• Journal of Elementary Mathematics Education in Korea
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• v.18 no.3
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• pp.425-439
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• 2014

The concept of a fraction as division is a core idea which serves as a axiom in the process of a extension of the natural number system to rational number system. Also, it has necessary position in elementary mathematics. Nevertheless, the timing and method of the introduction of this concept in Korean elementary math textbooks is not well established. In this thesis, I suggested a solution of a various topics which is related to this problem, that is, transforming improper fraction to mixed number, the usage of quotient as a term, explaining the algorithm of division of fraction, transforming fraction to decimal.

• Journal of Life Science
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• v.24 no.8
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• pp.910-914
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• 2014

For the identification of the Jeju black cattle, Hanwoo and imported beef, we performed a multiplex polymerase chain reaction (PCR) associated with microsatellite (MS) and melanocortin 1 receptor (MC1R) gene. The MC1R gene plays an important role in regulation of the melanin synthesis within mammalian melanocytes. MC1R encoded by extension (E) locus was almost fixed with recessive red e allele in the Hanwoo. We estimated that the specific genotypes ($E^+/E^+$, $E^+/e$) of MC1R gene were characteristic genotypes of Jeju black cattle. But the PCR products resulted from using the MC1R gene derived primers only are not sufficient to identify Jeju black cattle from other relatives. We performed two times of successive multiplex PCR to provide a more accurate result for the identification of Jeju black cattle. The results suggest that two types of successive multiplex PCR methods using MC1R gene and Microsatellite derived primer set will be more useful to identification of Jeju black cattle, Hanwoo and imported beef.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.677-683
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• 2006

If a node stops functioning in an ad-hoc wireless network, routing paths involving the node will also fail, when construction of replacement routes is required. A major cause of node failure is energy exhaustion, and route replacements may in turn lead to successive node failures by making more nodes consume their energy. The result could be performance degradation of networks. Therefore it is important to ensure that nodes with limited remaining energy are not included in route construction from the beginning. In this paper we propose a new routing protocol, which takes residue energy of nodes into account in order to prevent node failures resulting from energy shortage. Our routing protocol examines the smallest value of node residue energy ($E_{m}$) from each of all possible routing paths and selects the path which has the largest value of $E_{m}$. We prove, through simulation, that our routing protocol extends the lifetime of nodes which have limited amount of energy, reducing chances of path replacement. It is also shown that our proposed protocol helps alleviate network performance degradation.

• IE interfaces
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• v.16 no.spc
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• pp.99-104
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• 2003

While demands for express service are rapidly increasing according to recent progress of electronic commerce, express service companies are struggling to take a larger delivery service market share through ongoing improvement in their service processes. Extension of cut-off time for express service centers can provide the express company with increase of total sales, but it may also cause to increase the possibility not to satisfy customer needs due to work delay in the consolidation terminal. Therefore, compromised decision for cut-off time of each service center should be made by taking operation characteristics of the consolidation terminal into account. This study suggests an approach for determining the cut-off time for express service centers according to operational characteristics of the consolidation terminal with the objective of maximizing expected incremental sales. The problem defined in this study can be represented as two successive models; one is an integer programing model in which the best cut-off time for each sales center are determined, and the other is a single machine scheduling model in which a working schedule in the consolidation terminal is obtained. A genetic algorithm is developed to solve the two models simultaneously. Finally, an example problem is carried out to verify applicability and performance of the algorithm with the data set collected from an express company.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.189-200
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• 2012

Many companies have endeavored to build a quality cost management system in order to be more productive business organization. This study shows the detail procedures of constructing a quality cost management system which is believed to be appropriate for their business system. That is, the method to calculate the quality cost and the linking logic between the quality improvement and its financial impact are explained based on a particular industry case. In this sense, the changes of business performance measures such as market share, customer satisfaction, etc. were analyzed in the longitudinal perspective for the consecutive 4 years (2003~2006). As the quantitative results of this study, the improvement activities based on the quality cost management system resulted in the 32% reduction of quality cost and the 121% increase of business profit, compared 2005 with 2006. In the qualitative perspective, the successive practice of quality cost reduction and the job information sharing in business unit were obtained by providing the best practices and bench-marking cases. Finally, the customer satisfaction has increased so that the customer-friendly management system has been accomplished. With these efforts, the 3.4% increase of the market share and the 3% increase of the customer satisfaction were obtained in 2005. As the future study, the current study can be extended to the concept of COPQ (cost of poor quality) which focuses on the hidden quality cost of the whole business activities. Such extension of analysis will help us understand the wider role of a quality cost management system in the business.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1C
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• pp.79-85
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• 2008

Dirty Paper Coding(DPC) can achieve the sum capacity of a multiuser multiple-input multiple-output(MU MIMO) broadcast channels. However, due to the high computational complexity of the successive encoding and decoding, deploying DPC in real systems is impractical. As one of practical alternatives to DPC, Block Diagonalization(BD) was researched. BD is an extension of the zero-forcing preceding technique that eliminates interuser interference(IUI) in downlink MIMO systems. Though BD has lower complexity than DPC, BD shows poor sum capacity performance. We show that sum capacity performance of BD is degraded due to no IUI constraint. Then, we modify BD to improve its sum capacity performance with relaxing the constraint and sub optimal channel set searching. With simulation results, it can be verified that our modification in BD induces some improvement in sum capacity performance.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.717-721
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• 2011

In case of plastic film greenhouses cultivating fresh vegetables on paddy soil, soil characteristics must be considered as more important factor than any other factors. Generally after the four years of cultivation, soils tend to increase electrical conductivity value, nutrient unbalance and soil pests. As a result, degradation of agricultural products occurred, therefore it is necessary to improve soil conditions. In this study, yield and economic cost of cucumber were analyzed. The best soil conditions for cucumber cultivation were alluvial or valley in soil topology, moderately or poorly drainage in soil drainage classes, coarse loamy soil in texture. In addition, rich-sunlight and-deep groundwater would be proper for the cucumber cultivation. Good environmental managements of plastic film greenhouse were as follows. The temperature needed to be adjusted three times. The optimal daytime temperature could be $22{\sim}28^{\circ}C$, the one from 12 until night could be $14{\sim}15^{\circ}C$, and the temperature from 24 to sunrise could be $10{\sim}12^{\circ}C$. During plant growth period, soil moisture content was as low as 10~15%, and it needed to be maintained as 15~20% during reproductive growth period. To control pests, catch crop cultivation and solar treatment were carried out, after those EC was reduced and the root-knot nematode was controled too. Cucumber yield from the plot with improved soil managements increased to $158.4Mg\;ha^{-1}$, but plot with successive cropping injury yielded $140.3Mg\;ha^{-1}$. The income from the plot with improved soil managements was 215,676 thousand won $ha^{-1}$, the plot with successive cropping injury was 131,649 thousand won $ha^{-1}$. Income rate of each plot was 51.8% and 38.4%, respectively.

• Korean Journal of Plant Resources
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• v.31 no.2
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• pp.136-148
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• 2018

The study was performed to investigate basic tree growth and fruit characteristics of 'Nero' black chokeberry (Aronia melanocarpa) depending on the different cultivation regions and altitudes in 2014, 2015. Tree growth and change of developmental stages of 'Nero' were similar regardless of meteorological environment of the four cultivation regions (Danyang, Okcheon, Yeongdong, and Geumsan) in 2014. Fruit characteristics of 'Nero' were significant differences in berry weight and anthocyanin content among the four orchards due to difference in cultivation techniques and relatively wide daily temperature range just before harvest, respectively. Tree growth and change of developmental stages of 'Nero' grown at the two orchards with different altitudes appeared to be similar during the successive years 2014 and 2015. Soluble solids content of the berries cultivated at low altitude (117 m) was higher than at high altitude (342 m). Acidity showed an inverse pattern with soluble solids content. Anthocyanin content increased progressively until at the middle of August, 2014-15 and then it decreased. Our results showed that black chokeberry is a species adaptive to the domestic environment as there were no differences in tree growth and change of developmental stages of 'Nero'. Considering fruit quality of black chokeberry such as soluble solids content, acidity, and anthocyanin content, our results suggest that optimal harvest period of black chokeberry 'Nero' is August 8 to 19.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.160-167
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• 2011

Shallot is a foreign crop introduced from France in 1995 as a new overwintering field crop with an aim to develop as an export crop. During the introductory cultivation trials, several problems were raised such as premature growth depression in early summer, sensitivity to summer moisture, and weakened vigor of the seed bulbs following successive propagations. This study was conducted to develop proper cultural methods based on annual productivity and adaptability of growing area to address and suggest solutions to some of these problems. Bulb weight was 18.7 g and bulb yield per 10a was 4,113 kg in 1995. In 1996, bulb weight increased to 25.8 g, while bulbs yield per 10a deceased to 2,013 kg. This trend continued in 1997 so that bulb weight increased, and yield per 10a decreased as compared to those in 1996. However, in 1998, both bulb weight (21.1 kg) and yield per 10a (1,246 kg) decreased significantly as compared to those of the previous years. Plant growth from planting to April in the coastal area was better than in other areas. However, the plant growth thereafter until early July was better in the semi-highland area. As a result, the bulb yield in the semi-highland area was 57% more than that in the lowland areas such as the coastal area.

• Journal of Plant Biology
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• v.24 no.1
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• pp.1-12
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• 1981

Phosphorus dynamics in terms of specific absorption rate, inflow and outflow rates. turnover rate, demand and supply, and utility index of a high yield Zea mays L. cv. Bokgyo field were evaluated using an analysis of successive production structures. The analysis was adopted for measuring quantitative changes in the population by stratified clip technique on every two weeks during the growing season. The seasonal trends of specific absorption rate (2. 4 mg P/g/day in maximum) and specific absorption efficiency (0. 03) closely correlated with that of relative growth rate of the population. The overall inflow and outflow of phosphorus was 3.41 g P/$m^2$/yr showing the maximum inflow of 2.99 g P/$m^2$/month in July. While the maximum phosphorus standing crop was 1.4 g P/$m^2$ showing the maximum turnover rate of 178% in late June. The accumulation of phosphorus along plant height declined monotonically in stems and roots but increased in foliage after heading. The proportions of the total annual demand of phosphorus were 24.4% for leaves, 22.5% for stems, 49.6% for fruits and 3.5% for roots. These demands were met with internal (18.2 %) and external (81.8 %) supplies. The seasonal highest phosphorus utility index was 1,091 in early June, while the average value was 655.