• 한국정보전자통신기술학회논문지
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• 제2권2호
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• pp.29-36
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• 2009

비선형적인 위상 변화를 지닌 비정상(non-stationary)신호는 레이더(Radar), 통신(telecommunication), 생체공학, 지질탐사, 음향 등 여러 분야에서 쉽게 접하는 신호이다. 비정상신호는 일반적으로 시간에 따라 신호의 물리적 특성이 변화하는 신호를 의미하며, 순간 주파수는 신호의 특정시간에 해당하는 신호의 주파수를 의미한다. 이 논문에서는 순간 주파수를 결정하기 위한 연속 웨이브렛 변환의 적용에 대하여 논하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제2권2호
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• pp.49-56
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• 1998

In this paper, by the use of an Ostrowski type integral inequality for double integrals, we establish an upper bound for the estimation error variance of a continuous stream with stationary variogram.

• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.620-623
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• 2010

A brush type chiral stationary phase (CSP 2) derived from ${\alpha}$-amino ${\beta}$-lactam was prepared for the separation of the enantiomers of ${\beta}$-blockers. Compared to the CSP derived from ${\alpha}$-amino phosphonate (CSP 1), in general, the conformationally rigid CSP 2 showed greater scope and much enhanced enantioselectivity for the resolution of ${\beta}$-blockers. The effect of various salt additives on enantioseparation of ${\beta}$-blockers in the mobile phase was investigated. The unusual effect of temperature on the chromatographic behaviors was observed on CSP 2. It also afforded appreciable increases in enantioselectivity without significantly affecting resolution, as the column temperature was reduced.

• Communications for Statistical Applications and Methods
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• 제23권5호
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• pp.423-432
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• 2016

In this paper, we stochastically analyze the continuous time surplus process in a risk model which involves a continuous type investment. It is assumed that the investment of the surplus to other business is continuously made at a constant rate, while the surplus process stays over a given sufficient level. We obtain the stationary distribution of the surplus level and/or its moment generating function by forming martingales from the surplus process and applying the optional sampling theorem to the martingales and/or by establishing and solving an integro-differential equation for the distribution function of the surplus level.

• Journal of Magnetics
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• 제18권2호
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• pp.207-211
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• 2013

In a coaxial magnetic gear, bridges connecting separate pole pieces are useful for fabrication and also improve mechanical reliability. However, they have a negative influence on electromagnetic performance parameters such as transmission torque and iron loss. This paper investigates the effect of stationary pole pieces connected by bridges on the electromechanical characteristics. The bridge type and thickness are the main parameters influencing the performance of a coaxial magnetic gear. The inner, center, and outer bridge types each show the best performance in terms of different characteristics. However, for any bridge type, an increase in the bridge thickness reduces the overall electromagnetic performance, except for the torque ripple, and improves the overall mechanical performance, including the deformation, von Mises stress, and natural frequency of the stationary part.

• Bulletin of the Korean Chemical Society
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• 제15권1호
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• pp.15-20
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• 1994

The adsorption model in reversed phase liquid chromatography has been critically examined. It has been found that use of the Everett type surface activity coefficient for the solute in the stationary phase is not useful to study the retention characteristics of a nonpolar solute. We suggest a modified model. In this model it is assumed that the displaced modifier molecules from the surface monolayer do not transfer into the bulk mobile phase but stick to the nonpolar solute which has displaced them. In addition, we prefer to use an apparent stationary phase activity coefficient of the soluie instead of the Everett type activity coefficient. This modified adsorption model well explains the mobile and stationary phase effects on the solute retention upon variation of mobile phase composition.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.100.2-101
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• 2003

The global regulator, GacS (global antibiotic and cyanide sensor kinase), was required for the increased resistance to hydrogen peroxide occurring as cultures of the rhizobacterium, P. chlororaphis O6, matured. Specific stationary-phase peroxidase and catalase isozymes were absent in the GacS mutant, whereas a manganese-superoxide dismutase isozyme was expressed earlier and to a great extent than wild type. In the wild type cell, transcript accumulation of rpoS was higher in late logarithmic-phase cells than cells from mid logarithmic- or stationary-phase. Transcripts from rpoS in the GacS mutant were reduced in each of these growth phases compared to the wild type expression. The down stream sequence from rpoS lacked sequences encoding a small RNA, rsmZ, found in other pseudomonads and implicated in control of genes activated by the GacS system. These findings suggest that GacS-mediated regulation of RpoS plays role in control of oxidative stress in P. chlororaphis O6 by as yet an unknown mechanism.

• Journal of the Korean Statistical Society
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• 제35권2호
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• pp.143-156
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• 2006

In the present paper, various solutions for generalized canonical correlation analysis (GCCA) are considered depending on the criteria and constraints. For the comparisons of some characteristics of the solutions, we provide with certain unifying stationary equations which might to also useful to obtain various generalized canonical correlation analysis solutions. In addition, we suggest an approach for the generalized canonical correlation analysis by exploiting the concept of maximum eccentricity originally de-signed to test the internal independence structure. The solutions, including new one, are compared through unifying stationary equations and by using some numerical illustrations. A type of iterative procedure for the GCCA solutions is suggested and some numerical examples are provided to illustrate several GCCA methods.

• 대한수학회논문집
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• 제28권2호
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• pp.383-396
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• 2013

We consider an M/PH/1 queue with deterministic impatience time. An exact analytical expression for the stationary distribution of the workload is derived. By modifying the workload process and using Markovian structure of the phase-type distribution for service times, we are able to construct a new Markov process. The stationary distribution of the new Markov process allows us to find the stationary distribution of the workload. By using the stationary distribution of the workload, we obtain performance measures such as the loss probability, the waiting time distribution and the queue size distribution.

• 한국경영과학회지
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• 제29권4호
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• pp.1-10
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• 2004

In this paper we study bounds for characteristics of stationary waiting times in (max, +)-linear systems with a Poisson arrival process. which are prevalent in manufacturing systems, kanban systems, cyclic and acyclic fork-and-join type systems, finite or infinite capacity tandem queues with various kinds of blocking, transportation systems, and telecommunication networks, and so on. Recently, some results on series expansion for characteristics, such as higher moments, Laplace transform, and tail probability, of transient and stationary waiting times in a class of (max, +)-linear systems via Taylor series expansions have been studied. In order to overcome the computational complexity in those results, we consider bounds for characteristics of stationary waiting times using valuable stochastic ordering results. Some numerical examples are also provided.