• ETRI Journal
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• 제34권4호
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• pp.625-628
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• 2012

In this letter, a novel method for localizing a user in a smart home environment is presented. We propose a two-level structure, in which the first level determines an occupant's location in the block level using RSSI in a ZigBee network, while the second level accurately estimates the occupant's location using a particle filter to handle the variations in the signal strength measurement. We devise an experimental setup with people performing significant tasks in the smart home. The results obtained from the testbed indicate that the proposed model leads to an improvement in the mean distance error.

• 전자공학회논문지C
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• 제34C권3호
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• pp.1-10
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• 1997

We present an approach to high-level synthesis for a specific target architecture-partitioned bus architecture. In this approach, we have specific goals of minimizing data transfer length and number of buses in addition to common synthesis goals such as minimizing number of control steps and satisfying given resource constraint. Minimizing data transfer length and number of buses can be very important design goals in the era of deep submicron technology in which interconnection delay and area dominate total delay and area of the chip to be designed. in partitioned bus architecture, to get optimal solution satisfying all the goals, partitioning of operation nodes among segments and ordering of segments as well as scheduling and allocation/binding must be considered concurrently. Those additional goals may impose much more complexity on the existing high-level synthesis problem. To cope with this increased complexity and get reasonable results, we have employed two ideas in ur synthesis approach-extension of the target architecture to alleviate bus requirement for data transfer and adoption of genetic algorithm as a principal methodology for design space exploration. Experimental results show that our approach is a promising high-level synthesis mehtodology for partitioned bus architecture.

• 영어어문교육
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• 제12권4호
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• pp.185-210
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• 2006

This study has two purposes. First, it aims to suggest an appropriate approach to English writing education for Korean high school students in a cooperative learning situation. It also aims to suggest what type of learner grouping, either homogeneous or heterogeneous, is appropriate by comparing the learners' writing abilities and the changes of their affective factors after being exposed to cooperative EFL writing instruction. Two homogeneous classes were selected and instructed to write in English for 11 weeks. One was composed of homogeneous small groups based on the students' writing scores, and the other was composed of heterogeneous small groups, again based on the students' writing scores. The results showed that the improvement between the two class types was quite different across different proficiency levels. For example, although there is little difference between the homogeneous and the heterogeneous classes of low and intermediate-level learners in writing ability improvement, high-level students showed a significant difference between the classes. In addition, it was found that class participation correlated significantly to writing ability improvement. Cooperative learning was proved to be an effective writing instructional approach to encourage learners' interest and increase their self-confidence; however, the results did not show any significant differences in learners' affective domain between the homogeneous and the heterogeneous classes. Similarly, the learners' grouping preference was not affected by the grouping method.

• 대기
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• 제31권1호
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• pp.29-43
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• 2021

In this study, two-step statistical approach including Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) was employed, and main meteorological factors explaining the high-PM2.5 episodes were identified in two regions: Seoul and Busan. We first performed PCA to isolate the Principal Component (PC) that is linear combination of the meteorological variables observed at two levels: surface and 850 hPa level. The employed variables at surface are: temperature (T2m), wind speed, sea level pressure, south-north and west-east wind component and those at 850 hPa upper level variables are: south-north (v850) and west-east (u850) wind component and vertical stability. Secondly we carried out MLR analysis and verified the relationships between PM2.5 daily mean concentration and meteorological PCs. Our two-step statistical approach revealed that in Seoul, dominant factors for influencing the high PM2.5 days are mainly composed of upper wind characteristics in winter including positive u850 and negative v850, indicating that continental (or Siberian) anticyclone had a strong influence. In Busan, however, the dominant factors in explanaining in high PM2.5 concentrations were associated with high T2m and negative u850 in summer. This is suggesting that marine anticyclone had a considerable effect on Busan's high PM2.5 with high temperature which is relevant to the vigorous photochemical secondary generation. Our results of both differences and similarities between two regions derived from only statistical approaches imply the high-PM2.5 episodes in Korea show their own unique characteristics and seasonality which are mostly explainable by two layer (surface and upper) mesoscale meteorological variables.

• Communications for Statistical Applications and Methods
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• 제17권3호
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• pp.309-318
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• 2010

The construction of asymptotic confidence intervals is considered for the difference of binomial proportions in two doubly sampled data subject to false-positive error. The coverage behaviors of several likelihood based confidence intervals and a Bayesian confidence interval are examined. It is shown that a hierarchical Bayesian approach gives a confidence interval with good frequentist properties. Confidence interval based on the Rao score is also shown to have good performance in terms of coverage probability. However, the Wald confidence interval covers true value less often than nominal level.

• The Journal of Asian Finance, Economics and Business
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• 제8권12호
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• pp.363-370
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• 2021

This study aims to revisit the issues and misconceptions about financial inclusion (FI) indices. For indices construction, this study uses two approaches: one approach following the methodology of Sarma (2008) which is based on UNDP methodology, while the other is the Dynamic Factor Model (DFM)-based index of Stock and Watson (2002) and Rehman et al. (2021). The data of 18 economies of Asia from 1997 till 2017 is used for indices construction and analysis. The authors constructed macro and micro-level financial inclusion indices based on the different types of financial inclusion indicators. Second, the authors have critically evaluated two different approaches, and the results show that Sarma (2008)-based index show financial inclusion's level, while DFM-based index reveal fluctuation in the current year's financial inclusion level due to the prior variations. For measuring the level of financial inclusion, the Sarma (2008) index is effective, while for forecasting the level of financial inclusion, the DFM approach is more appropriate. Furthermore, the micro and macro aspects of financial inclusion should be reflected in separate indices for better understanding and in-depth insights.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권12호
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• pp.865-872
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• 2013

Two-level 형태소 분석 방법은 규칙 기반 방법 중 하나로 형태소의 변화 현상을 규칙으로 처리하고, 기본 어휘 사전을 기반으로 형태소 결합관계를 분석한다. 이는 언어에 독립적인 방법으로 한국어에 대해서도 일부 구축되어 적용됨이 증명되었다. 그러나 기존 한국어에 대한 Two-level 형태소 분석기는 사전을 수동으로 구축하여 규모가 매우 작고 실제 사용에 제한적이었으며, 과분석이 많아 효율성이 매우 떨어졌다. 본 논문은 세종 품사부착 말뭉치에서 대규모의 Two-level 어휘 사전을 자동으로 구축하여 형태소 분석기의 적용 범위를 넓히고, 형태소간의 결합관계를 어휘 정보와 어휘 형태에 따른 하위품사 정보를 이용하여 분석함으로써 형태소 분석기의 성능을 향상시킬 수 있는 방법을 제시한다. 실험 결과, 기존의 방법보다 형태소 분석기의 과분석을 68% 이상 줄여 f-measure를 25.5% point 이상 향상시킬 수 있었다.

• 한국학교수학회논문집
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• 제12권4호
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• pp.493-508
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• 2009

본 연구는 실제적 발단과 잠재적 발달간의 거리, 즉 근접발달영역의 특징들을 조사하는 것이다. 선시험과 후시험이 18명의 대학생들을 대상으로 실시되었으며 반힐레 수준 이론을 통해 실제적 발달이 같은 두 학생이 잠재적 발달 조사를 위해 선발되었다. 인지-의사소통이론을 바탕으로 삼차원 면대칭에 대한 두 학생의 담화 특징들을 확인하였다. 잠재적 발달 조사결과 두 학생사이에 상당한 차이가 있었다. 수학교육연구에서 학생들의 근접발달영역을 조사하기위한 연구방법론적 시사점을 제안한다.

• 통상정보연구
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• 제13권3호
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• pp.511-541
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• 2011

본 연구에서는 앞으로 있을 한 중 FTA협상 추진 전략을 중국의 낮은 수준의 FTA 체결 선(先)제의에 대한 우리나라의 최적 대응전략 측면에서 고찰하였다. 국제협상 분석 게임모델 중 비협조게임의 기본 모형인 죄수의 딜레마 게임을 기본 틀로 하여 Putnam의 2단계 게임 론을 활용하여 결론을 도출하였다. 향후 한 중 FTA 추진의 전략적 기본원칙은 정부가 주장하는 높은 관세양허 수준의 포괄적 FTA보다는 비록 경제적 효과가 다소 떨어지더라도 가능한 빠른 시일 내 '중간 수준'의 FTA(포괄적이나 전반적으로 낮은 관세양허 방안)를 시작하는 정책을 추진함이 바람직 할 것으로 결론지었다. 이러한 관점에서 한 중 양국이 상대국으로부터의 수입액 중 일정 비율, 가령 70-80%에 해당하는 품목에 대해 협상개시와 함께 관세를 내리는 조기수확 프로그램(EHP: Early Harvest Program)을 활용하는 전략도 한 방법이 될 것이다.

• Steel and Composite Structures
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• 제47권5호
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• pp.569-585
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• 2023

This paper proposes an efficient approach for the structural topology optimization of bi-directional functionally graded structures by incorporating popular radial basis functions (RBFs) into an implicit level set (ILS) method. Compared to traditional element density-based methods, a level set (LS) description of material boundaries produces a smoother boundary description of the design. The paper develops RBF implicit modeling with multiquadric (MQ) splines, thin-plate spline (TPS), exponential spline (ES), and Gaussians (GS) to define the ILS function with high accuracy and smoothness. The optimization problem is formulated by considering RBF-based nodal densities as design variables and minimizing the compliance objective function. A LS-RBF optimization method is proposed to transform a Hamilton-Jacobi partial differential equation (PDE) into a system of coupled non-linear ordinary differential equations (ODEs) over the entire design domain using a collocation formulation of the method of lines design variables. The paper presents detailed mathematical expressions for BiDFG beams topology optimization with two different material models: continuum functionally graded (CFG) and mechanical functionally graded (MFG). Several numerical examples are presented to verify the method's efficiency, reliability, and success in accuracy, convergence speed, and insensitivity to initial designs in the topology optimization of two-dimensional (2D) structures. Overall, the paper presents a novel and efficient approach to topology optimization that can handle bi-directional functionally graded structures with complex geometries.