• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.161-168
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• 2000

The purpose of this study was to develop a practical caries activity test using laser fluorescence. The subjects of study were 30 children of $7\sim10$ years old. Fluorescence from initial carious lesion of teeth illuminated by an argon laser(488nm) was observed through barrier alter. For evaluation of accuracy and propriety of this method fer caries activity test, teeth with initial caries lesion on buccal or labial surface of children was examined with visual inspection and laser fluorescence. Visual examination for the dDfFtT and the $Cariescreen^{(R)}$ test were also done. The results from the present study can be summarized as follows: 1. Laser fluorescence test could differentiate initial caries lesions more easily than visiual inspection. 3. There was highest correlation(= 0.73) between laser fluorescent test and $Cariescreen^{(R)}$ test and. And also apparent correlation(= 0.66) exists between laser fluorescent test and caries experience measured by dDfFtT.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.2
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• pp.465-486
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• 2010

Studying the definition and building a foundation about variables during elementary school is a crucial factor before students study the variable in depth in middle school. So, forming a basis for understanding variable in this period should be treated with importance, because it is the first step in forming a clear understanding of the concept of variables. According to analysis of the types of letters used in current textbooks, we can see that too much emphasis was placed on type 1(letter evaluated), type 3(letter used as an Object). By not utilizing the various types of letter usage we reduce the situation to one which is removed from the context and an automatous style of learning. Therefore, the purpose of this study was the development about early algebra learning materials which use diverse types of letters. We have analyzed the types of letters used from the 4-ga to 6-na mathematics textbooks and the 4-ga to the 6-na workbooks. To make learning materials for well-balanced letter use, we developed learning materials focused on early algebra with the 6-ga and the 6-na textbooks.

• Journal of the Korea Concrete Institute
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• v.13 no.5
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• pp.447-456
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• 2001

Many investigators have tried to represent the nonlinear behavior of stress-strain relationship of concrete using mathematical curves. Most of empirical expressions for stress-strain relationship, however, have focused on old age concrete, and were not able to represent well the behavior of concrete at an early age. Where wide understanding on the behavior of concrete from early age to old age is very important in evaluating the durability and service life of concrete structures. In this paper, effect of 5 different strength levels and ages of from 12 hours to 28 days on compressive stress-strain relationship was observed experimentally and analytically. Tests were carried out on $\phi$100${\times}$200mm cylindrical specimens water-cured at 20${\pm}$3$^{\circ}C$. An analytical expression of stress-stain relationship with strength and age was developed using regression analyses on experimental results. For the verification of the proposed model, the model was compared with present and existing experimental data and some existing models. The analysis shows that the proposed model predicts well experimental data and describes well effect of strength and age on stress-strain relationship.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.1
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• pp.12-17
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• 2003

Optimal determination of cluster size has an effect on the result of clustering. In K-means algorithm, the difference of clustering performance is large by initial K. But the initial cluster size is determined by prior knowledge or subjectivity in most clustering process. This subjective determination may not be optimal. In this Paper, the genetic algorithm based optimal determination approach of cluster size is proposed for automatic determination of cluster size and performance upgrading of its result. The initial population based on attribution is generated for searching optimal cluster size. The fitness value is defined the inverse of dissimilarity summation. So this is converged to upgraded total performance. The mutation operation is used for local minima problem. Finally, the re-sampling of bootstrapping is used for computational time cost.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.10 no.1
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• pp.121-133
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• 1999

Lethal catatonia is one of catatonic spectrum, but it differentiates itself to a separate entity as a syndrome because of its severity and lethality. The prevalence of this disorder may have declined worldwide, coinciding with the advent of modern psychopharmacologic agents and other advances in medical treatment. The patient reported here was an 11-year old boy, showing catatonic excitement and stuporous condition with high fever, autonomic dysfunction and several catatonic symptoms. This is a case of successful treatment by using intensive medical monitoring and conservative treatment in an intensive care unit, combined with pharmacological treatment and electroconvulsive therapy during the early phase of lethal catatonia with mild symptoms.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.170-178
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• 2004

This paper deals with six degree-of-freedom HILS(hardware-in-the-loop-simulation) of KSR-III rocket using a TAFMS(three axis flight motion simulator). This TAFMS HILS test is accomplished before main HILS tests in order to verify the control stability in the presence of TAFMS dynamic effects. The TAFMS HILS test includes initial attitude holding tests for INS initial alignment procedures, timer synchronization tests with an auxiliary lift-off signal, real-time calibration tests using an external thermal recorder, open-loop TAFMS operating tests, and final closed-loop TAFMS HILS tests using the TAFMS attitude measurements as inputs to the closed control loop. The HILS tests are accomplished for several flight conditions composed with nominal flight condition, TWD effect added condition, slosh modes and/or bending modes existing condition, and windy condition, etc.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.19-26
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• 1995

The assessment of maneuverability of a ship is very important from the view point of safety of human beings and of pollution of ocean. And, it is quite natural that every ship yard wants to have some tools with which they can build a ship with good maneuverability. But, maneuvarability of a ship is very subtle problem, and to calculate the exact maneuvering motion, lots of captive model tests must be carried out. Futhermore, in the initial design stage we can not make the scale model, because the lines of a ship is not fixed. In this paper, some approximate method to calculate the maneuvering motion of a ship, with the principal dimensions of hull, and propeller, rudder characteristics only, is studied. And, proposed approximate method is used to calculate the turning and zig-zag maneuver of several ships. The results of those calculations and the usability of the method are discussed.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.1
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• pp.94-101
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• 1994

This paper describes a short-term prediction model for the movement of an oil slick in shallow waters. Under the assumption that the initial movement of the oil slick is governed by spreading and advection, the model has been developed and applied to Kyungki-Bay near Incheon Harbor. The initial spreading is estimated by using an empirical formula. The depth-averaged momentum equations are solved numerically for the volume transport velocities, in which the $M_2$ tide is the main driving source. A staggered grid system is adopted fur spatial discretization and the half-time method is implemented for time marching. The numerical result is visualized with the help of animation and thus the contaminated area is displayed on a monitor in time sequence. The input data are the time, the location and the volume of spill accident as well as environmental data such as md and $M_2$ tide.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.71-78
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• 2022

Recently, the number of people wishing to return to farming is increasing, However, the lack of farming experience and management information of returnees is one of the main reasons for increasing the probability of agricultural failure. This study proposes an interface to support early facility cultivation management decision-making for returnees who want facility cultivation. The proposed interface is designed with UML(Unified Modeling Language) and provides key decision-making information such as land/crop suitability, land/facility costs, and management costs according to input data such as cultivation areas, selected crops, and cultivation types selected by the user. Through the proposed interface, facility cultivators can effectively and quickly acquire initial decision-making information for facility cultivation in the desired target area.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.385-390
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• 1998

The effect of agglomeration treatment was examined to prevent the parched cereal powder from clumping when it is blended with water. Parched cereal powder was composed of 66.9% carbohydrate, 7% water, 12.1% crude protein, 12.1% crude fat and 1.9% ash, respectively. Particle size of parched cereal powder was generally enlarged by agglomeration treatment. This phenomenon was confirmed by particle size analyzer and microscopic observation. The color of agglomerated sample was shown to be slightly darker than the untreated sample. The water absorption indices of agglomerated samples which were steamed for 2min and re-dried were significantly increased as compared with the untreated sample. The water solubility indices of agglomerated samples showed generally lower values than those of untreated samples. In views of quality and processing time, the optimum condition of agglomeration treatment for manufacturing well-dispersable parched cereal powder in water was 15min re-drying after 2min steaming. It is concluded that the agglomeration treatment improves the dispersibility of parched cereal powder and thus facilitates the intake of it after mixing with water.