• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.3
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• pp.238-243
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• 2001

Purpose : The purpose of this study was to determine radiologic variables affecting extraction of impacted mandibular third molar. Materials and Methods : This study was investigated on 44 consecutive extractions of unilateral impacted mandibular third molars (Male;34, Female;10, Mean age;24.98, Age range;19-35). Fourteen radiologic variables, which were actual value except only one, were evaluated to establish their relation to the operation time. The Pearson correlation coefficient and Stepwise procedures for regression analysis were carried out. Results : Eight variables (depth, angulation, ramus width, relationship to the second molar, distal ramus depth, mesial ramus depth, mesial periodontal ligament width and follicle) showed a statistically significant relation to the operation time(Pearson correlation coefficient, p<0.05). Two variables, depth and mesial periodontal ligament width, showed the most powerful and just relation to the operation time($r^2$ = 0.349, p<0.05). Conclusion : This study shows that our results can help general practioner to estimate the operation time of extraction of impacted mandibular third molars by measuring two radiologic variables ; depth and mesial periondontal ligament width.

• ETRI Journal
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• v.41 no.5
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• pp.637-647
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• 2019

Separating highly correlated users can reduce the loss caused by spatial correlation (SC) in multiuser multiple-input multiple-output (MU-MIMO) systems. However, few accurate analyses of the loss caused by SC have been conducted. In this study, we define signal-to-interference-plus-noise ratio (SINR) loss to characterize it in multiuser multiple-input single-output (MU-MISO) systems, and use coefficient of correlation (CoC) to describe the SC between users. A formula is deduced to show the accurate relation between SINR loss and CoC. Based on this relation, we propose a user selection method that utilizes CoC to minimize the average SINR loss of users in massive MU-MISO systems. Simulation results verify the correctness of the relation and show that the proposed user selection method is very effective at reducing the loss caused by SC in massive MU-MISO systems.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.1
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• pp.115-131
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• 2005

The fishery buy-back programs were studied to analyze fishery production and CPUE. The results from this study during the concerned period can be derived as follows: 1. In total offshore fisheries, CPUE for each boat increased 8.7%, and 8 fishing categories were increased in CPUE for each boat. CPUE for tonnage increased 4.2% in total offshore fisheries field, and 7 fishing categories increased in CPUE for tonnage. In total offshore fisheries, CPUE for HP increased 6.8%, and 8 fishing categories increased in CPUE for HP. 2. The correlation coefficient of the number of fishing boats vs. production and that of the tonnage vs. production were 0.91. This means that there is a strong relation between them. The correlation coefficient of the number of fishing boats vs. CPUE for each boat and that of the tonnage vs. CPUE for tonnage were -0.73 and -0.88 respectively. This reveals that there is a relatively strong reverse relation between them.

• Geomechanics and Engineering
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• v.19 no.6
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• pp.523-532
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• 2019

Based on the formation characteristics, wellbore parameters and insulated tubing (IT) parameters of the Shengli oilfield, Shandong, China, a geomechanical model is built to predict the temperature distributions of the wellbore and formation. The effects of the IT heat conductivity coefficient (HCC), well depth and IT joint on the temperature distribution of the IT, completion casing, cement sheath, and formation are investigated. Results show the temperature of the formation around the wellbore has an exponentially decreasing relation with the distance to the wellbore. The temperature of the formation around the wellbore has an inverse relation with the IT HCC when the temperatures of the steam and the formation are given. The temperature of the casing outer wall is mainly determined by the steam temperature and IT HCC rather than by the initial formation temperature. The temperature of the casing at the IT joint is much larger than that of the other location. Due to the IT joint having a small size, the effects of the IT joint on the casing temperature distribution are limited to a small area only.

• Journal of Photoscience
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• v.4 no.3
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• pp.105-112
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• 1997

The fluorescence quenching of 2, 5-di-(5-tert-butyl-2-benzoxazolyl)-thiophene (BBOT) by aniline in five different solvents namely heptane, hexane, cyclohexane, dioxane and acetonitrile has been carried out at room temperature with a view to understand the quenching mechanisms. The experimental results show positive deviation in the Stern-Volmer plots in all the solvents. In order to interpret these results we have invoked the Ground state complex and sphere of action static quenching models. Using these models various rate parameters have been determined. The magnitudes of these parameters suggest that sphere of action static quenching model agrees well with the experimental results. Hence this positive deviation is attributed to the static and dynamic quenching. Further, with the use of Finite Sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R$^1$ and mutual diffusion coefficient D. Finally an attempt has been made to correlate the values of R$^1$ and D with the values of the encounter distance R and the mutual diffusion coefficient D determined using the Edward's empirical relation and Stokes-Einstein relation.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1798-1802
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• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation.The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall.The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.95-102
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• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation. The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall. The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.11 no.1
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• pp.8-14
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• 1975

The optical properties of the sea water were studied by use of underwater lux-meters in the coastal waters of Busan from May to November 1975. The absorption coefficient of the sea water in the area ranges from O. 169 to 1. 049 and the mean absorpflOn coefficient is 0.413. Maximum monthly mean absorption coefficient (0. 56) was observed in August, while the minimum was O. 338 in September. There was a distinct discontinuity layer of the absorption coefficient in accordance with the thermocline and the halocline in summer. The mean transparency of the area was 3. 8 meters, and transparency in autumn was higher than that in summer. The relation between absorption coefficient (m) and transparency (D) was deduced, m=1. 57/ D. The rate of light penetration at 5 m-layer of sea water was 2. 5 percent when the solar altitude was six degree in July 1975.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.176-179
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• 2008

In a numerical simulation of open channel turbulent flows, the determination of wall roughness height for wall function was studied. The roughness constant, based on the law-of-the -wall for flow on rough walls, obtained by experimental works for pipe flows is employed in general wall functions. However, this constant of wall function is the function of Froude number in open channel flows. Thus, the wall roughness should be determined by taking into account the effect of Froude number. In addition, the wall roughness should be corresponding to Manning's roughness coefficient widely used for open channels. In this study, the relation between wall roughness height as an input condition and Manning's roughness coefficient was investigated, and an equation for effective wall roughness height considering the characteristics of numerical models was proposed as a function of Manning's roughness coefficient.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1109-1114
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• 2003

The initial crack often occurs on the bonded interface and it is the general cause of the interface fracture. It is very significant to establish the measurement method of interfacial crack by applying the ultrasonic technology into the interface of bonded dissimilar materials. In this paper, the interfacial crack length was measured by ultrasonic attenuation coefficient in the Al/Epoxy bonded dissimilar materials of double-cantilever beam(DCB). The energy release rate, G, was obtained by the experimental and Ripling's equation measurement of compliance. The experimental results represent that the relation between interfacial crack length for the ultrasonic attenuation coefficient and energy release rate is increased proportionally. From the experimental results, a measurement method of the interfacial crack length by the ultrasonic attenuation coefficient was proposed and discussed.