• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.412-415
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• 1994

The fundamental assumption that thresholds exist for noncarcinogenic toxic effects of chemicals is reviewed; this assumption forms the basis for the no-observed-effect level/ safety-factor (NOEL/SF) approach to risk assessment for such effects. The origin and evolution of the NOEL/SF approach are traced, and its limitations are discussed. The recently proposed use of dose-response modeling to estimate a benchmark dose as a replacement for the NOEL is explained. The possibility of expanding dose-response modeling of non carcinogenic effects to include the estimation of assumed thresholds is discussed. A new method for conversion of quantitative toxic responses to a probability scale for risk assessment via dose-response modeling is outlined.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.380-391
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• 2014

In this study, the scale effect on the performance of the podded propeller of tractor type is investigated. Turbulent flow computations are carried out for Reynolds numbers increasing progressively from model scale to full scale using the CFD analysis. The result of the flow calculation for model scale Reynolds numbers agrees well with that of the experiment of a large cavitation tunnel. The existing numerical analysis indicates that the performance of the podded propeller blades is mainly influenced by the advance coefficient and relatively little by the Reynolds number. However, the drag of pod housing with propeller in operation is different from that of pod housing without propeller due to the acceleration and swirl of propeller slipstream which is altered by propeller loading as well as the pressure recovery and friction according to Reynolds number, which suggests that the pod housing drag under the condition of propeller in operation is the key factor of the scale effect on the performance between model and full scale podded propellers. The so called 'drag ratio', which is the ratio of pod housing drag to total thrust of podded propeller, increases as the advance coefficient increases due to accelerated flow in the slipstream of the podded propeller. However, the increasing rate of the drag ratio reduces continuously as the Reynolds number increases from model to full scale progressively. The contribution of hydrodynamic forces, which acts on the parts composed of the pod housing with propeller operating in various loading conditions, to the thrust and the torque of the total propeller unit are presented for a range of Reynolds numbers from model to full scales.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.4
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• pp.667-681
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• 1996

The purposes of this study were 1) to identify the effects of age and sex on adolescent's psychological characteristics-egocentrism, self-consciousness, body cathexis and clothing behaviors and 2) to identify the effects of psychological characteristics on clothing behaviors in each of the 6 groups classified by sex and age. Egocentrism was measured by Kim's Imaginary Audience Scale, and body cathexis, by the modified record and Jourard"s Body Cathexis Scale. Buss's Self-Consciousness Scale was slightly modified to assess public and private self-consciousness, and five aspects of clothing behavior were assessed with the questionnaires from the previous studies. The questionnaire were administered to 713 middle and high school boys and girls, and college students living in Seoul. Data were analyzed by frequency, factor Analysis, two-way ANOVA, and multiple regression analysis. The results of this study were as follows: 1) Four factors of egocentrism were identified : Potency, Appearance/populatity, Sympathy and Justice. Four factors of clothing behavior were Clothing exhibition/dressing for others, Clothing interest, Psychological dependence, and Clothing conformity. 2) Sex and age were found to have effects on psychological variables and clothing behaviors of adolescence. Females showed higher egocentrism, self- consciousness, clothing behaviors, but lower body cathexis than males. The mean scores of egocentrism, self-consciousness, clothing behaviors tended to increase with age. However, high school boys showed unique tendency, as they showed higher scores in those variables than the other two age groups. 3) Egocentrism (Appearance/populality factor) and public self- consciousness were the most influencial variables on adolescent's clothing behavior among psychological characteristics. Private self-consciousness was found to be an important variable in explaining Psychological dependence.ence.

• Journal of Korean Medical classics
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• v.30 no.3
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• pp.133-141
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• 2017

Objectives : As of 2013, South Korea ranked number one in the world in smartphone penetration rate with 67.6%. Unfortunately, with the rise of smart phone use, side effects such as fraud, loss of personal information, identity theft, formation and widening of a mobile information gap, and last, but not least, smart phone addiction, also increased. Methods : Seventh (7th)graders from a girls' junior high school in Seoul, the capital of South Korea, we reevaluated the Smart phone Addiction Proneness Scale (S-scale). Among the 9 students classified as high risk users, 5 were randomly selected for a study group, and the remaining 4 students, meanwhile, were designated as a control group. The study group received Korean medicine music therapy (KMMT) in a total of 8 sessions, each session lasting 50 minutes. Both pre- and post-interventions, the two groups completed the S-scale, Harris and Harris' concentration grid exercise, STAI, and STAXI-K. We analyzed the data by t-test and paired t-test using IBM SPSS Statistics. Results : KMMT had a significant influence on proneness to smart phone addiction (t=3.130, p=.035). KMMT had positive effects on concentration improvement (t=-2.935, p=.043), trait-anxiety symptoms improvement (t=2,992, p=.040), and anger-expression control (t=4.416, p=.012). Conclusions : KMMT had positive, improving effects on trait anxiety and anger expression, which in turn enhanced the improvement of concentration as well as the decrease of smart phone-addiction proneness.

• Wind and Structures
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• v.13 no.6
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• pp.557-580
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• 2010

A new inflow turbulence generation method and a combined dynamic SGS model recently developed by the authors were applied to evaluate the wind effects on 508 m high Taipei 101 Tower. Unlike the majority of the past studies on large eddy simulation (LES) of wind effects on tall buildings, the present numerical simulations were conducted for the full-scale tall building with Reynolds number greater than $10^8$. The inflow turbulent flow field was generated based on the new method called discretizing and synthesizing of random flow generation technique (DSRFG) with a prominent feature that the generated wind velocity fluctuations satisfy any target spectrum and target profiles of turbulence intensity and turbulence integral length scale. The new dynamic SGS model takes both advantages of one-equation SGS model and a dynamic production term without test-filtering operation, which is particular suitable to relative coarse grid situations and high Reynolds number flows. The results of comparative investigations with and without generation of inflow turbulence show that: (1) proper simulation of an inflow turbulent field is essential in accurate evaluation of dynamic wind loads on a tall building and the prescribed inflow turbulence characteristics can be adequately imposed on the inflow boundary by the DSRFG method; (2) the DSRFG can generate a large number of random vortex-like patterns in oncoming flow, leading to good agreements of both mean and dynamic forces with wind tunnel test results; (3) The dynamic mechanism of the adopted SGS model behaves adequately in the present LES and its integration with the DSRFG technique can provide satisfactory predictions of the wind effects on the super-tall building.

• Journal of the Korean society of biological therapies in psychiatry
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• v.24 no.3
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• pp.218-229
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• 2018

Objectives : Antipsychotic-induced hyperprolactinemia causes physical symptoms, such as amenorrhea, galactorrhea, gynecomastia, sexual dysfunction, and bone density loss, as well as psychiatric symptoms, such as depression and cognitive impairments. This study aimed to clarify the associations among hyperprolactinemia caused by antipsychotics in patients with schizophrenia, psychiatric pathology, and psychosocial factors. Methods : Ninety-nine patients with schizophrenia in the psychiatry department of a university hospital were registered between 2015 and 2017. All participants were assessed using structured questionnaires to elucidate psychopathology, social function, quality of life, and hyperprolactinemia-related side effects. The standard levels for hyperprolactinemia were 24ng/mL for women and 20ng/mL for men. Results : The average prolactin levels were $73.45{\pm}49.37ng/mL$ in patients with hyperprolactinemia and $9.16{\pm}6.42ng/mL$ in those without hyperprolactinemia. The average prolactin level in women was significantly higher than that in men(p=0.04). Risperidone was most commonly administered in patients with hyperprolactinemia(58.1%, p<0.01), while aripiprazole was most commonly administered in those without hyperprolactinemia(44.7%, p<0.01). Patients with hyperprolactinemia had significantly higher Positive and Negative Syndrome Scale(p=0.03) and Patient Health Questionnaire-9(p=0.05) scores and had significantly lower Social and Occupational Functioning Assessment Scale(p=0.04) and Strauss-Carpenter Levels of Functioning Scale(p=0.03) scores than patients without hyperprolactinemia. There were no significant differences in side effects or quality of life between the two groups. Conclusion : These findings demonstrate that hyperprolactinemia confers negative effects on depression and social function, but does not directly affect the quality of life. These results suggest that patients with schizophrenia who take antipsychotics that increase prolactin or cause side effects of hyperprolactinemia need to be assessed and receive interventions for depression.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.75-75
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• 2022

Traditional agriculture mostly focused on activity in the field, but current agriculture faces problems such as reduction of agricultural inputs, labor shortage and so on. Accordingly, traditional agricultural experiments generally considered the simple treatment effects, but current agricultural experiments need to consider the several and complicate treatment effects. To analyze such several and complicate treatment effects, data collection has the first priority. Remote sensing is a quite effective tool to collect information in agriculture, and recent easier availability of UAVs (Unmanned Aerial Vehicles) enhances the effectiveness. LAI (Leaf Area Index) is one of the most important information for evaluating the condition of crop growth. In this study, we utilized UAV with multispectral camera to evaluate plant-based LAI of sweetcorn in a small-scale field experiment and discussed the feasibility of a new experimental design to analyze the several and complicate treatment effects. The plant-based SR measured by UAV showed the highest correlation coefficient with LAI measured by a canopy analyzer in 2018 and 2019. Application of linear mix model showed that plant-based SR data had higher detection power due to its huge number of data although SR was inferior to evaluate LAI than the canopy analyzer. The distribution of plant-based data also statistically revealed the border effect in treatment plots in the traditional experimental design. These results suggest that remote sensing with UAVs has the advantage even in a small-scale experimental plot and has a possibility to provide a new experimental design if combined with various analytical applications such as plant size, shape, and color.

• Geophysics and Geophysical Exploration
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• v.6 no.4
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• pp.165-170
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• 2003

Recently, resistivity surveys have been frequently carried out over the irregular terrain such as mountainous area. Such an irregular terrain itself can produce significant anomalies which may lead to misinterpretations. In this study, topographic effects in resistivity survey were studied using the physical scale modeling as well as the numerical one adopting finite element method. The scale modeling was conducted at a pond, so that we could avoid the edge effect, the inherent problem of the scale modeling conducted in a water tank in laboratory. The modeling experiments for two topographic features, a ridge and a valley with various slope angles, confirmed that the results by the two different modeling techniques coincide with each other fairly well for all the terrain models. These experiments adopting dipole-dipole array showed the distinctive terrain effects, such that a ridge produces a high apparent resistivity anomaly at the ridge center flanked by zones of lower apparent resistivity. On the other hand, a valley produces the opposite anomaly pattern, a central low flanked by highs. As the slope of a terrain model becomes steeper, the terrain-induced anomalies become stronger, and moreover, apparent resistivity can become even negative for the model with extremely high slope angle. All the modeling results led us to the conclusion that terrain effects should be included in the numerical modeling and/or the inversion process to interpret data acquired at the rugged terrain area.

• Structural Engineering and Mechanics
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• v.67 no.5
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• pp.505-516
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• 2018

In this paper, the effects of particle size and model scale of concrete has been investigated on the failure mechanism of PFC2D numerical models under uniaxial compressive test. For this purpose, rectangular models with same particle sizes and different model dimensions, i.e., $3mm{\times}6mm$, $6mm{\times}12mm$, $12mm{\times}24mm$, $25mm{\times}50mm$ and $54mm{\times}108mm$, were prepared. Also rectangular models with dimension of $54mm{\times}108mm$ and different particle sizes, i.e., 0.27 mm, 0.47 mm, 0.67 mm, 0.87 mm, 1.07 mm, 1.87 mm and 2.27 mm were simulated using PFC2D and tested under uniaxial compressive test. Concurrent with uniaxial test, direct shear test was performed on the numerical models. Dimension of the models were $75{\times}100mm$. Two narrow bands of particles with dimension of $37.5mm{\times}20mm$ were removed from upper and lower of the model to supply the shear test condition. The particle sizes in the models were 0.47 mm, 0.57 mm, 0.67 mm and 0.77 mm. The result shows that failure pattern was affected by model scale and particle size. The uniaxial compressive strength and shear strength were increased by increasing the model scale and particle size.

• Journal of Science Education
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• v.35 no.2
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• pp.119-126
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• 2011

The purpose of this study was to examine the effects of experimental learning using the small-scale chemistry (SSC) on high school students' academic achievement, scientific attitude and science-related attitude in high school chemistry I. For this study, two high school 2nd grade classes were divided into an experimental group and a control group. Experimental learning using the SSC in the experimental group, traditional experimental learning presented in the textbook in the control group were performed. The results showed that experimental learning using the SSC compared to traditional experimental learning was effective in improving academic achievement. The experimental learning also was effective in improving voluntary, patience, cooperativity in the scientific attitudes and social implications of science, attitude for science curriculum, attitude toward science in the science-related attitudes. Therefore, experimental learning using the SSC is necessary to actively utilize in high school chemistry curriculum.