• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.898-906
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• 2019

In this study, basic research was conducted to provide guidelines for selecting fluorescent dye and using proper concentration of fluorescent dye to use evaluation of cell viability and fluorescent dye delivery efficiency. Propidium iodide and Yo-Pro-1 were used as fluorescent dyes. In the evaluation of cell viability and the efficiency of delivery using Propidium Iodide and Yo-Pro-1, the histogram of each fluorescent dye was different depending on the type of fluorescent dye and the concentration used. These results were related to the characteristics of the fluorescent dyes used. This was related to the properties of the fluorescent dyes used. From these results, it was found that the analytical results depending on the characteristics of the fluorescent dyes used in the cell analysis. The effect of the fluorescent dye on the cell was confirmed, but it was confirmed that it did not affect the analysis result. In addition, the influence of interference between fluorescent signals was confirmed when two or more kinds of fluorescent dyes were used for analysis. The higher the concentration of Yo-Pro-1 was, the larger the effect of interference was, and the concentration of Propidium Iodide did not affect the interference of fluorescence signal. This study confirmed that the evaluation of the cell viability and the evaluation of the delivery efficiency were influenced by the type and concentration of the fluorescent dyes and it was related to the characteristics of the fluorescent dyes. Based on the results, appropriate concentrations of fluorescent dyes suitable for evaluation of cell viability and delivery efficiency were suggested.

• Food Science and Preservation
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• v.24 no.7
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• pp.1034-1042
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• 2017

The quality characteristics of Yakju and survival rate of yeast were investigated by modifying the drying method for the cold adapted yeast strain Saccharomyces cerevisiae Y297 (SCY297). Viability and fermentation characteristics of the freeze-dried, air blast-dried, and liquid SCY297 cultures were compared after storing them at $25^{\circ}C$. In addition, 5% skimmed milk, ${\alpha}$-lactose, or trehalose was added as a protective agent for examining the effects of drying methods. During the 15-week storage period, the liquid and freeze-dried SCY297 cultures containing a protective agent showed a survival rate of 80%. However, the air blast-dried SCY297 culture showed 80% survival rate only in the skimmed milk supplemented group. Compared to the untreated cells, the acidity and amino acidity of Yakju prepared using freeze-dried or air blast-dried cultures of SCY297 increased by 2 fold and 5.7 fold respectively, while the alcohol content decreased by 5.07%. Compared to the untreated cells, the pH and amino acidity of Yakju prepared using the liquid culture of SCY297 increased by 1.5 fold and 2.5 fold respectively. Although the alcohol content decreased by 2.9%, decrease rate was lower than that observed for the freeze-dried and air blast-dried yeast cultures. Therefore, the results of this study showed that using a liquid starter culture was more advantageous than using the conventional solid culture.

• Journal of Technology Innovation
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• v.23 no.4
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• pp.205-244
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• 2015

In response to the recent rapid technological and market changes, the importance of the design of ambidextrous organization has been increasingly emphasized as one of the dynamic capabilities. Firms that show a high performance in the rapid technological and market changes appear to design and implement ambidextrous organization successfully. They have achieved both exploitative competence for continuous innovation with product development and exploratory competence for discontinuous innovation with new market and new technologies. We have examined why and how to design and operate ambidextrous organizations and the effects of ambidextrous organizational characteristics on the performance from structural, contextual and leadership perspectives. We conducted case studies on 3 Korean firms that showed different characteristics of industrial product, company size, etc. Longitudinal case studies exhibit different processes of design and operating ambidextrous organization according to innovative strategy and industrial characteristics.

• Journal of Technology Innovation
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• v.26 no.4
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• pp.98-121
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• 2018

This article analyzes the survival of Korean software firms from 1995 to 2015 by Cox regression model and product-limit method. The results show that survival rates are different for each sector: IT service, package software, game software and internet service. In addition, firm growth and investment in research and development positively affect software firm's survival, while slack resources negatively affect the software firm's survival. The implication of this study is that characteristics of the software industry and technologies should be taken into consideration in survival strategy of software firms and government policy. Previous research on survival analysis has been mainly conducted in the manufacturing industry or at the special circumstance such as the foreign exchange crisis of Korea in the late 1990s. The contribution of this study is that expanding the survival analysis to software firms in Korea which are becoming more important recently.

• Journal of Industrial Convergence
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• v.21 no.1
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• pp.111-122
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• 2023

The purpose of this study is to verify the factors affecting survival time by estimating survival rate and survival time using non-financial information of social enterprises using credit guarantee in credit guarantee institutions, and provide information to stakeholders to improve survival rate and employ to contribute to maintaining and expanding the As a research method, survival analysis was performed using a non-parametric analysis method, Kaplan-Meier Analysis. As a sample, 621 companies (577 normal companies, 44 insolvent companies) established between 2009 and 2018 were selected as the target companies. As a result of examining the factors affecting survival time by classifying social enterprise representative information and corporate information, representative credit rating, representative home ownership, credit transaction period, and corporate credit rating were derived as significant variables affecting survival time. In the future, financial institutions will be able to induce corporate soundness by reflecting factors that affect survival when examining loans for social enterprises, contributing to job retention and reduction of social costs. Supporting organizations such as the government and private organizations will be able to use it in various ways, such as policy establishment and education and training for the growth and sustainability of social enterprises. With this study as an opportunity, I hope that research will continue with more interest in the factors influencing social enterprise performance as well as corporate insolvency.

• Journal of the Korean Society for information Management
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• v.35 no.2
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• pp.115-139
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• 2018

Due to the value and the importance of preservation of disaster web records, to build disaster archives is globally becoming a national challenge. This study proposes a acquisition methods based on the issue life cycle model for collecting disaster web records. We firstly analyzed web records acquisition status, methods and period of domestic and foreign disaster archives. In addition, the issue life cycle model was derived by collecting and analyzing the disaster issues in the last 10 years. As the results of the analysis, the issue life cycle model was divided into the sudden type and periodic type according to the characteristics of the disaster. In conclusion, this study propose a method to collect web records according to each model and verify its applicability.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.3
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• pp.132-139
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• 2002

The implementation of passive optical network in the access network will result in design of the network that have characteristics of broadband, long distance transmission, transparency. Particularly, optical technologies of WDM and WGR have made a new access network of WDM-PON. This paper proposes the algorithm that determines structural elements of a survivable optical access network, and simulates the cost of various scheme of proposed network architectures. Our results show that multistage star is the most cost effective scheme than the other architectures and show that network architecture designed by proposed algorithm provides survivability with single link and 1st node failure.

• Korean Journal of Head & Neck Oncology
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• v.7 no.1
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• pp.45-51
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• 1991

최근 횡문근육종을 치료함에 있어서 수술적 요법, 방사선 치료, 강암 약물요법을 적절히 병행함으로써 치료에 따르는 후유증을 극소화하면서 괄목할만한 생존율 향상을 가져오게 되었다. 특히 두경부의 횡문근육종은 소아에서 다발하고 병소의 위치에 따라서 각각 다른 임상적 특성을 가지며 수술적 절제를 했을 때 기능 및 외견상 결손이 크므로 별도의 연구 대상이 되어 왔으며 수술적 방법보다는 방사선 치료 및 항암 약물요법이 강조되고 있다. 저자들은 1976년부터 1987년까지 두경부 횡문근육종으로 진단받고 연세 암센터에서 항암 약물요법 및 방사선 치료를 받은 22명의 환자를 대상으로 하여 발생 부위, 조직 병리, 병기별 분포 및 생존율, 치료 방법에 따른 생존율을 후향성으로 분석하였다. 22명의 환자중 10 세 미만이 12 예로 가장 많았고, 13명이 배아세포형이였으며, 임상병기는 병기 III 이 가장 많아서 14 예였다. 병소의 위치는 안와가 6명으로 가장 많았고, 뇌수막주변부가 7명 (상악동 3명, 중이도 2명, 비강 l명, 비인강 1명), 기타 9명 (경부 5명, 이하선 2명, check 2명) 이었다. 5년 무병 생존율은 안와 종양에서 가장 높아서 50% 였고, 안와외 두경부가 37.5%, 뇌수막주변부가 16.7% 로 가장 낮았으며, 낮은 병기(병기 III), 배아세포형, 항암 약물 요법 병용군에서 상대적으로 높은 생존율이 관찰되었다.

• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.35-47
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• 2022

The receiver operating characteristic (ROC) curve was developed to quantify the classification ability of marker values (covariates) on the response variable and has been extended to survival data with diverse missing data structure. When survival data is understood as binary data (status of being alive or dead) at each time point, the ROC curve expressed at every time point results in time-dependent ROC curve and time-dependent area under curve (AUC). In particular, a follow-up study brings the change of cohort and incomplete data structures such as censoring and competing risk. In this paper, we review time-dependent ROC estimators under several contexts and perform simulation to check the performance of each estimators. We analyzed a dementia dataset to compare the prognostic power of markers.

• Clinical and Experimental Pediatrics
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• v.48 no.9
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• pp.939-945
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• 2005

Purpose : The purpose of this study was to report outcome of fetal infants with birth weight below 500 g known as lower limit of viability and to evaluate treatment characteristics and short-term morbidity of their survivors. Methods : We retrospectively analyzed the medical records of all fetal infants with birth weight below 500 g who were delivered at Samsung Medical Center(SMC), or transferred to neonatal intensive care unit(NICU) of SMC within 24 hrs after birth between 1994 and 2004. Data for all interventions and morbidity outcome were analyzed for infants who were admitted to the NICU and were compared between NICU survivors and deaths. Results : Among 53 infants with birth weights of 400 to 499 g who were born in SMC during the study period, 8(15.1%) infants were admitted to the NICU and one was transferred to NICU from other hospital. Overall, 4(44%) of 9 survived and were discharged from the NICU. The smallest infant who survived weighed 439 grams. The least gestational age was $23^{+3}$ among the survivors. Compared with NICU deaths, NICU survivors had larger gestational age($24^{+2}{\pm}1^{+3}$ vs. $25^{+4}{\pm}2^{+3}$) and birth weight($424{\pm}17$ vs. $453{\pm}19$)(P<0.05). Median survival duration of NICU deaths was 15 days. None of NICU survivors had severe IVH, but 3(75%) had laser therapy for retinopathy of prematurity and bronchopulmonary dysplasia, respectively. Conclusion : Fetal infants with birth weight below 500 g known as lower limit of viability survived successfully. Study for their long-term follow-up will be needed to define our limit of viability and indication for their active resuscitation.