• Communications for Statistical Applications and Methods
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• 제19권6호
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• pp.781-791
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• 2012

A $2{\times}2$ Cross-over design is widely used in clinical trials for comparison studies of two kinds of drugs or medical treatments. This design has many statistical methods such as Hills-Armitage's (1979) method or Koch's (1972) method. In this paper, we propose a nonparametric test for $2{\times}2$ Cross-over design based on a two-sample test suggested by Baumgartner et al. (1998). In addition, a Monte Carlo simulation study is adapted to compare the power of the proposed methods with those of previous methods.

• Communications for Statistical Applications and Methods
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• 제17권6호
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• pp.899-907
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• 2010

무응답 대체(non-response imputation) 방법에 관한 많은 이론과 방법이 제안되었으며 실제 자료 분석에 이용되고 있다. 흔히 횡단면 무응답 대체를 위하여 다중대체법(multiple imputation)이 사용되고 있으며 2차년도 이상의 패널자료에는 종시점회귀대체법(cross-wave regression imputation)이 사용되고 있다. 본 연구에서는 패널자료 분석을 위하여 종시점회귀대체법의 일반형태인 시계열 대체법과 횡단면 무응답 대체법을 결합한 시계열-횡단면 다중 대체법을 제안하였다. 노동부의 매월노동통계 자료를 이용하여 제안한 방법과 기존의 종시점회귀대체법을 비교하여 우수함을 보였다.

• 비교문화연구
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• 제24권
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• pp.170-183
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• 2011

This study explored how a Chinese college student who previously had not reached a threshold level of Korean proficiency used L1 (Chinese) and L2 (English) as a tool to socialize into Korean (L3) culture of learning over the course of study. From a perspective of language socialization, this study examined the cross-linguistic influence of L1 and L2 on the L3 acquisition process by tracing an approach to language learning and practices taken by the Chinese student as a case study. Data were collected through three methods; interview protocols, various types of written texts, and observations. The results showed that the student used English as a means to negotiate difficulties and expertise by empowering her L2 exposure during the classroom practices. Her ways of using L2 in oral practices could be characterized as the 'Inverse U-shape' pattern, under which she increased L2 exposure at the early stage of the study and shifted the intermediate language to L3 at the later stage of the study. When it comes to the language use in written practices, the sequence of "L2-L1-L3" use gradually changed to the "L2-L3" sequence over time, signifying the importance of interaction between L2 and L3. However, the use of her native language (L1) in a Korean-speaking classroom was limited to a certain aspect of literacy practices (i.e., vocabulary learning or translation). This study argues for L2 communication channel in cross-cultural classrooms as a key factor to determine sustainable learning growth.

• 경영정보학연구
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• 제19권3호
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• pp.179-199
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• 2017

멀티채널 소비자들의 크로스오버 쇼핑행동이 두드러지는 시점에서 최근 사용자 행동 메커니즘에 대한 관심이 높아지고 있다. 단순한 멀티채널 사용자행동에 대한 이해 차원을 넘어 면밀한 관찰을 통해 기존 연구방식에서 발견할 수 없었던 크로스 오버 쇼핑행동에 대한 연구 축적이 필요한 시점이라 할 수 있다. 본 연구는 근거이론(grounded theory)를 활용하여 멀티채널 사용자들이 왜, 어떻게 크로스오버 쇼핑행동을 하는지를 살펴보는데 그 목적이 있다. 본 연구에서는 총 25명의 응답자를 대상으로 인터뷰를 진행하였으며, 근거자료의 분석을 통해 118개의 개념을 추출하였고, 유사 개념간의 통합과정을 통해 28개의 범주를 제시하였다. 본 연구는 근거이론을 적용하여 기존 설문연구에서는 파악하기 어려웠던 사용자들의 동적인 탐색과 구매행동의 메커니즘을 포착함으로써 멀티채널 환경에서 설명 가능한 행동연구 방안을 제안하고 있다는 점에서 의의가 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.2266-2284
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• 2012

Recent studies have indicated that a significant improvement in wireless video throughput can be achieved by Cross Layer Design with Side-information (CLDS) protocols. In this paper, we derive the operational rate of a CLDS protocol operating over a realistic wireless channel. Then, a Rate-Distortion (R-D) empirical model for above-capacity Scalable Video Coding (SVC) is deduced to estimate the loss of video quality incurred under inaccurate rate estimation scenarios. Finally, we develop a novel Unequal Error Protection (UEP) scheme which leverages the characteristics of LDPC codes to reduce the distortion of video quality in case of typically-observed burst wireless errors. The efficacy of the proposed rate adaptation architecture over conventional protocols is demonstrated by realistic video simulations using actual IEEE 802.11b wireless traces.

• Journal of Korea Trade
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• 제23권8호
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• pp.132-144
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• 2019

Purpose - The purpose of this paper is to suggest countermeasures to reduce the damage of manufacturers in halal industries and to increase the transparency of the halal market along with raising some problems of halal supply chain management (HSCM). Design/methodology/approach - To achieve to the aim of this research, halal supply chain is categorized as a green zone or a red zone according to the possibility of cross-contamination, and the study introduces 2 examples in Malaysia and Indonesia regarding cross-contamination. Findings - More than 70% of the companies producing halal-certified products are, ironically, non-Muslim suppliers under the halal certificate system and by using halal supply chain. Most Muslim countries do not exercise control over the completed halal supply chain. In most Muslim countries which do not exercise control over halal supply chain properly, there is always a possibility of cross-contamination of products during the processes of distribution. Research limitations/implications - This research has been conducted by accessing cases in halal supply chain. These cases are found in some Muslim countries, not all Muslim countries. Nevertheless, the authors found the possibility of these cross-contaminations in all Muslim countries, and it will damage the halal market. Originality/value - While existing studies have focused on protecting Muslim consumers by ensuring the integrity of halal products in halal supply chain, there is no research on how to protect halal product manufacturers as another important axis of halal SCM.

• 응용통계연구
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• 제23권5호
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• pp.909-921
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• 2010

패널 자료에서 무응답이 발생한 경우에는 횡시점회귀대체법(cross-wave regression imputation) 등과 같은 대체법을 이용하여 무응답 문제를 해결한다. 최근 표본 틀(sampling frame) 자료를 이용하여 무응답 가중치 보정을 하는 BLS 무응답 보정법은 패널 자료에도 적용 가능한 방법으로 알려져있다. 본 논문에서는 패널자료에서 BLS 무응답 보정법을 이용한 대체법을 연구하였으며 자료가 경향이 있는 비정상시계열(nonstationary process with drift)을 따른 다는 조건하에서 BLS 무응답 보정법과 횡시점회귀대체법의 하나인 이월대체법(carry-over imputation)과의 이론적 관계를 살펴보았다. 모의실험을 통하여 이론적인 결과를 확인하였으며, 2007년 매월노동통계 자료를 이용하여 두 방법의 우수성을 비교하였다.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.651-662
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• 2017

We propose an alternative procedure to select penalty parameter in $L_1$ penalized robust regression. This procedure is based on marginalization of prior distribution over the penalty parameter. Thus, resulting objective function does not include the penalty parameter due to marginalizing it out. In addition, its estimating algorithm automatically chooses a penalty parameter using the previous estimate of regression coefficients. The proposed approach bypasses cross validation as well as saves computing time. Variable-wise penalization also performs best in prediction and variable selection perspectives. Numerical studies using simulation data demonstrate the performance of our proposals. The proposed methods are applied to Boston housing data. Through simulation study and real data application we demonstrate that our proposals are competitive to or much better than cross-validation in prediction, variable selection, and computing time perspectives.

• Bulletin of the Korean Chemical Society
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• 제12권4호
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• pp.423-429
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• 1991

Global and local memory functions, defined by Quack and Troe, were calculated for the rotationally inelastic collision of O + SO(v, j)→ [O--S--O]→O + SO(v, j'). It is seen to decrease steadily as total energy increases. Distribution of scattering cross section over product rotational states also shows the decreasing memory of initial state as total energy is increased. These results are interpreted in terms of energy scrambling at high energy due to the availability of more phase space and also the influence of strong dynamical constraints.

• Current Optics and Photonics
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• 제4권1호
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• pp.16-22
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• 2020

In high resolution imaging devices, smaller aperture in the color filter causes cross talk which provides incorrect information. Plasmonic color filters (PCFs) have been reported as an alternative of the conventional color resist based-color filter (CRCF) and many studies on PCFs demonstrated the filtering function by PCFs with a sub-micron size. In this work, we investigated the cross talk performance of PCFs compared to CRCFs. The effect of cross talk over distance from the filter were measured for each filter. Despite poorer spectral filtering characteristics, PCFs were more robust against cross talk than CRCFs. Also, the further away from the filter, the more cross talk appeared. As a result, PCFs showed less cross talk than CRCFs at about 82% of the results measured at a distance of 2~10 ㎛. This study will help to make practical use of PCFs in high-resolution imaging applications.