• Survey Research
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• v.12 no.3
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• pp.25-48
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• 2011

In this paper, we overview the sample design, sampling error, non-response rate and prediction errors of the exit poll conducted for 2010 local elections and discusses how to detect a prediction bias in exit poll. To investigate the bias problem in exit poll in regional(Si-Do) level, we analyze exit poll data for 2007 presidential election and 2006 local elections as well as 2010 local elections in Korea. The measure of predictive accuracy A proposed by Martin et al.(2005) is used to assess the exit poll bias. The empirical studies based on three exit polls clearly show that there exits systematic bias in exit poll and the predictive bias of candidates affiliated to conservative party (such as Hannara-Dang) is serious in the specific regions. The result of this study on systematic bias will be very useful to improving the exit poll methodology in Korea.

• The Korean Journal of Applied Statistics
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• v.22 no.2
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• pp.375-385
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• 2009

For 2007 Korea presidential election, most polls by telephone surveys indicated Lee Myung-Bak led the second runner-up Jung Dong-Young by certain margin. The margin between two candidates can be estimated accurately by averaging individual poll results, provided there exists no systematic bias in telephone surveys. Most Korean telephone surveys via telephone directory are based on quota samples, with the region, the gender and the age-band as quota variables. Thus the surveys may result in certain systematic bias due to unbalanced factors inherent in quota sampling. The aim of this study is to answer the following questions by the analytic methods adopted in Huh et al. (2004): Question 1. Wasn't there systematic bias in estimates of support rates. Question 2. If yes, what was the source of the bias? To answer the questions, we collected eighteen surveys administered during the election campaign period and applied the iterated proportional weighting (the rim weighting) to the last eleven surveys to obtain the balance in five factors - region, gender, age, occupation and education level. We found that the support rate of Lee Myung-Bak was over-estimated consistently by 1.4%P and that of Jung Dong-Young was underestimated by 0.6%P, resulting in the over-estimation of the margin by 2.0%P. By investigating the Lee Myung-Bak bias with logistic regression models, we conclude that it originated from the under-representation of less educated class and/or the over-representation of house wives in telephone samples.

• Smart Media Journal
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• v.13 no.2
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• pp.44-51
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• 2024

The construction of a stress measurement detaset plays a curcial role in various modern applications. In particular, for the efficient training of artificial intelligence models for stress measurement, it is essential to compare various biases and construct a quality-controlled dataset. In this paper, we propose the construction of a stress measurement dataset with quality management through the comparison of various biases. To achieve this, we introduce strss definitions and measurement tools, the process of building an artificial intelligence stress dataset, strategies to overcome biases for quality improvement, and considerations for stress data collection. Specifically, to manage dataset quality, we discuss various biases such as selection bias, measurement bias, causal bias, confirmation bias, and artificial intelligence bias that may arise during stress data collection. Through this paper, we aim to systematically understand considerations for stress data collection and various biases that may occur during the construction of a stress dataset, contributing to the construction of a dataset with guaranteed quality by overcoming these biases.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2002.05a
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• pp.119-124
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• 2002

공간적 관계정보(spatial relation)가 언어적 표상시스템과 비언어적 표상시스템에서 어떻게달라지는가를 범주화 모델의 원형이론 모델을 적용하여 알아보고자 하였다. 이전의 연구들에 따르면 공간적 관계정보에 대한 프로토타입이 언어적 범주와 비언어적 범주에서 다르다는 연구 결과(Crawford 등 2000, Huttenlocher 등 1991)와 동일하다. (Hayward & Tarr 1995)는 상반된 연구 결과가 제기되고 있다. 하지만 이전 연구들에서의 문제점은 언어/비언어 표상체계 간의 편향을 통제하지 못했기 때문에 과제에 따라 서로 다른 결과가 나온 것이라고 볼 수 있다 본 연구에서는 두 대상간의 관계정보를 문장으로 제시한 조건, 그림으로 제시한 조건, 그리고 두 조건을 혼합한 조건을 사용하여 편향에 의한 효과를 제거하고자 하였다. 실험은 각 조건에 따라 짝으로 구성된 자극을 학습한 후 검사자극을 공간적 관계정보를 다양하게 하여 학습자극과 동일한지 아닌지를 판단하게 하였다. 실험결과 관계정보를 언어적으로 제시한 조건과 비언어적으로 제시한 조건간에 대상의 위치에 따른 반응시간의 경향성에서 차이가 없었으며, 대상이 단어인지 그림인지에 따라서 반응시간에서 통계적으로 차이가 나타났다. 그리고 두 표상체계에서 공간적 관계에 대한 프로토타입을 분석한 결과 수직축을 중심으로 전형성 효과가 나타나는 것을 알 수 있었다.

• Survey Research
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• v.7 no.2
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• pp.39-52
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• 2006

Most of Korean survey institutions adopt quota sampling for telephone surveys based on region, gender and age-band. In weekdays, it is well blown that there exist substantial differences in day time in-house rate by individual's socio-demographic attributes. So, quota sampling may induce systematic respondent selection bias. To solve the problem, we propose "time-balanced quota sampling" in which interviewer's call time-band is added as an quota variable. Furthermore, we propose "time-balanced quasi-quota sampling" which is derived by partially relaxing evening time quotas in time-balanced quota sampling. We compare the conventional and the newly proposed quota sampling schemes by drawing Monte Carlo samples from the hypothetical population for which the Korea 2004 time use survey data is assumed.

• The Korean Journal of Applied Statistics
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• v.21 no.3
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• pp.361-375
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• 2008

We propose proper methods to impute the item nonresponse in 4-8-4 rotation sample survey. We consider nonignorable nonresponse mechanism that can happen when survey deals with sensitive question (e.g. income, labor force). We utilize modeling imputation method based on Bayesian approach to avoid a boundary solution problem. We also estimate a interview time bias using imputed data and calculate cell expectation and marginal probability on fixed time after removing estimated bias. We compare the mean squared errors and bias between maximum likelihood method and Bayesian methods using simulation studies.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.713-722
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• 2024

This study highlights the impact of Artificial Intelligence (AI) technology on journalism, discussing its utility and addressing major ethical concerns. Broadcasting companies and media institutions, such as the Bloomberg, Guardian, WSJ, WP, NYT, globally are utilizing AI for innovation in news production, data analysis, and content generation. Accordingly, the ecosystem of AI journalism will be analyzed in terms of scale, economic feasibility, diversity, and value enhancement of major media AI service types. Through the previous literature review, this study identifies key ethical and social issues in AI journalism as well. It aims to bridge societal and technological concerns by exploring mutual development directions for AI technology and the media industry. Additionally, it advocates for the necessity of integrated guidelines and advanced AI literacy through social consensus in addressing these issues.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.579-580
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• 2016

본 연구에서는 군집 로봇 체계에서 next-best-view(NBV)의 결정과 경로 계획(path planning)을 동시에 수행하는 효율적인 3차원 탐사 알고리즘을 제안한다. NBV 결정 및 경로 계획을 동시에 수행하는 단일 로봇 탐사 알고리즘에는 최근에 제안된 RH-NBVP[1]가 있다. 우리는 각 로봇에게 효율적으로 탐사 영역을 분배하는 Voronoi-biased multi-RRTs(VB-MRRTs)를 제시하며, 이를 통해 군집 로봇 체계에 RH-NBVP를 적용한다. 제시한 VB-MRRTs가 공간을 얼마나 점유하는지 분석하였으며, 3차원 시뮬레이션 상의 군집 로봇 체계에서 VB-MRRTs가 적용된 RH-NBVP의 탐사율 향상을 확인하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.109-112
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• 2004

Of late, the thrust vectoring control, using fluidic co-flow and counter-flow concepts, has been received much attention since it not only improves the maneuverability of propulsive engine but also reduces an additional material load due to the trailing control wings, which in turn reduce the aerodynamic drag. However, the control effects are not understood well since the flow field involves very complicated non: physics such as shock wave/boundary layer interaction, separation and significant unsteadiness. Existing data are not enough to achieve the effectiveness and usefulness of the thrust vectoring control, and systematic work is required for the purpose of practical applications In the present study, computational study has been performed to investigate the effects of the thrust vector control using the fluidic co-and counter-flow concepts. The results obtained show that, for a given pressure ratio, the thrust deflection angle has a maximum value at a certain suction flow rate, which is at less than $5\%$ of the mass flow rate of the primary jet. With a longer collar, the same vector angle is achievable with smaller mass flow rate.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.118-127
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• 2010

Resistivity logging instruments are designed to measure the electrical resistivity of a formation, and this can be directly interpreted to provide a water-saturation profile. However, resistivity logs are sensitive to borehole and shoulder-bed effects, which often result in misinterpretation of the results. These effects are emphasised more in the presence of tool eccentricity. For precise interpretation of short- and long-normal logging measurements in the presence of tool eccentricity, we simulate and analyse eccentricity effects by combining the use of a Fourier series expansion in a new system of coordinates with a 2D goal-oriented high-order self-adaptive hp finite-element refinement strategy, where h denotes the element size and p the polynomial order of approximation within each element. The algorithm automatically performs local mesh refinement to construct an optimal grid for the problem under consideration. In addition, the proper combination of h and p refinements produces highly accurate simulations even in the presence of high electrical resistivity contrasts. Numerical results demonstrate that our algorithm provides highly accurate and reliable simulation results. Eccentricity effects are more noticeable when the borehole is large or resistive, or when the formation is highly conductive.