• Radiation Oncology Journal
• /
• v.36 no.2
• /
• pp.139-146
• /
• 2018

Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%-5%, 5%-10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

• Korean Journal of Construction Engineering and Management
• /
• v.14 no.5
• /
• pp.84-91
• /
• 2013

In 2012, Korean overseas construction market has achieved 64.9 billion dollars of contract order and its amount has increased since the mid 2000's. However, importance of qualitative growth based on profitability as well as quantitative growth is also emphasized. This study analyzed overseas plant project's subcontract process management which is closely related to cost management as one of the qualitative growth methods. In order to select major subcontract processes, extensive literature review and focus group interview(FGI) were implemented and then professionals with years of experience in the overseas plant projects were participated in the questionnaire survey. The collected data were analyzed by Benefit-Structure Analysis(BSA) model. The findings of this study include: (1) the seven and six subcontract processes are positioned in the area of importance control factor and in the area of maintenance/control factor, respectively; (2) administration capability attainment is needed for the six subcontract processes in the area of importance control factor and sustainable management system is required for the processes in the maintenance/control factor area. The further research will identify key subcontract processes to be managed for overseas plant projects by Korean EPC contractors based on the findings of this research.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.4
• /
• pp.76-91
• /
• 2017

The Area of a domestic railway station is designed based on the 4-step traffic demand forecasting model with the average daily passenger count as one of its parameter. However, nowadays, due to increasing rate of railway station's function, the non-passengers are increasing. In order to consider those non-passengers who aren't using trains, assumed volume are added to the average daily passenger count of station to estimate the area, but the criteria being applied has no concrete basis. Therefore, this study aimed to recalculate the increasing non-passenger rate based on actual survey data of station users in any type of railway station to obtain the optimum area. Subsequently, the the design area was performed through pedestrian simulation. According to the result of the simulation, it was found that the total space of the exciting railway stations can be reduced up to 45% and will still satisfy the level of service(LOS) requirement.

• Journal of Digital Convergence
• /
• v.18 no.1
• /
• pp.129-135
• /
• 2020

This study examined the consumer response of the current O2O service between service types. Previous studies mainly focused on the quality factor of O2O service or Technology Acceptance Model or extended TAM, This study is different from the fact that there are differences in factors that consumers consider important and consumer reactions by service type. It is also significant that we compared between representative food delivery services and car sharing services that are actively used among O2O services. As O2O service is closely related to consumer's life, this study chose three factors that the issue of personal information security and trust of intermediary platform companies, and finally subjective norm based on individuals and groups who are aware of new O2O service. To test hypotheses, data were collected and analyzed for 301 samples, focusing on delivery and car sharing service, As a result, the delivery service among the O2O services was more positive to attitude toward service in the consumer group with lower personal information security, trust in platform, and subjective norm than car sharing service. Based on these results, implications and future research directions were presented.

• Journal of Korea Water Resources Association
• /
• v.46 no.4
• /
• pp.425-437
• /
• 2013

This study performed the bivariate drought frequency analysis for duration and severity of drought, using copula functions which allow considering the correlation structure of joint features of drought. We suggested the confidence intervals of duration-severity-frequency (DSF) curves for the given drought duration using stochastic scheme of monthly rainfall generation for 57 sites in Korea. This study also investigated drought risk via illustrating the largest drought events on record over 50 and 100 consecutive years. It appears that drought risks are much higher in some parts of the Nakdong River basin, southern and east coastal areas. However, such analyses are not always reliable, especially when the frequency analysis is performed based on the data observed over relatively short period of time. To quantify the uncertainty of drought frequency curves, the droughts were filtered by different durations. The 5%, 25%, 50%, 75%, and 95% confidence intervals of the drought severity for a given duration were estimated based on the simulated rainfall time series. Finally, it is shown that the growing uncertainties is revealed in the estimation of the joint probability using the two marginal distributions since the correlation coefficient of two variables is relatively low.

• Food Science and Preservation
• /
• v.14 no.5
• /
• pp.474-480
• /
• 2007

Response surface methodology (RSM) was employed to optimize extraction conditions preserving valuable functional properties of fluid Cheonggukjang obtained from red ginseng. Based on a central composite design, the study plan was established using variations in microwave power, ethanol concentration, and extraction time. Regression analysis was applied to obtain a mathematical model. A maximum electron donating ability (EDA) of 99.09% was obtained under the specific extraction conditions of microwave power 135.62 W, ratio of solvent to sample contents. 3.60 g/mL, and an extraction time of 11.79 min. The maximum inhibitory effect on tyrosinase activity was 10.02% at 119.16 W, 4.02 g/mL, and 5.57 min. The maximum superoxide dismutase (SOD)-like activity was 63.83% under the extraction conditions of 125.29 W, 4.04 g/mL, and 11.02 min. Based on superposition of four-dimensional RSM data obtained to optimize electron donating ability, nitrite-scavenging ability, inhibitory effect on tyrosinase activity, and SOD-like activity, the optimum ranges of extraction conditions were found to be a microwave power of $l{\sim}85 W$, a ratio of solvent to sample content of $1.4{\sim}2.8\;g/mL$, and an extraction time of $6.5{\sim}11\;min$.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.6
• /
• pp.1753-1764
• /
• 2014

Numerical flow simulation models in the riverine environments have been widely utilized for analyzing flow dynamics in various degrees in researches and practical applications. However, most of the simulated results have been validated based on the data from indoor experimental models or very limited in-situ measurements. Therefore, it has been required to more accurately validate the performance of the numerical models in terms of the detailed field observations. In particular, it was also hard to validate the performances of the existing numerical models in the real meandered river channels that encompass more sophisticated flow and geometric structures. Recently, advancements of the modern flow measuring instrumentations such as acoustic Doppler current profilers (ADCPs) enabled us to efficiently acquire the detailed flow field in the broad range of river channels, thus that it became to be possible to accurately validate any numerical models with the field observations. In this study, based on the detailed flow measurements in a actual meandered river channel using ADCP, we validated FaSTMECH model in iRIC in terms of water surface elevation, which is relatively new but began to get highlighted in the research areas. As the validation site, a meandering channel in River Experiment Center of KICT was chosen, which has 6.5 m of width, 0.38m of flow depth, 1.54 m3/s of flow discharge, 0.61 m/s of mean flow velocity, and 1.2 of sinuosity. As results, whereas the FaSTMECH precisely simulated water surface elevation, simulated velocity field in the bend did not match well with ADCP dataset.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.4
• /
• pp.705-716
• /
• 2017

As many environmental pollution problems have arisen, various studies related to the environmental evaluation have been carried out in the construction industry. However, there is no methodology for estimating the environmental load quickly for design alternatives of civil facilities in the design phase. This study aim to establish criteria of works information and designed parts which can efficiently estimate environmental loads of PSC beam bridge based on standard quantity at the early design phase. For this purpose, a detailed environmental loads database was constructed by performing Life Cycle Assessment (LCA) based on detailed design data of 25 bridges. In addition, major work with high impact on environmental load were selected, and the analysis of characteristics of environmental load according to the required materials and 8 impact categories were conducted. As a result, the superstructure accounted for 42.91%. In the superstructure, remicon of the material base and PSC beam work occupied 53.13% and 31.25%. In the substructure, remicon, rebar, and cement, which are material base, accounted for more than 93%. It is expected that this major work and material information for each part of bridge can be utilized in the construction of the model, which can estimate the approximate environmental load, reflecting the characteristics of the structure in the design phase.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.6
• /
• pp.67-73
• /
• 2014

Landslide disasters including debris flows are the one of the most frequent natural disasters in Korea, and losses of lives and property damages due to these catastrophic events have been increased every year. Various mitigation programs and related policies have been conducted in order to respond and prepare landslide disasters. Most landslide reduction programs are, however, focused on recovery actions after the disasters and lead to unrealistic consequences to the affected people and their properties. The main objective of this study, therefore, is to evaluate the landslide hazard based on the identification of geomorphological features, which is for the preparedness of the landslide disasters. Two methodologies, SINMAP and vector dispersion analyses are used to simulate those characteristics where landslides are actually located. Results showed that both methods well discriminate geomorphic features between stable and unstable domains. This proves that geomorphological characteristics well describe a relationship with the existing landslide hazard. SINMAP analysis which is based on the consecutive model considering external factors like infiltration is well identify the landslide hazard especially for debris flow type landslides rather than vector dispersion focusing on a specific area. Combining with other methods focusing specific characteristics of geomorphological feature, accurate landslide hazard assessments are implemented.

• Child Health Nursing Research
• /
• v.7 no.1
• /
• pp.85-95
• /
• 2001

The purpose of this study was to reveal what influences the divergent methodological researches have brought the nursing practice in during the past 3 decades. The nursing record sheets ie, the nursing discourses were analyzed to know the knowledges that were recorded, accepted and communicated in nursing practice at pediatric intensive care units, and unclosed the philosophical and methodological position of that knowledges. The texts were 13 sheets, 3 kinds of nursing record(7 24hours flow charts, 4 nursing information record sheets and 2 transfer record sheets) used at 4 hospitals. The unit of analysis was 'word'. First, all words of the sheets were listed up, clustered into categories based on their contents. And then, the larger conceptual themes were drawn to elucidate the effect of the knowledge/power and the philosophical and methodological position of that knowledges. To enhanced the validity of the analysis, the data were analyzed by two researchers. The 'words' were classified into 3 categories; 'general information', 'assessment' and 'inter-vention'. The conceptual themes of the texts were 'the gaze for quantification and objectification' and 'technical/assimilated caring'. This themes reflected the logic positivistic and biomedical view that had dominated at clinical practice. Nursing has endeavored to resist the logic-positivistic knowledge/power and to established the nursing knowledge/power based on multiple philosophies and methodologies, especially phenomenological-interpretative. But the results of this study revealed that such efforts in nursing theory and research couldn't influenced the knowledge of practice. Logic positivism was yet so strong and the biomedical model yet dominated in the clinical practice. It identified that the borrowed theory and the knowledge from the received view gave nursing the power. But they were modalities that reinforced the dominant, medical power. Nursing has investigate the other positions (feminism, Habermas' critical social theory and Foucault's discourse theory). This positions suggest different assumptions but share the common concepts; equality, emancipation and freedom. The important point is how make these concepts the practical for nursing knowledge/power in practice. We must recognize that the praxis at clinical setting take place at the field unlike theoretical praxis. The change of clinical practice is the social, economic and political change.