• Journal of Korean Elementary Science Education
• /
• v.27 no.4
• /
• pp.385-398
• /
• 2008

The purpose of this study is to understand the effect of The Model of Phases of the Moon on conception changes for preservice teachers. The researcher interviewed two preservice teachers under the agreement with them on their participation in the research just before he performed a class using The New Model of Phases of the Moon. The post-interview with the same content as the pre-interview was preformed one month later. The main content of the interview is as follows; 'Explain the shape of the Moon by drawing it.', 'Explain the relative different position among the Sun, Earth, and Moon depending on phases of the Moon by drawing them.', 'What do you think of the cause of phases of the Moon?', 'Draw a picture to explain why we always see only one side of the moon.' The results of the research are as follows. First, the class with New Model of Phases of the Moon was able to perceive the relationship of Sun, Earth, and Moon in three-dimensions rather than in two-dimensions and it helped to change their misconception that the Moon's shadow causes the Moon's shape. Secondly, the class with New Model of Phases of the Moon helped preservice teachers understand better the different positional relationships among the Sun, Earth, and Moon depending on the Moon shapes. Third, the class adopting the New Model of Phases of the Moon help preservice teachers form scientific conceptions on the causes of phase change of the Moon. Fourth, the class with the New Model of Phases of the Moon is not appropriate for explaining the reason why only one face of the Moon is seen. Based upon the results above, the researcher realized the limitation of this model and suggested that this model would help learners understand phase change of the Moon and increase space perception ability.

• The Korean Journal of Applied Statistics
• /
• v.29 no.5
• /
• pp.897-906
• /
• 2016

We augment an unrelated quantitative attribute to Bar-Lev et al.'s model (2004) which is composed of sensitive quantitative variable and scrambled one to present a multiplicative unrelated quantitative randomized response model(MUQ RRM). We also establish theoretical grounds to estimate the sensitive quantitative attribute according to circumstances irrespective of known or unknown unrelated quantitative attribute. Finally, we explore the relationship among the suggested model, Eichhorn-Hayre model, Bar-Lev et al.'s model and Gjestvang-Singh's model, and compare the efficiency of our model with Bar-Lev et al.'s model.

• Journal of KIISE:Software and Applications
• /
• v.26 no.12
• /
• pp.1455-1467
• /
• 1999

소프트웨어 품질을 정의하기 위한 여러 가지 소프트웨어 품질 모형(SQM : Software Quality Model)이 개발되어 왔다. 이 모형들은 두 가지 목적을 가진다. 한 가지는 소프트웨어 품질 측정이고, 또 다른 목적은 개발 프로세스에서의 소프트웨어 품질 제어이다. 국제 표준인 ISO/IEC 9126은 소프트웨어 측정을 위한 소프트웨어 품질 모형을 제시하였다. ISO/IEC 9126의 품질 모형은 사용 관점에서 소프트웨어 품질을 정의한 모형이다. 이 모형은 개발 프로세스에서의 품질 제어를 하는 측면에서는 불완전한 모형이다. 소프트웨어의 품질이 프로세스 내에서 어떻게 만들어지는지 볼 수 없는 모형이기 때문이다. 따라서, 개발 관점에서의 소프트웨어 품질 모형이 필요하다.본 논문에서는 사용 관점인 ISO/IEC 9126 품질 모형을 기반으로 하여 개발 관점에서의 소프트웨어 품질 모형을 제안한다. 이 모형은 ISO/IEC 9126과 같이 하위 품질 요소가 중복되지 않는 계층적 품질 모형이면서, 개발 프로세스 내에서 제어 가능한 제품 특성에 기반을 둔 개발 관점의 소프트웨어 품질 모형이다. 본 논문에서는 소프트웨어 품질 모형 구축 시, 품질 속성간의 선후조건관계를 설정하여 품질 속성간 중복되었던 제품 특성을 한 품질 속성 내 귀속시킨다. 품질 속성 별 제품 특성을 기반으로, 프로세스 내에서 제품 특성을 측정하는 메트릭스를 제안한다. 본 논문에서 제안한 품질 모형과 ISO/IEC 9126을 비롯한 기존 품질 모형과 비교 분석한다.Abstract Several SQMs(Software Quality Models) have been developed to define a software quality. These models have two goals. One is to measure a software quality, the other is to control a software quality. The SQM of ISO/IEC 9126 is defined from the user's viewpoint. This model is an incomplete model in controlling a software quality in the development process. Since this model cannot show how to build a high quality software, the SQM of the developer's view is needed.We suggest the SQM of the developer's view. This model is a completely hierarchical model and is based on product properties. For this model, we define implicative relations among quality attributes for 1:m relations of quality attributes and product properties. So, we solve the problem of a quality attribute overlapping with other quality attributes. We suggest metrics based on our SQMs. Further, we evaluate our SQM by comparing our SQM with other SQMs.

• The Korean Journal of Applied Statistics
• /
• v.21 no.6
• /
• pp.1037-1044
• /
• 2008

In this paper, we show the performance of the power transformation GARCH(PGARCH) model to analyze the internet traffic data. The long memory property which is the typical characteristic of internet traffic data can be explained by the PGARCH model rather than the linear GARCH model. Small simulation and the analysis of the real internet traffic show the out-performance of the PARCH MODEL over the linear GARCH one.

• Water for future
• /
• v.22 no.3
• /
• pp.307-313
• /
• 1989

This study is aimed to develop a long-term daily runoff simulation model. The model is theoretically constructed and is applied to the practical problems to verify its reasonableness. A lumped, nonlinear model is proposed and is calibrated as quasilinearization procedures. The hydrological data used in the paper are precipitation, runoff, and evaporation records in the Bochong Stream which is one of the tributaries of the Geum River.

• Communications for Statistical Applications and Methods
• /
• v.15 no.3
• /
• pp.333-342
• /
• 2008

Variable selection theorem in the linear regression model is extended to the analysis of covariance model. When some of regression variables are omitted from the model, it reduces the variance of the estimators but introduces bias. Thus an appropriate balance between a biased model and one with large variances is recommended.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.7
• /
• pp.11-18
• /
• 2008

Korean morphological analyzer generally generates multiple candidates, and then selects the most likely one among multiple candidates. As the number of candidates increases, the chance that the correctly analyzed candidate is included in the candidate list also grows. This process, however, increases ambiguity and then deteriorates the performance. In this paper, we propose a new rule-based model that produces one best analysis. The analysis rules are automatically extracted from large amount of Part-of-Speech tagged corpus, and the proposed model does not require any manual construction cost of analysis rules, and has shown high success rate of analysis. Futhermore, the proposed model can reduce the ambiguities and computational complexities in the candidate selection phase because the model produces one analysis when it can successfully analyze the given word. By combining the conventional probability-based model. the model can also improve the performance of analysis when it does not produce a successful analysis.

• Journal of the Korean Data and Information Science Society
• /
• v.28 no.5
• /
• pp.1077-1085
• /
• 2017

In this study, we have found the major factors which affect Korean women's wage analysing the data provided by 2015 Korea Labor Panel Survey (KLIPS). In general, wage data is difficult to analyze because random sampling is infeasible. Heckman sample selection model is the most widely used method for analysing the data with sample selection. Heckman proposed two kinds of selection models: the one is the model with maximum likelihood method and the other is the Heckman two stage model. Heckman two stage model is known to be robust to the normal assumption of bivariate error terms. Recently, Marchenko and Genton (2012) proposed the Heckman selectiont model which generalizes the Heckman two stage model and concluded that Heckman selection-t model is more robust to the error assumptions. Employing the two models, we carried out the analysis of the data and we compared those results.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.36C no.5
• /
• pp.13-26
• /
• 1999

This paper presents a metric that can guide to optimal circuit models for interconnects among various models, given interconnect parameters and operating environment. To get this goal, we categorize interconnects into RC~c1ass and RLC-c1ass model domains based on the quantitative modeling error analysis using total resistance, inductance and capacitance of interconnects as well as operating frequency. RC~c1ass circuit models, which include most on~chip interconnects, can be efficiently analyzed by using the model~order reduction techniques. RLC-c1ass circuit models are constructed using one of three candidates, ILC(Iterative Ladder Circuit) macromodels, MC(Method of Characteristics) macromodels, and state-based convolution method, the selection process of which is based upon the allowable modeling error and electrical parameters of interconnects. We propose the model domain diagram leading to optimal circuit models and the division of model domains has been achieved considering the simulation cost of macromodels under the environmental assumption of the general purpose circuit simulator such as SPICE. The macromodeling method presented in this paper keeps the passivity of the original interconnects and accordingly guarantees the unconditional stability of circuit models.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.4 no.1 s.12
• /
• pp.41-50
• /
• 2004

The objective of this study is to investigate the feasibility of the developed Fuzzy control techniques in dam operation. The simulated results for the 1984, 1990, and 1995 flood events are compared with historical operation results in the view of flood control and disaster prevention. The three models developed in this study determine the outflows based on the two conditions the first one is to consider only two inputs such as reservoir water level and inflow, for operation of the existing situations, the second one is that the possible maximum discharge from each dam does not exceed the allowable design maximum discharge for disaster prevention in downstream area. As the results, it was shown that the suggested models based on Fuzzy control technique could reduce both the peak water level and the maximum peak discharge compared with the historical operation results.