• Education of Primary School Mathematics
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• v.20 no.2
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• pp.177-192
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• 2017

In theory, mixed methods that incorporate both quantitative and qualitative approaches can maximize strengths of each method while minimize the short comings of each. Mixed methods research is a feature of educational research nowadays, and the number of studies applied mixed methods research has been gradually increasing. This study investigates how mixed methods research was applied in the field of mathematic education, especially focusing on how qualitative and quantitative methods are combined to best address their research questions. With this in mind, this study carefully selects and analyzes 4 research articles that used mixed methods and were published by Journal of Elementary Mathematics Education in Korea in 2015. This study provides detailed result of qualitative analysis on mixed methods research while other a few previous analysis on mixed methods research were tend to focusing on quantitative analysis, producing numeric quantitative information. The result of this study provides practical and in-depth analysis on how to improve validity and possibility of mixed methods research, addressing alternative ways to combine two different research methods and key elements to take into account.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.11-19
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• 1975

Yellow croaker, Pseudosciaena manchurica Jordan et Thompson, in the Yellow Sea and the East China Sea are subjected to be caught by trawl nets, stow nets and gill nets throughout the year. Monthly indices of population size are calculated. Mathematic models (I) were used in order to determine catchability coefficient, natural mortality, fishing mortality, coefficient coefficient of the fishing ground and dispersion coefficient from the fishing ground. The results are summarized as follows: 1971 1972 1973 $$Catchability\;coefficient\;(C)=1.9369\times10^{-5}\;7.5459\times10^{-6}\;1.2670\times10^{-5}$$ Natural mortality (M) = 0.1645 0.6152 0.4367 Population for the first half season (February 1 to May 31) 1971 1972 1973 Initial\;population=\;107,100M/T 209,100M/T 214,400M/T Dispersion=83,000' 159,700' 133,400' Natural mortailty= 4,700' 32.700' 19,100' Final population= 2,800' 4,500' 49,000' Population for the latter half season (June 1st to the following January 31st) 1971 1972 1973 Initial population= 44,500M/T 67,500M/T 83,800MT Recruitment= 19,000' 183,900' 67,100' Natural mortality= 5,900' 67,900' 38,500' Final population= 37,000' 168,300' 92,400'.

• The Korean Journal of Food And Nutrition
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• v.16 no.3
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• pp.180-186
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• 2003

In order to prediction of lethal effects on target microorganisms, this study was developed the program in the basis of Excel that was systemized with Visual Basic. This program was automatically calculated the lethal effects (L and Fo value) by using thermal characteristics (D and z value), kinetic model and mathematic model. For the selection of target microorganisms, we are selected two microorganisms because of spoilage increasing by acid production and decreasing quality of food, and heat resistance microorganisms. The target microorganisms were Bacillus cereus (D$_{121.1}$=0.0065 min, z=7.8$^{\circ}C$) and Bacillus subtilis (D$_{121.1}$=0.5 min, z =12$^{\circ}C$). The program was developed for the target microorganisms, and that was very useful for various microorganisms that direct introducing known D and z value.

• School Mathematics
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• v.13 no.4
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• pp.581-598
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• 2011

Given the growing agreement that algebra should be taught in the early stage of the curriculum, considerable studies have been conducted with regard to early algebra in the elementary school. However, there has been lack of research on how to organize mathematic lessons to develop of algebraic reasoning ability of the elementary school students. This research attempted to gain specific and practical information on effective algebraic teaching and learning in the elementary school. An exploratory qualitative case study was conducted to the fourth graders. This paper focused on the associative law of the multiplication. This paper showed what kinds of activities a teacher may organize following three steps: (a) focus on the properties of numbers and operations in specific situations, (b) discovery of the properties of numbers and operations with many examples, and (c) generalization of the properties of numbers and operations in arbitrary situations. Given the steps, this paper included an analysis on how the students developed their algebraic reasoning. This study provides implications on the important factors that lead to the development of algebraic reasoning ability for elementary students.

• Journal of Chest Surgery
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• v.51 no.3
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• pp.172-179
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• 2018

Background: This study aimed to compare preliminary data on the outcomes of sutureless aortic valve replacement (SU-AVR) with those of aortic valve replacement (AVR). Methods: We conducted a retrospective study of SU-AVR in moderate- to high-risk patients from 2013 to 2016. Matching was performed at a 1:1 ratio using the Society of Thoracic Surgeons predicted risk of mortality score with sex and age. The primary outcome was 30-day mortality. The secondary outcomes were operative outcomes and complications. Results: A total of 277 patients were studied. Ten patients (50% males; median age, 81.5 years) underwent SU-AVR. Postoperative echocardiography showed impressive outcomes in the SU-AVR group. The 30-day mortality was 10% in both groups. In our study, the patients in the SU-AVR group developed postoperative thrombocytopenia. Platelet counts decreased from $225{\times}10^3/{\mu}L$ preoperatively to 94.5, 54.5, and $50.1{\times}10^3/{\mu}L$ on postoperative days 1, 2, and 3, respectively, showing significant differences compared with the AVR group (p=0.04, p=0.16, and p=0.20, respectively). The median amount of platelet transfusion was higher in the AVR group (12.5 vs. 0 units, p=0.052). Conclusion: There was no difference in the 30-day mortality of moderate-to high-risk patients depending on whether they underwent SU-AVR or AVR. Although SU-AVR is associated with favorable cardiopulmonary bypass and cross-clamp times, it may be associated with postoperative thrombocytopenia.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.2 s.7
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• pp.23-31
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• 2005

ITS(Intelligent Transportation System) implementing information collection services and information support services for cars of moving fast needs a communication system of special aim such as RF-DSRC(Radio Frequency Dedicated Short Range Communication). Before RSE(Road Side Equipment) and OBE(On-Board Equipment) will be able to communicate RF-DSRC, OBE first have to request Link Initialization Access using ACTC(Activation Channel) in allocated ACTS(Activation Slot) by Slotted ALOHA. Even though Link Initialization Access is a important element to decide performance of communication system, optimal mathematic modeling study of Link Initialization Access which is adapted RF-DSRC characteristics is not enoush. So, in this paper, we propose mathematical modeling about Link Initialization Access of RF-DSRC. And then we computed Link Initialization Access probability defining offer load(G) which is adapted RF-DSRC characteristics for analyzing performance of modeling.

• Journal of the Korean School Mathematics Society
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• v.8 no.2
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• pp.249-271
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• 2005

The study was aimed to show effects of the newly step branch's feedback models on the mathematics underachievers' mathematics achievement and attitude toward the mathematics, extent of self-check. The subject are 26 mathematics underachievers in the End grade of H middle school located in Taejeon. They were divided into an experimental group and a control group, and the attribution disposition. Experiment group was provided step branch's feedback and control group was provided general formative' feedback. The duration of the treatment was over a period of six weeks. The result of study, the step branch's feedback was effects for increasing he mathematics achievement and attitude toward the mathematics than the general formative' feedback(p<.05). In addition, the step branch's feedback group had better extent of self-check than the general formative' feedback.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.437-464
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• 2014

Curriculum for mathematic sis the system that selects and organizes the contents which have to be taught in school. Ultimately it can be the whole plan of school mathematical education. The study about curriculum for mathematics is the basic study field of the mathematical education, so curriculum-related studies have been continuously promoted in terms of character, organization and implement of the curriculum, learning contents contained by the curriculum, the connection between school levels, and comparison and analysis of domestic and foreign curricula. Thus, this paper investigated the 2009 Revised Curriculum for Mathematics, which is the curriculum of Korea and the CCSSM which is the curriculum of the U.S. Both have been adopted in schools recently. The purpose of this study is to understand the curricula for mathematics in elementary school of Korea and the U.S. in depth and obtain the implication for the further curriculum revision, by comparing and analyzing the curricula of two countries.

• Journal of the Korean School Mathematics Society
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• v.23 no.1
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• pp.111-127
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• 2020

In many studies, mathematics anxiety (MA) is a major factor affecting students' mathematical achievement (MC) and is reported to have a greater negative effect on female students. In the study, we developed a complex treatment program consisting of 10 lesson units, to reduce mathematic anxiety and applied it to 26 male and female students with high MA. For this purpose, we analyzed the differences between the two gender groups collected by the Math Anxiety Scale for Students(MASS) and Mathematical Achievement Scale(MCS) before and after. As a result of the treatment program, MA was decreased in both groups, but only female students scored higher in MC. The program that had been effective for both boys and girls in MA satisfied the main purpose of which was to treat MA with integrated mathematical and psychological aspects, and implied that additional procedures and guidance should be followed for boys' MC.

• Journal of KIISE:Software and Applications
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• v.35 no.1
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• pp.33-40
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• 2008

In this paper, we propose a method to enhance adaptability in a dialogue system using the reinforcement learning that reduces response errors by trials and error-search similar to a human dialogue process. The adaptive dialogue strategy means that the dialogue system improves users' satisfaction and dialogue efficiency by loaming users' dialogue styles. To apply the reinforcement learning to the dialogue system, we use a main-dialogue span and sub-dialogue spans as the mathematic application units, and evaluate system usability by using features; success or failure, completion time, and error rate in sub-dialogue and the satisfaction in main-dialogue. In addition, we classify users' groups into beginners and experts to increase users' convenience in training steps. Then, we apply reinforcement learning policies according to users' groups. In the experiments, we evaluated the performance of the proposed method on the individual reinforcement learning policy and group's reinforcement learning policy.