• 제목/요약/키워드: ${\alpha}$-stable process

검색결과 48건 처리시간 0.037초

H$\"{O}$LDER CONTINUITY OF H-SSSI S$\alpha$S PROCESSES

  • Kim, Joo-Mok
    • 대한수학회논문집
    • /
    • 제15권1호
    • /
    • pp.123-131
    • /
    • 2000
  • Let {X(t) : t $\geq$B 0} be a Symmetric $\alpha$ Stable and H-Self-similar process with stationary increments. We examine a.s. Holder unboundedness of S$\alpha$S H-sssi Chentsov processes and H-sssi Chentsov fields for order ${\gamma}$>H. Finally, we prove a.s. Holder continuity of S$\alpha$S H-sssi processes with ergodic seating transformations for the case of H>1/$\alpha$.

  • PDF

웨이브렛 변환과 파워스펙트럼 분석을 통한 EEG 안정상태의 정량적 인식 (Quantitative Recognition of Stable State of EEG using Wavelet Transform and Power Spectrum Analysis)

  • 김영서;박승환;남도현;김종기;길세기;민홍기
    • 융합신호처리학회논문지
    • /
    • 제8권3호
    • /
    • pp.178-184
    • /
    • 2007
  • 일반적으로 EEG 신호는 Alpha파, Beta파, Theta파, Delta파로 구분할 수 있다. Alpha파는 사람에게 있어서 가장 우세한 파형으로써 정신적으로 안정 시 잘 나타나는 뇌파이며, Beta파는 흥분 시 우세하게 나타난다. 본 연구에서는 EEG의 안정 상태를 정량적으로 나타내기 위해 웨이브렛 변환과 파워 스펙트럼 분석을 이용하였다. EEG신호를 웨이브렛 변환을 통해 Alpha파와 Beta파만 검출하여 고속 푸리에 변환을 이용 Alpha파와 Beta파의 파워 스펙트럼을 구하였다. 이후 Beta파의 파워 스펙트럼에 대한 Alpha파의 파워 스펙트럼 비율로 정의되는 상대적 안정상태비(Stable State Ratio)를 계산하였다. 그 결과 피험자가 정상적인 활동 상태에서 정신적으로 편안한 안정 상태에 이르기까지 5분 이내가 16%, $5{\sim}10$분 사이가 9%, 그리고 최소 10분 이상의 시간이 소요되는 피험자집단이 총 69%로 우세하게 나타났다.

  • PDF

Stochastic analysis of external and parametric dynamical systems under sub-Gaussian Levy white-noise

  • Di Paola, Mario;Pirrotta, Antonina;Zingales, Massimiliano
    • Structural Engineering and Mechanics
    • /
    • 제28권4호
    • /
    • pp.373-386
    • /
    • 2008
  • In this study stochastic analysis of non-linear dynamical systems under ${\alpha}$-stable, multiplicative white noise has been conducted. The analysis has dealt with a special class of ${\alpha}$-stable stochastic processes namely sub-Gaussian white noises. In this setting the governing equation either of the probability density function or of the characteristic function of the dynamical response may be obtained considering the dynamical system forced by a Gaussian white noise with an uncertain factor with ${\alpha}/2$- stable distribution. This consideration yields the probability density function or the characteristic function of the response by means of a simple integral involving the probability density function of the system under Gaussian white noise and the probability density function of the ${\alpha}/2$-stable random parameter. Some numerical applications have been reported assessing the reliability of the proposed formulation. Moreover a proper way to perform digital simulation of the sub-Gaussian ${\alpha}$-stable random process preventing dynamical systems from numerical overflows has been reported and discussed in detail.

MULTIDIMENSIONAL SYMMETRIC STABLE PROCESSES

  • Chen, Zhen-Qing
    • Journal of applied mathematics & informatics
    • /
    • 제6권2호
    • /
    • pp.329-368
    • /
    • 1999
  • This paper surveys recent remarkable progress in the study of potential theory for symmetric stable processes. It also contains new results on the two-sided estimates for Green functions Poisson kernels and Martin kernels of discontinuous symmetric $alpha$ -stable process in bounded $C^{1,1}$ open sets. The new results give ex-plicit information on how the comparing constants depend on pa-rametrer $alpha$ and consequently recover the green function and Poisson kernel estimates for Brownian motion by passing $alpha{\uparrow}2$. In addition to these new estimates this paper surveys recent progress in the study of notions of harmonicity integral representation of harmonic func-tions boundary harnack inequality conditional gauge and intrinsic ultracontractivity for symmetric stable processes. Here is a table of contents.

웨이브렛 변환과 파워 스펙트럼 분석을 이용한 EEG의 안정 상태 인식에 관한 고찰 (Recognition of Stable State of EEG using Wavelet Transform and Power Spectrum Analysis)

  • 김영서;길세기;임선아;민홍기;허웅;홍승홍
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2006년도 하계종합학술대회
    • /
    • pp.879-880
    • /
    • 2006
  • The subject of this paper is to recognize the stable state of EEG using wavelet transform and power spectrum analysis. An alpha wave, showed in stable state, is dominant wave for a human EEG and a beta wave displayed excited state. We decomposed EEG signal into an alpha wave and a beta wave in the process of wavelet transform. And we calculated each power spectrum of EEG signal, an alpha wave and a beta wave using Fast Fourier Transform. We recognized the stable state by making a comparison between power spectrum ratios respectively.

  • PDF

SAMPLE PATH PROPERTY OF CHENTSOV FIELDS

  • Kim, Joo-Mok
    • 충청수학회지
    • /
    • 제11권1호
    • /
    • pp.35-44
    • /
    • 1998
  • Let {X(t), $t{\in}\mathbb{R}^n$} be a $S{\alpha}S$ H-sssis Chentsov random field with control measure m. We consider a geometric construction for L$\acute{e}$vy-Chentsov random fields and Takenaka random fields. Finally, we proved some property of conjugate classes and a.s. H$\ddot{o}$lder unboundedness of $S{\alpha}S$ H-sssis Chentsov random fields for all order ${\gamma}$ > H.

  • PDF

Robust Multiuser Detection Based on Least p-Norm State Space Filtering Model

  • Zha, Daifeng
    • Journal of Communications and Networks
    • /
    • 제9권2호
    • /
    • pp.185-191
    • /
    • 2007
  • Alpha stable distribution is better for modeling impulsive noises than Gaussian distribution in signal processing. This class of process has no closed form of probability density function and finite second order moments. In general, Wiener filter theory is not meaningful in S$\alpha$SG environments because the expectations may be unbounded. We proposed a new adaptive recursive least p-norm Kalman filtering algorithm based on least p-norm of innovation process with infinite variances, and a new robust multiuser detection method based on least p-norm Kalman filtering. The simulation experiments show that the proposed new algorithm is more robust than the conventional Kalman filtering multiuser detection algorithm.

최적의 luminescence 신호 분석을 위한 유전자 전달 방법의 비교연구 (Comparative studies of various transfection processes for the optimal luminescence signal analysis)

  • 박서현;이승호
    • 한국산학기술학회논문지
    • /
    • 제17권11호
    • /
    • pp.640-647
    • /
    • 2016
  • 형광 간섭 현상을 최소화시켜 상대적으로 민감한 측정이 가능한 aequorin기반 luminescence기술은 $G_{{\alpha}16}$ 단백질 도입을 통해 세포 내부의 칼슘 이동 신호를 감지하여 G 단백질 결합 수용체(G protein-coupled receptor, GPCR)의 기능 분석을 가능하게 하는 세포 기반 분석 기술로 수용체 및 G 단백질 유전자 전달의 최적화 과정이 필수적이다. 본 연구를 위해 corticotropin releasing factor receptor subtype 2(CRF2) 수용체를 모델 시스템으로 CRF2와 $G_{{\alpha}16}$ 단백질이 구축된 세 가지 안정화 세포주를 제작하였고, 이들을 이용한 서로 다른 세 가지 조건의 임시 발현 세포주에서 작용제(sauvagine)와 길항제(K41498)의 반응성을 분석하여 최적의 유전자 전달 방법을 도출하고자 하였다. 그 결과 sauvagine 및 K41498의 농도에 따른 반응에서 CRF2-$G_{{\alpha}16}$ 안정화 세포주가 임시 발현 세포주보다 10배 이상의 유효신호 비율을 나타내었고(z'=0.77) 임시 발현 세포주의 경우 $G_{{\alpha}16}$의 안정화 발현 이후에 CRF2를 전달하는 경우가 다른 임시 발현 조건보다 2배 이상 높은 효율을 보였다(z'=0.84). 따라서 임시 유전자 전달 기술을 GPCR 세포 기능 분석 시스템에 활용할 경우 $G_{{\alpha}16}$ 단백질에 대한 안정화 세포주를 우선적으로 구축하고, 목표하는 다양한 수용체들을 단계적으로 발현시키는 것이 최선의 방법이라 판단된다.

Characterization of Multiphase in $Fe_2O_3$ Thin Film by PECVD

  • Kim, Bum-Jin;Lee, Eun-Tae;Jang, Gun-Eik;Chung, Yong-Sun
    • 한국결정성장학회:학술대회논문집
    • /
    • 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
    • /
    • pp.79-85
    • /
    • 1997
  • Fe$_2$O$_3$ thin films were prepared on $Al_2$O$_3$ substrate by PECVD(Plasma-Enhanced Chemical Vapor Deposition) process. The phase transformation of iron oxide film was determined as the substrate temperature and reduction-oxidation process. $\alpha$-Fe$_2$O$_3$ was stable in deposition temperature ranges of 80~15$0^{\circ}C$. Fe$_3$O$_4$ phase was obtained by the reduction process of $\alpha$-Fe$_2$O$_3$ phase in H$_2$ ambient. Fe$_3$O$_4$ phase was transformed into a ${\gamma}$-Fe$_2$O$_3$ thin film under controlled oxidation conditions at 280~30$0^{\circ}C$.

  • PDF

A Novel Integrative Expression Vector for Sulfolobus Species

  • Choi, Kyoung-Hwa;Hwang, Sungmin;Yoon, Naeun;Cha, Jaeho
    • Journal of Microbiology and Biotechnology
    • /
    • 제24권11호
    • /
    • pp.1503-1509
    • /
    • 2014
  • With the purpose of facilitating the process of stable strain generation, a shuttle vector for integration of genes via a double recombination event into two ectopic sites on the Sulfolobus acidocaldarius chromosome was constructed. The novel chromosomal integration and expression vector pINEX contains a pyrE gene from S. solfataricus P2 ($pyrE_{sso}$) as an auxotrophic selection marker, a multiple cloning site with histidine tag, the internal sequences of malE and malG for homologous recombination, and the entire region of pGEM-T vector, except for the multiple cloning region, for propagation in E. coli. For stable expression of the target gene, an ${\alpha}$-glucosidase-producing strain of S. acidocaldarius was generated employing this vector. The malA gene (saci_1160) encoding an ${\alpha}$-glucosidase from S. acidocaldarius fused with the glutamate dehydrogenase ($gdhA_{saci}$) promoter and leader sequence was ligated to pINEX to generate pINEX_malA. Using the "pop-in" and "pop-out" method, the malA gene was inserted into the genome of MR31 and correct insertion was verified by colony PCR and sequencing. This strain was grown in YT medium without uracil and purified by His-tag affinity chromatography. The ${\alpha}$-glucosidase activity was confirmed by the hydrolysis of $pNP{\alpha}G$. The pINEX vector should be applicable in delineating gene functions in this organism.