• Journal of the Korean School Mathematics Society
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• v.21 no.2
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• pp.161-181
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• 2018

This paper summarized the changes in elementary school mathematics education that took place at the national level during the Enlightenment Elementary Mathematics Education period from 1876 to 1910. For this purpose, we divided the enlightenment period into three periods and examined major changes related to elementary school mathematics education at each period. The necessity of arithmetic education began to be recognized before the reform of the Taoist reform, and arithmetic education became a national curriculum in the beginning of the Taoist reform period. Particularly, during the reforming period of the Gap, the elementary mathematics textbooks of mixed Korean and Chinese were published. In the period when the intervention of the Japanese imperialism began, the arithmetic education has been reduced or weakened in accordance with the education policy of 'simple' and 'use'. It is also remarkable that an arithmetic book for elementary teachers was published at this time.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.1
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• pp.32-40
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• 1994

Continuous measurements of the extinction coefficient( $b_{ext}$ ) and scattering coefficient due to Particle( $b_{sp}$ ) were made during the fall 1993 in Seoul along with the measurements of the size distribution, ionic composition of particles. On the average, $b_{sp}$ values are 55% and 79% of $b_{ext}$ values during the clear and smoggy Periods respectively. Also the average values of $b_{ext}$ and $b_{sp}$ were 0.791$\times$10$^{-3}$ $m^{-1}$ (visual range 4.9km) and 0.628$\times$10$^{-3}$ $m^{-1}$ (visual range 6.2km) during the smoggy Period, and 0.297$\times$10$^{-3}$ $m^{-1}$ (visual range 13.1km) and 0.164$\times$10$^{-3}$ $m^{-1}$ (visual range 23.8km) during the clear period, respectively. The Peak at about 1${\mu}{\textrm}{m}$ of the Particle size distribution during the smoggy period is about four times higher than that during the clear period while the peaks at about 5${\mu}{\textrm}{m}$ during both periods are similar. Also, the concentrations of sulfate and nitrate at about 1${\mu}{\textrm}{m}$ during the smoggy Period are much higher than these during the clear Period.eriod.

• Journal of the Korean Society of Food Culture
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• v.15 no.4
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• pp.307-312
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• 2000

The purpose of this study is to understand the Chinese noodles(mian tiao). Wheat seems to have been cultivated 3-4,000 years before according to the archaeological evidences from the neolithic sites. The five grains(rice, millet, beans, barley, barnyard millet) already appeared in the period prior to Chin dynasty and were used as whole grain, but it was not until Chun Chu Zhan Guo period that the introduction of the flouring method stimulated the cultivation of wheat. In Chin-Han period, when water power and animal force were put into usage to facilitate the mass production of wheat flour, 'Bing', a designation for all the food made of wheat first appeared in the literature, and it was this 'Bing' that had later developed into noodles. In Wei Chin Nan Bei Chao period, roasted 'Bing', namely 'Kao-Bing' made its first appearance, and in Tang period, various noodles were created with the increase of restaurants specialized in noodles. In Song dynasty, 'La-Mian', the noodles stretched and beat from noodle dough, was first introduced, and in Yuan period, invention of drying method made the appearance of dried noodles, 'Gua-Mian', possible, which was good for easy and long preservation. Qing dynasty developed the noodles with a variety of assorted ingredients. The Chinese noodles are classified by various standards such as main ingredients, cooking methods, kinds of sauce, secondary ingredients, shape, eating method, flavor, and look.

• Korean Institute of Interior Design Journal
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• v.14 no.5 s.52
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• pp.218-225
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• 2005

In this apartment market, many apartments are being reconstructed within even less than 20 years from their first construction. This entails many problems in environmental and economical facets, for which many researches are under way in several institutions and universities. International cases show that the international trend goes for remodeling of maintenance, management, and repairing rather than new building. The purpose of this study is to investigate the factors of cost evaluation for establishing the time period of apartment based on durability of material and equipment while considering the economic feasibility of apartment, when remodeling as a concept of sustainability regarding building is being vitalized. This study investigates the proper period of remodeling in consideration of weight accruing to the LC(Life Cycle) and cost based on the standardized durability. The weight of cost, period establishment analysis, and LC according durability varies the data values of remodeling periods. The physical durability and cost from this data enable the investigation into not only the repair period of individual materials of the apartment but also remodeling period.

• Industrial Engineering and Management Systems
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• v.7 no.3
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• pp.257-265
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• 2008

This paper deals with the joint decisions on pricing and ordering for a monopolistic retailer who sells perishable goods with a fixed lifetime or demand period. The newsvendor-typed problem is formulated as a two-period inventory system where the first period represents the inventory of fresh or new-arrival items and the second period represents the inventory of items that are older but still usable. Demand may be for either fresh items or for somewhat older items that exhibit physical decay or deterioration. The retailer is allowed to adjust the selling price of the deteriorated items in the second period, which stimulates demand and reduces excess season-end or stale inventory. This paper develops a stochastic dynamic programming model that solves the problem of preseason decisions on ordering-pricing and a within-season decision on markdown pricing. We also develop a fixed-price model as a benchmark against the dual-price dynamic model. To illustrate the effect of the dual-price policy on expected profit, we conduct a comparative study between the two models. Extension to a generalized multi-period model is also discussed.

• Earthquakes and Structures
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• v.3 no.1
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• pp.17-35
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• 2012

Simplified equations for fundamental period of vibration of skeletal structures provided by most seismic design provisions suffer from the absence of any associated confidence levels and of any reference to their empirical basis. Therefore, such equations may typically give a sector of designers the false impression of yielding a fairly accurate value of the period of vibration. This paper, although not addressing simplified codes equations, introduces a set of mathematical equations utilizing the theory of error propagation and First-Order Second-Moment (FOSM) techniques to determine bounds on the relative error in theoretically calculated fundamental period of vibration of skeletal structures. In a complementary step, and for verification purposes, Monte Carlo simulation technique has been also applied. The latter, despite involving larger computational effort, is expected to provide more precise estimates than FOSM methods. Studies of parametric uncertainties applied to reinforced concrete frame bents - potentially idealized as SDOF systems - are conducted demonstrating the effect of randomness and uncertainty of various relevant properties, shaping both mass and stiffness, on the variance (i.e. relative error) in the estimated period of vibration. Correlation between mass and stiffness parameters - regarded as random variables - is also thoroughly discussed. According to achieved results, a relative error in the period of vibration in the order of 19% for new designs/constructions and of about 25% for existing structures for assessment purposes - and even climbing up to about 36% in some special applications and/or circumstances - is acknowledged when adopting estimates gathered from the literature for relative errors in the relevant random input variables.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1258-1262
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• 1999

With an attempt to elucidating the lipid metabolism of Tsaiya ducks, thirty ducks at growing (8 weeks of age) and laying periods (10 weeks after the onset of laying) were examined, respectively. The ducks were randomly allocated into ad libitum feeding and 3-day fasting groups, to investigate their in vitro hepatocytes lipogenesis capacity and adipocytes lipolysis rate. Results indicate that (1) the capacity of hepatocytes incorporation of glucose and acetate into total lipid and metabolite of $^{14}CO_2$ production during the laying period was greater than during the growing period. Approximately 50% of the glucose or acetate converted into triacylglycerol (TG) by the hepatocytes were recovered as fatty acid during the growing period, while it was 65-70% during the laying period. (2) Acetate used for lipogenesis ability was superior to glucose in both periods. (3) The adipocytes lipolysis rate was increased significantly (p<0.05) by fasting. In contrast, the capacity of incorporated glucose or acetate into total lipid, triacylglycerol, fatty acid and glycerol by hepatocytes was reduced significantly (p<0.05) by fasting.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.139-146
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• 2011

This study investigated physical and physiological changes of normal young adults, who are cadets of the Air Force Academy, have kept long-term physical activities and healthy behavior. The physical and physiological indices were the blood and body composition. Data were collected at the first year period, and then 4th year period from same group of cadets. The amounts of blood components were not changed, but variation among cadets was significantly reduced in the 4th grade period. The red blood cells(RBCs) were significantly reduced and the concentration of hemoglobin(HGB) were significantly increased. The body weight was significantly decreased in the 1st grade period since the body fat was rapidly decreased after the basic military drill, and then it was recovered with building up of the skeletal muscle in the 4th grade period. Asymmetry of the arms was decreased with the increased physical activities and usage of various equipments. The muscular endurance were significantly enhanced in the 4th grade period. The long-term physical activities and healthy behaviors may keep the physical strength through enhanced blood stream and oxygen supply by reduction of the RBCs and increased HGB concentration, and fat and muscle control.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.677-682
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• 2003

The long-period gravity wave, the wave period from some ten seconds to some minutes, induces not only the big sway of a ship moored and berthed in the harbor due to the horizontal long-distance motion of a water but also strong exfoliated flow and vortices near the harbor entrance. They muse serious problems on the safety navigation of vessels entering and leaving the harbor, but this gravity wave has not been searched sufficiently yet. Then it is quite important to reveal the characteristics of this long-period gravity wave ana to solve various problems induced by this wave. The long-period gravity wave measurement system with arrayed buoys installed the kinematic GPS was already proposed, which provides the precise propagating direction of the long-period gravity wave. In this paper, the observation results of the wave measurement system are shown by the MUSIC method And the propagating wave direction was estimated precisely enough in comparison with other results used other method.

• Earthquakes and Structures
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• v.6 no.2
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• pp.201-216
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• 2014

Many building codes use the empirical equation to determine fundamental period of vibration where in effect of length, width and the stiffness of the building is not explicitly accounted for. Also the equation, estimates the fundamental period of vibration with large safety margin beyond certain height of the building. An attempt is made to arrive at the simple empirical equations for fundamental period of vibration with adequate safety margin, using soft computing technique of Genetic Programming (GP). In the present study, GP models are developed in four categories, varying the number of input parameters in each category. Input parameters are chosen to represent mass, stiffness and geometry of the buildings directly or indirectly. Total numbers of 206 buildings are analyzed out of which, data set of 142 buildings is used to develop these models. It is observed that GP models developed under B and C category yield the same equation for fundamental period of vibration along X direction as well as along Y direction whereas the equation of fundamental period of vibration along X direction and along Y direction is of the same form for category D. The equations obtained as an output of GP models clearly indicate the influence of mass, geometry and stiffness of the building over fundamental period of vibration. These equations are then compared with the equation recommended by other researcher.