• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.3
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• pp.23-33
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• 2012

Dynamic response measurements from natural excitation were carried out for three 18-story office buildings to determine their inherent properties. The beam-column frame system was adopted as a typical structural form, but a core wall was added to resist the lateral force more effectively, resulting in a mixed configuration. To extract modal parameters such as natural frequencies, mode shapes and damping ratios from a series of vibration records at each floor, the most advanced operational system identification methods based on frequency- and time-domain like FDD, pLSCF and SSI were applied. Extracted frequencies and mode shapes from the different identification methods showed a greater consistency for three buildings, however the three lower frequencies extracted were 1.2 to 1.7 times as stiff as those obtained using the initial FE models. Comparing the extracted fundamental periods with those estimated from the code equations and FE analysis, the FE analysis results showed the most flexible behavior, and the most simple equation that considers the building height as the only parameter correlated fairly well with test results. It is recognized that such a discrepancy arises from the fact that the present tests exclude the stiffness decreasing factors like concrete cracking, while the FE models ignore the stiffness increasing factors, such as the contribution of non-structural elements and the actual material properties used.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.79-87
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• 2015

This paper proposes a floating-type wave energy conversion system that consists of a mechanical part (yo-yo vibrating system, motion rectifying system, and power transmission system) and electrical part (power generation system). The yo-yo vibrating system, which converts translational input to rotational motion, is modeled as a single degree-of-freedom system. It can amplify the wave input via the resonance phenomenon and enhance the energy conversion efficiency. The electromechanical model is established from impedance matching of the mechanical part to the electrical system. The performance was analyzed at various wave frequencies and damping ratios for a wave input acceleration of 0.14 g. The maximum output occurred at the resonance frequency and optimal load resistance, where the power conversion efficiency and electrical output power reached 48% and 290 W, respectively. Utilizing the resonance phenomenon was found to greatly enhance the performance of the wave energy converter, and there exists a maximum power point at the optimum load resistance.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.6
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• pp.879-886
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• 2016

As is in all economic activities, the highest yield per unit area is the main goal in animal production, while addressing the temperamental needs of animals often is ignored. Animal welfare is not only an ethical fact; it also has an economic value. Spatial environmental enrichment contributes positively to animal welfare by addressing their behavioral and mental requirements. The present study was conducted to determine the effects of weaning and spatial environmental arrangements on behaviors of goat-kids. Experimental groups were arranged in structured and unstructured spatial environments. Roughage feeder, semi-automatic concentrate feeder, bunk, bridge, and wood block were placed in the structured environment. No equipment was placed in the unstructured environment and paddock sides were enclosed with an iron sheet to prevent bipedal stance and to provide environmental isolation. In the study 10 male and 10 female Turkish Saanen goat kids were used in each group. Spatial environmental arrangements did not have significant impacts on the growth performance of kids (p>0.05). All objects in the structured group were accepted by the kids. Average use ratios of roughage feeder, semi-automatic concentrate feeder, bunk, bridge and wood block were observed as 19.3%, 14.0%, 12.6%, 3.8%, and 0.7%, respectively. There were significant differences between before- and after-weaning in use of all objects except for underneath bridge ($p{\leq}0.05$). Concentrate feed consumption, locomotion, and resting behaviors in kids showed significant differences by structural group and growth period. Roughage consumption was similar between groups, while it differed by growth period ($p{\leq}0.05$). Interaction frequency was significantly higher in structured group (p = 0.0023). Playing behavior significantly differentiated based on the growth period rather than on groups ($p{\leq}0.05$). Playing behavior significantly decreased after weaning. Abnormal oral activity was significantly higher in the structured group before weaning ($p{\leq}0.05$). Despite there being no installations facilitating climbing and bipedal stance, the kids of the unstructured group were able to exhibit 1/3 as much bipedal stance behavior as the kids of the structured group through leaning over slippery paddock wall or over their groupmates. Bipedal stance behavior of unstructured group was similar before and after weaning, while bipedal stance behavior before weaning was about 2 times that of after weaning in structured group. It was concluded that unstructured environmental arrangement limited the behavior repertoire of the goat kids.

• Journal of Preventive Medicine and Public Health
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• v.11 no.1
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• pp.65-75
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• 1978

This study was carried out to investigate air pollution by total suspended particulate(T.S.P.), benzene soluble matter and benzo(a) pyrene in Seoul city. The sampling areas were divided into commercial(Kwang Hwa Moon), indus-trial(Ku Ro Dong) and residensial area(Shin Chon). Sampling was undertaken by High Voulme Air Sampler for four seasons from January 1917 to November 1977. The T.S.P. was extracted with Soxhlet apparatus by benzene and benzo(a) pyrene was separated by column chromatography and thin layer chromatography. The concentrations of benzo(a) pyrene were measured by means of fluorophotometer, and following results were obtained. 1. Arithmetic average concentration for 1-day averaging time of total suspended particulate were $275.6ug/m^3$ in Kwang Hwa Moon, $325.9ug/m^3$ in Ku Ro Dong and $193.0ug/m^3$ in Shin Chon. 2. The seasonal variance of total suspended parti-culate at Ku Ro Dong and Shin Chon were $102.7ug/m^3\;99.6ug/m^3$ respectively and at Kwang Hwa Moon $39.9ug/m^3$. And the concentration of autumn is higher than of that spring at Ku Ro Dong and at Shin Chon, but at Kwang Hwa Moon, the seasonal variance is very little. 3. The concentrations of 50% frequency from geometric mean for 1-day averaging time were $264ug/m^3,\;300ug/m^3\;and\;178ug/m^3$ at Kwang Hwa Moon, Ku Ro Dong and Shin Chon. And geometric standard deviation were 1.27, 1.38 and 1.41 respectively. 4. The concentrations of benzene soluble mater were $26.9ug/m^3$ at Kwang Hwa Moon, $22.7ug/m^3$ at Ku Ro Dong and $15.5ug/m^3$ at Shin Chon, and the ratios to the T.S.P. were 9.8%(range 5.6-14.8%), 7.0%(range 2.4-14.4%) and 8.0%(range 5.5-22.1%) respectively. 5. The concentrations of benzo(a) pyrene were $8.5ug/m^3$ (range $0.8-29.9ug/m^3$) at Kwang Hwa Moon $10.9ug/m^3$(range $1.1-52.0ug/m^3$) at Ku Ro Dong and $5.8ug/m^3$(range $1.5-11.4ug/m^3$) at Shin Chon. 6. The results of this investigation were relatively high in compared with the recommended standards of suspended particulate in air of U.S. Environmental Protection Agency and observed levels of benzo(a)-pyrene in U.S. city.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.295-309
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• 2006

The present study was aimed to evaluate the incidence, etiological factors, and management of cleft lip and palate. Two hundred and twenty patients with cleft lip and/or cleft palate who were treated at Department of Oral and Maxillofacial Surgery, Chonnam National University Hospital, during the period between January 1994 and December 2003 were reviewed. The ratios of cleft lip : cleft lip with cleft palate : and cleft palate were 0.4:1.1:1. Males were more common than females in cleft lip (1.3:1) and cleft lip and palate (2.5:1), while females were more common than males in cleft palate (1:1.3). In the cleft side, left clefts were more prevalent than right clefts (cleft lip 1.3:1, cleft lip and palate 1.6:1). Unilateral clefts were more common than bilateral clefts in cleft lip (79:21). Cleft lip and cleft palate were more common in those with blood type A (34.5%) than those with other types. There was no significant relationship between birth season and frequency of clefts. The clefts were common in the first-born (48.8%), and in mothers aged between 25 and 29 (51.7%). Medication (24.7%) and stress (16.7%) during the first trimester were noted. Positive familial history was noted in 13 cases (5.9%). Thirty-two cases (15%) were associated with other congenital anomalies, in which tonguetie (40.6%) and congenital heart disease (21.9%) were most common. Among 100 patients with cleft palate, 77 patients had middle ear disease (77%), which occurred predominently in the incomplete cleft palate. Seventy-six among the 77 patients received myringotomy and ventilation tube insertion, and the remaining one received antibiotic medication only. Cleft lips were treated primarily at 3 to 6 months, and cleft palates were at 1 to 2 years. Treatment regimens included modified Millard method mainly in the cleft lip, and Wardill V-Y, Dorrance method, and Furlow method in the cleft palate. The percentage of palatal lengthening as type of cleft palate was greater in the incomplete cleft palate group (11.2%) than in the complete cleft palate group (9.6%). The percentage of palatal lengthening as operating method was no difference between the Furlow method (10.9%) and the push back method (10.7%). As postoperative complications, hypertrophic scar was most frequent in the cleft lip, and oronasal fistula in the cleft palate. In summary, it was shown that medication and stress during the first trimester of pregnancy were frequently associated with cleft lip and cleft palate, adequate timing and selection of method of operation are important factors to obtain morphologically and functionally good results. Furthermore prevention and treatment of middle ear disease are important in cleft palate patients because of its high co-occurrence.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.610-618
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• 2001

This paper investigates the relationships between dynamic elastic modulus and static elastic modulus or compressive strength according to curing temperature, aging, and cement type. Based on this investigation, the new model of the relationships we proposed. Impact echo method estimates the resonant frequency of specimens and uniaxial compression test measures the static elastic modulus and compressive strength. Type I and V cement concretes, which have the water-cement ratios of 0.40 and 0.50, are cured under the isothermal curing temperatures of 10, 23, and 50$\^{C}$ Cement type and aging have no large influence on the relationship between dynamic and static elastic modulus, but the ratio of dynamic and static elastic modulus comes close to 1 as temperature increases. Initial chord elastic modulus which is calculated at lower strain level of stress-strain curve, has the similar value to dynamic elastic modulus. The relationship between dynamic elastic modulus and compressive strength has the same tendency as the relationship between dynamic and static elastic modulus according to cement type, temperature and aging. The proposcd relationship equations between dynamic elastic modulus and static elastic modulus or compressive strength properly estimates the variation of relationships according to cement type md temperature.

• Journal of The Korean Astronomical Society
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• v.49 no.6
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• pp.295-306
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• 2016

We present the results of BV time-series photometry of the globular cluster NGC 288. Observations were carried out to search for variable stars using the Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes and a 4k pre-science CCD camera during a test observation from August to December, 2014. We found a new SX Phe star and confirmed twelve previously known variable stars in NGC 288. For the semi-regular variable star V1, we newly determined a period of 37.3 days from light curves spanning 137 days. The light-curve solution of the eclipsing binary V10 indicates that the system is probably a detached system. The pulsation properties of nine SX Phe stars were examined by applying multiple frequency analysis to their light curves. We derived a new Period-Luminosity (P-L) relation, ${\langle}M_V{\rangle}=-2.476({\pm}0.300){\log}P-0.354({\pm}0.385)$, from six SX Phe stars showing the fundamental mode. Additionally, the period ratios of three SX Phe stars that probably have a double-radial mode were investigated; $P_{FO}/P_F=0.779$ for V5, $P_{TO}/P_{FO}=0.685$ for V9, $P_{SO}/P_{FO}=0.811$ for V11. This paper is the first contribution in a series assessing the detections and properties of variable stars in six southern globular clusters with the KMTNet system.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.211-222
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• 2020

This study tried to find out whether there is a change over time in the functional classification of forests in relation to human demand for forests. The level in which the concept of ecosystem services has been considered in national forest management plans was also examined. A total of 98 current and previous national forest management plans were available for this study. The composition ratios of the six functions of forests in both the current and previous national forest management plans were surveyed. We used a parametric t-test when the mean values of two (current and previous) groups were normally distributed and used nonparametric Wilcoxon code rank test when the assumption of normality was not met. Timber production forests were shown to follow a normal distribution, while five others, including water regeneration forests, disaster prevention forests, natural environment conservation forests, recreation forests, and living environment conservation forests were not shown to follow a normal distribution. Timber production forests and natural environment forests showed significant changes in the proportion of forest area between previous and current forest management plans. The concept of 'ecosystem services' began to actively appear in the 6th Basic Forest Plan, which started in 2018. However, the level of frequency of the ecosystem services mentioned varied by Regional Forest Services.

• Journal of Life Science
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• v.22 no.6
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• pp.736-743
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• 2012

The aim of the study is to investigate the food habits of the Eurasian otter, Lutra lutra, and to examine any effects of the construction of the Busan New Port (BNP) on the prey. The frequencies and bulk estimate ratios of the biological debris, taken from spraints collected seasonally during the period from 2005 to 2011 at 16 areas, were analyzed. As the results, it was demonstrated that otters prey mainly on fish but occasionally on crustaceans and gastropods, etc., and the Mugiliformes was the most preferred fish. Although fish debris was observed throughout the season, it was suggested that the amount of fish eaten by the otter seemed to be associated with the amount of fish inhabiting the study area, judging from the striking similarities in the pattern of seasonal variations in each order of the fish between the frequency from the spraints and the fish catch. On the other hand, the frequencies of most of the fish, crustaceans, and gastropods from the spraints decreased from 2010, indicating the decrease of the amount of the prey by the construction of BNP and the strong possibility of the decrease in the number of otters in the near future. This is supported by the other studies, such as one showing a sudden decrease in the number of spraints since 2010, recent decrease in the fish catch, and the increase of marine pollution at this study area.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.580-584
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• 2001

We have investigated the deposition characteristics of Ti-Si-N films obtained by rf magnetron sputtering with ratios of Ti/Si targets in an $Ar/N_2$ gas mixture. The growth rate and stoichiometry dependence of the Ti-Si-N films on the ratio of Ti/Si and $N_2$ flow rate ratio were found to be due to the different nitriding rate of Ti and Si targets. Additionally, their different sputtering yield of nitrified Ti and Si make a reason as well. Lowering Si content in the film favored the formation of crystalline TiN, leading to the low resistivity. Increasing N content led to the Ti-Si-N films having a higher density and compressive stress, suggesting that the N content in the film is one of the most important factors determining the diffusion barrier characteristics. In the current work, the optimum process conditions for the formation of efficient diffusion barrier of Ti-Si-N film has successfully obtained by manipulating the Ti/Si ratio of target and $N_2$ flow rate ratio.