• Proceedings of the KSRS Conference
• /
• 1998.09a
• /
• pp.138-148
• /
• 1998

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about loom underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the way of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. A new hybrid method has been developed for estimating the origin of the underground acoustic source by coupling both methods. The Nelder-Meade simplex search algorithm is then used to numerically estimate the position of the source in those methods. For each method the sound localization is carried out in three dimensions underground. The distance between the true and estimated origins of the source is in some cases less than 6m for a search area of radius 250m.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.240-240
• /
• 2015

As Simpson et al. (1990) emphasized the importance of the straining process in the stratification and mixing in the estuarine circulation process, various researches have investigated on the relative contribution of each process to the overall potential energy anomaly dynamics. However, many numerical works have done only for two dimensional modeling along channel or the short distance cross sectional three dimensional simulations as Burchard et al. (2008) and the estuarine channel was not simulated so far. But, in the study on the physics of shallow coastal seas, spatial dimension in the three dimensional way affects significantly on results of a particular numerical model. Therefore, the comparison of two and three dimensional models is important to understand the real physics of mixing and stratification in an estuary. Also, as Geyer and MacCready (2013) pointed out that the lateral process seems to be important in determining the periodic stratifications, to study such process the three dimensional modeling must be required. The present study uses a numerical model to show the signification roles of each term of the time-dependent dynamic equation for the potential energy anomaly (PEA) in controlling along and lateral channel flows and different stratification structures. Moreover, we present the relationships between the ${\Phi}$-advection, the depth mean straining, vertical mixing and vertical advection can explain well how water level, salinity distribution and across velocity 2D model are slightly different from 3D.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.56 no.1
• /
• pp.88-93
• /
• 2011

This experiment was carried out to find suitable sample type for the more accurate prediction and non-destructive way in the application of near infrared reflectance spectroscopy (NIRS) technique for estimation the protein, total amino acids, and total isoflavone of soybean by comparing three different sample types, single seed, whole seeds, and milled seeds powder. The coefficient of determination in calibration ($R^2$) and coefficient of determination in cross-validation (1-VR) for three components analyzed using NIRS revealed that milled powder sample type yielded the highest, followed by single seed, and the whole seeds as the lowest. The coefficient of determination in calibration for single seed was moderately low($R^2$ 0.70-0.84), while the calibration equation developed with NIRS data scanned with whole seeds showed the lowest accuracy and reliability compared with other sample groups. The scatter plot for NIRS data versus the reference data of whole seeds showed the widest data cloud, in contrary with the milled powder type which showed flatter data cloud. By comparison of NIRS results for total isoflavone, total amino acids, and protein of soybean seeds with three sample types, the powder sample could be estimated for the most accurate prediction. However, based from the results, the use of single bean samples, without grinding the seeds and in consideration with NIRS application for more nondestructive and faster prediction, is proven to be a promising strategy for soybean component estimation using NIRS.

• Restorative Dentistry and Endodontics
• /
• v.42 no.3
• /
• pp.216-223
• /
• 2017

Objectives: The aim of this study was to compare the mechanical properties of various nickel-titanium (NiTi) files with similar tapers and cross-sectional areas depending on whether they were surface-treated. Materials and Methods: Three NiTi file systems with a similar convex triangular cross-section and the same ISO #25 tip size were selected for this study: G6 (G6), ProTaper Universal (PTU), and Dia-PT (DPT). To test torsional resistance, 5 mm of the straightened file's tip was fixed between polycarbonate blocks (n = 15/group) and continuous clockwise rotation until fracture was conducted using a customized device. To evaluate cyclic fatigue resistance, files were rotated in an artificial curved canal until fracture in a dynamic mode (n = 15/group). The torsional data were analyzed using 1-way analysis of variance and the Tukey post-hoc comparison test, while the cyclic fatigue data were analyzed using the Mann-Whitney U test at a significance level of 95%. Results: PTU showed significantly greater toughness, followed by DPT and G6 (p < 0.05). G6 showed the lowest resistance in ultimate torsional strength, while it showed a higher fracture angle than the other files (p < 0.05). In the cyclic fatigue test, DPT showed a significantly higher number of cycles to failure than PTU or G6 (p < 0.05). Conclusions: Within the limitations of this study, it can be concluded that the torsional resistance of NiTi files was affected by the cross-sectional area, while the cyclic fatigue resistance of NiTi files was influenced by the surface treatment.

• Earthquakes and Structures
• /
• v.10 no.2
• /
• pp.429-450
• /
• 2016

An attempt has been made to incorporate the concept of collapse safety margin into the procedures proposed in the performance-based earthquake engineering (PBEE) framework for direct earthquake loss estimation, in which the collapse probability curve obtained from incremental dynamic analysis (IDA) is mathematically characterized with the S-type fitting model. The regressive collapse probability curve is then used to identify non-collapse cases and collapse cases. With the assumed lognormal probability distribution for non-collapse damage indexes, the expected direct earthquake loss ratio is calculated from the weighted average over several damage states for non-collapse cases. Collapse safety margin is shown to be strongly related with sustained damage endurance of structures. Such endurance exhibits a strong link with expected direct earthquake loss. The results from the case study on three concrete frames indicate that increase in cross section cannot always achieve a more desirable output of collapse safety margin and less direct earthquake loss. It is a more effective way to acquire wider collapse safety margin and less direct earthquake loss through proper enhancement of reinforcement in structural components. Interestingly, total expected direct earthquake loss ratio seems to be insensitive a change in cross section. It has demonstrated a consistent correlation with collapse safety margin. The results also indicates that, if direct economic loss is seriously concerned, it is of much significance to reduce the probability of occurrence of moderate and even severe damage, as well as the probability of structural collapse.

• Journal of Korean Society for Quality Management
• /
• v.43 no.3
• /
• pp.253-272
• /
• 2015

Purpose: The purpose of this study is to enhance the reliability of quality inspection by standardize the fineness test method of the thermal insulator of military textiles Methods: We have measured the thermal insulator of military textiles by microscope with three different ways and the effectiveness of their difference were analyzed by one-way layout design. Results: We have suggest the standardized the fineness test method of the thermal insulator of military textiles through advanced research. As a result we have verified hollow ratio of heat insulating fiber affect fineness test methods. The fineness test method for the thermal insulator applied with different methods following hollow ratio. We have verified that when the hollow ratio over 90%, the fineness of the thermal insulator measured from fiber-length, if it has over 80%, the cross-section length of hollow and if it has less 80%, the cross-section area of hollow is applied, respectively. Conclusion: This study indicated that the test method of fineness shows high reliability. Heat insulating fibers which have high evenness shows narrow variations(5/% or less, only CV 25%) irrespectively under different testing equipment or institute. Based ons the results, we have suggest the standardization of test methods for fineness by microscope method and produced the registration of Group Standard in Korean Standards Association.

• Journal of Families and Better Life
• /
• v.21 no.3
• /
• pp.29-38
• /
• 2003

A three-year longitudinal design was employed to ascertain whether different types of behavioral inhibition(i.e. traditional, peer-social) were stable from toddler to preschool age(2-4 year), and whether inhibited temperament and/or parenting style would independently and interactively predict children's subsequent social and behavioral outcomes. At time 1, 113 toddlers (55 males, 58 females) and their mothers were observed in the traditional inhibition paradigm. At time 2, 36 4-year-old children were observed with unfamiliar peers in the nontraditional inhibition paradigm. Maternal ratings of psychological functioning of children and maternal behaviors were also obtained for both time 1 and 2. Results showed that behavioral inhibition was not stable from toddler to preschool age. Maternal authoritative behaviors at age 2 were negatively associated with preschooler's social reticence. Toddler's behavioral inhibition was negatively associated with maternal authoritative behaviors at age 4. In a cross-lag correlation analysis, maternal authoritative behaviors appeared to affect child's behavioral inhibition more strongly than the other way around.

• Cross-Cultural Studies
• /
• v.30
• /
• pp.187-222
• /
• 2013

In this study, From 1,560 entry-level of TOPIK standard vocabularies are 702 Sino-Korean words selected which account for 45% of the whole vocabularies in TOPIK. In addition, the same form and morpheme words in Sino-Korean are sorted out by comparing them with 5,000 words of the NEW HSK vocabularies in Sino-Korean morpheme, array position of morpheme, meaning, and usage. Those are categorized into three parts : type of completely the same form-morpheme and same meaning, use, class(189 pairs), type of completely the same form-morpheme and partly same meaning, use, class(28 pairs), and type of completely the same form-morpheme and different meaning, use, class(10 pairs). The first type of words that account for 83.26% of them are used in exactly the same way in both Chinese and Korean. Through an accurate understanding of these vocabularies could either Chinese-speaking Korean learners or Korean-speaking Chinese learners apply those words in their mother tongue to the acquisition of the target language and get more effective means of learning methods for language proficiency test.

• Cross-Cultural Studies
• /
• v.30
• /
• pp.125-165
• /
• 2013

The purpose of this study is to find methods that allow learners to improve their listening comprehension skills. To do this, we have divided this article into three parts. In the first part, we analyzed studies focus on the skill of listening. In the second part, we are dedicated to the process steps in the study of listening comprehension. In the last part, we tried to demonstrate this by examples according to the difference in levels of learners. More specifically, we applied the questionnaires according to a typological difference. Most teachers recognize the importance of listening to complete the language proficiency of learners. Nevertheless, there are many difficulties in implementing effective methods for improving listening comprehension skills. In addition, there is a strong tendency not to consider listening as an autonomous field, but as a part of oral proficiency. In addition, we can not ignore the importance of the method of application, because it can motivate learners to both concentrate on their studies and to voluntarily participate in the course. In this sense, the Professors and teaching staff can use the examples of DELF to establish concrete goals for the course of listening. It is difficult to confirm that this study is the most effective way with regard to the methodology, but we hope it may be useful to improve the skills of listening comprehension French learners.

• Advances in concrete construction
• /
• v.1 no.1
• /
• pp.1-27
• /
• 2013

Discrete steel fibres can increase significantly the bending and the shear resistance of concrete structural elements when Steel Fibre Reinforced Concrete (SFRC) is designed in such a way that fibre reinforcing mechanisms are optimized. To assess the fibre reinforcement effectiveness in shallow structural elements failing in bending and in shear, experimental and numerical research were performed. Uniaxial compression and bending tests were executed to derive the constitutive laws of the developed SFRC. Using a cross-section layered model and the material constitutive laws, the deformational behaviour of structural elements failing in bending was predicted from the moment-curvature relationship of the representative cross sections. To evaluate the influence of the percentage of fibres on the shear resistance of shallow structures, three point bending tests with shallow beams were performed. The applicability of the formulation proposed by RILEM TC 162-TDF for the prediction of the shear resistance of SFRC elements was evaluated. Inverse analysis was adopted to determine indirectly the values of the fracture mode I parameters of the developed SFRC. With these values, and using a softening diagram for modelling the crack shear softening behaviour, the response of the SFRC beams failing in shear was predicted.