• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.4B
• /
• pp.323-332
• /
• 2011

In order to properly manage trees in rivers, the impact of trees on flooding and their ecological characteristics need to be considered and a plan needs to be established. The hydraulic impact by trees is reduction of conveyance and hydraulic structure's function due to overturn arising from flow force. A field pulling test was carried out to measure the critical resistance force for when trees break in order to discover the level of resistance that trees inside the river have to external force. The relevant factors for discovering the critical breaking moment for trees include tree species, which determines the external characteristic of trees, tree diameter at breast height, and tree height. In this study, the correlation between critical breaking moment and diameter at breast height were used. The tree's limit or critical breaking moment was tested using 100 shrubs and tall trees with a breast height diameter of 4.9 to 32.8 cm. It was difficult to derive a correlation between diameter at breast height and critical breaking moment when shrubs and tall trees were being considered together, but when only tall trees were considered, a consistent correlation was found between them.

• Journal of Periodontal and Implant Science
• /
• v.43 no.2
• /
• pp.58-63
• /
• 2013

Purpose: The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants. Methods: Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The periimplant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed. Results: Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger. Conclusions: This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.

• Journal of agriculture & life science
• /
• v.43 no.4
• /
• pp.9-14
• /
• 2009

The purpose of this study was to estimate height growth pattern and to derive site index equation for Pinus densiflora grown at Mt. Osu region, Chungnam. A total of 21 repre - sentative trees from the established temporary plots around Boryeng and Cheongyang regions were destructively sampled to measure diameter, height, volume growth per 1-year interval by using of DTRS- 2000 measurement instrument. The Schnute growth function was select ed for height growth prediction using 181 height-age paired observations and derived anamorphic base age invariant site index curves (base index age 30 years). The fitted index and the asymptotic value of Schnute model indicated both 0.96 and 10.8 meter, respectively. The results suggested in this study could be very useful to understand the height growth pattern and productivity of the site quality on Pinus densiflora grown at Mt. Osu region, Chungnam.

• The Korean Journal of Ecology
• /
• v.17 no.2
• /
• pp.105-112
• /
• 1994

Structure of grassland communities was investigated, and performance of populations of Themeda triandra var. japonica and Miscanthus sinensis were compared on limestone and granite soils. Forty three and forty taxa occurred on the limestone and granite grasslands, respectively, but their similarity was very low. Shoot height and number of hills per patch, as a measure of performance, of Themeda on the limestone grassland were higherthan those on the granite grassland. In contrast, shoot height and number on hills per patch of Miscanthus were higher on limestone than granite grassland. Evidence shows that poor growth of Micanthus population on the limestone soil was associated with higher content of insoluble divalent cations than soluble ones in shoot tissue.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.13 no.1
• /
• pp.21-28
• /
• 1993

If the infinitesimal delamination exists and the two waves can hardly be distinguished from each other on account of being much closer, we cannot measure the thickness of delamination by the time difference method. On this study, we calculated the thickness of infinitesimal delamination model by means of measuring echo height due to the deflection of material particles and utilized Newton Ring for optical measurement as a delamination model. From the result of Newton Ring expressed in the delamination model, we can calculate the infinitesimal delamination thickness up to $0.2{\sim}0.3{\mu}m$ due to the difference of acoustic impedance by the ratio of the echo height to the total reflection.

• Child Health Nursing Research
• /
• v.13 no.1
• /
• pp.51-57
• /
• 2007

Purpose: The purpose of this study was to look for physical growth and developmental retardation of the disabled children in registered educational institutions. Method: The participants in this study were 103 children. The data was collected from January to September 2006. Body weight, height and head circumference were measured and the Denver II developmental screening tool was used to measure personal-social development. Results: For 40.8% of the children body weight was less than the average for Korean children of the same age, for 49.5% height was lower than average and for 44.7% head circumference was lower. For 84.5% of the children there was a delay in personal-social development, for 87.4% a delay in fine motor-adaptive development, for 80.6% a delay in speech development and for 81.6% a delay in gross motor development. Conclusion: Based on the findings of this study, it is necessary to develop an individual developmental programs for these children based on their growth and development status.

• Journal of the Ergonomics Society of Korea
• /
• v.16 no.3
• /
• pp.37-48
• /
• 1997

It is very common for women wear shoes with a high heel. It has been known that the high heel could disfigure the foot shape and cause various joint problems including back pain. However, few quantitative studies have been conducted. Therefore, in this study, the low back muscle has been investigated in order to find fatifue effect due to different heights of the heel. In particular, 0, 4, 6 and 8cm heel and two different shapes of heel have been used for an experiment. Ten healthy female subjects volunteered for the study. Isometric Trunk Exertion Frame(ITEF) and Electromyography were used to measure tha Median Frequency via Spectral analysis. The results indicated that the heel height significantly affected the local muscle fatigue of the back. After post hoc analysis, it was found that a proper heel height ougth to be lower than 5cm not to have severely fatigued back muscle after a casual walk for an hour. Such results could be applies to female industrial workers in order to prevent a cumulative trauma disorder of the back, and also to design a female dress shoes minimizing low back fatigue.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.11
• /
• pp.1363-1370
• /
• 1999

A study of scaling and heat transfer has been carried out for a vertical tube evaporator in which $CaSO_4$ saturated water flows upward. Experimental apparatus including vacuum chambers and heaters has been designed and manufactured to study scaling phenomena for three different pressures(1atm, 0.27atm and 0.16atm). Overall heat transfer coefficients have been measured and shown to decrease with time as scaling proceeds. After the end of experiments, the vertical tube has been cut to measure the thickness of scale at different heights. Below the height where the bulk fluid temperature does not reach saturated temperature, the thickness of scale increases, however, beyond that height occurring saturated condition, the thickness does not vary much or even decreases a little. The measured fouling resistances also support these variations of scale thickness.

• Journal of the Korean housing association
• /
• v.18 no.1
• /
• pp.43-51
• /
• 2007

This study examines and analyzes view hindrance factors of high-storied apartment houses at small town like 'Eup' where county office locates and it is found that hindrance factors include designation of residential area and height, length and form of main building. On recognition of view, most subjects of research considered high-storied apartment houses hindered urban view and its regulation is needed. Apartment houses at small cities become main factors of hindering urban view because they were located randomly regardless of scale of city and surrounding situation, but there is no measure to control it. Accordingly, view control through enaction of regulations is urgently needed with establishment of guidelines such as height of large buildings including high-storied apartment houses, length of main building, location and regulation of exterior design.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.979-982
• /
• 2003

In this study, because of change in electromagnetic force, deformation of the free surface motion of a magnetic fluid is changed. Deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed and carried out theoretically and experimentally on the basis of Rosensweig Ferrohydrodynamic Bernoulli Equation. Objective of this study explicates free surface motion by electromagnetic force and planes to designed controller. To control free surface of magnetic fluid, it embody designed two-dimensional free surface form of magnetic fluid. By using this characteristics, they applied to oscillator for surface control, flow control, boundary layer control. Strength of magnetic field and height of free surface of magnetic fluid measure as a hall-effect sensor. As performing height control of magnetic fluid, the result will be presented possibility of free surface deformation control.