurred by crack growth, so AE system was used to detect the crack signal. Features calculated by the AE signals were analyzed to evaluate the steps divided the crack growth into three. The steps, initiation, growth and breaking, were separated by velocity of the crack growth. Time waveform and power spectrum were created by the AE signal of each one of the steps and compared. In the feature domains, it was found that AE values changed rapidly as the velocity of the crack increasing.

• 융합신호처리학회논문지
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• 제8권4호
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• pp.285-292
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• 2007

SoC는 소프트웨어와 하드웨어가 통합 설계되는 시스템 수준 설계 플랫폼이며 상위 수준 합성은 SoC 설계방법론의 중요한 과정이다. 최근 SPARK라 불리는 병렬 상위 수준 합성 툴이 개발되었다. SPARK는 C코드를 입력받아 코드 이동과 다양한 변형 기술을 이용해서 스케줄하고 최종적으로 합성 가능한 RTL VHDL를 생성한다. 기본 적인 디지털 신호 및 영상처리 알고리즘은 반복 순환문으로 표현되며, 합성을 동해 SPARK는 다양한 루프 변형 알고리즘을 적용한다. 그러나 이 기법에 의한 합성 결과는 디자이너가 수동으로 직접 설계한 최적구현과 비교했을 때 성능 면에서 만족할 만한 결과를 생성하지 못한다. 본 논문에서는 전용 프로그램 논리소자를 가지는 새로운 SoC 플랫폼을 제안하고, C로 기술된 행위 수준 반복 순환문을 2차원 시스톨릭 어레이로 매핑하는 과정을 기술한다. 최종적으로 유도된 시스톨릭 어레이는 제안된 SoC 플랫폼 상의 전용 프로그램 논리소자 상에 구현된다.

• BMB Reports
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• 제32권3호
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• pp.215-225
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• 1999

Phytochromes (with gene family members phyA, B, C, D, and E) are a wavelength-dependent light sensor or switch for gene regulation that underscore a number of photo responsive developmental and morphogenic processes in plants. Recently, phytochrome-like pigment proteins have also been discovered in prokaryotes, possibly functioning as an auto-phosphorylating/phosphate-relaying two-component signaling system (Yeh et al., 1997). Phytochromes are photochromically convertible between the light sensing Pr and regulatory active Pfr forms. Red light converts Pr to Pfr, the latter having a "switch-on" conformation. The Pfr form triggers signal transduction pathways to the downstream responses including the expression of photosynthetic and other growth-regulating genes. The components involved in and the molecular mechanisms of the light signal transduction pathways are largely unknown, although G-proteins, protein kinases, and secondary messengers such as $Ca^{2+}$ ions and cGMP are implicated. The 124-127 kDa phytochromes form homodimeric structures. The N-terminal half contains the tetrapyrrolic phytochromobilin for red/far-red light absorption. The C-terminal half includes both a dimerization motif and regulatory box where the red light signal perceived by the chromophore-domain is recognized and transduced to initiate the signal transduction cascade. A working model for the inter-domain signal communication within the phytochrome molecule is proposed in this Review.