• Geophysics and Geophysical Exploration
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• v.1 no.2
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• pp.116-126
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• 1998

I present a datuming scheme for poststack data that uses wavefield depth extrapolation. The method I have developed allows the use of any depth extrapolation technique, such as phase-shift, split-step, and finite-difference extrapolation. I derive the datuming algorithms by transposing and taking the complex conjugate (i.e. taking adjoint) of the corresponding forward modeling operator, which does upward extrapolation from a flat surface to an irregular surface. The exact adjoint relation between the forward modeling operator and the datuming operator is demonstrated algebraically. Testing the poststack datuming algorithms with synthetic data, using several depth extrapolation algorithms, has shown that the method works well.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1607-1615
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• 1996

A new simply computable operator named DBAH(difference between arithmetic mean and mean)and fuzzy reasoning technique of local thresholds for extracting sketch features are proposed in this paper.The DBAH operator provides some advantages, for example dependence on local intensities and small reponses with small rates of intensity change in very dark regions. Also, the proposed fuzzy reasoning technique has a good performance extracting sketch features without human intervention.

• Kyungpook Mathematical Journal
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• v.34 no.2
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• pp.193-197
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• 1994

• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1401-1422
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• 2015

Under the restriction of finite order, we prove two uniqueness theorems of nonconstant meromorphic functions sharing three values with their difference operators, which are counterparts of Theorem 2.1 in [6] for a finite-order meromorphic function and its shift operator.

• The Pure and Applied Mathematics
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• v.24 no.4
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• pp.191-200
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• 2017

The theory of $u_0-positive$ operators is applied to obtain smallest eigenvalue comparison results for right focal boundary value problems of Atici-Eloe fractional difference equations.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.759-762
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• 2005

Recently, Intelligent Transportation System(ITS) has been applied to satisfy increasing traffic demand every year and to solve many traffic problems. Especially, Advanced Traveller Information System(ATIS) is a transportation system to optimize the trip of each other vehicle. It is important to provide the driver with quick and comfortable path from source to destination. However, it is difficult to provide a shortest path in a road network with dynamic cost. Because the existing research has a static cost. Therefore, in this paper we propose an operator for searching traffic dependent shortest path. The proposed operator finds the shortest path from source to destination using a current time cost and a difference cost of past time cost. Such a method can be applied to the road status with time. Also, we can expect a predicted arrival time as well as the shortest path from source to destination. It can be applied to efficiently application service as ITS and have the advantages of using the road efficiently, reducing the distribution cost, preparing an emergency quickly, reducing the trip time, and reducing an environmental pollution owing to the saving the fuel.

• Journal of Korea Port Economic Association
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• v.27 no.4
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• pp.145-164
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• 2011

The Northeast Asia has been the fastest growing region in the world for the past few decades. And now the economic bloc maintains its status as a major powerhouse of the world economy. On the way of its economic growth, Russia and Central Asian countries have emerged as major trading partners. The Trans-Siberian Railway(TSR) has been playing a pivotal role in promoting economic cooperation between the two regions. This paper investigates economic environment of the Korean TSR service operators through the SWOT analysis, then proposes management strategies for them. For this purpose, the authors analyze characteristics and roles of the TSR service operators. In addition, a comparison of difference between service operators and shippers about their recognition of economic environment of the TSR transportation service is also carried out.

• Journal of Sasang Constitutional Medicine
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• v.28 no.4
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• pp.309-319
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• 2016

Objectives This study was aimed to analyze the reliability of vocal features and probabilities for being in Sasang constitutional types calculated from Sasang constitutional voice diagnosis system according to operator presence. Methods We acquired 96 voice recordings from one male and one female for 4 days. For the first 2 days, the subjects recorded their voice by themselves. For the last 2 days, they recorded according to the instruction of an operator following the standard operating procedure. We analyze the standard deviations of vocal features, probabilities for being three constitutional types, Tae-Eum (TE), So-Yang (SY), and So-Eum (SE) Results In the case of the female, coefficients of variations of the voice variables and the probabilities for being each constitutional type were all within 20%. In the case of the male, coefficients of variations were all within 20% except one variable. Even if there was no instruction from the operator, standard deviations of the probability did not increase for both genders. When recorded without the operator, for male, the probability for being SE decreased by 3.2%. For female, the probability for being TE increased by 5.438%, and that of SE decreased by 3.057%, and that of SY decreased by 2.394%. Conclusions When recorded without operators, for men, there was a significant difference in the probability for being SE. And for women, there were significant differences in the probabilities for all constitutional types.

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.222-226
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• 2013

Objectives: The aim of this study was to assess the influence of operator experience level on the lifespan of the WaveOne Primary file (Dentsply Maillefer, Ballaigues, Switzerland) in extracted teeth. Materials and Methods: Moderately curved canals of extracted maxillary and mandibular molars were randomly distributed into 2 groups: experienced and inexperienced operators. Ten files were allocated to each group (n = 10). Each canal was prepared until the working length was reached, and the same file was used to prepare additional canals until it separated. The number of canals prepared before file separation was recorded. The fragment length of each file was measured, and the location of the fragment in the canal was determined. Data were statistically analysed using the independent 2-sample t-test. Results: The 2 operators prepared a total of 324 moderately curved canals of maxillary and mandibular molars. There was no significant intergroup difference in the mean number of canals prepared (p = 0.27). The average lifespan of the WaveOne Primary file was 17.1 and 15.3 canals, and the longest lifespan was 25 and 20 canals, when used by experienced and inexperienced operators, respectively. There were no statistically significant intergroup differences in separated fragment length and location. Conclusions: Within the limitations of this study, operator experience level appears to have no effect on the lifespan of the WaveOne Primary file in preparation of moderately curved canals. Single teeth with multiple canals can be prepared safely even by a novice operator by using a single file.

• Journal of the Chungcheong Mathematical Society
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• v.29 no.3
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• pp.503-508
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• 2016

We propose a number of finite difference methods for the prices of a European option under the CGMY model. These numerical methods to solve a partial integro-differential equation (PIDE) are based on three time levels in order to avoid fixed point iterations arising from an integral operator. Numerical simulations are carried out to compare these methods with each other for pricing the European option under the CGMY model.