• ETRI Journal
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• v.9 no.3
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• pp.74-85
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• 1987

In this paper, a new kind of dual tone multifrequency receiver(DTMFR) is proposed, in which detection is made in terms of the partial correlation(PARCOR) coefficients for efficient DTMF signal detection against both temporary decoding errors by crosstalks possibly coming from adjoint telephone lines during transmission and so-called digit simulation by background voice or noise signals during interdigit period. A simulation study on the behaviour of PARCOR coefficients for tone signals and non-signals has been performed in order to provide the rationale on the feasibility of the proposed DTMFR algorithm. Based upon simulation results, a more refined detection strategy as an example is presented and explained together with the corresponding decision logic.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.470-477
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• 2017

Ceramic processing to fabricate 3D complex ceramic structures is crucial for structural, energy, environmental, and biomedical applications. A unique process is ceramic stereolithography, which builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This approach directly writes layers in liquid ceramic suspension and allows one to fabricate ceramic parts and products having more accurate, complex geometries and smooth surfaces. In this paper, both UV curable materials and processes are presented. We focus on the basic material principles associated with free radical polymerization and rheological behavior, cure depth and broadening of cured lines, scattering at ceramic interface and their corresponding simulation. The immediate potentials for ceramic AM to change industry fabrication are also highlighted.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.172-174
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• 2003

Power system restoration following a large black-out starts with charging of primary transmission lines. As the power systems are gradually enlarged and become more complex, the power plant and transmission of electricity units are being expanded continuously. Accordingly, evaluation and reconfiguration of the primary transmission system is needed. So far it has been decided to analyze and evaluate with the knowledge and experience of the corresponding expert. This paper presents an expert system for configuring the optimum primary transmission system based on expert knowledge, static analysis and configuration data.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.399-408
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• 2015

This paper concentrated on the ultimate uniaxial compressive strength of stiffened panel with opening under lateral load and also studied the design-oriented formulae. For this purpose, three series of well executed experiments on longitudinal stiffened panel with rectangular opening subjected to the combined load have been selected as test models. The finite element analysis package, ABAQUS, is used for simulation with considering the large elasticplastic deflection behavior of stiffened panels. The feasibility of the numerical procedure is verified by a good agreement of experimental results and numerical results. More cases studies are executed employing nonlinear finite element method to analyze the influence of design variables on the ultimate strength of stiffened panel with opening under combined pressure. Based on data, two design formulae corresponding to different opening types are fitted, and accuracy of them is illustrated to demonstrate that they could be applied to basic design of practical engineering structure.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.264-268
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• 1997

In order to study the structure-activity relationship of 7, 8-dimethoxy-2-methyl-3-(4, 5-methylenedioxy-2-vinylphenyl)isoquinoline-1(2H) -one (2), which has exhibited significant antitumor activity, chemical modifications of 2 were performed to yield the corresponding products (3-7). Further systematic uses of an efficient procedure for the synthesis of 3-arylisoquinoline derivatives produced the substituted compounds (9a-9g), which were tested for in vitro antitumor activity against five different human cancer cell lines.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.283-287
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• 1997

In order to identify the structural requirement at 4-position of 1-arylsulfonyl-4-phenyl-4,5-dihydro-2-limidazolones 3 for their cytotoxicity, the corresponding 1-arylsulfonyl-4-cyclohexyl-4,5-dihydro-2-imidazolones 4 were synthesized and their in vitro cytotoxicity against human solid tumor cell lines were measured. Unlike compounds 3a-c, cyclohexyl analogues 4a-c do not show the cytotoxicity. This dramatic loss of activity of these analogues on the volume change with the bulkier cyclohexyl group indicates that the planar structure at 4-position of 1-arylsulfonyl-4-pheny-4,5-dihydro-2-limidazolones 3 is required for their activity as an important pharmacophoric moiety.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.85-88
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• 1999

We fabricated resistive superconducting fault current lmiters based on YBa$_2$Cu$_3$O$_{7}$ thin films and investigated their quench propagation characteristics. The YBa$_2$Cu$_3$O$_{7}$ film was coated with a gold layer and patterned into 1 mm wide meander lines by photolithography. The limiters were tested with simulated fault currents of various fault angles and amplitudes. The quench propagation characteristics were explained based on the heat transfer within the film as well as between the film and the surrounding liquid nitrogen. The quench completion time strongly depended on the potential fault current. It was 1 msec at the peak fault current of 76 A/peak/ and corresponding quench propagation speed was 43 m/sec (film cross section: 4 x 10$^{-6}$ $\textrm{cm}^2$).

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1172-1176
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• 1999

Nucleophilic substitution reaction of Y-benzyl bromide with X-pyridines are investigated in DMSO at 45.0℃. Biphasic rate dependence is observed on varying the substituents in the substrate (Y) as well as in the nucleophile (X). The two well-defined straight lines in the Hammett (ρy) and Bronsted ( βx) plots are interpreted to indicate the changes in transition-state structure, a decrease in bond cleavage as the substituent on the substrate is changed from electron-donors ( ρy < 0) to electron-acceptors ( ρy > 0), and an increase in the extent of bond formation with the corresponding changes of the substituent on the pyridine. A Jencks' type analysis of separate polar (ρ) and resonance (ρr) effects can also be accounted for by the change of the transition-state structure, not by the variable combination of polar and resonance effects.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.279-285
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• 2018

Different English terms indicating a same part in insect head were arranged according to position and function, and their corresponding different Korean terms were suggested. The terms include lines on head surface, head regions of embryo, external and internal skeletons, internal parts of mouth, long mouths, external parts and basic segments of antenna, antennal shapes, and hairs on surface.

• Journal for History of Mathematics
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• v.32 no.1
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• pp.17-25
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• 2019

This essay elucidates the way the geometries of space-time theories explain material bodies' motions. A conventional attempt to interpret the way that space-time geometry explains is to consider the geometrical structure of space-time as involving a causally efficient entity that directs material bodies to follow their trajectories corresponding to the laws of motion. Newtonian substantival space is interpreted as an entity that acts but is not acted on by the motions of material bodies. And Einstein's curved space-time is interpreted as an entity that causes the motions of bodies. This essay argues against this line of thought and provides an alternative understanding of the way space-time geometry explain the laws of motion. The workings of the way that Newton's flat and Einstein's curved space-time explains the law of motion is such that space-time geometry encodes the principle of inertia which specifies straight lines of moving bodies.