• Journal of the Korean Society of Costume
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• v.58 no.3
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• pp.116-122
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• 2008

This study aims at defining the meaning of Pobeckchuck in the historical view-point, which appeared in the History of Joseon Dynasty, regarding the periods from the ruling period of Sunjo to that of Sunjong as the latter part of history. Pobeckchuck used in King Sejong was redressed in accordance with the measurement in the Kyeonggukdadejeon(code), in which time one Pobeckchuck was 46.80cm long. It is known that Juchuck, Hwangjongchuck, Youngjochuck, Joraegichuck etc. which had been used in the ruling period of Sejong Dynasty, were used till the period of Youngjo. Also, the document shows that in the 12th ruling period of Sunjo, Pobeckchuck was used for measurement, and in the 20th ruling period of Sunjo, newly-made ruler was only used for the measurement of fields, but no more details about how long it was. But according to the document complied at that time, one Pobeckchuck was 46.80cm long, which fact reveals that the same measurement was used as in the ruling period of Sunjo. When all the measurement laws which were established in the 3rd year of Junghee, the 6th year of Kwangmu were abolished, Pobeckchuck was solely banned from its use, which fact offers a glimpse of how confusing at that period was. The comparison and examination among many documents in the latter part of Joseon Dynasty show the differences within about 4cm that one Pobeckchuck ranged from 44.80cm to 48.80cm long. But no other document on measurement appeared in the History of Joseon Dynasty, except for the 46.80cm. Thus, the 46.80cm corrected in the ruling period of Sunjo proves that one chuck in Pobeckchuck adopted by the dynasty was used as the measurement of length till the ruling period of Sunjong.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.41-49
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• 2007

In this paper, we proposed a new ultrasonic distance measurement system with high accuracy and long range. To improve accuracy and enlarge range, the time of flight of ultrasonic is calculated by the period detecting method. In the proposed ultrasonic distance measurement system, the ultrasonic transmitter and receiver are separated but synchronized by RF(Radio frequency) module. The experiment has been implemented from short distance 1m to maximum available distance 30m. And the period detecting method is compared with the conventional threshold level method. Experimental results show the accuracy and range of the distance measurement are improved by this period detecting method.

• Journal of Astronomy and Space Sciences
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• v.35 no.3
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• pp.163-173
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• 2018

This paper presents relative navigation using intermittent laser-based measurement data for spacecraft flying formation that consist of two spacecrafts; namely, chief and deputy spacecrafts. The measurement data consists of the relative distance measured by a femtosecond laser, and the relative angles between the two spacecrafts. The filtering algorithms used for the relative navigation are the extended Kalman filter (EKF), unscented Kalman filter (UKF), and least squares recursive filter (LSRF). Numerical simulations reveal that the relative navigation performances of the EKF- and UKF-based relative navigation algorithms decrease in accuracy as the measurement outage period increases. However, the relative navigation performance of the UKF-based algorithm is 95 % more accurate than that of the EKF-based algorithm when the measurement outage period is 80 sec. Although the relative navigation performance of the LSRF-based relative navigation algorithm is 94 % and 370 % less accurate than those of the EKF- and UKF-based navigation algorithms, respectively, when the measurement outage period is 5 sec; the navigation error varies within a range of 4 %, even though the measurement outage period is increased. The results of this study can be applied to the design of a relative navigation strategy using the developed algorithms with laser-based measurements for spacecraft formation flying.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.375-382
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• 1999

The fundamental vibration period of a shearwall apartments cannot estimate accurately by means of empirical formulas specified in present codes, The objective of this paper is to estimate the period of a shearwall apartments by microtremor measurement. A micretremor is the continuous small oscillation of the ground cause by traffic and operation machinery. Microtremors are extensively studied primarily in Japan to estimate conveniently subsurface structures of soil deposits and building vibrations. It is obtained the results that the fundamental periods estimated by microtremor measurement are shorter than those values by dynamic analysis of building.

• Journal of the Korean Society of Costume
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• v.53 no.4
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• pp.87-99
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• 2003

The measurement in ruling period of King Sejong in Chosun Dynasty remained unchanged compared with that of Goyeo Dynasty. But Hwangjongchuck, the basis of measurement was amended in the 7th year in ruling period of King Sejong, Juchuck, Youngchochuck, Cholegichuck in the 12th, and Pobeckchuck in the 13th. The record of Pobeckchuck first appeared in the true record of Chosun Dynasty in the 4th year in ruling period of Sejong, and first record on the amendment of the Pobeckchuck was found in the 13th year in his ruling period. The presentation of the comparison of Pobeckchuck with Cholegichuck in volume 128 of true record of Sejong makes help the estimation of the length of Pobeckchuck. To calculate one Chuck of Pobeckchuck with this measurement comes to 44.75cm in present measurement, and the length at this time had remained unchanged to Yeonsangun period. Important fact which was newly found in the true record of Chosun Dynasty was that Pobeckchuck had been used for diverse purposes. Pobeckchuck was used to measure width, length and thickness in manufacturing wardrobe. and also to measure cloth decorating wardrobe. This is the first record(4th year of reign of Sejong) showing that Pobeckchuck was first used to measure cloth in Chosun Dynasty The record shows that Pobeckchuck was also used to measure the length of circumference of castle for its construction. to measure distances between people, the length of hook of wooden handle, and the height of man.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.677-682
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• 2003

The long-period gravity wave, the wave period from some ten seconds to some minutes, induces not only the big sway of a ship moored and berthed in the harbor due to the horizontal long-distance motion of a water but also strong exfoliated flow and vortices near the harbor entrance. They muse serious problems on the safety navigation of vessels entering and leaving the harbor, but this gravity wave has not been searched sufficiently yet. Then it is quite important to reveal the characteristics of this long-period gravity wave ana to solve various problems induced by this wave. The long-period gravity wave measurement system with arrayed buoys installed the kinematic GPS was already proposed, which provides the precise propagating direction of the long-period gravity wave. In this paper, the observation results of the wave measurement system are shown by the MUSIC method And the propagating wave direction was estimated precisely enough in comparison with other results used other method.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.10
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• pp.611-617
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• 2003

A mechanical or electrical stimulation to the mandibular symphysis during a maximal voluntary clenching of the teeth always produces a jaw jerk followed by a silent period (transient stops) in the masseteric EMG (electromyogram). Generally, a mechanical stimulation is followed by a single silent period, and an electrical stimulation is followed by multiple silent periods. In this paper, we propose a new algorithm for determining the duration of the masseter silent period. The decision approach in essentially based upon a segmentation algorithm consisted of variance filter, median filter and gaussian filter. The new adaptive digital notch filter using R-CLMS(reverse constrained least mean-squared) algorithm is proposed for the elimination of powerline(60Hz) noise. At the same time, we design a real time measurement system for the EMG silent period under Window base.

• Journal of Korean Association for Spatial Structures
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• v.6 no.3 s.21
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• pp.43-50
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• 2006

This paper is concerned with the natural periods of ambient vibration and eigenvalue analysis. Ambient vibration tests were conducted to four bearing-wall reinforced concrete buildings ranging from twelve to nineteen stories. The performance of modeling in eigenvalue analysis was investigated using consideration of rigidity out of the plane in the slab and the non-structural bearing wall. Measured natural period was also compared with the value by the KBC2005. Natural period of the short direction in eigenvalue analysis is well fitted with the measured one. In the other hand, Natural period of the long direction in eigenvalue analysis is slightly more overestimated than the measured one. Natural period of the long direction in eigenvalue analysis was found to be enhanced by considering the effect of the stiffness out of the plane of the slab and non-structural wall in the structural modeling.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.3
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• pp.179-191
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• 1997

The concentrations of organic and elemental carbon were determined using fine particle samples collected from Kosan, Cheju Island during the summer seasons of 1994 and 1995. The daily mean concentrations of organic and elemental carbon for each measurement period were 3.74 and 0.27 $\mu\textrm{g}$/㎥ in 1994, while those of 1995 were 2.36 and 0.10 $\mu\textrm{g}$/㎥, respectively The concentrations of organic carbon were higher than those commonly observed from clean areas around the world, but those of elemental carbon were lower than, or comparable to, other clean areas in the world. The resulting ratios of total carbon to elemental carbon at this site were thus higher than those seen from other metropolitan and non-polluted regions abroad. In addition according to our analysis, the 1994 measurement period can be classified into two periods: enhanced (July 20 and August 1) and reduced levels (August 2 and 9) of the carbonaceous species. The observed difference between two periods may be in part accounted for by the air trajectories representing each period. During the former period, the air masses from the Asian continent and Japan were dominant, while the air masses from the North Pacific Ocean came during the latter period. OC/EC ratios at the site were calculated to predict the possible formation of secondary organic aerosol . Based on our observations, we suggest that the formation of secondary organic aerosol might be an important pathway to the production of organic carbons.

• Korean Journal of Human Ecology
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• v.16 no.3
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• pp.623-630
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• 2007

The remarkable fact regarding the History of Chosun Dynasty(from Jungjong- Youngjo) is that any slightest evidence can't be found that Pobeckchuck was used to measure clothes or various Pobecks. There remains the document that in the 22nd years of Myeonjong, Japan required that Pobeckchuck be used, but it couldn't be allowed because of the reason it was made in the former king. This fact raises the high possibility that Pobeckchuck could be the most trustworthy standardized ruler at that time, and in other point of view, it can be presumed that the measurement in the period of King Sejong continued to have been used until this time. It can be seen that the length of one Chuck of Pobeckchuck at this time must have been equivalent to 46. 73cm of Pobeckchuck of Samchuck in the period of Sejong. In the History of Sunjo Period, many records on Pobeckchuck can be found, which fact seemed to have rectified the measurement system which was disordered by military revolt, though the reason is not clear. Also a record can be found that in the period of Sunjo, Chinese envoy required the Sunjo Regime to use Pobeckchuck for the measurement of copper pillar, which record supports the fact that Pobeckchuck is the standardized ruler. Another record that in the 26th period of Youngjo, Pobeckchuck of Samchuck was corrected according to the Kyeongkukdaejeon shows that the length of Pobeckchuck was 46.80cm at that time. Also, the record which rectified many rulers with the comparison of Hwangjong-chuck, Ju-chuck, Joryeki-chuck, Yongjo-chuck, etc. with one another reveals that the rulers used in the period of Sejong continued to have been used unchanged until in the period of Youngjo.