• School Mathematics
• /
• v.13 no.3
• /
• pp.363-384
• /
• 2011

This study is based on the recognition that the school mathematics education should reinforce the heuristic and constructional aspects related with discoveries of mathematical rules and understanding of mathematical concepts from real world situations as well as the deductive and formal aspects emphasizing on mathematical contents precisely. The 11th grade students of one class from a city high school with average were chosen. They were given time to learn various functions of Excel in regular classes of "Information Society and Computer" subject. They don't have difficulty using cells, mathematical functions and statistical functions in spreadsheet. Experiment was performed for six weeks and there were two hours of classes in a week. Considering the results of this research, teaching materials using spreadsheets play an important role in helping students to experience probabilistic and statistical reasoning and construct mathematical thinking. This implies that teaching materials using spreadsheet provide students with an opportunity to interact with probabilistic and statistical situations by adopting engineering which can encourage students to observe and experience various aspects of real world in authentic situations.

• Journal of Educational Research in Mathematics
• /
• v.22 no.1
• /
• pp.101-115
• /
• 2012

Analogy, a plausible reasoning on the basis of similarity, is one of the thinking strategy for concept formation, problem solving, and new discovery in many disciplines. Statistics educators argue that analogy can be used as an useful thinking strategy in statistics as well. This study investigated the characteristics of students' analogical thinking in statistics. The mathematically gifted were asked to construct similar problems to a base problem which is a statistical problem having a statistical context. From the analysis of the problems, students' new problems were classified into five types on the basis of the preservation of the statistical context and that of the basic structure of the base problem. From the result, researchers provide some implications. In statistics, the problems, which failed to preserve the statistical context of base problem, have no meaning in statistics. However, the problems which preserved the statistical context can give possibilities for reconceptualization of the statistical concept even though the basic structure of the problem were changed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.32 no.4_1
• /
• pp.343-351
• /
• 2014

The correlation between regional Walkability Index and their physical socio-economic characteristics has evaluated by the spatial statistical analysis to understand the urban pedestrian environments, where has been emerging the significance, recently. Following to the study, the Walkability Indexes were calculated quantitatively from two administrative districts of Busan and measured Global Local spatial autocorrelation indices. Additionally, the Geographically Weighted Regression model was applied to define the correlation between Walkability Indexes and urban environmental variables. The spatial autocorrelation values and clusters on the Walkability Indexes were derived in statistically significant level. Furthermore, the Geographically Weighted Regression model has been derived more improved inference than the OLS regression model, so as the influence of local level pedestrian environment was identified. The results of this study suggest that the spatial statistical approach can be effective on quantitative assessing the pedestrian environment and navigating their associated factors.

• Communications for Statistical Applications and Methods
• /
• v.17 no.4
• /
• pp.599-609
• /
• 2010

Many of financial data are explained via diffusion models in modern financial research. Various types of estimation methods of diffusion processes were suggested by many authors. In this paper, we tested the properties of the NLL estimation method, suggested by Shoji and Ozaki (1998), of diffusion processes in the view of the bias and variance of the estimators and applied the method to estimate the model parameters for the U.S. fedral funds rate data and Korean inter-bank exchange rate data. By simulation study we showed that the NLL method provides relatively good estimators, in the meaning that the estimator has less bias than the Euler method, while keeping the variance similar level. We also provide the NLL estimates of U.S fedral funds rate data and Korean inter-bank exchange rate data.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06d
• /
• pp.140-142
• /
• 2012

최근 상황인지에 관한 연구가 활발히 진행되고 있으며 스마트폰의 각종 센서를 통해 사용자의 컨텍스트 파악이 가능해졌다. 이에 따라서 스마트폰의 컨텍스트 파악을 통해서 사용자에게 각종 친화적 서비스 모델이 많이 생겨 나고 있다. 사용자의 경로 추론, 실내에서의 사용자의 위치파악, 사용자 위치기반 편의시설 추천 등이 그 예이며, 그 중 애플리케이션 추천은 대표적인 서비스라 할 수 있다. 애플리케이션 추천은 사용자의 컨텍스트에 따라서 애플리케이션 사용내역을 로그 데이터로 만들고, 로그 데이터를 기반으로 컨텍스트에 따라서 사용자의 애플리케이션 추천을 해주는 시스템이다. 여기서 로그 데이터를 가공하지 않고 통계를 통해 추천이 가능하지만, 로그 데이터를 사용하여 의사 결정 트리를 만들게 되면 보다 정확하고, 빠르게 추천이 가능하며 적은 로그 데이터로 더 많은 컨텍스트에 적용하여 추천 할 수 있다는 이점이 있다. 본 논문에서는 사용자의 컨텍스트 추출하고 이 데이터를 기반으로 의사결정트리를 만들어 앱을 추천하는 시스템을 제안한다. 이러한 컨텍스트 수집 방법과 추론모델을 이용한 애플리케이션 추천 시스템은 추후 사용자 친화적 서비스 연구에 많은 도움이 될 것이다.

• Communications for Statistical Applications and Methods
• /
• v.16 no.2
• /
• pp.265-275
• /
• 2009

This paper considers a linear regression model with a spatial autoregressive disturbance with ill-posed data and proposes the generalized maximum entropy(GME) estimator of regression coefficients. The performance of this estimator is investigated via Monte Carlo experiments. The results show that the GME estimator provides efficient and robust estimate for the unknown parameter.

• Communications for Statistical Applications and Methods
• /
• v.19 no.2
• /
• pp.237-246
• /
• 2012

Bayesian methods have been recently used to identify multiple change-points. However, the studies for small data are limited. This paper suggests the Bayesian noncentral t distribution change-point model for small data, and applies the Metropolis-Hastings-within-Gibbs Sampling algorithm to the proposed model. Numerical results of simulation and real data show the performance of the new model in terms of the quality of the resulting estimation of the numbers and positions of change-points for small data.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.57-57
• /
• 2019

최근 수문기상학 분야에서 레이더 강수량을 활용한 응용연구가 활발하게 진행되고 있다. 하지만 레이더 강수량은 경험적으로 설정된 레이더 반사도-강우강도 관계식을 활용하여 레이더 강수량을 산정하기 때문에 실제지상에 도달하는 강수량과 정량적인 오차가 필연적으로 발생한다. 따라서 고해상도의 레이더 강수량을 활용한 신뢰도 높은 수문해석을 위하여 레이더 강수량의 편의보정이 필수적으로 선행되어야한다. 본 연구에서는 불확실성을 고려한 레이더 강수량 편의보정을 위하여 Bayesian 추론기법과 일반화 선형모형(generalized linear model)을 연계하여 레이더 강수량 편의보정 매개변수를 산정하였다. 일반화 선형모형을 적용한 레이더 강수량 편의보정 결과는 현재 널리 사용되고 있는 평균보정(mean field bias) 기법에 비하여 통계지표가 개선된 레이더 강수량 편의보정 결과를 도출하였다. 추가적으로 지형학적 특성에 따른 레이더 강수량 편의보정 매개변수의 변동성을 분석하여 고도 및 이격거리에 따른 편의보정 매개변수의 지역화 공식을 제시하였다. 본 연구를 통하여 개발된 레이더 강수량 편의보정 매개변수 산정 및 지역화 연구는 레이더 관측전략 수립과정에 유용한 기초자료로 활용될 것으로 판단된다.

• Journal of The Korean Association For Science Education
• /
• v.37 no.1
• /
• pp.25-37
• /
• 2017

The purpose of this study is to analyze the effects on particulate concept formation based on abductive reasoning model for elementary science class. For this study, an author selected two groups in the sixth grade. One group is an ordinary textbook-based control group (N=26) and the other group is an abductive reasoning model-based treatment group (N=26). After twelve lessons, the scores of Concepts Test for Gas were analyzed by t-test and two-way ANOVA. The result of t-test showed both the control and treatment groups have higher score than before they take the lesson. But after the lesson, an author found out that the treatment group had higher score than that of the control group. And compared to the number of particles expressed, the number of the treatment group were higher than that of the control class. The two-way ANOVA result revealed that the interaction effect between their cognitive level and treatment was not significant. And regardless of the level of cognition, the scores of treatment group are higher than those of control group. Therefore, abductive reasoning model-based elementary science class were found to be more effective for particulate concept formation. Based on the results, an author concluded that abductive reasoning model is very effective in teaching particulate concepts to elementary students.

• Journal of Oral Medicine and Pain
• /
• v.30 no.1
• /
• pp.35-44
• /
• 2005

Purpose: The aim of this preliminary study was to evaluate the effect of Problem-Based Learning (PBL) curriculum on development of comprehension of basic medical knowledge and quality of semi-structured problem solving including scientific reasoning skill. This scientific reasoning contained five components including: size of simple, design of research cause-effect, construction of risk factor, analysis statistic of data, interpretation of result. Materials and Methods: Seoul National University Dental students (100) participated in this experience during two weeks, 2004. Forty eight multiple-choice questions (MCQ) concerned "Infection Control and Prevention" were asked before and after two sections of Lecture-Based Learning (LBL) and PBL (pretest-posttest control group design). A semi-structured problem in epidemiological research was asked to these students after two sections (posttest-only control group design). Data (mean and SD) were analysed using the t Test for two independent samples (p<.05), comparing PBL versus LBL. Results: Our analyse of scores show no difference between LBL and PBL in the development of comprehension of "Infection Control and Prevention". The quality problem solving (epidemiological research) was significantly different between the two groups (p=.029); specially, two components' scores of reflection on scientific reasoning cause-effect (p=.000) and interpretation of result (p=.001) were significantly better for PBL than for LBL. Conclusion: Theses results indicate that comparing LBL and PBL, PBL curriculum have not been disadvantaged in comprehension of basic knowledge, and have contributed to develop the scientific reasoning in problem solving.