• 대한수학회보
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• 제55권5호
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• pp.1463-1481
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• 2018

Let $X=\{X_t\}_{t{\geq}0}$ be a $L{\acute{e}}vy$ process in ${\mathbb{R}}^d$ and ${\Omega}$ be an open subset of ${\mathbb{R}}^d$ with finite Lebesgue measure. The quantity $H_{\Omega}(t)={\int_{\Omega}}{\mathbb{P}}^x(X_t{\in}{\Omega})$ dx is called the heat content. In this article we consider its generalized version $H^{\mu}_g(t)={\int_{\mathbb{R}^d}}{\mathbb{E}^xg(X_t){\mu}(dx)$, where g is a bounded function and ${\mu}$ a finite Borel measure. We study its asymptotic behaviour at zero for various classes of $L{\acute{e}}vy$ processes.

• Communications for Statistical Applications and Methods
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• 제19권5호
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• pp.639-646
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• 2012

The exponential continuous time GARCH(p,q) model for financial assets suggested by Haug and Czado (2007) is considered, where the log volatility process is driven by a general L$\acute{e}$vy process and the price process is then obtained by using the same L$\acute{e}$vy process as driving noise. Uniform ergodicity and ${\beta}$-mixing property of the log volatility process is obtained by adopting an extended generator and drift condition.

• 재무관리연구
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• 제24권4호
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• pp.1-43
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• 2007

전통적인 옵션가격결정모형인 블랙-숄즈 모형(Black-Scholes model)은 기초자산의 로그수익률(log-return)이 브라운운동(Brownian motion)을 따른다는 가정에 기반을 두고 있다. 그러나 이 가정은 현실적인 한계가 많은 것으로 비판을 받아 왔다. 이에 따라 지난 20여 년간 브라운 운동 이외에 새로운 확률과정을 도입한 모형들이 연구되고 도출되었다. 최근에는 레비과정(L$\acute{e}$vy process)에 기반한 모형들이 활발히 연구되어오고 있는데, 그 기원은 1994년 거버(Gerber)와 쉬우(Shiu)에 의한 거버-쉬우 모형(Gerber-Shiu model)이다. 2004년 치앙(Cheang)은, 거버-쉬우 모형이 하나의 레비과정을 가정한 데 비해, 복수의 독립적인 레비과정을 가정하여 옵션가격결정모형을 유도함으로써 거버-쉬우 모형을 추세(drift)와 도약(jump)을 갖는 경우로 확장할 수 있는 가능성을 제시하였다. 본 논문에서는 치앙의 모형을 이용하여 레비과정 하에서의 추세와 도약을 갖는 거버-쉬우 모형을 유도하였다. 여기에 감마분포를 도입하여 1993년에 도출된 헤스톤 모형(Heston model)에 도약을 도입한 형태의 모형을 유도하였다. 아울러 이렇게 유도된 모형에 대하여 KOSPI200 지수 옵션 자료를 사용해서 블랙-숄즈 모형과의 가격설명력을 비교하였다. 그 결과, 본 논문에서 유도된 모형이 블랙-숄즈 모형 이상의 가격설명력을 보이는 것으로 나타났다.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1305-1314
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• 2010

In this paper, we deal with a class of one-dimensional reflected backward stochastic differential equations driven by a Brownian motion and the martingales of Teugels associated with an independent L$\acute{e}$vy process having a stochastic Lipschitz coefficient. We derive the existence and uniqueness of solutions for these equations via Snell envelope and the fixed point theorem.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제15권4호
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• pp.277-290
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• 2011

We define some multi-type asset models derved from L$\acute{e}$vy proceses which emphasize coefficients of stochastic differential equations. Also these asset models can be represented by Doleance-Dade linear equations derived from jump-type semimartingales which are decomposed by various terms of time basically. For these asset models, we can construct optimal portfolio strategy by using filtered various information at each check time.

• 대한수학회논문집
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• 제12권3호
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• pp.725-741
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• 1997

This paper considers the problem of deriving exponential probability inequalities for product symmetric Poisson processes. As an application they are used to show the existence of regular version of some product process derived from L$\acute{e}$vy process.

• Communications for Statistical Applications and Methods
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• 제21권4호
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• pp.327-334
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• 2014

Various modified GARCH(1, 1) models have been found adequate in many applications. We are interested in their continuous time versions and limiting properties. We first define a stochastic integral that includes useful continuous time versions of modified GARCH(1, 1) processes and give sufficient conditions under which the process is exponentially ergodic and ${\beta}$-mixing. The central limit theorem for the process is also obtained.

• 충청수학회지
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• 제11권1호
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• pp.35-44
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• 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.

• 대한수학회지
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• 제50권5호
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• pp.1009-1031
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• 2013

In this paper, using elementary calculus only, we give a simple proof that Green function estimates imply the sharp two-sided pointwise estimates for Poisson kernels for subordinate Brownian motions. In particular, by combining the recent result of Kim and Mimica [5], our result provides the sharp two-sided estimates for Poisson kernels for a large class of subordinate Brownian motions including geometric stable processes.

• Communications for Statistical Applications and Methods
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• 제17권4호
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• pp.483-491
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• 2010

This study provides the explicit computation of the ruin probability of a Le￠vy process on finite time horizon in Theorem 1 with the help of a fluctuation identity. This paper also gives the numerical results of the ruin probability in Variance Gamma(VG) and Normal Inverse Gaussian(NIG) models as illustrations. Besides, the paths of VG and NIG processes are simulated using the same parameter values as in Madan et al. (1998).