• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.235-241
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• 1988

This study was carried out to identify the variation of culm characteristics of Phyllostachys bambusoides associated with attitudinal gradient in Mt. Jiri. The results obtained were summarized as follows : It was estimated that the average temperature at the altitude of 400 meters of Mt. Jiri was $12^{\circ}C$ which was closely associated with the horizontal distributions. It was observed that frequency distribution of the culm height, D.E.H. and clear length from the altitude of 200 meters to 400 meters shown at higher than that from 500 meters to 600 meters, and that frequency of clear length/culm height showed about equal for both altitude ranges. In the case of culm height, D.E.H. and clear length/culm height, coefficients of variation ranged from 15 percent to 25 percent, and those of clear length were over 25 percent for both altitude ranges. It was observed that culm height, D.E.H., clear length and clear length/culm height among each altitude ranges were significant at the 1 percent level. The Duncan's Test of culm characteristics among altitude ranges distinguished bamboos of below 400 meters from bamboos of over 500 meters. The correlation coefficients among culm characteristics of Phyllostachys bambusoides associated with attitudinal gradient were shown to be highly significant. In conclusion, the variation of calm characteristics of Phyllostachys bambusoides was large for below 400 meters and these results suggest that planting of the species should be done below 400 meters.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.577-584
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• 2018

In This study, length variation test, shock test, and noise test were conducted to evaluate the performance of synthetic resin form. In addition, the handling easiness of synthetic resin form was examined through field application. Results of both thermal length variation test and shock test satisfied the KS standards. for noise test, the result of uro-form was 106.7dB(A) in average while that of synthetic resin form was 100.4dB(A) in average. It is considered that the high sound pressure level of euro-form with this noise characteristic may have negative physical and psychological impact on people who are consistently exposed in the residential area. Finally, there was no warping or bulging of the mold during concrete placement in the field application. Also, the concrete surface finish of synthetic resin form was better than that of euro-form.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.2
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• pp.144-149
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• 2014

A ground firing test for hot-fire performance evaluation according to the characteristic length($L^*$) variation of thrust chamber was carried out for the hydrazine thruster which may be employed in space launch vehicles. A scrutiny into the performance characteristics of each thruster is made in terms of thrust, specific impulse, response characteristics, and characteristic velocity at steady-state firing mode with propellant inlet pressure of 2.41 MPa (350 psia). Through the test results, it has been verified that performance of characteristic velocity and specific impulse degrades as the characteristic length deviates from that of the standard model. Thus, it is confirmed that the thrust chamber configuration of standard model was suitably designed for the requirement specified.

• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.245-248
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• 2011

The scaling down of metal oxide semiconductor field-effect transistors (MOSFETs) for the last several years has contributed to the reduction of the scaling variables and device parameters as well as the operating voltage of the MOSFET. At the same time, the variation in the electrical characteristics of MOSFETs is one of the major issues that need to be solved. Especially because the issue with variation is magnified as the drive voltage is decreased. Therefore, this paper will focus on the variations between electrical characteristics and drain voltage. In order to do this, the test patterned multi-finger MOSFETs using 90-nm process is used to investigate the characteristic variations, such as the threshold voltage, DIBL, subthreshold swing, transconductance and mobility via parasitic resistance extraction method. These characteristics can be analyzed by varying the gate width and length, and the number of fingers. Through this modeling scheme, the characteristic variations of multi-finger MOSFETs can be analyzed.

• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.260-266
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• 2002

A numerical simulation has been performed to estimate the transient pressure variation in the tunnel when G7 test train passes through the test tunnel in the Kyoeng-Bu high-speed railway. A modified patched grid scheme is developed to handle the relative motion between a train and a tunnel. Also, a hybrid dimensional approach is proposed to calculate the train-tunnel interaction problem efficiently. An axi-symmetric unsteady Euler solve using the Roe's FDS is used for analyzing a complicated pressure field in tunnel during the test train is passing through the tunnel. Usually, this complex phenomenon depends ell the train speed, train length, tunnel length, blockage ratio between train and tunnel cross-sectional area, relative position between train and tunnel, etc. Therefore, numerical simulation should be done carefully in consideration of these factors. Numerical results in this study would be good guidance to make test plans, test equipments selection and to decide their measuring locations. They will also supply important information to the pressurization equipment for high-speed train.

• Journal of KIISE:Software and Applications
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• v.34 no.2
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• pp.104-111
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• 2007

This paper examines how the performance of an automatic speech recognizer was improved for Korean Point-of-Interest (POI) data by modeling pronunciation variation using structural prosodic information such as prosodic words and syllable length. First, multiple pronunciation variants are generated using prosodic words given that each POI word can be broken down into prosodic words. And the cross-prosodic-word variations were modeled considering the syllable length of word. A total of 81 experiments were conducted using 9 test sets (3 baseline and 6 proposed) on 9 trained sets (3 baseline, 6 proposed). The results show: (i) the performance was improved when the pronunciation lexica were generated using prosodic words; (ii) the best performance was achieved when the maximum number of variants was constrained to 3 based on the syllable length; and (iii) compared to the baseline word error rate (WER) of 4.63%, a maximum of 8.4% in WER reduction was achieved when both prosodic words and syllable length were considered.

• 한국생태학회:학술대회논문집
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• 2002.08a
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• pp.107-111
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• 2002

During the breeding season of 1998, breeding ecology of the Great Reed-Warbler (Acrocephalus arundinaceus orientalis) was studied at Yangsoo-ri and Yongdam-ri of the Yangpyung-gun, Kyunggi province, Korea. Egg-weight (CV: 6.25) was more variable than either length or breadth, and breadth was the least variable of the measures. Significant variations In overall egg-weight occurred between clutches, and that more of the total variation in egg-weight and shape are due to inter-clutch variation as to intra-clutch variation when the data were pooled. The last egg tends to be larger than the remaining eggs in the clutch of the Great Reed-Warbler, suggest- ing the Great Reed-Warbler may adopt the brood-survival strategy. When method 3 was used, the most common incubation period is 12 days. In the Great Reed-Warbler, the length of the incubation period was related to clutch-size when method 1 (r=0.485, p<0.05) and method 2 (r=0.621, p<0.01) were employed, but not related to egg weight. The average number of days of hatching asynchrony was 2.5, raging 0.5∼2.5. Asynchronous hatching was related to the clutch size (r=0.66, p<0.01). Hatching sequence was closely related to the laying sequence (r=0.93, p<0.001), suggesting Great Reed-Warblers incubate their eggs before clutch completion. The effect of egg weight on hatching asynchrony was found in Great Reed-Warblers (t-test, p<0.01).

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.340-345
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• 2003

In this paper, the ultrasonic attenuation coefficient was measured by variation of crack length for double-cantilever beam(DCB) specimen. The energy release rate, G, was obtained by the experimental measurement of compliance. The experimental results represents that the relation between crack length for the ultrasonic attenuation coefficient and energy release rate is increased proportionally. From the results of experiments, the measurement method of crack length by the ultrasonic attenuation coefficient was proposed and discussed.

• Journal of the Korea Concrete Institute
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• v.12 no.6
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• pp.99-108
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• 2000

The size effect on axial compressive strength in notched concrete specimens was experimentally investigated. Based on the concept of the fracture mechanics and size effect law, theoretical studies for axial compressive failure of concrete were reviewed, and two failure modes of concrete specimens under compression were discussed. In this study, experiments of axial compressive failure, which is one of the two failure modes, was carried out by using cylindrical specimens. Adequate notch length was taken from the experimental result of strength variation based on the notch length. And, by taking various sizes of specimens the size effect on axial compressive strength of concrete was investigated. Also, model equations were suggested by modified size effect law (MSEL). The test results show that size effect appears conspicuously for all series of specimens. Additionally, the effect of initial notch length on axial compressive strength was also apparent.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.386-393
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• 2004

In this paper, the ultrasonic attenuation coefficient was measured by variation of crack length for double-cantilever beam(DCB) specimen. The energy release rate, G, was obtained by the experimental measurement of compliance. The experimental results represents that the crack length for the ultrasonic attenuation coefficient and energy release rate is increases proportionally From the experimental results, we proposed a detecting method of the crack length by the ultrasonic attenuation coefficient and discussed it.