• 자원ㆍ환경경제연구
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• 제9권5호
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• pp.903-924
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• 2000

This paper examines the alternative method to measure the state of overall economic activity. The macroeconomic variables, used for business cycle, take more than a month after a period for collection and aggregation. The electricity generation data is compiled in mechanical ways just after the period. Based on this fact, we develop the two stage estimation method for coincident economic indicators in order to detect the business cycle in an earlier period, using Stock-Watson's Dynamic Factor Model. Using monthly data from 1970 to 1999, it is found that the experimental coincidence economic indicators are well-fitted to data and also that the estimates of two stage estimation method have good explanatory power, equivalent to the experimental coincidence economic indicators. While the RMSE of coincidence economic indicators is found to be 1.27%, that of the experimental coincidence economic indicators is found to be 1.31% and that of the two stage estimation method is around 1.44%. If we take consideration into the fact that it measures the business cycle in one month earlier, we come to the conclusion that the two stage estimation is of great use.

• 대한기계학회논문집
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• 제18권6호
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• pp.1365-1373
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• 1994

Elasto-dynamic deformation of flexible linkage mechanism was analyzed using the finite element method. A computer program was constructed and applied to analyze a specific crank-level 4-bar mechanism, in which the elasto-dynamic deformation of the mechanism system was obtained using mode superposition method in the case of constant input speed and the effect of geometric stiffness on the mechanism is included. Experimental verification of numerical results was conducted by measuring the elasto-dynamic deformation of mid-points of coupler and lever for the 4-bar lingkage mechanism using high speed camera and image data processing systeem. For the elasto-dynamic deformation at the lever mid-point, the numerical results including geometric stiffness almost agree with the experimental ones. However, the numerical results excluding geometric stiffness good agree with the experimental ones at the couper mid-point.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.285-291
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• 2003

An experimental method to measure Q-parameter in-situ is described. The basic idea comes from the fact that the side necking near a crack tip indicates the loss of stress triaxiality, which can be scaled by Q. From the out-of-plane displacement and the in-plane strain near the surface of side necking, stress field averaged through the thickness is calculated and then Q is determined from the difference between the stress field and the HRR field corresponding to the identical J-integral. To prove the validity, three-dimensional finite element analysis has been performed for a CT configuration with side-groove. Q-value which was calculated directly from the near-tip stress field is compared with that determined by simulating the experimental procedure according to the proposed method, that is, the Q-value determined from the lateral displacement and the inplane strain. Also, the effect of location where the displacement and strain are measured is explored.

• 사상체질의학회지
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• 제2권1호
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• pp.123-134
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• 1990

In order to investigate experimentally the clinical effects of Taeuminkalkunhaeki-tang (太陰人葛根解肌湯) that was prescribed to cure the Kansuyolriyolbyong (肝受熱裏熱病) of Taeumin, the author experimented various activities of mixed extract from Taeuminkalkunhaeki-tang by the methods prescribed in the experimental part. The results of the studies were summarized as follows: 1. Sedative effects such as malfunction of the spontaneous motor activity in the wheel cage method experiment and muscle relaxation in the rotor rod method experiment were noted. 2. In mice, the prolongation of the duration of hypnosis Induced by thiopental-Na was noted. 3. In the acetic acid method experiment and the pressing hind paw method experiment, analgesic effects were noted. 4. Inhibitory effects were noted on the convulsions incuced by strychine and picrotoxin. 5. The expansion of blood vessels by relaxation of smooth muscle was noted. According to the above results, effects based on oriental medical references approximate to the actual experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.359-364
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• 2002

Statistical energy method is widely used for the prediction of vibrational and acoustical behavior of complex structures, such as ship building and automobile in mid-, high frequency ranges. However. in order to convince this SEA result, it is important to verify estimated SEA parameters, e. g. modal density, energy in each subsystem, damping loss factor, coupling loss factor. with possible other method. For modal density parameter, the experimental estimations via Experimental Modal Analysis are checked with those from finite element method for both beam- plate and plate-plate cans. Loss factors are calculated by Lyon's simple method for the two subsystem. finally. modal experiments are carried out by varying the mass added on the junction of two subsystem for the purpose of investigating the influence on the coupling loss factor's behavior.

• 전기의세계
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• 제27권2호
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• pp.69-74
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• 1978

There have been a number of experimental or theorethical investigations of transport coefficient for electrons in the field of gas. In this paper the authors present the method by which Townsend first ionization doefficient (.alpha.) or attachment coefficient (.eta.) can be deduced easily and precisely by means of analyzing Townsend equation based on linealized least squares method. The apparent ionization coefficient (.alpha.-.eta.)/p have been analyzed from the experimental data by applying the new method above mentioned. And the values of (.alpha.-.eta.)/p in SF$_{6}$ as a function of E/p were agreement with the values measured by Bhalla et al. who analyzed th experimental pre-breakdown currents. In the same way (.alpha.-.eta.)/p in N$_{2}$O had a same tendency to that of Folkard et al.l.

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1493-1498
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• 2007

In this work, alkyl methacrylate-based microgels were synthesized by an experimental design method, and their sebum absorption characteristics were investigated. The results of fractional factorial experimentation indicated that the cross-linking agent content, solvent content, and stirring speed were the main parameters in the synthesis of the microgels. The suitable synthesis conditions were determined by the response surface design method. Through a study of the monomer and solvent effects, it was confirmed that the microgel shows the highest sebum absorption ratio when t-butyl methacrylate is used as a monomer or when acetone is used as a solvent. The optimal microgel synthesis conditions for cosmetic application were determined, and the resulting microgel had a mean particle size of 4.7 μm and a sebum absorption ratio of 435%.

• Journal of Welding and Joining
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• 제20권5호
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• pp.120-126
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• 2002

Ni-5%Al alloy powder is widely used as the bond coating powder to improve the adhesive strength between the substrate and coating. The important properties in the bond coating are the deposition efficiency and surface roughness. In this study, it was tried to optimize the plasma spray parameters to maximize the deposition efficiency and surface roughness. In the first step, spray current and hydrogen gas flow rate were optimized in order to increase the deposition efficiency. In the next step, the seven plasma spray variables were selected and optimized to improve both the deposition efficiency and surface roughness using the Taguchi experimental method. By these optimization, the deposition efficiency was improved from about 10 % at the frist time to 51.2 % by the optimization of spray current and hydrogen gas flow rate and finally to 65.2 % by the Taguchi experimental method. The average surface roughness was increased from about $12.9\mu\textrm{m}$ to $15.4\mu\textrm{m}$.

• 아동학회지
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• 제23권6호
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• pp.103-119
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• 2002

In this investigation of the effectiveness of the Project Approach Method the 32 4-to 5-year-old subjects (16 each in the experimental and comparative groups) were pre-tested before the Project Approach Method was applied (23 times over 7 weeks) in the experimental group while the comparative group had science activities using standard unit methods of instruction. Then, all the children had a posr-test. Data were analyzed by t-test and ANCOVA. Results showed differences between the experimental group and the comparative group in their scientific problem solving ability. Specifically, effects were found on 14 sub-factors, but no difference were found on 3 sub-factors.

• 설비공학논문집
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• 제11권6호
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• pp.871-879
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• 1999

Present study explains some experimental results on the aerodynamic noise of the cross-flow fan usually installed in the indoor unit of the room air-conditioners and provides a simple reduction method of radiating sound to decrease the total noise level. The spectrums of the noise of the cross-flow fan were analyzed by the spectral decomposition method to characterize the generated sound. The unsteady fluctuating flow field was also measured using the I-type hot-wire probe. Comparing the spectral characteristics of the sound and the flow velocity, a useful noise reduction method was proposed which bounds the region with a fence where the flow fluctuations were noticeably changed in the same fashion as the source spectral distribution functions vary. To validate the proposed method for reducing noise generated by the cross-flow fan, the sound pressure levels of the cross-flow fan system were compared of the experimental rig with and without the bounding fence for various flow rates.