• Journal for History of Mathematics
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• v.26 no.2_3
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• pp.197-210
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• 2013

The late 18C Malthus studied population growth for the first time, Verhulst the logistic model in 19C and, after that, the study of the predation competition between two species resulted in the appearance of Lotka-Volterra model and modified model supported by Gause's experiment with bacteria. Instable coexistence equilibrium being found, Solomon and Holling proposed functional and numerical response considering limited abilities of predator on prey, which applied to Lotka Volterra model. Nicholson and Baily, considering the predation between host and parasitoid in discrete time, made a model. In 20C there were developed various models of disease dynamics with the help of mathematics and real data and named SIS, SIR or SEIR on the basis of dynamical phenomena.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.185-192
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• 2000

This experiment was canied out to determine the effect of management practices on the quality of round baled oat silage at experimental field of Grassland and Forage Crops division, National Livestock Research Institute, RDA, Suwon from 1997 to 1998. The experiments are consist of randomized block design with 3 replications. The treatments are 3 wilting dates(0, 2 and 4 days), 3 wrap colors(white, black and green and 3 inoculant(untreated, Inoculant A and Inocuant B). The crude protein(CP) content was increased by prolonged wilting periods, but the effect of wrap color and inoculant were not founded. Acid detergent fiber(ADF) and neutral detergent fiber(NDF) content of all silages were not founded significant difference, but in vitro dry matter digestibility of oat silage with inoculant was significantly higher compare with control. Wilting treatment increased the mean silage acidity compare with control and inoculant treatment significantly reduced silage acidity. Wrap color did not influence the silage acidity. Wilting or inoculant treatments increased lactic acid content but, decreased the content of acetic and butyric acid. The quality grade of all silage were grade 3, except inoculant treated silage. Wilting or inoculant decreased silage DM loss, but wrap color did not effect on siage DM loss. The result of this study indicate that wilting for 2-4 days and inoculant will improve the silage fermentation and quality of round baled oat silage. (Key words : Oat, Wilting, Inoculant, Wrap color, Round bale silage)

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.369-374
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• 2016

Recently, due to the rapid development of smart computing technology, there have been a lot of studies on 3D navigation, and consequently the advanced commercial 3D navigation system and 3D VTS system are on the market. Even the 3D technology is well known and wide spreaded, unfortunately, the secret of code behind is still unleashed. The purpose of this paper is to show the basic methodologies to display ENC features under 3D display environment to meet the requirement of S-52 standards. The OpenGL ES is used to develop 3D ENC Viewer for further use on mobile platforms and web based vessel monitoring system. P articularly, area object triangulation, complex line drawing, polygon pattern filling and symbol drawing by texture mapping are explained in detail. The result of performance test is shown as table for correlation of SENC file size to display speed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.593-600
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• 2014

This paper proposes a torque assist strategy for operating a hybrid agricultural tractor in the field. In general, different field operations such as baling and rotary tillage require different patterns and amounts of torque. Thus, a large agricultural tractor is used to improve the farming efficiency. Therefore, this research has the goal of developing a hybrid tractor that uses a small electric motor to provide additional torque for specific field operations. To achieve this objective, a rule-based torque assist strategy is proposed and validated for a simulation model in the Autonomie framework, which is a commercial simulation tool. Finally, the work efficiencies and fuel consumptions of a conventional tractor and the hybrid tractor with the proposed torque assist strategy are compared using simulations.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.82-90
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• 2009

It is very important to utilize effectively fibrous waste paper in terms of cost savings, environmental effects, and governmental policies. The quality of final products and runnability of papermaking process are primarily affected by constitutions of fibrous raw materials. In specific, board grade paper depends directly on compositions of waste paper bales. At present, the raw materials of board grade paper are mainly derived from lots kinds of wastepaper. Some papermaking countries, like EU, USA and Japan have advanced classification and management systems of recycled fiber, but Korea has not yet organized systematically. In this study, evaluation of wastepaper bale compositions and their fiber properties were carried out for effective utilization of fibrous raw materials for board grade paper production. 3 kinds of wastepaper bales were classified to fibrous or non-fibrous materials. In case of fibrous materials, KOCC, kraft sack paper and white duplex board matters were main component in total weight basis, and in case of non-fibrous materials, vinyl, plastic and cloth matters were main component, in turns. 3 representative kinds of waste paper were disintegrated and classified, and then prepared to handsheet for evaluation of recycled fiber property. Consequently, fines and ash content of waste paper, isolated from KOCC and white duplex board were higher than that of kraft sack paper. pH values of all kinds of waste fibers were neutral or weak alkaline.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.750-754
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• 1991

The perceived intensities of Cheddar cheese flavor were investigated in terms of cheese processing conditions and types of panels participated. The mean intensities of sensory properties for Cheddar cheese were higher in untrained panels compared to those in trained panels. There are significant differences in Cheddar cheese flavor between six-month and eight-month ripening. Cheddar cheese ripening at 1$13^{\circ}C$ resulted in positive effects on sensory attributes compared to ripening at $8^{\circ}C$. The addition of lactobacilli as starter culture caused an increase of sharpness and a decrease of bitterness. Sharpness and bitterness were not related to other cheese sensory properties, and revealed a positive relationship each other. Cheese acidity was negatively related to rancidity and fruitiness.

• Clinical and Experimental Pediatrics
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• v.45 no.6
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• pp.700-711
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• 2002

Purpose : Early identification and treatment of developmental disabilities is of considerable importance in the health care of children. Screening of development is aimed at identifying infants who may need more comprehensive evaluations. Methods : A new test, the Ewha Infant Development Screening Test(EDST) has been created to screen the development of infants, 0-4 years of age. EDST was constructed so that results can be calculated into developmental ages and developmental quotients. The test consists of three sectors, e.g. language, social-adaptive and motor, and of 158 test items. A total of 104 infants, aged from one month to four years, including healthy infants as well as 10 with chief complaints of developmental delay, who visited the pediatric clinic of Ewha Womans University Dongdaemun Hospital, from June, 25 to November 30, 2001, were given the Bayley Scale of Infant Development as a base test and EDST. Results : The result showed the appropriate cut-off of EDST was 90 with better sensitivity and specificity, compared to cut-offs of 85 or 80. Conclusion : Further study with a large number of infants in the future is needed to make EDST more reliable and accurate.

• Journal of Biosystems Engineering
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• v.27 no.3
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• pp.195-202
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• 2002

In order to make a winter cereal wrap silage, a tractor attached round bale wrapper was developed locally. Its specific structure and various functions were reported in the last submitted paper. In this study a control system of bale wrapper combining with the actuators of various processes was developed to make round bale wrapper compatible in the field. Also. its performance was tested by making the rye round bale. The results can be summarized as fellow. 1. The field capacity of round bale wrapping was investigated around 0.5 ha/hr, and the operating time of bale wrapper was about 3 min for each 500kg round bale 2. Plastic film which has maximum elongation rate of 796% was stretched to 150∼170% of original length and was lessened to 80∼90% of original width. 3. In the quality test of bale produced by developed bale wrapper, there was no significant changes of moisture contents if it was wrapped more than 4 layers of 25 ㎛-plastic film. 4. Also. temperature of the wrapped bale was about 33$\^{C}$ in the beginning of fermentation and was stabled to 26∼29$\^{C}$ during one month or more storage. Therefore, wrapping performance of the developed bale wrapper was properly.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.292-300
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• 2007

Not many types of roughage cutters have been introduced in Korea so far. However, those machines could not satisfy farmers to cut rice straw or barley wrap-silage properly. Stiffness and firmness of roughage bale were two obstructing factors. In order to solve this problem, a tractor attached cut-feeding machinery for the round baled roughage was developed for dairy and beef cattle farm in Korea. A series of tests were performed and acquired data were analyzed by using the several imported roughage cutters, which have been already introduced in dairy farm in Korea. And, a prototype of forage cutter was selected, analyzed, designed and manufactured to develop a tractor attached roughage cut-feeder for round bale. Also, the prototype machine was tested, modified and improved through revising model. As a result, a tractor attached roughage cut-feeder for round bale was manufactured. In order to evaluate the performance of the model machinery. a series of test were performed by the prototype machinery both at the plant and field. The model machinery developed satisfied in both power requirement and cutting capacity. As a conclusion, one of the obstacles against feeding the round baled roughage in the korea cattle farm can be eliminated by developing the tractor attached round baled roughage cut-feeder.

• Journal of Fashion Business
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• v.24 no.2
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• pp.1-16
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• 2020

Hijab as a symbol of women's oppression due to the opening and reform of Islamic State group, is becoming more diverse as younger generation begins to dress more freely than ever before, spreading the perception that it is a fashion item. In response, this research conducted a theoretical review about the history of hijab, various forms of hijab, and characteristics of hijab using relevant literature, media reports, and fashion media articles. As an empirical study, image-oriented photo data shared by Tehran Street Fashion from 2015 to November 2019 were analyzed separately by fashion majors into color, pattern, and hijab-making forms. According to the analysis, six different fashion images were categorized as romantic feminine, modern chic, natural elegant, classic formal, sporty casual and gorgeous ethnic. For Muslim women in the past, hijab was worn as a repressive and closed sense by the religious system. However, in modern times, it is a way to express one's style and ideas as a fashion item. It is also and a means to express one's thoughts and beliefs. Through aesthetic consideration of Hijab as a fashion item, it was found that it was a medium for freedom of expression and a medium for beauty and individuality.