• Management Science and Financial Engineering
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• v.13 no.2
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• pp.141-157
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• 2007

In this paper, we address a design problem and a case study of a K-stage back-light-unit(BLU) inspection system, which is composed of K stages, each of which includes an inspection process and a rework process. Assuming the type I, II errors and the inspection-free policy for items classified as good, we determine the smallest integer of K which can achieve a given target defective rate. If K does not exist, holding the current values of the type I, II errors, we search reversely the defective rate of an assembly line and the defective rate of a rework process, to meet the target defective rate. Our formulae and methodology based on a K-stage inspection system could be applied and extended to similar situations with slight modification.

• Korean Journal of Head & Neck Oncology
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• v.15 no.1
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• pp.22-28
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• 1999

Purpose: We performed this study retrospectively to evaluate local control, survival, prognostic factors, and failure patterns in patients with non-Hodgkin's lymphoma of Waldeyer's ring. Materials and Methods: From April 1984 to November 1996,41 patients with non-Hodgkin's lymphoma of Waldeyer's ring were treated with combined chemotherapy and radiation therapy. Age was ranged from 19 to 73 years old with a median age of 55 years, and there were 26 male and 15 female patients. Primary site was tonsil in 26 and base of the tongue in 7 and nasopharynx in 8, and stage distribution showed stage I in 12 and stage II in 29 patients. Pathologic classification was done according to Working Formulation. There were 1 with follicular mixed small cleaved and large cell, 8 with diffuse small cleaved cell, 7 with diffuse mixed small and large cell, and 25 cases with diffuse large cell. All patients were treated with combination of chemotherapy and radiation therapy. Chemotherapy regimen consisted of either CHOP-Bleo(cyclophosphamide, adriamycin, vincristine, prednisolone, bleomycin) or COP-BLAM III(cyclophosphamide, vincristine, prednisolone, bleomycin, adriamycin, procarbazine). Radiation dose ranged from 3600cGy to 6620cGy with a median dose of 5040cGy. Follow-up time was ranged from 15 months to 159 months(median 55 months). Results: The complete response was achieved in 98%(40/41) and partial response in 2%(1/41). The complete response rate were the followings: 66.7% for stage I and 51.7% for stage II after chemotherapy, 100% for stage I and 96.6% for stage II after overall treatment respectively. The overall survival rate and disease-tree survival rates at 5 years were 82.6% and 79.5%, respectively. Prognostic factors for overall survival were age(p=0.007), stage(p=0.03), nodal status(p=0.006) and radiation dose(p=0.003). The factors associated with disease-tree survival were stage(p=0.04), nodal status(p=0.004) and radiation dose(p=0.009). The failure patterns were analized in evaluable 35 patients with complete response. Locoregional failure was noted in 2 patients and distant metastasis in 5 patients. Conclusion: Our results suggest that combined modality therapy is the appropriate treatment for stage I-II intermediate grade non-hodgkin's lymphoma of the Waldeyer's ring. However, our material is small and the analysis is retrospective. Randomized prospective studies for combined therapy, radiation therapy alone and chemotherapy alone are needed.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.108-115
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• 2002

Purpose : A retrospective study was undertaken to determine the role of conventional radiotherapy with or without surgery for treating a supraglottic carcinoma in terms of the local control and survival. Materials and Methods : From Jan. 1986 to Oct. 1996, a total of 134 patients were treated for a supraglottic carcinoma by radiotherapy with or without surgery. Of them, 117 patients who had completed the radiotherapy formed the base of this study. The patients were redistributed according to the revised AJCC staging system (1997). The number of patients of stage I, II, III, IVA, IVB were $6\;(5\%),\;16\;(14\%),\;53\;(45\%),\;32\;(27\%),\;10\;(9\%)$, respectively. Eighty patients were treated by radical radiotherapy in the range of $61.2\~79.2\;Gy$ (mean : 69.2 Gy) to the primary tumor and $45.0\~93.6\;Gy$ (mean : 54.0 Gy) to regional lymphatics. All patients with stage I and IVB were treated by radiotherapy alone. Thirty-seven patients underwent surgery plus postoperative radiotherapy in the range of $45.0\~68.4\;Gy$ (mean : 56.1 Gy) to the primary tumor bed and $45.0\~59.4\;Gy$ (mean : 47.2 Gy) to the regional lymphatics. Of them, 33 patients received a total laryngectomy (${\pm}lymph$ node dissection), three had a supraglottic horizontal laryngectomy (${\pm}lymph$ node dissection), and one had a primary excision alone. Results : The 5-year survival rate (5YSR) of all patients was $43\%$. The 5YSRs of the patients with stage I+II, III+IV were $49.9\%,\;41.2\%$, respectively (p=0.27). However, the disease-specific survival rate of the patients with stage I (n=6) was $100\%$. The 5YSRs of patients who underwent surgery plus radiotherapy (S+RT) vs radiotherapy alone (RT) in stage II, III, IVA were $100\%\;vs\;43\%$ (p=0.17), $62\%\;vs\;52\%$ (p=0.32), $58\%\;vs\;6\%$ (p<0.001), respectively. The 5-year actuarial locoregional control rate (5YLCR) of all the patients was $57\%$. The 5YLCR of the patients with stage I, II, III, IVA, IVB was $100\%,\;74\%,\;60\%,\;44\%,\;30\%$, respectively (p=0.008). The 5YLCR of the patients with S+RT vs RT in stage II, III, IVA was $100\%\;vs\;68\%$ (p=0.29), $67\%\;vs\;55\%$ (p=0.23), $81\%\;vs\;20\%$ (p<0.001), respectively. In the radiotherapy alone group, the 5YLCR of the patients with a complete, partial, and minimal response were $76\%,\;20\%,\;0\%$, respectively (p<0.001). In all patients, multivariate analysis showed that the N-stage, surgery or not, and age were significant factors affecting the survival rate and that the N-stage, surgery or not, and the ECOG performance index were significant factors affecting the locoregional control. In the radiotherapy alone group, multivariate analysis showed that the radiation response and N-stage were significant factors affecting the overall survival rate as well as locoregional control. Conclusion : In early stage supraglottic carcinoma, conventional radiotherapy alone is an equally effective modality compared to surgery plus radiotherapy and could preserve the laryngeal function. However, in the advanced stages, radiotherapy combined with concurrent chemotherapy for laryngeal preservation or surgery should be considered. In bulky neck disease, all the possible planned neck dissections after induction chemotherapy or before radiotherapy should be attempted.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.771-774
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• 2016

Thymic tumors are the most common tumors in the anterior mediastinum. Total resection is the main treatment and predictor of longer survival. Adjuvant radiotherapy alone or in combination with chemotherapy is recommended with incomplete excision or advanced disease. Thirty seven patients with thymic tumors were included in this retrospective study from January 2001 till December 2012. They were studied regarding age, sex, performance status, tumor size and invasion, stage, pathology, treatment given, overall and progression free survival. Myasthenia gravis was present in 18.1% of the patients. Masaoka stage III was diagnosed in 40.5% of the cases followed by stage II in 24.3% and the other stages with lower percentages. Pathology type B3 was the most frequent followed by B2 and B1 with percentages of 27, 24.3 and 21.7 respectively. Complete resection was conducted in 11 cases (29.75%). Partial resection or debulking was done in 15 (40.5%) and a biopsy was taken in 11 cases (29.8%) Adjuvant chemotherapy was given to 14 patients (37.8%) and neoadjuvant to 13 (35.2%). Adjuvant radiotherapy was given to 17 patients (46%) and neoadjuvant to 14 (37.8%). The 5-year overall survival by was 83% for stage I, 71% for stage II, 60% for stage III, and 44% for stage IV (p=0.0426). Five year progression free survival was 71% for stage I, 62% stage II, 42% stage III, and 37% for stage IV (p=0.0532). In conclusion with the rare thymic tumors early stage and complete resection have the highest impact on overall and progression free survival.

• Korean Journal of Environment and Ecology
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• v.20 no.4
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• pp.464-472
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• 2006

To investigate the forest structure and to suggest a basic management data of the forest in the Kumsaenggol area of Wolchulsan National Park, thirty plots were set up and surveyed. According to the analysis of classification by TWINSPAN, the community was divided into the four groups of Quercus variabilis(I), Q. acutissima(II), Pinus densiflora(III) and P. densiflora-Q. acutissima(IV). From the results of the above, it could be determined that communities I and II were in a developmental stage of the ecological succession, in which the Quercus app. community progressed from Pinus densiflora. Additionally, communities III and IV are also in a developmental stage and will be expected to show competition regarding Pinus densiflora.

• Journal of the Mineralogical Society of Korea
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• v.29 no.3
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• pp.141-153
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• 2016

The Manjang deposit is emplaced in Hwajeonri formation comprising limestone that is interbeded with slate and phyllite in the central Okcheon Group. It consists of the Main and the Central orebody of Cu-bearing hydrothermal vein deposit and the Western orebody of iron skarn deposit. Based on coexisting mineral assemblage the skarnization can be divided into prograde skarnization (stage I : clinopyroxene ${\pm}$ magnetite ${\pm}$ quartz, stage II : garnet + clinopyroxene ${\pm}$ magnetite ${\pm}$ quartz) and retrograde hydrothermal alteration (stage III: magnetite + amphibole + quartz ${\pm}$ garnet ${\pm}$ clinopyroxene ${\pm}$ chlorite ${\pm}$ epidote ${\pm}$ fluorite ${\pm}$ calcite, stage IV: fluorite ${\pm}$ pyrrhotite ${\pm}$ chalcopyrite ${\pm}$ amphibole ${\pm}$ quartz ${\pm}$ calcite). Diopside is abundant in stage I, and hedenbergite was produced in stage II and III. Garnet compositions change from grandite to andradite, which suggests a redox transition from relatively reduced to oxidized condition during the skarn formation. Magnetite in stage I and II has relatively constant Fe contents, while in the stage III it has increased Si and Ca concentrations. This variation could indicate that magnetite was more strongly affected by host rocks during the retrograde stage. Sulfur isotope compositions of pyrrhotite and chalcopyrite produced in stage IV are within the range of + 5.9~6.9 ‰, corresponding to igneous origin, but slightly high sulfur isotope values could be attributed to an interaction with host rocks, limestone.

• Journal of the Korean Arthroscopy Society
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• v.9 no.2
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• pp.206-213
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• 2005

Purpose: To evaluate the outcome of symptomatic osteochondritis dissecans of the talus treated with arthroscopic debridement and multiple drilling. Materials and Methods: Between 1997 and 2003, 14 arthroscopic debridement(group I) and 15 arthroscopic multiple drilling(group II) were performed. There are 21 male and 8 female patients. Mean age was 34.4 years(33.8 years in group I, 37.5 years in group II) and average follow-up period was 43.2 months(46.4 months in group I, 40.1 months in group II). Simple radiographs and MRI were performed preoperatively and postoperatively, and the progressive stage of the lesions was evaluated through the arthroscopic surgery. Clinical results were evaluated with ankle-hindfoot scale and scoring scale for subjective and objective functional outcomes. The results were compared between 2 groups. Results: There are 20 medial(7 in group I, 13 in group II), 6 lateral(5 in group I, 1 in group II), and 3 both-side(2 in group I, 1 in group II) lesions. According to the classification of Berndt and Harty, there are 4 stage II(4 in group I, 0 in group II), 19 stage III(9 in group I, 10 in group II), and 6 stage IV(1 in group I, 5 in group II). According to the ankle-hindfoot score, the mean score was significantly improved $53.1{\pm}2.7$ points preoperatively to $85.1{\pm}8.5$ points postoperatively in group I and $54.6{\pm}6.8\;to\;80.7{\pm}8.5$ points group II. Subjective and functional scores was also improved $49.6{\pm}10.5$ points preoperatively to $84.6{\pm}7.7$ points postoperatively in group I and $50.7{\pm}9.2\;to\;83.0{\pm}9.6$ points in group II. But there were no statistical significance between them. Conclusion: Arthroscopic debridement and multiple drilling for the treatment of osteochondral lesions of the talus showed successful results and there was no statistically significant difference between them.

• Journal of Korean Medical Science
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• v.33 no.43
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• pp.277.1-277.10
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• 2018

Background: To examine survival rates and renal function after partial nephrectomy (PN) and radical nephrectomy (RN) in patients with chronic kidney disease (CKD). Methods: We studied 4,332 patients who underwent PN or RN for pathological T1a-T2N0M0 renal cell carcinoma from 1988 to 2014. Patients were divided into two subgroups of CKD stage I-II and stage III. Kidney function, and survival outcomes were compared between groups. Results: We included 1,756 patients with CKD I-II and 276 patients with CKD III in the final pair-matched analysis. Kidney function was significantly better preserved in the PN than in the RN group among all patients. However, the beneficial effect of PN on kidney function gradually disappeared over time in CKD III patients. The 5-year overall survival (OS) rates after PN and RN differed in patients with CKD I-II disease (99.4% vs. 96.5%, respectively, P = 0.015). The 5-year OS rates after surgery were not affected by mode of nephrectomy in CKD III patients (97.8% vs. 93.5%, P = 0.103). The 5-year cancer-specific survival rates did not differ between treatment groups in all CKD stage. Cox hazard analysis showed that the operative method was a significant factor for OS in CKD I-II patients (hazard ratio [HR], 0.320; confidence interval [CI], 0.122-0.840; P = 0.021). However, PN was not beneficial in terms of OS in CKD III patients (HR, 0.395; CI, 0.086-1.172; P = 0.117). Conclusion: PN is associated with a higher OS rate and better kidney function in patients with preoperative CKD stage I and II, but not in those with CKD stage III.

• Journal of Chest Surgery
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• v.23 no.4
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• pp.715-719
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• 1990

Thymoma is defined as a neoplasm of the epithelialreticular framework cells of the thymus. The treatment of choice and the prognosis for patients with thymoma are still controversial subjects due to lack of a uniform histological classification and standardized criteria for typing thymic tumors. Between June 1985 and May 1989, eight patients underwent thymomectomy at the Department of Thoracic and Cardiovascular Surgery, Korea University Medical Center. A clinical analysis was performed and the following result was obtained. In histologic cell type, epithelial type was 2 cases, lymphocytic type 3 cases, and mixed type was 3 cases. The clinical stage was classified by Masaoka’s classification that Stage I was 4 cases, Stage II; 2 cases, Stage III; 2 cases and Stage IV was none. Myasthenia Gravis was associated with thymoma in 5 patients. In 8 patients, thymomectomy were performed. Adjuvant radiotherapy was performed in one patient with Stage I due to suspicious tumor remnant and in Stage II, III patients routinely. Combined chemotherapy was performed in one patient with Stage III due to local recurrence. We concluded that the most important prognostic factor of thymoma is extent of tumor invasion. And the presence of Myasthenia Gravis is no more prognostic factor. Surgical resection of thymoma is treatment of choice, If local invasion or distant dissemination is present, postoperative radiotherapy and /or combined chemotherapy is recommended.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.247-256
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• 2008

Purpose: The purpose of this study is to evaluate anal sphincter preservation rates, survival rates, and prognostic factors in patients with rectal cancer treated with preoperative chemoradiotherapy. Materials and Methods: One hundred fifty patients with pathologic confirmed rectal cancer and treated by preoperative chemoradiotherapy between January 1999 and June 2007. Of the 150 patients, the 82 who completed the scheduled chemoradiotherapy, received definitive surgery at our hospital, and did not have distant metastasis upon initial diagnosis were enrolled in this study. The radiation dose delivered to the whole pelvis ranged from 41.4 to 46.0 Gy (median 44.0 Gy) using daily fractions of $1.8{\sim}2.0\;Gy$ at 5 days per week and a boost dose to the primary tumor and high risk area up to a total of $43.2{\sim}54\;Gy$ (median 50.4 Gy). Sixty patients (80.5%) received 5-fluorouracil, leucovorin, and cisplatin, while 16 patients (19.5%) were administered 5-fluorouracil and leucovorin every 4 weeks concurrently during radiotherapy. Surgery was performed for 3 to 45 weeks (median 7 weeks) after completion of chemoradiotherapy. Results: The sphincter preservation rates for all patients were 73.2% (60/82). Of the 48 patients whose tumor was located at less than 5 cm away from the anal verge, 31 (64.6%) underwent sphincter-saving surgery. Moreover, of the 34 patients whose tumor was located at greater than or equal to 5 cm away from the anal verge, 29 (85.3%) were able to preserve their anal sphincter. A pathologic complete response was achieved in 14.6% (12/82) of all patients. The downstaging rates were 42.7% (35/82) for the T stage, 75.5% (37/49) for the N stage, and 67.1% (55/82) for the overall stages. The median follow-up period was 38 months (range $11{\sim}107$ months). The overall 5-year survival, disease-free survival, and locoregional control rates were 67.4%, 58.9% and 84.4%, respectively. The 5-year overall survival rates based on the pathologic stage were 100% for stage 0 (n=12), 59.1% for stage I (n=16), 78.6% for stage II (n=30), 36.9% for stage III (n=23), and one patient with pathologic stage IV was alive for 43 months (p=0.02). The 5-year disease-free survival rates were 77.8% for stage 0, 63.6% for stage I, 58.9% for stage II, 51.1% for stage III, and 0% for stage IV (p<0.001). The 5-year locoregional control rates were 88.9% for stage 0, 93.8% for stage I, 91.1% for stage II, 68.2% for stage III, and one patient with pathologic stage IV was alive without local recurrence (p=0.01). The results of a multivariate analysis with age (${\leq}55$ vs. >55), clinical stage (I+II vs. III), radiotherapy to surgery interval (${\leq}6$ weeks vs. >6 weeks), operation type (sphincter preservation vs. no preservation), pathologic T stage, pathologic N stage, pathologic overall stage (0 vs. I+II vs. III+IV), and pathologic response (complete vs. non-CR), only age and pathologic N stage were significant predictors of overall survival, pathologic overall stage for disease-free survival, and pathologic N stage for locoregional control rates, respectively. Recurrence was observed in 25 patients (local recurrence in 10 patients, distant metastasis in 13 patients, and both in 2 patients). Acute hematologic toxicity ($\geq$grade 3) during chemoradiotherapy was observed in 2 patients, while skin toxicity was observed in 1 patient. Complications developing within 60 days after surgery and required admission or surgical intervention, were observed in 11 patients: anastomotic leakage in 5 patients, pelvic abscess in 2 patients, and others in 4 patients. Conclusion: Preoperative chemoradiotherapy was an effective modality to achieve downstaging and sphincter preservation in rectal cancer cases with a relatively low toxicity. Pathologic N stage was a statistically significant prognostic factor for survival and locoregional control and so, more intensified postoperative adjuvant chemotherapy should be considered in these patients.