• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.160-170
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• 2006

Background : The aberrant promoter hypermethylation of p16INK4a, as a tumor suppressor gene, is contributory factor to non-small cell lung cancer(NSCLC). However, its potential diagnostic impact of lung cancer is unclear. This study measured the level of $p16^{INK4a}$ promoter hypermethylation in the sputum and blood, and compared this with the level measured in the tissue obtained from NSCLC and pulmonary inflammation. Methods : Of the patients who visited the Our Lady of Mercy Hospital in Incheon, Korea for an evaluation of a lung mass and underwent blood, sputum, and tissue tests, 23patients (18 NSCLC, 5 pulmonary inflammation) were enrolled in this study. DNA was extracted from each sample and the level of p16INK4amethylation was determined using methylation-specific polymerase chain reaction. Results : $p16^{INK4a}$ methylation of the blood was observed in 88.9% (16 of 18) and 20.0% (1 of 5) of NSCLC and from pulmonary inflammation samples, respectively (P=0.008). Methylation of the sputum was observed in 83.3% (10 of 12) 80.0% (4 of 5) of NSCLC and pulmonary inflammation samples, respectively (P=1.00). Among the 8 NSCLC tissue samples, methylation changes were detected in 75.0% of samples (6 cases). Four out of seven tissue samples (57.1%) showed concordance, being methylated in both the blood and sputum. Conclusions : There was a higher level of $p16^{INK4a}$ methylation of the blood from NSCLC patients than from pulmonary inflammation. The tissue showed a high concordance with the blood in the NSCLC samples. These findings suggest that $p16^{INK4a}$ promoter hypermethylation of the blood can used to discriminate between NSCLC and pulmonary inflammation.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.419-426
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• 2021

Purpose: In the surgical treatment of pyogenic lumbar spondylodiscitis, screw insertion at the affected vertebra has been avoided because of biofilm formation, and the risk of infection recurrence. The authors analyzed the success rate of infection treatment while minimizing the number of instrumented segments by inserting pedicle screws into the affected vertebrae. Therefore, this study examined the usefulness of this technique. Materials and Methods: From January 2000 to June 2018, among patients with pyogenic lumbar spondylodiscitis treated surgically, group A consisted of patients with pedicle screws inserted directly at the affected vertebrae (28 cases), and group B underwent fusion by inserting screws at the adjacent normal vertebrae due to bone destruction of the affected vertebral pedicle (20 cases). The classified clinical results were analyzed retrospectively. All patients were treated via the posterior-only approach, so the affected disc and sequestrum were removed. Posterior interbody fusion was performed with an autogenous strut bone graft, and the segments were then stabilized with pedicle screw systems. The hospitalization period, operation time, amount of blood loss, EQ-5D index, duration of intravenous antibiotics, and the clinical and radiological results were analyzed. Results: In group A, the number of instrumented segments, operation time, blood loss, and EQ-5D index at one month postoperatively showed significant improvement compared to group B. There were no significant differences in the duration of antibiotic use, hospitalization, radiological bone union time, sagittal angle correction rate, and recurrence rate. Conclusion: Minimal segmental fixation, in which pedicle screws were inserted directly into the affected vertebrae through the posterior approach, reduced the surgery time and blood loss, preserved the lumbar motion by minimizing fixed segments and showed rapid recovery without spreading or recurrence of infection. Therefore, this procedure recommended for the surgical treatment of lumbar pyogenic spondyodiscitis.

• Information Systems Review
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• v.17 no.2
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• pp.179-192
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• 2015

Collaborative research has been actively done on the basis of academic relationships among various study area. The importance of collaboration has also been increased. Collaborative researchers can reduce time, cost, and research risk to maximize research productivity. This study aims to develop a framework for understanding the behavior of professional groups through network characteristics. To achieve the goal, we collected data of the co-authored network and that of the reviewer network from from 2006 to 2012. Total 230 submitted papers were analyzed on the views of research performance and productivity. Various analytical methods such as centrality analysis, sub-group analysis, correlation, and regression were conducted for assuring the reliability and validity of our research. The results shows that the productivity of the co-authored network was increased and the efficiency of the reviewer network was also identified through several network indexes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2309-2315
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• 2013

VANET(Vehicular Ad-hoc Network) is getting attention as an application to improve driver safety through inter-vehicle communication. For activation of VANET, privacy-preserving mutual authentication has to be guaranteed. In previous works, authors proposed various group-based authentication protocols. However, risks on ID exposure due to repeated use of group key and RSU(Road Side Unit) DoS attack were not considered. In this paper, we propose a probabilistic approach for robust anonymous authentication protocol. We evaluated our proposed method in a sets of criteria in VANET and verified it is an efficient solution for enhancing privacy.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.600-612
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• 2009

Special banks primarily using Internet have different properties in transactions with customers, risk management, capital strength, and branch networks with general banks. The success and failure factors of Internet banks have been explained only by the economies of scale, and learning and experience effects of Internet banks based on the perspective of organizational ecologies. In this study, the success factors of Internet banks are investigated based on strategic choice by organizations and resource-based view of the firms instead of organizational ecology perspective. To this end, 31 major Internet banks operating in overseas market have been classified by the size and profitability of banks, and three strategic groups have been derived. three representative company cases were analyzed. critical success factors of Internet banks were derived, and considerable points when operating Internet banks were discussed.

• Korean Journal of Head & Neck Oncology
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• v.31 no.2
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• pp.29-35
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• 2015

목적 : 국소 재발한 진행된 갑상선 유두암의 치료로 수술 후 외부방사선의 역할을 알아보고자 하였다. 대상 및 방법 : 원자력병원에서 2000년 1월부터 2012년 2월까지 사이버나이프 혹은 외부방사선 치료를 받은 수술과 방사선요오드 치료 후 국소 재발한 진행된 갑상선 유두암 환자 13 명을 대상으로 하였다. 경과관찰 기간 동안 국소 및 부위 재발이 발생환 환자는 6 명이었다. 몇몇의 위험인자를 찾기 위해서 Kaplan-Meier method와 log-rank test를 이용하여 성별, 종양단계, 방사선 치료 전 수술 횟수, 방사선요오드치료 횟수, 수술 후 잔존 암의 여부, 원격전이에 대해 단변량 분석하였다. 결과 : 방사선 치료 후 평균 추적관찰기관은 53.8개월(범위, 36 ~ 108개월)이고 그중 남자는 4 명이었다. 1년, 2년의 무진행 생존률은 각각 76.9와 53.8%였다. 단병량 분석은 성별과 잔존 암여부(p = 0.0475 and p = 0.0475, 각각)에 따라 무진행 생존률이 진행한 그룹과 진행하지 않은 그룹 사이에 유의한 차이가 있다는 것을 보여줬다. 결론 : 외부 방사선 치료 전에 잔존 암이 없었던 환자의 100%에서 국소 및 부위 재발이 일어나지 않았다. 외부방사선 치료는 수술과 방사선요오드 치료에 반응하지 않는 환자 중 수술 후 잔존 암이 없는 경우에 효과적인 치료 방법이 될 수 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2108-2114
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• 2011

I examine propping within chaebolgroups, using changes of bond rating events made by corporate credit evaluation institutions. Much studies related to the internal capital market and tunneling have enhanced our understanding of the important function of chaebolgroups in emerging market, but relatively little is known about propping within affiliated firms. In a common sense, propping implies capital reallocation within affiliated firms to save a financially troubled affiliate. In event study on announcement the changes of corporate bond rating, I found most positive numbers in chaebolgroup's CAR. Particularly when lower change than higher change, decrease ratio of CAR is higher positively in chaebolgroups, which relatively shows that there is more propping effects in chaebolgroups than non-chaebolgroups. In multi-regression analysis, after strengthen restriction of internal mutual investment, propping effects are decreased positively in chaebolgroups than non-chaebolgroups when credit rating adjust lower, which implies there was more propping in chaebolgroups.

• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.715-727
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• 2015

This study was conducted to explore the impact of nursing staffing on inpatient nursing outcomes in long term care hospitals. A secondary analysis was done of national data from the Health Insurance Review and Assessment Services including evaluation of long term care hospitals. Patients per RN was a significant indicator of foley catheter ratio in high risk group and low risk group. Patients per RN&NA was a significant indicator of decline in ADL for patients with dementia, non dementia, urinary incontinence and new pressure ulcer development in the high risk group. The average nursing outcome of inpatient in high grade was higher than that low grade in long care hospital. This higher level of nursing staffing and the higher the grade shown a positive effect on the nursing outcomes of the inpatient. We therefore recommend modifying the above nurse staffing policy so as to make it more effective in improving nursing outcomes.

• KDI Journal of Economic Policy
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• v.21 no.1
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• pp.3-58
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• 1999

본고는 위기 이전 우리나라의 상위 재벌기업이 과연 정부의 암묵적 투자손실보전(implicit loss-protection)에 기인하여 위험이 큰 사업에 과다하게 투자하였는가를 실증적으로 규명하여 보고자 하였다. 본고는 먼저 이론적 모형을 통하여 한 경제에 투자손실보전에 대한 기대하에서 투자를 한 기업과 그렇지 않은 기업이 공존할 때, 전자는 후자에 비하여 1) 투자를 많이 하게 될 뿐 아니라, 2) 불확실성의 증가에 대하여 투자를 더욱 늘릴 유인이 존재한다는 것을 보여주었다. 본고는 실증분석에서는 우리나라 상장기업(제조업 및 전산업)의 투자함수를 1992년~97년 기간에 대해 매출액 가속도모형(sales accelerator model)을 이용하여 추정한 결과, 투자손실보전에 대한 기대가 투자결정시 가장 중요하게 작용하였을 것으로 선험적으로 판단되는 5대 재벌기업과 이러한 기대가 가장 작았을 것으로 판단되는 독립기업간에 이론적으로 예상되었던 차이가 관찰되었다. 먼저 전체표본기업에 대한 분석(pooled regressions)에서는 5대 재벌기업은 여타기업에 비하여 매출액의 시차분포와 같은 통상적인 투자의 결정요인으로 설명될 수 없는 높은 투자수준의 차이가 두 그룹간 미래 수익성 전망의 차이, 유동성제약의 정도에 있어서의 차이, 기업규모에서의 차이 등에 기인할 가능성은 작은 것으로 나타났다. 한편 그룹별 분석(regressions by group)에서 5대 재벌기업은 수익률의 불확실성이 증가할 때 오히려 투자를 늘리는 것으로 관찰되었는데, 이는 여타기업에서 불확실성의 계수가 유의하지는 않지만 음수로 추정된 것과는 대조적이었다. 위의 결과는 과거 우리나라의 상위 재벌기업들이 재벌의 부도를 정부가 정치 경제적으로 수용하기 어려울 것이라는 대마불사(大馬不死)의 기대하에 고위험사업에 과다하게 투자하였다는 주장을 뒷받침한다고 판단된다. 향후 유사한 문제의 재발 방지를 위해서는 투자결과에 대한 책임을 투자자인 기업이 져야 함을 철저히 인식하도록 제도 및 관행상 개선노력이 필요하다고 판단되며, 특히 부실기업정리과정에서 부실에 대한 책임을 투자자가 지는 선례(先例)를 확립해 나가는 것이 무엇보다 중요할 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6168-6175
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• 2014

Several studies regarding the effects of academic achievement on mental health problems have been conducted in adolescents but not in elementary school students. Therefore, the aim of the current study was to examine the effects of school achievement on depression in Korean elementary school students. The participants were 1,048, 5th to 6th elementary students in Seoul, Korea. The Spearman correlations between school achievement and depression were -0.31 for boys and -0.37 for girls (p<0.001 for both). After controlling for grader, the family economic status and self-esteem, higher achiever group showed a significantly low risk for depression in boys and girls. This study suggests that the lower school achievement is associated with a depressive mood in Korean elementary students. Therefore, students with lower academic performance are a risk group for depression.