• Title, Summary, Keyword: 혼합연구방법

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Trends of Mathematics Education Research and Mixed Methods - Focusing on Domestic Mathematics Education Journals for the Last 10 years (수학교육연구 및 혼합 연구방법 동향 - 최근 10년간 발표된 국내 학술지 논문을 중심으로 -)

  • Kim, Dong-Joong;Bae, Sung-Chul;Kim, Won;Lee, Da-Hee;Choi, Sang-Ho
    • Communications of Mathematical Education
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    • v.28 no.3
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    • pp.303-320
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    • 2014
  • The purpose of research is to analyze research trends and methods in a total of 709 studies published in five domestic mathematics education journals issued by Korea Citation Index (KCI) for the last 10 years (2003-2013) and strands in stages of research methods among mixed methods studies. As a result, the majority of articles in the five journals used either qualitative or quantitative methods and mixed methods research was less than 10 % of the total number of studies. The majority of mixed methods was research equally mixing qualitative and quantitative methods. The mixed methods research consisted primarily of quantitative with descriptive statistics and very little qualitative with conceptual framework based on theoretical background. Our results provide not only trends of the current research methods, but also implications for various future research paradigms in mathematics education.

Comparison of Three Parameter Estimation Methods for Mixture Distributions (혼합분포모형의 매개변수 추정방법 비교)

  • Shin, Ju-Young;Kim, Sooyoung;Kim, Taereem;Heo, Jun-Haeng
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.45-45
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    • 2017
  • 상이한 자연현상으로 발생된 자료들은 때때로 통계적으로 다른 특성을 가지는 경우가 있다. 이런 자료들은 다른 두 개 이상의 모집단에서 자료가 발생한 것으로 가정할 수 가 있다. 기존에 널리 사용되어온 분포형 모형의 경우 단일한 모집단으로부터 자료가 발생한다는 가정하에서 개발된 모형들로 위에서 언급한 자료들을 적절히 모의할 수 없다. 이런 상이한 모집단에서 발생된 자료를 모형화 하기 위해서 혼합분포모형(mixture distribution)이 개발되었다. 홍수나 가뭄 등과 같은 극치 사상의 경우 다양한 자연현상들로부터 발생하기에 혼합분포모형을 적용할 경우 보다 정확한 모의가 가능하다. 혼합분포모형은 두 개 이상의 비혼합분포모형들을 가중합하여 만들어진다. 혼합 분포모형의 형태로 인하여 기존의 분포형 모형의 매개변수 추정 모형으로 널리 사용되던 최우도법 (maximum likelihood method), 모멘트법(method of moment), 확률가중모멘트법 (probability weighted moment method) 등을 이용하여 혼합분포모형의 매개변수를 추정하는 것이 용이 하지 않다. 혼합분포모형의 매개변수 추정 방법으로는 Expectation-Maximization (EM) 알고리즘, Meta-Heuristic Maximum Likelihood (MHML) 방법, Markov Chain Monte Carlo (MCMC) 방법 등이 적용되고 있다. 현재까지 수자원 분야에서 사용되는 극치 자료를 혼합분포모형을 이용하여 모의할 때 매개변수 추정방법에 따른 특성에 대한 연구가 진행되지 않았다. 본 연구에서는 우리나라 연최대강우량 자료를 이용하여 혼합분포모형의 매개변수 추정방법 (EM 알고리즘, MHML 방법, MCMC 방법) 들의 특성들을 비교 분석하였다. 혼합분포모형으로는 Gumbel-Gumbel 혼합분포 모형을 적용하였다. 본 연구의 결과는 향후 혼합분포모형을 이용한 연구에 좋은 기초자료로 사용될 수 있을 것으로 판단된다.

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Estimation of Areal Reduction Factor using a two Parameter Mixed Gamma Distribution (2변수 혼합감마분포를 이용한 면적감소계수의 산정)

  • Yoo, Chulsang;Kim, Kyoungjun
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.584-588
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    • 2004
  • 본 연구에서는 혼합 확률밀도함수를 이용한 면적감소계수의 추정법을 제안한다. 기존 면적감소계수의 추정에는 동시간 강우자료가 필요하나 그런 자료를 충분히 추하기는 쉽지 않다. 본 연구에서 제안하는 방법은 보다 가용한 일 강우자료를 이용하는 방법으로 강우의 간헐성을 고려하기 위해 연속분포가 아닌 혼합분포를 이용한다. 본 연구에서는 혼합감마분포를 이용하여 금강유역의 면적감소계수를 추정하였으며, 그 결과 보다 쉽게 아울러 기존의 방법에 의한 결과와 잘 대비되는 결과를 얼을 수 있었다.

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Characteristics of Natural Hydraulic Lime Mortar Mixed with Basalt Fiber (바잘트 섬유를 혼합한 천연수경성석회 모르타르의 특성)

  • Moon, Ki-Yeon;Cho, Jin-Sang;Cho, Kye-Hong;Hong, Chang-Woo
    • Journal of the Korean Institute of Resources Recycling
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    • v.24 no.6
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    • pp.61-68
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    • 2015
  • In this study, the strength properties of NHL based mortar with blending basalt fiber were investigated. In the first step, it was evaluated that physical properties of NHL based mortar according to mixing method of four types of basalt fiber and then mixing method of one type was selected. As a result of assessment, it showed that the physical properties with mixing method of dry blending were better than that of wet blending and mixing method that basalt fiber pre-mixed with NHL for 5 min in a blender was selected and water and aggregate were finally added. Secondly, the investigation of blending fiber length on the compressive and flexural strength for basalt fiber reinforced NHL based mortars was carried out. The compressive strength was decreased with adding fiber, and the flexural strength was increased more than plain mortar. In the case of adding 6 mm fiber, the compressive and flexural strength were improved more than that of others.

A Study on Optimization of Decision Tree based State Tying Model (결정트리 기반 상태공유 모텔 최적화에 관한 연구)

  • 한명희;이호준;김순협
    • Proceedings of the Korea Multimedia Society Conference
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    • pp.17-20
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    • 2003
  • 본 논문에서는 공유 모델링의 대표적인 방법인 결정트리 기반 상태공유 모델을 기반으로 하여 그 출력 확률 분포의 혼합 가우시안 수를 줄임으로써 모델을 최적화하고자 하였다. 결정트리 기반의 상태공유 모델링은 일반적인 방법을 따랐으며 혼합 가우시안 수를 늘려 인식률이 최대가 되는 지점에서 혼합 가우시안을 클러스터링하여 그 수를 줄였다. 클러스터링 시에 필요한 거리 측정 방법이나 가까운 두 가우시안의 합성 방법을 여러 기법을 실험하였다. 이때 인식률은 클러스터링 이전인 97.2%를 유지하였으며 총 혼합 가우시안의 감소율은 1.0%를 보임으로써 모델을 최적화할 수 있었다.

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Qualitative Analysis on Mixed Research in the field of Mathematics for Elementary Students (초등 수학교육 관련 혼합 연구에서 적용된 질적 연구 방법에 대한 분석)

  • Na, Jang Ham;Kim, Jinho
    • Education of Primary School Mathematics
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    • v.19 no.1
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    • pp.47-60
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    • 2016
  • The purpose of this study is to analyze how the qualitative research is applied to mixed method research and thereby to gain an insight to suggest reasonable ways of employing qualitative method in order to accomplish intended goal of research, especially in the field of mathematics education. For that purpose, this study carefully selects and analyzes 5 article that used mixed method and were published by Education of Primary School Mathematics Journal in 2012. Unlike those a few previous studied on mixed method that focused on producing general trend by simply showing quantitative information on what the frequence of used research topic, content, methods combination, quantitative methods, and qualitative methods, this study provides detailed result of qualitative analysis on mixed studies. In sum, this study concludes with practical and in-depth suggestions on how to improve validity of mixed research and qualitative research in the field of mathematic of education.

Adaptive Hybrid Fingerprint Matching Method Based on Minutiae and Filterbank (특징점과 필터뱅크에 기반한 적응적 혼합형 지문정합 방법)

  • 정석재;박상현;문성림;김동윤
    • Journal of KIISE:Software and Applications
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    • v.31 no.7
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    • pp.959-967
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    • 2004
  • Jain et al. proposed the hybrid matching method which was combined the minutia-based matching method and the filter-bank based matching method. And, their experimental results proved the hybrid matching method was more effective than each of them. However, this hybrid method cannot utilize each peculiar advantage of two methods. The reason is that it gets the matching score by simply summing up each weighted matching score after executing two methods individually. In this paper, we propose new hybrid matching method. It mixes two matching methods during the feature extraction process. This new hybrid method has lower ERR than the filter-bank based method and higher ERR than the minutia-based method. So, we propose the adaptive hybrid scoring method, which selects the matching score in order to preserve the characteristics of two matching methods. Using this method, we can get lower ERR than the hybrid matcher by Jain et al. Experimental results indicate that the proposed methods can improve the matching performance up to about 1% in ERR.

Application of Discoll Method to Blend Fine Aggregate for Concrete (콘크리트용 잔골재 혼합을 위한 Driscoll 방법의 적용)

  • Lee, Seong Haeng;Ham, Hyeong Gil;Kim, Tae Wan;Oh, Yong Ju
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.3
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    • pp.178-185
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    • 2011
  • Recently depletion of natural resources makes a deficiency of sand aggregation in the concrete works. In this study, the quality characteristics of concrete and aggregate according to blending fine aggregate in the river sand and the crash sand was analyzed by Normal method and Driscoll method which has used mixing of fine aggregate for asphalt mostly. Application of Discoll method to blend fine aggregate for concrete was studied in the first step to blend fine aggregates concrete. The fineness modulus, grading, slump, air content and compressive strength were tested by the two method, the results of Driscoll method was very similar to degree of err limits in comparison with those of Normal method in the same condition. As a result, Driscoll method is reasonable to use the fine aggregates mixture for concrete in river sand and crash sand.

A Review Study of Ocean Surface Mixed Layer Modelling (해양 표면 혼합층 모델링에 대한 고찰)

  • 오임상;이영로
    • 한국해양학회지
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    • v.27 no.4
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    • pp.311-323
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    • 1992
  • The study of ocean surface mixed layer modelling has three different approaches: integral models. diffusive models including K theory and higher turbulence closure scheme, and transilient models. None of them is suitable for all occasions because each model has its specific merits and defects. In the present paper, these three types mixed layer models are described, and their relative advantages and applicabilities are discussed in order to guide the researchers who initiate ocean mixed layer study.

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Characteristics of Fatigue Resistance of Recycled Asphalt Concretes by Modified Mixing Process (재생 아스팔트 콘크리트 혼합물의 혼합방법 개선에 따른 피로저항 특성)

  • Doh, Young-Soo;Ko, Tae-Young;Kim, Kwang-Woo
    • International Journal of Highway Engineering
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    • v.8 no.4
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    • pp.135-143
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    • 2006
  • This study evaluated the fatigue resistance characteristics of hot-mix recycled asphalt mixtures which were prepared by a new blending method. Since the binder of RAP shows higher viscosity without being rejuvenated in the ordinary recycled mixture, this new(modified) blending method was developed for obtaining more uniform level of binder viscosity in the recycled mixture. Cold-planned RAP was collected and mix design was performed using 15% RAP content for two virgin aggregate, gneiss and granite. Penetration grade of 60-80 asphalt was used in mixing recycled mixture together with a polymer modifier, LDPE. Indirect tensile fatigue tests were carried out to evaluate characteristics of fatigue resistance of performance of recycled asphalt mixtures. The recycled mixtures with LDPE 6% showed higher repeated loading fatigue life. Fatigue life ratio of new(N) mixing method mixtures was approximately 0.6-0.7 before aging and 0.8-1.0 after aging treatment of ordinary(O) mixing method mixture. This means the N mixture becomes stronger with aging process increase. If further aging is treated, N mixture may be showing stronger resistance than O mixture.

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