• Journal of the Korean Statistical Society
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• v.35 no.3
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• pp.239-250
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• 2006

A $2{\times}2$ crossover design including carryover effect is considered for assessment of population bioequivalence of two drug formulations in a Bayesian framework. In classical analysis, it is complex to deal with the carryover effect since the estimate of the drug effect is biased in the presence of a carryover effect. The proposed method in this article uses uninformative priors and vague proper priors for objectiveness of priors and the posterior probability distribution of the parameters of interest is derived with given priors. The posterior probabilities of the hypotheses for assessing population bioequivalence are evaluated based on a Markov chain Monte Carlo simulation method. An example with real data set is given for illustration.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.2
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• pp.91-100
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• 2009

"How does advertising affect sales?" is the fundamental issue of modern advertising research. There is an interesting issue for estimating carryover effects of advertising on sales, and the aggregated data biases exist in the duration of advertising effect. This research suggests an extended model of Koyck Model which is employed for micro-data (Koyck 1954) to estimate aggregated advertising data, and empirically shows the aggregated data bias. Our developed model with the aggregated level of actual advertising data is more appropriate than the basic Koyck model for micro-data. The result figures out that it is important to consider the disaggregated data level in the analysis of dynamic effects of adverting such as carryover effects.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.373-381
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• 2022

The Fukushima nuclear power plant water spill caused by the Great East Japan Earthquake in March 2011 raised fears about radiation exposure through consumption of radioactively contaminated seafood. The Korean government banned importing agricultural and fishery products from eight prefectures near Fukushima, but the related news were continuously reported partly due to the WTO dispute with Japan, which seems to have aggravated consumers' anxiety about seafood. In this study, data on daily purchases of products for three years (2018-2020) were collected and the effect of Japanese radiation-related news on domestic consumers' purchases of seafood was estimated using a polynomial lag distributed model. As a result of the analysis, it was found that radiation-related news had a statistically significant negative effect on the purchase of seafood on the 5th and 6th days after exposure to consumers through the media. It captures the carryover effect in which consumers' perceptions are reflected in the purchase of seafood after exposure to related news.

• Korean Journal of Veterinary Service
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• v.37 no.4
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• pp.253-261
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• 2014

Porcine circovirus disease (PCVD) is a major problem of swine industry worldwide, and diagnosis of PCV2, causal agent of PCVD, has been doing in clinical laboratories of pig disease by polymerase chain reaction (PCR) methods. But the PCR analyses have a serious problem of misdiagnosis by contamination of DNA, in particular, from carryover contamination with previously amplified DNA or extracted DNA from field samples. In this study, an uracil DNA glycosylase (UNG)-based direct PCR (udPCR) without DNA extraction process and DNA carryover contamination was developed and evaluated on PCV2 culture and field pig samples. The sensitivity of the udPCR combined with dPCR and uPCR was same or better than that of the commercial PCR (cPCR) kit (Median diagnostics, Korea) on PCV2-positive serum, lymph node and lung samples of the pigs. In addition, the udPCR method confirmed to have a preventing ability of mis-amplification by contamination of pre-amplified PCV2 DNA from previous udPCR. In clinical application, 170 pig samples (86 tissues and 84 serum) were analysed by cPCR kit and resulted in 37% (63/170) of positive reaction, while the udPCR was able to detect the PCV2 DNA in 45.3% (77/170) with higher sensitivity than cPCR. In conclusion, the udPCR developed in the study is a time, labor and cost saving method for the detection of PCV2 and providing a preventing effect for DNA carryover contamination that can occurred in PCR process. Therefore, the udPCR assay could be an useful alternative method for the diagnosis of PCV2 in the swine disease diagnostic laboratories.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.3
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• pp.208-215
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• 2017

This study was designed to investigate the carryover effects of high-forage to concentrate (F: C) diet in bred heifers on feed intake, feed efficiency (FE) and milk production of primiparous lactating Holstein cows. The experiment was conducted for 589 days (d) from onset of pregnancy through to the end of first lactation. Twenty-four bred heifers (Body weight: $BW=345.8{\pm}45.4kg$ and $15{\pm}1.2mon$ of age) randomly assigned to two groups of 3 pens containing 4 heifers each and fed high forage (HF) diet with F: C ratio of 91.7: 8.3% and low forage (LF) diet with F: C ratio of 77.8: 22.2% throughout the pregnancy period. After calving, lactating cows were fed total mixed ration (TMR) based diet. No differences (p > 0.05) were observed in dry matter intake (DMI) of bred heifers and primiparous lactating cows in both HF and LF groups. The FE of mid-to-late lactation period was higher (p< 0.05) in HF than LF group. However, the HF group showed higher (p < 0.05) milk yield, 4 % fat corrected milk (FCM) and energy corrected milk (ECM) than LF group during the 305 d lactation. The LF group showed higher (p < 0.05) milk fat, crude protein (CP), milk urea nitrogen (MUN), solid not fat (SNF) and somatic cell count (SCC) than HF group. It is concluded that restriction of F: C ratio to 91.7: 8.3% to bred heifers has the potential carryover effects to maintain higher milk yield and FE with no adverse effect on feed intake and milk composition of primiparous lactating Holstein cows.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.601-610
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• 1999

Crossover design is officially except for special occasions recommended by KFDA and FDA for assessing Bioequivalence between two drugs one for reference and the other for innovator. Such design is regarded as a special case of latin square split-polt or repeated measurement design and its main difference with other designing methods is that each subject in an experiment is exposed two drugs in sequence. Therefore general statistical analysis is not suitable since the model for this experiment includes carryover effect in addition to period and sequence effect. in this paper analysis for crossover model with two drugs and its interpretation are mainly discussed and an example is given for illustration.

• Communications for Statistical Applications and Methods
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• v.10 no.1
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• pp.115-123
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• 2003

In this paper, we discuss the usefulness of AB/BA/AA/BB crossover design sense of sample size. The result is that the AB/BA/AA/BB crossover design is more economical than AB/BA one if large carryover effect exists and so is it in the comparison with completely randomized design within-subject correlation is large.

• Journal of Distribution Science
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• v.14 no.4
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• pp.47-53
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• 2016

Purpose - The objective of this study is to investigate the dynamic relationships among Advertising Cost (AD), Newly Registered Users(NRU), and Buying Users(BU) of Social Network Game(SNG). SNG is getting pervasive mainly due to the rapid growth of mobile game and Social Network Service(SNS). It would be helpful for marketing researchers interested in SNG and related practitioners to understand the changes in AD, NRU, and BU with time as well as the effects on one another in mutual and dynamic way. Research Design, Data, and Methodology - Necessary data were collected from Social Network Game(SNG) company. AD, NRU, and BU are endogenous variables, but new event such as launching (event) and holidays(holiday) are exogenous dummy variables. Vector Auto regression (VAR) model is generally used to examine and capture the dynamic relationships among endogenous variables. VAR model can easily capture dynamic and endogenous relationships among time-series variables. Vector Auto regression with Exogenous variables(VARX) is a model in which exogenous variables are added to VAR. To investigate this study, VARX is applied. Result - By estimating the VARX model, the author finds that the past periods' NRU affect negatively and significantly the present AD, and past periods' BU have a positive and significant impact on the increase of AD. In addition, the author shows that the past periods' AD and BU have a positive and significant effect on the increase of NRU, and the past periods' AD affect positively and significantly BU. While the impact of AD on NRU happens after 3 or 4 days (carryover effect), that of AD on BU comes about within just 1 or 2 days (immediate effect). The effect of BU on NRU can be considered as word of mouth (WOM effect). Therefore, SNG companies can obtain not only the growth of revenue but also the increase of NRU by increasing BU. Through those results, the author can also find that there are significant interactions between endogenous variables. Conclusion - This study intends to investigate endogenous and dynamic relationships between AD, NRU, and BU. They also give managerial implications to practitioners for SNS and SNG firms. Through this study, it is found that there exist significant interactions and dynamic relationships between those three endogenous variables. The results of this study can have meaningful implications for practitioners and researchers of SNG. This research is unique in that it deals with "actual" field data and intend to find "actual" relationships among variables unlike other related existing studies which intend to investigate psychological factors affecting the intention of game usage and the intention of purchasing game items. This study is also meaningful by showing that the increase of BU can be a good strategy for "killing birds with one stone" (i.e., revenue growth and NRU increase). Although there are some limitations related with future research topics, this research contributes to the current research on SNG marketing in the above mentioned ways.

• Journal of Pharmaceutical Investigation
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• v.34 no.5
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• pp.379-383
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• 2004

Statistical interpretations in a bioequivalence trial are considered and studied when the missing observations occurred in $2\;{\times}\;2$ crossover experiment. Patel (1985) suggested the approximate test procedures for carryover effect and drug effect in $2\;{\times}\;2$ crossover design when some of data are missing in the second period. A modified Patel method is newly proposed to the bioequivalence trial and it is compared with the current method through the simulation study.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.208-213
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• 1996

This paper reports a preliminary investigation on the time course of intersyllabic coarticulation in Standard Chinese. In this investigation, around 3800 phonetically compact C1V1-C2V2 type disyllabic structures 3re employed to observe the acoustic effect of coarticulation in general, and about 400 disyllabic words are designed as the materials to examine: (1) How the articulators move from one syllable to the next？ (2) What is the extent to which the syllables overlapped？ And (3) In what sense, the syllables are produced in parallel; and in what sense, they are in sequence？ For the convenience of description, we just take the offset transition of V1 end the onset transition of C2 os the rough representations for anticipatory and carryover effect respectively, durational measurements are made correspondingly. To evaluate the possible influence on the behavior of gestural overlap from stress contrast and constituent difference of the syllables, analysis of variance are counducted as well. Based on this study, Some impressions about general nature of coarticulation behined the intersyllabic gesture overlapping in this language are discussed.