• Korean Journal of Environmental Biology
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• v.24 no.3
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• pp.240-247
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• 2006

The dynamic of zooplankton community and its relationship with dissolved oxygen were studied at the Soho area of Gamak Bay from 22 August to 15 September in summer. We found that zooplankton were in low abundance or absent from bottom waters when oxygen concentrations were <3 mg $L^{-1}$. The relationship between summer low-oxygen in bottom-layer and zooplankton community structure was discussed at vertical abundance in Soho area of Gamak Bay. To examine effects of bottom-layer low-oxygen on abundance and vertical distributions in the stratified Soho area, zooplankton was surveyed near-surface, within the near-bottom in the study area under a range of near-bottom dissolved oxygen conditions. There were vertical variation in total zooplankton abundance in the study area (ANOVA, P<0.05). Overall abundance of zooplankton: copepod nauplii, Oithona sp. and tintinnids were lower throughout the water column when bottom-layer DO was low (${\leq}3mg\;L^{-1}$). In this context it was postulated that zooplankton distribution in the Soho area of Gamak Bay might be controlled by dissolved oxygen condition.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.1-11
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• 2001

The geological characteristics of Korea are that we can encounter the rock layer only after 10m of excavation, methods to presume the rock pressure distribution of the rock layer is urgently needed. When using the existing empiric science of Terzaghi-Peck, Tschebotarioff to measure the rock pressure of the rock layer, underestimate the real strength because of the cohesion is ignored. Therefore calculating the horizontal sliding force of wedge block, which includes the dips and shear strength of discontinuities and surcharge load etc., think to be to getting a closer rock stress of the real rock pressure acting upon the earth structure in rock mass. This research use Coulomb soil pressure theory assuming that the backfill soil will yield wedge failure when it has cohesion, applying Prakash-Saran(l963), and then it uses equilibrium of force and shear strength $\tau$=c+$\sigma$tan $\Phi$ of the cliscontinuities. Analyzing shear strength and dips of cliscontinuities using calculated theory according to the status of discontinuities aperture, we were able to find out that because the cohesion and friction angle of the rock layer itself is large enough, how the dip directions and dips facing the excavation face is the only factor deciding whether or not the rock stress is applied. The evaluated theory of this research should be strictly estimated, so that the many parameters such as c, $\Phi$value, types and structures of rock class, excessive lateral pressure, dynamic load, earthquake, needed later when calculating shear strength of discontinuities and especially the ground water effect acting on rock layer should be coumpted with many measuring data achieve at the insite to study the application.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.27 no.1
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• pp.25-29
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• 2016

Background and Objectives : The clinical reports for the treatment of vocal fold scar and sulcus vocalis are limited, also there is no best one for the treatment of them. This study is to evaluate the effect of Injection laryngoplasty (IL) for the treatment of vocal fold scar and sulcus vocalis. Materials and Methods : from January 2013 to May 2015, the Nineteen patients who were diagnosed as vocal fold scar, sulcus and atrophy, and underwent IL, were engaged in this study. Clinical information and voice parameters were analyzed by retrospective chart review. Pre and post voice parameters were compared. Results : Subgroups of diagnosis were classified into sulcus vocalis for 12 patients, vocal fold scar for 5, and atrophy for 2. IL was performed under local anesthesia through cricothyroid membrane except one patient. Atesense$^{(R)}$, Radiessess$^{(R)}$, and Rofilan$^{(R)}$ were used as injected materials in 9, 9, and 1 patients respectively. Maximal phonation time (p=0.0124), dynamic range (p=0.0028), pitch range (p=0.0141), voice handicap index (p=0.028), glottal closure (p=0.0229), and mucosal wave (p=0.0132) had significant improvement for post-IL voice assessment than Pre-IL. While GRBAS, Mean flow rate, Jitter, Shimmer, Harmony to Noise ratio didn't have improvement. Conclusion : IL is a feasible option for the treatment of glottis incompetence with normally mobile vocal folds such as sulcus vocalis and vocal fold scar.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1476-1484
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• 2004

Aging is characterized by an age-dependent reduction in bone density. Pronounced bone loss by postmenopausal estrogen deficiency induces a bad effect on dynamic balance of bone metabolism. When the bone density is reduced to the level below the fracture threshold, the risk for fracture is greatly increased. The purpose of this study is to examine what are the effects of the Guisinhwan(GSH : 歸腎丸) on the ovariectomized rat model of postmenopausal osteoporosis. The results of the experiment are as follows: Body weight in control group showed significant increase in comparison with sham, but that in GSH-treated showed no change in comparison with control. The level of serum albumin in control group showed significant decrease in comparison with sham. That in GSH-treated was slightly decreased in comparison with control. The level of serum ALP activity in control group showed significant increase in comparison with sham, but that in GSH-treated was significantly decreased in comparison with control. The level of serum phosphorous, calcium, GOT, GPT, T3 did not significant change among the three groups. The level of serum estrogen in control group showed slightly decreased in comparison with sham, but that in GSH-treated showed no change in comparison with control. The level of serum T4 in control group showed significant increase in comparison with sham, but that in GSH-treated was significantly decreased in comparison with control. Trabecular bone area as well as trabecular thickness in control group showed significant decrease In comparison with sham. Those in GSH-treated showed significant increase in comparison with control. Trabecular number did not significant change among the three groups. Trabecular separation only in GSH-treated showed significant decrease in comparison with control. Osteoclast number in control group showed significant increase in comparison with sham. That in GSH-treated showed significant decrease in comparison with control. Oseoblast surface in control group showed significant increase in comparison with sham, but that in GSH-treated showed no change in comparison with control. According to the above these results, GSH has shown to be capable of preventing and curing osteoporosis caused by old-aged and postmenopause.

• International Journal of Highway Engineering
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• v.2 no.3
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• pp.129-144
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• 2000

This paper presents the characteristics of viscoelastic properties and fatigue performance of SBS modified asphalt mixtures depending on the aggregate gradation. Dynamic shear rheometer (DSR) and uniaxial tensile creep tests are performed to analyze the thermomechanical behavior of asphalt binders and mixtures, respectively. Uniaxial tensile fatigue tests for seven different asphalt mixtures are conducted to evaluate the effects of aggregate gradations and SBS modifier on the fatigue performance of the mixtures. DSR and uniaxial tensile creep tests results show that the SBS modified asphalt mixtures have better rutting resistance than the unmodified mixtures at high temperatures regardless of the aggregate gradations used. Fatigue factor $G^*sin\delta$ in Superpave binder specification may not be adequate for evaluating the fatigue Performance of asphalt mixtures. It is observed from uniaxial tensile fatigue tests that SBS modified asphalt mixtures compared to unmodified mixtures have ten times longer fatigue lives regardless of the aggregate gradations(dense, SMA, and Superpave gradations) used in the mixtures. The better fatigue performance of the SBS modified mixtures is observed even after long-term aging process. The effect of aggregate gradations on the fatigue performance is not as significant as the SBS modifier. The cellulose fiber added in the SMA mixture has negligible effects on the viscoelastic Properties and fatigue performance of the mixture, but is effective in reducing draindown. Although the SBS modified asphalt binder is used, it may be necessary to add the cellulose fiber into the SMA mixture to prevent the draindown.

• Parasites, Hosts and Diseases
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• v.54 no.3
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• pp.291-299
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• 2016

Human hydatid disease (cystic echinococcosis, CE) is a chronic parasitic infection caused by the larval stage of the cestode Echinococcus granulosus. As the disease mainly affects the liver, approximately 70% of all identified CE cases are detected in this organ. Optical molecular imaging (OMI), a noninvasive imaging technique, has never been used in vivo with the specific molecular markers of CE. Thus, we aimed to construct an in vivo fluorescent imaging mouse model of CE to locate and quantify the presence of the parasites within the liver noninvasively. Drug-treated protoscolices were monitored after marking by JC-1 dye in in vitro and in vivo studies. This work describes for the first time the successful construction of an in vivo model of E. granulosus in a small living experimental animal to achieve dynamic monitoring and observation of multiple time points of the infection course. Using this model, we quantified and analyzed labeled protoscolices based on the intensities of their red and green fluorescence. Interestingly, the ratio of red to green fluorescence intensity not only revealed the location of protoscolices but also determined the viability of the parasites in vivo and in vivo tests. The noninvasive imaging model proposed in this work will be further studied for long-term detection and observation and may potentially be widely utilized in susceptibility testing and therapeutic effect evaluation.

• Journal of Korean Society of Steel Construction
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• v.25 no.4
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• pp.335-346
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• 2013

AASHTO LRFD and Korean Bridge Design Code (Limit State Design) specify to consider Truck and Lane load simultaneously determined from reliability-based live load model, and impact shall be applied to the truck load while it shall not be applied to the lane load. In this paper, vehicle-bridge interaction analysis under moving truck and lane loads were performed to estimate impact factor of the cables and girders for the selected multi-cable-stayed composite bridges with 230m, 400m and 540m main span. A 6-d.o.f. vehicle was used for truck load and a series of single-axle vehicles was applied to simulate equivalent lane load. The effect of damping ratio on the impact factor was estimated and then the essential parameters to impact factor, i.e., road surface roughness and vehicle speed were considered. The road surface roughness was randomly generated based on ISO 8608 and it was applied to the truck load only in the vehicle-bridge interaction analysis. The impact factors evaluated from dynamic interaction analysis were also compared with those by the influence line method that is currently used in design practice to estimate impact factor in cable-stayed bridge.

• Journal of Technology Innovation
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• v.22 no.1
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• pp.23-58
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• 2014

This study investigates the effects of product strategies and CEO characteristics on the growth of venture firms. These factors are related with strategic behaviors and managerial capabilities of small and dynamic firms. According to empirical results of FGLS regression with the data of the Korean venture firms, both product strategies and CEO characteristics have significant effects on firm growth and additionally explanatory powers. In general, the growth rates of venture firms tend to increase with the level of product's diversity and marketing-enhancing strategy, but decrease with the degree of product's innovation-enhancing strategy. The growth rates are higher when CEO is non-founder and has sufficient experience related to current business, and CEO's career development is focused on general management area. The effects of product strategies and CEO characteristics are moderated by the firm-internal factor such as organizational growth stage. The positive effects of some product strategies (e.g. marketing-enhancing strategy) and CEO characteristics(e.g. career focused on general management) become stronger for firms operating in the stage of start-up or initial growth, while their effects become negative or insignificant for firms operating in the mature or declining stage in which the negative effect of innovation-enhancing strategy does not exist.

• Journal of Educational Research in Mathematics
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• v.14 no.2
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• pp.207-219
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• 2004

There have been studies reporting the increase in student confidence in mathematics when using technology. However, past studies indicating a positive correlation between technology and confidence in mathematics do not explain why they see this positive outcome. With increased availability and easy access to the Internet in schools and the development of free online virtual manipulatives, this research was interested in how the use of virtual manipulatives in mathematics can affect students confidence in their mathematical abilities. Our hypothesis was that the classes using virtual manipulatives which allows students to connecting dynamic visual image with abstract symbols will help students gain a deeper conceptual understanding of math concept thus increasing their confidence and ability in mathematics. The participants in this study were 46 fifth-grade students in three ability groups: one high, one middle and one low. During a two-week unit on fractions, students in three groups interacted with several virtual manipulative applets in a computer lab. Data sources in the project included a pre and posttest of students mathematics content knowledge, Confidence in Learning Mathematics Scale, field notes and student interviews, and classroom videotapes. Our aim was to find evidence for increased level of confidence in mathematics as students strengthened their understanding of fraction concepts. Results from the achievement score indicated an overall main effect showing significant improvement for all ability groups following the treatment and an increase in the confidence level from the preassessment of the Confidence in Learning Mathematics Scale in the middle and high ability groups. An interesting finding was that the confidence level for the low ability group students who had the highest confidence level in the beginning did not change much in the final confidence scale assessment. In the middle and high ability groups, the confidence level did increase according to the improvement of the contest posttest. Through interviews, students expressed how the virtual manipulatives assisted their understanding by verifying their answers as they worked and facilitated their ability to figure out math concept in their mind and visually.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.95-104
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• 2005

The research conducted to study the potential practicability of recycled aggregate concrete by analyzing the characteristics of concretes made of recycled quality aggregates produced by wet and dry process has found the following results. The air content of recycled aggregate concrete increased with increase of the substitut on rate due to mortar included while producing recycled aggregates. However, the concretes with aggregate produced by dry process had relatively low rate of increase in air content. The slump showed generally decreasing trend as the substitution rate of recycled aggregate increased regardless of the wet or dry process. It was assumed that the mortar particles remained in recycled aggregate absorbed the surplus hydration in concrete and decreased fluidity The compressive strength generally decreased as the substitution rate of recycled aggregate increased, however there was an increasing trend as well due to decreasing effect of water-cement ratio when the substitution rate of recycled aggregate reached 25, 50% after mix. This phenomena also appeared in early age, which meant that recycled aggregate concrete should not be retarded in setting when applied in the field. The tensile strength also reached the maximum when wet or dry recycled aggregate replaced with 25%. To conclude, recycled aggregates for concrete produced by wet or dry process are expected to demonstrate essential characteristics of concrete without significant decline in physical or dynamic quality when the substitution rate is below 25% although there are variations subject to water-cement ratio. However, slight differences are expected due to types of recycled aggregate and physical quality.