• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.71-82
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• 2006

One of the most popular pre-reinforcement methods of tunnel heading in cohesionless soils would be the fore-polling of grouted pipes, known as RPUM (reinforced protective umbrella method) or UAM (umbrella arch method). This technique allows safe excavation even in poor ground conditions by creating longitudinal arch parallel to the tunnel axis as the tunnel advances. Some previous studies on the reinforcing effects have been performed using numerical methods and/or laboratory-based small scale model tests. The complexity of boundary conditions imposes difficulties in representing the tunnelling procedure in laboratory tests and theoretical approaches. Full-scale study to identify reinforcing effects of the tunnel heading has rarely been carried out so far. In this study, a large scale model testing for a tunnel in granular soils was performed. Reinforcing patterns considered are four cases, Non-Reinforced, Crown-Reinforced, Crown & Face-Reinforced, and Face-Reinforced. The behavior of ground and pipes as reinforcing member were fully measured as the surcharge pressure applied. The influences of reinforcing pattern, pipe length, and face reinforcement were investigated in terms of stress and displacement. It is revealed that only the Face-Reinforced has decreased sufficiently both vertical settlement in tunnel heading and horizontal displacement on the face. Vertical stresses along the tunnel axis were concentrated in tunnel heading from the test results, so the heading should be reinforced before tunnel advancing. Most of maximum axial forces and bending moments for Crown-reinforced were measured at 0.75D from the face. Also it should be recommended that the minimum length of the pipe is more than l.0D for crown reinforcement.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1591-1604
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• 2023

In ocean color remote sensing, atmospheric correction is a vital process for ensuring the accuracy and reliability of ocean color products. Furthermore, in recent years, the remote sensing community has intensified its requirements for understanding errors in satellite data. Accordingly, research is currently addressing errors in remote sensing reflectance (R_rs) resulting from inaccuracies in meteorological variables (total ozone, pressure, wind field, and total precipitable water) used as auxiliary data for atmospheric correction. However, there has been no investigation into the error in R_rs caused by the variability of the water vapor profile, despite it being a recognized error source. In this study, we used the Second Simulation of a Satellite Signal Vector version 2.1 simulation to compute errors in water vapor transmittance arising from variations in the water vapor profile within the GOCI-II observation area. Subsequently, we conducted an analysis of the associated errors in ocean color products. The observed water vapor profile not only exhibited a complex shape but also showed significant variations near the surface, leading to differences of up to 0.007 compared to the US standard 62 water vapor profile used in the GOCI-II atmospheric correction. The resulting variation in water vapor transmittance led to a difference in aerosol reflectance estimation, consequently introducing errors in R_rs across all GOCI-II bands. However, the error of R_rs in the 412-555 nm due to the difference in the water vapor profile band was found to be below 2%, which is lower than the required accuracy. Also, similar errors were shown in other ocean color products such as chlorophyll-a concentration, colored dissolved organic matter, and total suspended matter concentration. The results of this study indicate that the variability in water vapor profiles has minimal impact on the accuracy of atmospheric correction and ocean color products. Therefore, improving the accuracy of the input data related to the water vapor column concentration is even more critical for enhancing the accuracy of ocean color products in terms of water vapor absorption correction.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.121-128
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• 1997

Purpose : To evaluate the effect of postoperative adjuvant radiation therapy and chemotherapy on the survival, pattern of failure and complication for locally advanced rectal carcinoma Materials and Methods : From October 1992 to September 1995, twenty eight patients with rectal carcinoma were treated by postoperative adjuvant radiation therapy and chemotherapy Radiation therapy was delivered with 6MV and 15MV linear accelerator, 180c0y fractions 5 day per week. Total radiation doses were 5040cGy in $B_{2+3}$ and 5580cGy in $C_{2+3}$. Within 4 weeks after radical surgery. 5-FU$(400mg/m^2/day)\;and\;Leucovorin(20mg/m^2/day)$ were administered by intravenous injection for 4 days during the first and fifth week of radiation therapy. The median follow up was 19 months with a range 2 to 47 months. Results : The 2 year overall survival and disease free survival rates were $78.6\%\;and\;70.8\%$, respectively. The 2 year overall survival was $93.0\%\;in\;B_{2+3}$ and $76.2\%\;in\;C_{2+3}$(p=0.11) The 2 year disease free survival was $79.4\%\;in\;B_{2+3}\;and\;69.2\%\;in\;C_{2+3}(p=0.13)$. The overall failure rate was $21.42\%$(6/28) including $10.72\%$(3/28) locoregional recurrence, $3.62\%$(1/28) distant metastasis and $7.12\%$(2/28) locoregional recurrence with distant metastasis. The overall locoregional recurrence rate was $17.92\%$(5/28). The 2 year locoregional recurrence rates were $13.32\%(2/15)\;and\;23.12\%$(3/13) for respectively for $B_{2+3}\;and\;C_{2+3}$ The difference between the locoregional recurrence of $B_{2+3}\;and\;C_{2+3}$ patients was not significant(p=0.07). Complications developed in 13 patients$(46.42\%)$, including 8 dermatitis, 7 loose stool, 6 leukopenia, 4 tenesmus, 2 diarrhea. In Univariate analysis, there was no statistically significant factor except for tumor grade in locoregional recurrence, disease free survival and overall survival rate(p=0.04, 0.05, 0.04). Conclusion : This study sugges1s that postoperative adjuvant radiation therapy and chemotherapy is effective in patients with locally advanced rectal cancer. Therefore these results need to be confirmed with a long term follow-up and larger number of patients with the further clinical trials including prospective controlled studies.

• Radiation Oncology Journal
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• v.25 no.2
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• pp.70-78
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• 2007

[ $\underline{Purpose}$ ]: This study analyzed the tumor response, overall survival, progression free survival and related prognostic factors in patients with muscle invasive bladder cancer subjected to bladder preserving treatment. $\underline{Materials\;and\;Methods}$: Between August 1995 and June 2004, 37 patients with muscle invasive (transitional cell carcinoma, clinically stage T2-4) bladder cancer were enrolled for the treatment protocol of bladder preservation. There were 33 males and 4 females, and the median age was 67 years (range $38{\sim}86\;years$). Transurethral resection of the bladder (TURB) was performed in 17 patients who underwent complete resection. The median radiation dose administered was 64.8 Gy (range $55.8{\sim}67\;Gy$). The survival rate was calculated by the Kaplan-Meier method. $\underline{Results}$: An evaluation of the response rate was determined by abdomen-pelvic CT and cystoscopy at three months after radiotherapy. A complete response was seen in 17 patients (46%). The survival rate at three years was 54.7%, with 54 months of median survival (range $3{\sim}91$ months). During the study, 17 patients died and 13 patients had died from bladder cancer. The progression free survival rate at three years was 37.2%. There were 24 patients (64.9%) who had disease recurrence: 16 patients (43.2%) had local recurrence, 6 patients (16.2%) had a distant recurrence, and 2 patients (5.4%) had both a local and distant recurrence. The survival rate (p=0.0009) and progression free survival rates (p=0.001) were statistically significant when compared to the response rate after radiotherapy. $\underline{Conclusion}$: The availability of complete TURB and appropriate chemoradiotherapy were important predictors for bladder preservation and survival.

• Tuberculosis and Respiratory Diseases
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• v.64 no.6
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• pp.433-438
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• 2008

Background: Measurement of the maximum oxygen uptake in patients with chronic obstructive pulmonary disease (COPD) has been used to determine the intensity of exercise and to estimate the patient's response to treatment during pulmonary rehabilitation. However, cardiopulmonary exercise testing is not widely available in Korea. The 6-minute walk test (6MWT) is a simple method of measuring the exercise capacity of a patient. It also provides high reliability data and it reflects the fluctuation in one' s exercise capacity relatively well with using the standardized protocol. The prime objective of the present study is to develop a regression equation for estimating the peak oxygen uptake ($VO_2$) for men with moderate to very severe COPD from the results of a 6MWT. Methods: A total of 33 male patients with moderate to very severe COPD agreed to participate in this study. Pulmonary function testing, cardiopulmonary exercise testing and a 6MWT were performed on their first visits. The index of work ($6M_{work}$, 6-minute walk distance [6MWD]${\times}$body weight) was calculated for each patient. Those variables that were closely related to the peak $VO_2$ were identified through correlation analysis. With including such variables, the equation to predict the peak $VO_2$ was generated by the multiple linear regression method. Results: The peak $VO_2$ averaged $1,015{\pm}392ml/min$, and the mean 6MWD was $516{\pm}195$ meters. The $6M_{work}$ (r=.597) was better correlated to the peak $VO_2$ than the 6MWD (r=.415). The other variables highly correlated with the peak $VO_2$ were the $FEV_1$ (r=.742), DLco (r=.734) and FVC (r=.679). The derived prediction equation was $VO_2$ (ml/min)=($274.306{\times}FEV_1$)+($36.242{\times}DLco$)+($0.007{\times}6M_{work}$)-84.867. Conclusion: Under the circumstances when measurement of the peak $VO_2$ is not possible, we consider the 6MWT to be a simple alternative to measuring the peak $VO_2$. Of course, it is necessary to perform a trial on much larger scale to validate our prediction equation.