• 한국ITS학회 논문지
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• 제11권5호
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• pp.46-55
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• 2012

본 연구에서는 공공재의 가치추정에 효율적인 방법론인 이중양분선택형 질문법에 의한 CVM(조건부가치측정법)을 이용하여 실시간 경로안내시스템에 대한 이용자의 지불의사액(WTP)을 추정하는 방안을 제시하고 지불의사액의 산정에 영향을 미치는 요인을 분석하는 것을 그 목적으로 한다. 제공되는 실시간 교통정보 안내서비스는 최단거리 정보가 아닌 최적경로 개념의 정보로 해당 OD간의 교통상황에 대응하여 실시간으로 경로유도정보가 제공된다고 가정하였다. 분석대상을 단거리와 중거리로 구분하여 실시간 경로안내서비스에 대한 연 단위의 지불의사액을 추정하기 위해 개인속성, 정보이용 실태 및 만족도, 정보에 관한 이용자의 의식과 시설이용도 등을 변수로 사용하였으며, 생존분석 방법과 회귀모형을 이용하여 지불의사액을 산정하였다. 분석결과 단거리 구간의 실시간 경로안내서비스에 대한 평균 지불의사액은 4,034원/년이었고, 중거리 구간은 4,884원/년으로 나타나, 단거리 구간보다는 중거리 구간에 대한 실시간 경로안내시스템의 가치를 더욱 높게 평가 하고 있음을 확인하였다. 나아가 소득수준이 높을수록 정보의 필요성이 높고 자동차를 소유한 이용자일수록 그리고 해당경로에 대한 인지도가 낮을수록 지불의사액은 높게 나타났다.

• Journal of Trauma and Injury
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• 제24권2호
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• pp.89-94
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• 2011

Purpose: A few studies have assessed the factors affecting the prognoses for major trauma patients and those improving the circumstances when dealing with the trauma system. In that light, we analyzed factors, such as pre-hospital factors, the time to admission, the length of stay in the emergency department (ED) and emergency operation, influencing the outcomes for trauma patients. Methods: The patients who visited our emergency department from April 1, 2009, to February 29, 2011, due to major trauma were enrolled in the study. The inclusion criterion was a revised trauma score (RTS) < 7 or injury severity score (ISS) ${\geq}$ 16. We used reviews of medical records, to analyze each step of emergency medical care with respect to patients' sex, age, visit time and visit date. Continuous variables were described as a median with an interquartile range, and we compared the variables between the survival and the mortality groups by using the Mann-Whitney U test. Fisher's exact test was used for nominal variables. Using the variables that showed statistical significance in univariate comparisons, we performed a logistic regression analysis, and we tested the model's adequacy by the using the Hosmer-Lemeshow method. Results: A total of 261 patients with major trauma satisfied either the RTS score criterion or the ISS score criterion. Excluding 12 patients with missing data, 249 patients were included in this study. The overall mortality rate was 16.9%. Time to ED arrival, time to admission, time of ED stay, RTS, ISS, and visit date being a holiday showed statistically significant differences between the survival and the mortality groups in the univariate analysis. RTS, ISS, length of ED stay, and visit date being a holiday showed statistical significance in the multivariate analysis. Conclusion: The mortality rate did not show a significant relationship with the time to ED arrival, use of 119, on time to admission. Rather, it elicited a quite significant correlation with the trauma scoring system (RTS and ISS), the time of ED stay, and the visit date being a holiday.

• Radiation Oncology Journal
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• 제33권2호
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• pp.109-116
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• 2015

Purpose: To analyze prognostic factors for locoregional recurrence (LRR), distant metastasis (DM), and overall survival (OS) in cervical cancer patients who underwent radical hysterectomy followed by postoperative radiotherapy (PORT) in a single institute. Materials and Methods: Clinicopathologic data of 135 patients with clinical stage IA2 to IIA2 cervical cancer treated with PORT from 2001 to 2012 were reviewed, retrospectively. Postoperative parametrial resection margin (PRM) and vaginal resection margin (VRM) were investigated separately. The median treatment dosage of external beam radiotherapy (EBRT) to the whole pelvis was 50.4 Gy in 1.8 Gy/fraction. High-dose-rate vaginal brachytherapy after EBRT was given to patients with positive or close VRMs. Concurrent platinum-based chemoradiotherapy (CCRT) was administered to 73 patients with positive resection margin, lymph node (LN) metastasis, or direct extension of parametrium. Kaplan-Meier method and log-rank test were used for analyzing LRR, DM, and OS; Cox regression was applied to analyze prognostic factors. Results: The 5-year disease-free survival was 79% and 5-year OS was 91%. In univariate analysis, positive or close PRM, LN metastasis, direct extension of parametrium, lymphovascular invasion, histology of adenocarcinoma, and chemotherapy were related with more DM and poor OS. In multivariate analysis, PRM and LN metastasis remained independent prognostic factors for OS. Conclusion: PORT after radical hysterectomy in uterine cervical cancer showed excellent OS in this study. Positive or close PRM after radical hysterectomy in uterine cervical cancer correlates with poor prognosis even with CCRT. Therefore, additional treatments to improve local control such as radiation boosting need to be considered.

• 유통과학연구
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• 제10권3호
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• pp.31-42
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• 2012

After the rapidly changing business management environment and financial crisis, high prices and domestic recession in Korea posed threats to the business survival of small and medium enterprises (SMEs). This paper looks at the potential of micro business owners for sustainable development: those who have a spirit of entrepreneurship and the potential to be a hidden champion. Our study of micro business values uses structure equation modeling by LISREL. We have done so in order to understand the foundation of management innovation and success model of micro enterprise by increasing the entrepreneurship and management performance relationship analysis. A micro-enterprise is a type of small business, found only in Korea, often registered as having ten or fewer employees. We examine the successful type of hidden champions and the influence of entrepreneurship on start-ups in business. As compared to past research on the SME entrepreneurship, this study segments small businesses even further. Small business entrepreneurship was classified into three forms that are most appropriate for the Korean situation today: innovation, risk-taking, and pro-activeness. This research is meaningful as it is Korea's first empirical analysis on four business types: wholesale and retail sales, food and lodging business, service business, and manufacturing business. Thus far, research on small business entrepreneurship was carried out using small-scale investigative analysis. However, this research attempted to develop a model that can explain a cause-effect relation of the motivational level when it comes to the difference of entrepreneurship by each business type and small business start-up success factors. Various conceptual and operational definitions could be developed in a diverse and precise manner. Independent variables that are related to the success of small businesses can be developed additionally to examine the success factors related to the systematization in detailed manner. The research showed that the innovation, risk-taking and pro-activeness of the manifested difference in the degree of perception depending on the type of small businesses. Among the four business types, the ones that manifested the highest successful start-up rates were food, service, wholesale and retail sales and manufacturing. Results after conducting the regression analysis are shown on, which proves that the small business entrepreneurship exerts direct effect on the financial management performance of small businesses. In other words, small business entrepreneurship exerts a positive effect on the small business financial success and management performance. The R² value is 0.61. It is possible to know that the perception of systematization and variables on attitude explains the 61% of the success for small self-employed businesses management performance. We define start-up key factors that are helpful to achieve internal growth of firms by finding business survival strategies. The results also focus on Korean government policy for micro enterprise and small business support.

• Steel and Composite Structures
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• 제35권6호
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• pp.799-813
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• 2020

Fatigue cracks of rib-to-deck (RD) joints have been frequently observed in the orthotropic steel decks (OSD) using conventional U-ribs (CU). Thickened edge U-rib (TEU) is proposed to enhance the fatigue strength of RD joints, and its effectiveness has been proved through fatigue tests. In-depth full-scale tests are further carried out to investigate both the fatigue strength and fractography of RD joints. Based on the test result, the mean fatigue strength of TEU specimens is 21% and 17% higher than that of CU specimens in terms of nominal and hot spot stress, respectively. Meanwhile, the development of fatigue cracks has been measured using the strain gauges installed along the welded joint. It is found that such the crack remains almost in semi-elliptical shape during the initiation and propagation. For the further application of TEUs, the design curve under the specific survival rate is required for the RD joints using TEUs. Since the fatigue strength of welded joints is highly scattered, the design curves derived by using the limited test data only are not reliable enough to be used as the reference. On this ground, an experiment-numerical hybrid approach is employed. Basing on the fatigue test, a probabilistic assessment model has been established to predict the fatigue strength of RD joints. In the model, the randomness in material properties, initial flaws and local geometries has been taken into consideration. The multiple-site initiation and coalescence of fatigue cracks are also considered to improve the accuracy. Validation of the model has been rigorously conducted using the test data. By extending the validated model, large-scale databases of fatigue life could be generated in a short period. Through the regression analysis on the generated database, design curves of the RD joint have been derived under the 95% survival rate. As the result, FAT 85 and FAT 110 curves with the power index m of 2.89 are recommended in the fatigue evaluation on the RD joint using TEUs in terms of nominal stress and hot spot stress respectively. Meanwhile, FAT 70 and FAT 90 curves with m of 2.92 are suggested in the evaluation on the RD joint using CUs in terms of nominal stress and hot spot stress, respectively.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7101-7106
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• 2013

Background: The prognosis of patients with hepatocellular carcinoma (HCC) after curative resection varies greatly. Few studies had investigated the risk factors for early recurrence (recurrence-free time ${\leq}$ 1 year) of hepatitis B virus (HBV)-related HCCs meeting Milan criteria. Methods: A retrospective analysis was performed on the 224 patients with HCC meeting Milan criteria who underwent curative liver resection in our center between February 2007 and March 2012. The overall survival (OS) rate, recurrence-free survival (RFS) rate and risk factors for early recurrence were analyzed. Results: After a median follow-up of 33.3 months, HCC reoccurred in 105 of 224 patients and 32 died during the period. The 1-, 3- and 5-year OS rates were 97.3%, 81.6% and 75.6% respectively, and the 1-, 3- and 5-year RFS rates were 73.2%, 53.7% and 41.6%. Cox regression showed alpha-fetoprotein (AFP) > 800 ng/ml (HR 2.538, 95% CI 1.464-4.401, P=0.001), multiple tumors (HR 2.286, 95% CI 1.123-4.246, P=0.009) and microvascular invasion (HR 2.518, 95% CI 1.475-4.298, P=0.001) to be associated with early recurrence (recurrence-free time ${\leq}$ 1-year) of HCC meeting Milan criteria. Conclusions: AFP > 800 ng/ml, multiple tumors and microvascular invasion are independent risk factors affecting early postoperative recurrence of HCC. In addition resection appears capable of replacing liver transplantation in some situations with safety and a better outcome.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2953-2958
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• 2015

Although associations between thioredoxin interacting protein (TXNIP) and cancers have been recognized, the effects of TXNIP on non-small cell lung cancer (NSCLC) prognosis remained to be determined in detail. In addition, while hypoxia is a key characteristic of tumor cell growth microenvironment, the effect of hypoxia on TXNIP expression is controversial. In this study, formaldehyde fixed and paraffin embedded (FFPE) samples of 70 NSCLC patients who underwent resection between January 2010 and December 2011 were obtained. Evaluation of TXNIP and hypoxia inducible factor-$1{\alpha}$ ($HIF-1{\alpha}$) protein expression in FFPE samples was made by immunohistochemistry. By Kaplan-Meier method, patients with high TXNIP expression demonstrated a significantly shorter progression free survival (PFS) compared with those with low TXNIP expression (18.0 months, 95%CI: 11.7, 24.3 versus 23.0 months, 95%CI: 17.6, 28.4, P=0.02). High TXNIP expression level was also identified as an independent prognostic factor by Cox regression analysis (adjusted hazard ratio: 2.46; 95%CI: 1.08, 5.56; P=0.03). Furthermore, TXNIP expression was found to be significantly correlated with $HIF-1{\alpha}$ expression (Spearman correlation=0.67, P=0.000). To further confirm correlations, we established a tumor cell hypoxic culture model. Expression of TXNIP was up-regulated in all three NSCLC cell lines (A549, SPC-A1, and H1299) under hypoxic conditions. This study suggests that hypoxia induces increased TXNIP expression in NSCLC and high TXNIP expression could be a poor prognostic marker.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.3955-3960
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• 2012

Objective: To investigate the effects of $CD4^+$, IL17 and Foxp3 expression on prognosis of operable non-small cell lung cancer (NSCLC) with different pTNM stages. Methods: Expression of $CD4^+$, IL17 and Foxp3 in 102 cases of NSCLC tissues and adjacent cancer tissues was detected by immunohistochemistry and associations with prognosis with different pTNM stages were analyzed. The Chi-square test was used to compare count data. Survival differences were evaluated by Kaplan-Meier single factor analysis and the COX regression model was used to analyze the relationship between influential factors and the disease prognosis. The significance level was ${\alpha}$=0.05. Results: Expression of CD4, IL-17 and Foxp3 significantly varied in different pTNM stages of NSCLC tissues (P < 0.05). The same was true for CD4 expression (P < 0.05). The median survival time (MST) in the positive CD4 expression group was evidently higher than that in the negative group (25.8/23.9 months). Compared with stage III, the MST difference of stages I and II in the positive CD4 expression group were statistically significant (P < 0.05). The MST in positive IL-17 and Foxp3 expression groups was obviously lower than that in the corresponding negative group (P < 0.05) (25.6/35.1 months and 24/35.3 months, respectively). There was a significant difference of MST between any two of three stages of positive IL-17 expression group (P < 0.05), and it was the same with positive Foxp3 expression group. TNM stage, negative CD4 expression, and positive IL-17 and Foxp3 expression were the main risk factors for the prognosis of NSCLC. Conclusion: Surgical prognosis of NSCLC can be better assessed by the combination of clinical staging and expression of IL17 and Foxp3.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7459-7465
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• 2014

Background: A prior study showed blood type A/AB to be associated with an increased risk of nasopharyngeal carcinoma (NPC) compared to subjects with blood type O. However, the relationship between ABO blood groups and prognosis of NPC patients is still questionable. In addition, whether Epstein-Barr virus (EBV) infection is associated with prognosis of NPC patients with different ABO blood groups is unclear. Materials and Methods: We conducted univariate and multivariable Cox regression analyses based on a consecutive cohort of 1,601 patients to investigate the above issues. Results: There was no significant difference in overall survival (OS) between different ABO blood groups (p=0.629), neither between A vs. non-A blood groups (p=0.895) nor AB vs. non-AB blood group (p=0.309) in univariate analyses and after adjusting for other factors. Interaction tests revealed that high immunoglobulin A against Epstein-Barr virus viral capsid antigen (VcA-IgA) level was associated with a favorable prognosis in male patients with UICC stage II disease who had an A blood type (p=0.008), compared with those with non-A blood type. In addition, male patients with an A blood group with a high blood lymphocyte level showeda tendency towards better survival in UICC stage III (p=0.096). Conclusions: ABO blood group status is not associated with the prognosis of patients with NPC. Additionally, blood group A male NPC patients with high VcA-IgA level or high blood lymphocyte counts might be correlated with a favorable prognosis in UICC stage II or III, respectively.

• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3613-3618
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• 2014

Stathmin, also called oncoprotein 18, is a founding member of the family of microtubule-destabilizing proteins that play a critical role in the regulation of mitosis. At the same time stathmin has been recognized as one of responsible factors in cancer cells. The aim of this study was to assess stathmin status, its correlations with clinicopathological parameters and its role as a progosnostic marker in EC patients. The protein and mRNA levels of stathmin were examined byimmunohistochemistry (IHC) and in situ hybridization in 100EC tissues and adjacent noncancerous tissues. mRNA and protein expression of stathmin in three EC cell lines(EC9706, ECa109, EC1 commonly used in research) were also analyzed using immunocytochemistry, western blot and in situ hybridization. The prognostic value of Stathmin expression within the tumor tissues were assessed by Cox regression and Kaplan-Meier analysis. We showed that stathmin expression was significantly higher in EC tissues than in adjacent noncancerous tissues. High stathmin immunostaining score in the EC was positively correlated with tumor differentiation, Tumor invasion, Lymph node metastases, and TNM stage. In addition, we demonstrated that three EC cell lines examined, were constitutively expressing a high level of stathmin. Of those, EC-1 showed the strongest mRNA and protein expression for the stathmin analyzed. Kaplan-Meier analysis showed that significantly longer 5-year survival rate was seen in EC patients with high Stathmin expression, compared to those with low expression of Stathmin expression. Furthermore, multivariate Cox proportional hazard analyses revealed that Stathmin was an independent factors affecting the overall survival probability. In conclusion, our data provide a basis for the concept that stathmin might be associated with EC development and progression. High levels of Stathmin expression in the tumor tissues may be a good prognostic marker for patients with EC.