• Information Systems Review
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• v.23 no.4
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• pp.147-163
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• 2021

We investigate the effect of comment history disclosure on portal news comments. Specifically, based on the scraped news comments from Naver and Daum (two leading Korean news portals), we employ the difference-in-differences estimator to empirically tease out the impact of the comment history disclosure policy implemented in Naver on its news comments. Our result shows that the policy implementation significantly increased the length and the positiveness of online news comments but did not affect their quality.

• Korean Journal of Social Welfare Studies
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• v.41 no.2
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• pp.35-65
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• 2010

The purpose of this study is to identify the relationship between health insurance and health by evaluating the impacts of health insurance coverage expansion on health care utilization and health status. To analyze the causal relationship between health insurance and health, this study employed a "difference-in-difference method" that could compare changes in health care utilization and health status across groups in health insurance coverage expansion in 2005. The researcher predicted that the expansion of health insurance coverage would be an exogenous source of variation in the prices of health service use. First, the difference-in-differences estimator between 'illness group' and 'non-illness group' revealed that the increase in coverage of inpatient care services would result from the increases in the stay of length of 'non-illness group' rather than that of 'illness group'. However, the difference-in-differences estimator between 'serious illness group' and 'chronic illness group' identified that the policy change that focuses on expansion of the coverage for 'serious illness' effects on the increases in health care utilization and promotion of health status. In summary, the changes of health insurance coverage focusing on serious illness and inpatient care have positive effects on health care utilization and health status of serious illness group. But, 'non-illness groups' with acute illness receive more benefits from the policy change than 'illness group' with chronic illness.

• Asia Marketing Journal
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• v.22 no.1
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• pp.1-26
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• 2020

Firms employing hierarchical loyalty programs (HLPs) periodically demote customers from higher to lower status level to divest from unprofitable customers and boost profitability. However, existing literature lacks objective evidence on how customer demotion affects demoted customers' future purchase behaviors and ultimately profitability for the firm. Moreover, customers in the HLP's higher position may respond to customer demotion differently from those in the HLP's lower position. Drawing upon emotions and equity theories, this study quantifies how the profits that customers contribute to the firm change after customer demotion, and compares demoted customers' behavioral reactions from top-tier with those from bottom-tier based on customers' actual behavior data from a major retail bank in South Korea. The findings show that withdrawing customer status actually deteriorates customer profitability, and customers with top-tier status decrease their profitability more dramatically than those with bottom-tier status after demotion. The results contribute to previous literature on customer demotion and relationship marketing, and provide specific guidelines into how firms should design and implement customer demotion in HLPs.

• Journal of Korean Society for Quality Management
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• v.52 no.2
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• pp.287-301
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• 2024

Purpose: This paper aims to verify the difference in production resilience between local clusters and regions without clusters before and after a major crisis. Furthermore, this paper aims to identify the clusters' quality factors that impact clusters' shock vulnerability and resilience. Methods: Utilizing open-source data from the US Cluster Mapping platform, this paper compares regions with industrial clusters to those without using the Differences-in-Differences (DID) estimator. It considers the regions with industrial clusters as a treatment group and others as the control group, comparing the period before and after the pandemic. Additionally, the paper examines which cluster factors make a difference in economic resilience during the crisis using Regression Discontinuity Design (RDD). Results: The study finds that regions with industrial clusters show higher production resilience compared to regions without clusters. Moreover, the number of establishments, annual payrolls, and employment can have a positive impact on resilience during the pandemic shock. Conclusion: Though clusters could be vulnerable during the global crisis, industrial clusters can contribute to regional economic development and production resilience in the long-term aspect. Thus, it is required to construct a high-quality local cluster and support it during the economic crisis in the long-term aspect.

• Journal of Korean Medicine for Obesity Research
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• v.19 no.2
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• pp.97-105
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• 2019

Objectives: We investigated differences between the tracheostomized and the non-tracheostomized stroke patients through microbiological analysis for the purpose of preliminary explorations of full-scale clinical research in the future. Methods: We collected tracheal aspirates samples from 5 stroke patients with tracheostomy and expectorated sputum samples from 5 stroke patients without tracheostomy. Genomic DNA from sputum samples was isolated using QIAamp DNA mini kit. The sequences were processed using Quantitative Insights into Microbial Ecology 1.9.0. Alpha-diversity was calculated using the Chao1 estimator. Beta-diversity was analyzed by UniFrac-based principal coordinates analysis (PCoA). To confirm taxa with different abundance among the groups, linear discriminant analysis effect size analysis was performed. Results: Although alpha-diversity value of the tracheostomized group was higher than that of the non-tracheostomized group, there was no statistically significant difference. In PCoA, clear separation was seen between clusters of the tracheostomized group and that of the non-tracheostomized group. In both groups, Bacteroidetes, Proteobacteria, Fusobacteria, Firmicutes, Actinobacteria were identified as dominant in phylum level. In particular, relative richness of Proteobacteria was found to be 31% more in the tracheotomized group (36.6%) than the non-tracheostomized group (5.6%)(P<0.05). In genus level, Neisseria (24%), Prevotella (17%), Streptococcus (13%), Fusobacteria (11%), Porphyromonas (7%) were identified as dominant in the tracheostomized group. In the non-tracheostomized group, Prevotella (38%), Veillonella (20%), Neisseria (9%) were genera that found to be dominant. Conclusions: It is meaningful in that the tracheostomized group has been identified a higher rate of microbiotas known as pathogenic in respiratory diseases compared to the non-tracheostomized group, confirming the possibility that the risk of opportunity infection may be higher.