• Asia Marketing Journal
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• 제22권1호
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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.

• 국제지역연구
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• 제20권1호
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• pp.209-234
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• 2016

This study examines the effects of exporter agglomeration on purely local firms' decision to undertake internationalization and the resultant performance enhancement from internationalization using propensity score matching and difference-in-differences approach. We find that the likelihood of starting to export is higher when purely local firms are located in a region with a higher level of exporter agglomeration, as positive externalities allow them to overcome insufficient internal resources and reduce the large initial foreign market entry costs. We also find that newly exporting firms are more likely to experience greater performance enhancement from exporting when they are locate in a region with a lower level of exporter agglomeration.

• The Korean journal of internal medicine
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• 제33권6호
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• pp.1111-1118
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• 2018

Background/Aims: Chest pain is an essential symptom in the diagnosis of acute coronary syndrome (ACS). One-third of patients with ACS present atypically, which can influence their receiving timely lifesaving therapy. Methods: A total of 617 NSTEMI patients from the Korea Acute MI Registry (KAMIR) and the Korea Working Group on MI (KorMI) databases were analyzed. The study population was divided into two groups by symptoms at presentation (typical symptoms group, 128; atypical symptoms groups, 128). Results: In this study population, 23% of patients presented without chest pain. After propensity score matching, the contact-to-device time ($2,618{\pm}381minutes$ vs. $1,739{\pm}241minutes$, p = 0.050), the symptoms-to-balloon time ($3,426{\pm}389minutes$ vs. $2,366{\pm}255minutes$, p = 0.024), and the door-to-balloon time ($2,339{\pm}380minutes$ vs. $1,544{\pm}244minutes$, p = 0.002) were significantly higher in the patients with atypical symptoms than in those with typical symptoms, respectively. Atypical symptoms were an independent predictor for 1-year mortality (hazard ratio, 2.820; 95% confidence interval, 1.058 to 7.515; p = 0.038). The Kaplan-Meier estimates showed higher risk for 12-month mortality in patients with atypical symptoms (p = 0.048) and no significant difference for 12-month major adverse cardiac events (p = 0.487). Conclusions: Acute myocardial infarction patients with atypical symptoms were not rare in clinical practice and showed a high risk of delayed reperfusion therapy. After imbalance between the groups was minimized by use of propensity score matching, patients who presented atypically had a high mortality rate.

• 한국사회복지학
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• 제67권4호
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• pp.279-299
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• 2015

본 연구의 목적은 노인장기요양서비스를 이용하는 부양가구원과 여성가구원의 노동공급효과를 확인하는데 있다. 노인장기요양보험제도의 공식적 돌봄 서비스가 부양가구원들의 비공식적 돌봄을 대체한다면, 이는 부양가구원들의 시간제약을 변화시켜 노동공급을 증가시킬 것이다. 따라서 이러한 노동공급효과는 각국의 공적 돌봄 서비스의 제도적 수준에 따라 달라질 수 있다. 지금까지 서구국가들에서는 이에 대한 연구가 활발히 전개되어 왔으나, 이러한 실증분석들은 혼재된 결과를 보인다. 선행연구들에서는 무엇보다 방법론상 내생성의 문제가 지속적으로 제기되어 왔다. 본 연구는 이러한 문제를 해결하고자 유사실험설계인 PSM(Propensity Score Matching)과 DD(Double Difference) 결합모형을 활용하여 선택편의를 최소화하였다. 한국복지패널 3차, 9차 데이터를 활용한 분석 결과, 한국의 노인장기요양보험제도의 노동공급효과는 나타나지 않았다. 단순이중차이분석에서는 노동시간과 근로소득이 유의미하게 증가한 것으로 나타났지만, 더 엄격하다고 볼 수 있는 이중차이 고정효과모형분석에서는 그 효과가 나타나지 않았다. 이를 서구의 경험적 연구결과에 비춰보면, 한국의 공적 돌봄서비스인 노인장기요양보험제도가 비공식적 돌봄을 대체하지 못하고 일부만을 보완하는 수준에 머물러 있는 것이라고 해석할 수 있다. 본 연구의 분석결과는 그동안 제기되어온 노인장기요양서비스의 급여불충분성에 대한 증거가 될 수 있으며, 노인장기요양서비스의 제도적 배열이 대상자 및 부양가족의 욕구에 맞도록 선택되어져야 한다는 함의를 가진다.

• 한국산업정보학회논문지
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• 제28권1호
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• pp.57-69
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• 2023

전세계적으로 인공지능(AI)을 활용한 디지털전환을 위해 국가적 역량을 집중하고 있는 상황에서 국내 AI 기업 육성이나 AI 산업생태계 환경조성은 더디기만 하다. 정부는 대내외적으로 힘든 경제상황을 타개하기 위해 거액의 공적자금을 투입하고 있으나 그 효과에 대한 체계적 연구는 미진하다. 이런 이유로 본 연구는 성향점수매칭(PSM)과 이중차분법(DID)을 활용하여 정부 인공지능 솔루션 바우처 지원 사업이 수혜기업의 경제적 성과에 미치는 정책효과를 살펴보고자 하였다. 실증분석을 위해 정보통신산업진흥원에서 공개한 AI 중소기업 정보 중 바우처 지원 이력이 있는 461개 기업을 대상으로 2019년 이후 매출 실적을 활용해 PSM-DID 분석을 수행하였다. 실험군과 대조군을 비교 분석한 결과 수혜기업은 정부지원 이후 자산증가, 임금, 연구개발비 등이 전반적으로 증가한 반면, 수익측면에서는 유의미한 기여도를 확인할 수 없었다. 이는 AI 바우처 정책사업이 단기적으로 기업 외형성장에 직접적인 기여를 하였으나 수익창출 여부는 중장기적 시간이 필요하다는 점을 시사한다.

• Journal of Gastric Cancer
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• 제18권1호
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• pp.69-81
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• 2018

Purpose: It has been reported that the survival of patients with locally advanced gastric cancer (LAGC) is better in East Asia countries than in developed western countries; however, the prognosis of LAGC remains poor. This study aimed to evaluate the effects of perioperative chemotherapy on the long-term survival of East Asia patients with LAGC. Materials and Methods: From October 2006 through August 2008, 43 patients with LAGC received perioperative S-1 combined with weekly docetaxel in a phase II study (neoadjuvant group). These patients were matched using propensity scores to patients who underwent surgery without neoadjuvant chemotherapy during the same period (surgery group). The surgical outcomes and long-term survivals were compared between the 2 groups. Results: After matching, 43 and 86 patients were included in the neoadjuvant and surgery groups, respectively, and there was no significant difference in their baseline characteristics. Although the operating time was longer in the neoadjuvant group, there was no significant difference in postoperative complications between the 2 groups. The neoadjuvant group had a significantly higher 5-year overall survival (OS) rate (73.3% vs. 51.1%, P=0.005) and a trend towards higher 5-year progression-free survival (PFS) (62.8% vs. 49.9%, P=0.145). In the multivariate analysis, perioperative chemotherapy was an independent factor for OS, with a hazard ratio of 0.4 (P=0.005) and a marginal effect on the PFS (P=0.054). Conclusions: Perioperative chemotherapy was associated with better long-term survival without increasing postoperative complications in the setting of D2 surgery for patients with LAGC, suggesting that perioperative chemotherapy can be a therapeutic option in East Asia countries.

• Journal of Chest Surgery
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• 제56권2호
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• pp.90-98
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• 2023

Background: Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Totally thoracoscopic ablation (TTA) is a surgical treatment showing a high success rate as a hybrid procedure with radiofrequency catheter ablation to control AF. This study compared the early complications of warfarin and non-vitamin K antagonist oral anticoagulants (NOACs) in patients who underwent TTA. Methods: This single-center retrospective cohort study enrolled patients who underwent planned TTA for AF from February 2012 to October 2020. All patients received postoperative anticoagulation, either with warfarin or a NOAC (apixaban, rivaroxaban, dabigatran, or edoxaban). Propensity score matching was performed for both groups. Early complications were assessed at 12 weeks after TTA and were divided into efficacy and safety outcomes. Both efficacy and safety outcomes were compared in the propensity score-matched groups. Results: Early complications involving efficacy outcomes, such as stroke and transient ischemic attack, were seen in 5 patients in the warfarin group and none in the NOAC group. Although the 2 groups differed in the incidence of efficacy outcomes, it was not statistically significant. In safety outcomes, 11 patients in the warfarin group and 24 patients in the NOAC group had complications, but likewise, the between-group difference was not statistically significant. Conclusion: Among patients who underwent TTA, those who received NOACs had a lower incidence of thromboembolic complications than those who received warfarin; however, both groups showed a similar bleeding complication rate. Using a NOAC after TTA does not reduce efficacy and safety when compared to warfarin.

• Korean Circulation Journal
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• 제52권8호
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• pp.623-631
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• 2022

Background and Objectives: Pulmonary valve replacement (PVR) is the most common operation in adults with congenital heart disease (CHD). There is controversy regarding the best bioprosthesis. We compare the performance of stented bioprosthetic valves (the Mosaic [Medtronic^TM] porcine pericardial against Carpentier Perimount Magna Ease [Edwards^TM] bovine) in pulmonary position in patients with CHD. Methods: Between January 1999 and December 2019, all the PVRs were identified from hospital databases in 2 congenital heart centres in Spain. Valve performance was evaluated using clinical and echocardiographic criteria. Propensity score matching was used to balance the 2 treatment groups. Results: Three hundred nineteen patients were retrospectively identified. After statistical adjustment, 79 propensity-matched pairs were available for comparison Freedom from reintervention for the porcine cohort was 98.3%, 96.1%, and 91.9% at 3, 5, and 10 years and 100%, 98%, and 90.8% for the bovine cohort (p=0.88). Freedom from structural valve degeneration (SVD) for the porcine cohort was 96.9%, 92.8% and 88.7% at 3, 5, and 10 years and 100%, 98%, and 79.1% for the bovine cohort (p=0.38). Bovine prosthesis was associated with a reintervention hazard ratio (HR), 1.12; 95% confidence intervals (CIs), 0.24-5.26; p=0.89 and SVD HR, 1.69 (0.52-5.58); p=0.38. In the first 5 years, there was no difference in outcomes. After 5 years, the recipients of the bovine bioprosthesis were at higher risk for SVD (reintervention HR, 2.08 [0.27-16.0]; p=0.49; SVD HR, 6.99 [1.23-39.8]; p=0.03). Conclusions: Both bioprosthesis have similar outcomes up to 5 years, afterwards, porcine bioprosthesis seem to have less SVD.

• 한국융합학회논문지
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• 제12권12호
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• pp.331-338
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• 2021

본 연구는 에너지바우처제도가 서비스 이용자 가구의 소비·지출에 미친 영향을 파악하고자 하였다. 자료는 한국복지패널 10차년도(2015년)와 15차년도(2020년)을 이용하였다. 연구대상은 서비스를 이용한 실험군과 이용하지 않은 통제군으로 구성하였다. 집단간의 특성차이는 카이제곱검정 및 t-test를 이용하였으며, 다중이중차이회귀분석을 통해 소비·지출에 대한 영향을 파악하였다. 연구결과 에너지바우처제도 이용자 가구의 총생활비(𝛽=-5.37)와 보건의료비(𝛽=-2.37)는 감소하였으며, 기본비(𝛽=2.51)와 교육비(𝛽=0.54)는 증가하였다. 보건의료비와 기본비는 제도 효과에 통계적으로 유의한 차이가 있었다. 따라서 제도 효과를 증대시키기 위해서는 급여수준을 확대하고 급여대상자의 자격기준을 완화하는 제도개선이 요구된다.

• 치위생과학회지
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• 제20권1호
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• pp.44-50
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• 2020

Background: Smartphones are a modern necessity. While they are convenient to use, smartphones also have side effects such as addiction. This study assessed the relationship between smartphone use, a part of everyday life in modern society, and oral health. Methods: An analysis was conducted using 2017 Korea Youth Risk Behavior Web-based Survey data. The propensity score estimation algorithm used logistic regression and 1:1 matching algorithm using nearest-neighbor matching. After matching, a total of 15,032 participants were classified into two groups containing 7,516 teenagers each who did and did not use smartphones, respectively. Results: Comparison of oral health behaviors according to smartphone use revealed a statistically significant difference in the frequency of tooth brushing per day, use of oral hygiene products, intake of foods harmful to oral health, and experience of oral health education (p<0.05). The factors affecting oral pain experience of adolescents were examined. Compared to male participants, female participants had an odds ratio of 1.627 for oral pain (p<0.05). According to the household income level, compared to the group with higher income, the group with lower income showed higher oral pain experience (p<0.05). Oral pain experience was 1.601 times more frequent among teenagers using smartphones (p<0.05). Conclusion: The results of this study indicated that use of smartphones by adolescents affected their oral health. These findings indicate the need for improved oral health management through the use of effective school oral health programs and individual counseling by oral health professionals, promotion of information dissemination through public media, and development of prevention strategies.