• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.107-116
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• 1993

In the design and operation of robitic arm with flexible links, the equation of motion are required to exactly model the interaction between rigid body motion and elastic motion and to be formulated efficientlyl. In this paper, the flexible link is represented by applying the D-H rigid link representation method to measure the elestic deformation. And the equations of motion of robotic arm, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated from the principle of virtual power. Dynamic characteristics due to elastic deformation of each link are obtained by using F. E. M to model complex shaped link acurately and by eliminating elastic modes of higher order that do not largely affect motion to reduce the number of elastic degrees of freedom. Also presented is the result of simulation of flexible robotic arms whose joints are controlled by direct or PD control.

• Journal of The Korean Association For Science Education
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• v.34 no.4
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• pp.407-415
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• 2014

Genetic determinism of human behaviors is considered as a philosophical perspective that genes in humans determine biological as well as social traits. However, many biologists agree that human traits are determined by interactions between genes and genes, as well as between genes and environments. In this context, genetic determinism still affect ideas of the general public as well as research directions of biologists. According to Cl$\acute{e}$ment's KVP model (Cast$\acute{e}$ra & Cl$\acute{e}$ment, 2012), teachers' conceptions of genetic determinism influence students' concepts of genetics. This study intends to investigate teachers' conceptions on genetic determinism of human behaviors. For this end, a questionnaire adopted from a previous research (Cast$\acute{e}$ra & Cl$\acute{e}$ment, 2012) has been administered to 308 teachers including 151 pre-service and 157 in-service. Factor analysis has been conducted to extract major factors and one-way ANOVA has been employed to find out differences in extracted factors among different groups of teachers. Four factors have been extracted from 14 items of questionnaire, including factor 1, a perspective of genetic determinism of gender differences in intellectual ability, social status, and emotional traits; factor 2, a perspective of genetic determinism of individual differences in intellectual ability; factor 3, a perspective of genetic determinism of individual differences in biological immune function and behavioral trait; and factor 4, a perspective of genetic determinism of ethnic differences. From the results of One-way ANOVA among teacher groups on four factors, first, it has shown a significant difference in factor 1 (F=3.325, p=.006), factor 3 (F=3.320, p=.006) and factor 4 (F=4.325, p=.001) due to their subject matters. In post-hoc comparison there have been no significant difference between biology teachers and other teachers. It has also been found that there was a significant difference between pre-service and in-service teachers in factor 1 (t=-3.938, p=.000) and factor 4 (t=-3.121, p=.002) and in-service teachers are more genetic deterministic than pre-service teachers. Finally, different religions have no influence on teachers' conceptions of genetic determinism of human behaviors.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.615-619
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• 2019

Various fluorides, i.e., CaF₂, Na₃AlF₆, K₂SiF₆, MnF₃, MgF₂, were added to the flux cored wire, and their effects on the oxygen content of the weld metal were investigated. The investigation showed that the oxygen content of weld metal was not influenced by the type of metallic elements in the fluoride; rather, it was influenced by the stability of the arc during welding. While the wire containing MgF₂ showed the most stable arc and the least amount of oxygen in the weld metal, the wire containing MnF₃ showed the least stable arc and the greatest amount of oxygen. Since the deoxidation of the weld metal was not affected by the deoxidation elements, such as Ca and Mg, it was possible to predict the oxygen content of the weld metal by the equilibrium Si-Mn deoxidation thermodynamic model.

• Journal of the Korean Statistical Society
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• v.24 no.1
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• pp.149-160
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• 1995

We consider the problem of optimal adaptive estiamtion of the euclidean parameter vector $\theta$ of the univariate non-linerar autogressive time series model ${X_t}$ which is defined by the following system of stochastic difference equations ; $X_t = \sum^p_{i=1} \theta_i \cdot T_i(X_{t-1})+e_t, t=1, \cdots, n$, where $\theta$ is the unknown parameter vector which descrives the deterministic dynamics of the stochastic process ${X_t}$ and ${e_t}$ is the sequence of white noises with unknown density $f(\cdot)$. Under some general growth conditions on $T_i(\cdot)$ which guarantee ergodicity of the process, we construct a sequence of adaptive estimatros which is locally asymptotic minimax (LAM) efficient and also attains the least possible covariance matrix among all regular estimators for arbitrary symmetric density.

• Journal of Ship and Ocean Technology
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• v.4 no.1
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• pp.21-27
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• 2000

The slamming force occurring in the free fall impact of cylindrical bodies on the water surface is analyzed in both compressible and incompressible stages. In the compressible phase the hydrodynamic analysis is carried on by the acoustic approximation, obtaining a closed form expression for the maximum impact force. The incompressible analysis is approached through and unsteady boundary element method to compute the free surface evolution and the slamming force on the body. A similar behavior seems to characterize the maximum slamming force versus a dimensionless mass parameter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.349-354
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• 2014

Elevation of intracellular calcium ($Ca^{{+}{+}}$) triggers degranulation of mast cells by bypassing receptor activation. Flos Sophora japonica L. has been used as a natural dying source and has been reported to have biological activities such as anti-inflammatory and anti-allergic effects through $Fc{\varepsilon}RI$ and IgE crosslinking. In the present investigation, we report the regulatory effect of ethanolic extract of Flos Sophora japonica L. (S.F) on allergic mediators produced by $Ca^{{+}{+}}$ ionophore activation in mast cells. S.F significantly inhibited calcium ionophore (A23187)-induced interleukin (IL)-4 and tumor necrosis factor (TNF)-${\alpha}$ production as well as mast cell degranulation. Furthermore, administration of S.F suppressed allergic reactions in a 2,4-dinitrofluorobenzene (DNFB)-induced allergic dermatitis mouse model. Both oral administration and ear painting using 50 mg/kg of S.F significantly reduced levels of cytokines such as IL-4, TNF, and interferon-${\gamma}$ in ear tissues compared to the DNFB alone-treated group. Serum IgE level in the S.F-treated group also decreased compared to the DNFB alone-treated group. Weights of spleens and lymph nodes in the S.F-treated groups also decreased compared to the control group. Considering the data, we conclude that S.F mediates its anti-allergic effects not only through $Fc{\varepsilon}RI$ stimulation but also $Ca^{{+}{+}}$ influx in mast cells.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.216-222
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• 1996

This paper presents a computational technique to predict roof crush resistance in early design stage of passenger car development. This technique use a simple F.E. model with nonlinear spring elements which represent plastic hinge behavior at weak areas. By assuming actual sections as equivalent simple sections, maximum bending moments which weak areas in major members can stand are theoretically calculated. Results from prediction of roof crush resistance are correlated well with test results.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.331-337
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• 2008

Polycyclic aromatic hydrocarbons (PAHs) derived from leakage of fossil fuels and incomplete combustion of organic materials have been considered as harmful contaminants in environments. This study evaluated the effect of benzo[k]fluoranthene (BkF), one of the PAHs, using the multiple biomarkers and applied the integration model with those biomarker responses. After 10 days of the exposure at the measured concentrations of BkF (6, 25, and 45 ${\mu}g\;L^{-1}$), the changes of the four biomarkers, that is, 7-ethoxyresorufin-O-deethylase (EROD), DNA single-strand breaks (Comet), acetylcholinesterase (AChE) and vitellogenin (VTG) in the common carp (Cyprinus carpio) were observed. The standardized values of four biomarker responses were computed and integrated as star plots, representing Integrated Biomarker Respnse (IBR) values. DNA damage was induced in a dose-dependent manner, and increased significantly compared with that in the control. EROD and VTG levels were significantly elevated at low concentrations of BkF. On the other hand, AChE activities were not altered by BkF. IBR values increased as the exposure concentrations increased. Thus, the metabolic, endocrine and genetic changes of the biomarker responses in the common carp exposed to BkF should be considered in the case of the ecological risk assessment of the BkF in fish and it can be used as a biomonitoring tool in aquatic ecosystems. In addition, star plots can be used as a useful analysis tool in multibiomarker integration approach.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1772-1776
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• 2006

The Ministry of Environment is determining reference flows and goal water qualities in many stations over all around riverbasin to control TMDL. Reference flow is now defined to 10 years averaged 275th minimum flow$(Q_{275})$. Dam operation takes direct effect on flows downstream. The Yongdam mutipurposed dam was constructed in 2002 and TMDL managing stations between the Daecheong dam and the Yongdam dam are the Geumbon B, C, D, E, and F in main stream of the Geum river. Geumbon F is the Daecheong dam site. Observed flows are ideal to be used to set reference flows, but simulated flows are more practical to be used to set reference flows from the cause of the Yongdam dam's operation. A system for simulating daily storages of the Yongdam dam was constructed and the DAWAST model was selected to simulate daily streamflows. Analysis period was selected for 10 years from 1996 to 2005. Scenario was set as follows; Firstly, observed outflows from the Yongdam dam are used from 2002 to 2005 and the Yongdam dam does not exist from 1995 to 2001. Secondly, the Yongdam dam existed also from 1995 to 2001 and simulated outflows from the Yongdam dam are used from 1996 to 2005 with provision of constant outflow of $7.0m^3/s$ and water supply to the Jeonju region outsided watershed of $900,000m^3/day$. In case of scenario 1 reference flows at the Geumbon B, C, D, E, F are 4.52, 6.69, 7.96, 11.17, and $13.21m^3/s$, respectively. And in case of scenario 2 reference flows at the Geumbon B, C, D, E, F are 6.27, 8.48, 9.58, 12.73, and $15.12m^3/s$, respectively.

• Journal of Environmental Science International
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• v.24 no.7
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• pp.927-937
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• 2015

This study was performed to identify and quantify the asbestos fibers released from two types of asbestos-cement slate roofs. One is a plant roof installed in 1987 which contained 15% chrysotile, and the other is a residential roof installed before 1983 which contained 12% chrysotile. The concentrations of asbestos fibers in air surrounding asbestos-cement slate roofs and in the falling water harvested from the same roofs on rainy days ranged from 0.0012 to 0.0018 f/mL and from 1,764 f/L to 10,584 f/L, respectively. The concentration of inorganic fibers in the soil around asbestos-cement slate roofs was from 217 to 348 f/g. With the above results, the excess lifetime cancer risk (ELCR) for the risk assessment of the asbestos fibers released from asbestos-cement slate based on US EPA IRIS (Integrated risk information system) model is within 5.5E-06 ~ 6.5E-06 levels which indicates that the levels do not exceed "the acceptable risk(1.0E-05)" recommended by WHO. The asbestos concentration in air, drained rainfall and soil around the plant slate roof was higher than that around residential slate roof, but the excess lifetime cancer risk (ELCR) from residential slate was higher than that from plant slate. This suggested that the enclose and encapsulation of residential roofs have priority in removal policy to minimize the exposure risk.