• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.642-650
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• 2005

This research investigates the effects of adding oxidants such as $Fe^0$, $Fe^{2+}$, and ${S_2O_8}^{2-}$ in the sonolysis of 1,4-D. Results indicate that the degradation could be divided into two steps (initiation and acceleration) kinetically. The initial portion agreed with zero-order expression, while the second portion could be fitted with pseudo first-order expression. In the presence of ${HCO_3}^-$, as a radical scavenger, the degradations of 1,4-D and TOC were suppressed, indicating that OH radical is an important factor in the sonolysis. The overall degradation efficiency of 79.0% in the sonolysis was achieved within 200 minutes. While $Fe^0$, $Fe^{2+}$, and ${S_2O_8}^{2-}$ were individually combined with sonication, the degradation efficiency of 1,4-D increased 18.6%, 19.1%, and 16.5% after 200 min, respectively. The addition of oxidants not only changed the kinetic model from zero to pseudo first order at initiation step, but also increased the rate constants in the acceleration step. The addition of oxidants in the sonolysis of 1,4-D also improved the mineralization of 1,4-D, however, the effect of adding oxidants on the rate increase was similar regardless of the oxidants.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.2
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• pp.55-76
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• 1998

The first part of this article investigates the general characteristics and the advantages and disadvantages of the analytico-synthetic classification over the enumerative one. The second part analyzes the general steps and related problems in compiling an analytico-synthetic scheme, and investigates the steps further including facet analysis , choosing order in main classes, citation order and order in array : and adding notations, through an illustrative scheme for a matrimonial agency's records.

• Bulletin of the Korean Mathematical Society
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• v.54 no.6
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• pp.2155-2163
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• 2017

Zwegers showed that a mock theta function can be completed to form essentially a real analytic modular form of weight 1/2 by adding a period integral of a certain weight 3/2 unary theta series. This theta series is related to the holomorphic modular form called the shadow of the mock theta function. In this paper, we discuss the computation of shadows of the second order mock theta functions and show that they share the same shadow with a mock theta function which appears in the Mathieu moonshine phenomenon.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.23-28
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• 2010

According to increasing projection order, the AP algorithm bas noise amplification problem in large background noise. This phenomenon degrades the performances of the AP algorithm. In this paper, we analyze convergence characteristic of the AP algorithm and then suggest a noise robust modified AP algorithm for reducing this problem. The proposed algorithm normalizes the update equation to reduce noise amplification of AP algorithm, by adding the multiplication of error power and projection order to auto-covariance matrix of input signal. By computer simulation, we show the improved performance than conventional AP algorithm.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.472-474
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• 1999

The design procedure originally proposed by Manabe is involved, because experiences and manual skills are necessary, especially, in the case of designing low fixed-order controllers for high-order plants, and the concept of manual skills are not clearly defined. So we propose a concept and a design procedure of Approximate Pole Placement that substitute for the manual skills. And the validity of the procedure is shown by example problems. Moreover, we also propose a procedure of adding the role of improving transient response performance to the feedforward compensator that previously has only the role of tracking in steady-state the validity of the procedure is also shown by example problems.

• The Korean Journal of Applied Statistics
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• v.11 no.2
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• pp.451-459
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• 1998

The analysis of data from a multiresponse experiment requires careful consideration of the multivariate nature of the data. In a multiresponse sitation, the optimization problem is more complex than in the single response case. The biplot is a graphical tool which make the analyst to understand the correlation of the response variables, the relation of the response variables arid the explanatory variables and the relative importance of the explanatory variables. In case of good fitting of the first order model, we can draw the biplot with the first order experimental design. Otherwise, we can make the biplot with the second order experimental design by adding other experimental points.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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• pp.126-134
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• 1998

In order to increase the modeling power and productivity of CAD/CAM systems, demands for customization of CAD/CAM system increased. Customization of a CAM system involves making it easier to learn and use, adding new modeling features not supported in a general purpose CAM system, and providing parametric inputting mechanism. A customization from a commercial CAM system (OMEGA) has implemented for two dimensional free curve CNC glass scribing machine of medium size company in Cheonan. A CAD technician who has no CAM experience can operate this customized CAM system satisfactorily.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.450-455
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• 1998

In this paper, finite element with embedded discontinuous line is introduced in order to avoid the difficulties of adding new nodal points along with crack growth in discrete crack model. With the discontinuous element using discontinuous shape function, stiffness matrix of finite element is derived and dual mapping technique for numerical integration is employed. Using the finite element program made with employed algorithms, algorithm is verified and fracture analysis of simple concrete beam is performed.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.488-494
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• 1991

In this study, the effects of catalyst and DCCA content were investigated in order to determine the optimum conditions of monolithic silica gel formation through sol-gel process. Formamide, oxalic acid, glycerol and dimethylformamide are used as DCCA. To observe the phenomena in drying and heat-treating of gels, we examined structural exchange of gels using FT-IR, TG-DTA and XRD. Monolithic gels were obtained by adding formamide and dimethylformamide as DCCA. According to the heat treatment schedule, silica glass is prepared by heat-treatment up to 1050$^{\circ}C$.

• Journal of Korean Society for Quality Management
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• v.37 no.3
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• pp.83-93
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• 2009

This study proposes a stepwise approach to product safety management(PSM), of which roadmap consists of five phases. ISO 9001 QM model is assumed as the first-phase model and each higher-phase model is built by adding a corresponding module to the lower one. In the phase order, those modules are CCMS, a failure to warn, manufacturing defect and design defect. The progress in PSM of a domestic food company is discussed.