• Economic and Environmental Geology
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• v.41 no.6
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• pp.657-672
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• 2008

The purposes of this study are to investigate the hydrogeochemical characteristics of groundwaters around Keumsan municipal landfill, and to evaluate the contaminant dispersion from the landfill and its environmental impact. To achieve these goals, groundwater quality logging, hydrochemical analysis, multivariate statistical analysis, and contaminant transport modeling were performed. The water quality logging indicated a leaking from the landfill at the depth of 4-12m around a leachate sump. Electrical conductivity data indicated that groundwaters within 70-100m from landfill were affected by the landfill leakage. Principal components 1 and 2 obtained from principal components analysis (PCA) reflect the influence of leachate and the characteristics of aquifer media, respectively. The results of principal component analysis also indicated the natural attenuation processes such as cation exchange, sorption, and microbial biodegradation. The modeling results showed that groundwater flow westward along a valley from the landfill and contaminants transport accordingly.

• Analytical Science and Technology
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• v.34 no.3
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• pp.134-141
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• 2021

In this study, the fatty acid (FA) composition of commercial sesame oils (n = 62) was investigated using gas chromatography with flame ionization detector (GC-FID). Multivariate statistical techniques, including principal component analysis (PCA) and linear discriminant analysis (LDA), were applied to the chromatographic data of the FAs to discriminate the geographical origin of sesame oils. A statistically significant difference was observed in the content of C16:0, C18:0, C18:1, and C18:2 between domestic and imported sesame oils. A satisfactory recovery rate of 82.8-100.2 % was achieved for C16:0, C18:0, C18:1, C18:2, and C18:3. The correlation of C16:0, C18:1, and C18:2 in domestic sesame oils showed opposite trends compared to imported oils. The PCA plot demonstrated that sesame oils were clustered in distinct groups according to their origin. LDA was used to predict sesame oil samples in one of the two groups. C16:0 (Wilks λ = 0.361) and C18:1 (Wilks λ = 0.637) demonstrated the highest discriminant power for classifying the origin of the samples. The correct prediction rates were 88.9 % and 100 % for the domestic and imported samples, respectively. Further, 60 of the 62 sesame oil samples (96.8 %) were correctly classified, indicating that this approach can be used as a valuable tool to predict and classify the geographical origin of sesame oils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.2
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• pp.97-110
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• 2024

This study investigated 575 cultivated soybean landraces from different provinces in Korea, using 17 key agromorphological traits. The studied soybeans showed wide variations in both qualitative and quantitative traits, signifying the existence of genetic diversity. The standardized Shannon-Weaver index (H') ranged from 0.3 to 1.0, with seed-related traits having an H' value higher than 0.7. Similarly, quantitative traits showed significant variation, with the coefficient of variation ranging from 7.2% for days to maturity (DM) to 62.3% for the number of pods per plant (PPP). In terms of province, the Gyeongsangbuk-do and Gyeongsangnam-do accessions differed from the other accessions, with higher proportions of green and yellow seed coats and lower proportion of black hilums. Gyeongsangnam-do accessions also showed early maturation and flowering but had the lowest average one-hundred seeds weight (HSW). In contrast, Jeollanam-do accessions flowered and matured late but had the highest average seed weight per plant (SWPP). Hierarchical cluster analysis grouped the soybeans into 12 clusters, and further statistical analysis showed significant variations in all quantitative traits (p < 0.05). Principal component analysis grouped the accessions based on the clusters. DM, PPP, HSW, and SWPP were identified as major contributors to the observed variance along the axes of the first two principal components. Correlation analysis revealed significant associations between maturity and yield-related traits. Based on their relative performance, 37 promising accessions were identified. Overall, this study highlights the diversity of recently cultivated Korean soybean landraces and provides opportunities for future metabolomic and genomic studies.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.253-258
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• 1995

Purpose : To evaluate the effects of postoperative radiotherapy and chemotherapy on the pattern of failure and survival for locally advanced rectal carcinoma, we analyzed the two groups of patients who received curative resection only and who received postoperative radiochemotherapy retro-spectively. Materials and Methods : From June 1989 to December 1992, ninety nine patients with rectal cancer were treated by curative resection and staged as B2-3 or C. Group I(25) patients received curative resection only and group II(74) patients postoperative adjuvant therapy. Postoperative adiuvant group received radiation therapy (4500cGy/25fx to whole pelvis) with 5-FU (500mg/$m^2$, day 1-3 IV infusion) as radiosensitizer and maintenance chemotherapy with 5-FU(400mg/$m^2$ for 5 days) and leucovorin (20mg/m^2$ for 5 days) for 6 cycles. Results : The patients in group I and group II were comparable in terms of age sex, performance status, but in group II $74{\%}$ of patients showed stage C compared with $56{\%}$ of group I. All patients were followed from 6 to 60 months with a median follow up of 29 months. Three year overall survival rates and disease free survival rates were $68\%,\;64\%$ respectively in group I and $64\%,\;61\%$, respectively in group II. There was no statistical difference between the two treatment groups in overall survival rate and disease free survival rate. Local recurrences occurred in $28{\%}$ of group I, $21{\%}$ of group II (p>.05) and distant metastases occurred in $20{\%}$ of group I, $27{\%}$ of group II(p>.05). The prognostic value of several variables other than treatment modality was assessed. In multivariate analysis for prognostic factors stage and histologic grade showed statistically significant effect on local recurrences and lymphatic or vessel invasion on distant metastasis. Conclusion : This retrospective study showed no statistical difference between two groups on the pattern of failure and survival. But considering that group II had more advanced stage and poor prognostic factors than group I, postoperative adjuvant radiochemotherapy improves the results for locally advanced rectal carcinoma as compared with curative surgery alone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4914-4923
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• 2011

This study aims to investigate the factors influencing job satisfaction to job stress of physician assistant(PA) nurses. This research design was a descriptive study. The subjects in this study were 104 PA nurses. Data were collected from September 1, 2010 to January 10, 2011, and analyzed by SPSS PASW statistics 18.0 program. The mean score of men on the job stress was 43.47(${\pm}13.77$), The mean score of women was 45.07(${\pm}9.78$). The mean score of job satisfaction was 2.72(${\pm}0.30$). There was no statistical difference between general characteristics and job satisfaction. There were statistical difference between unmarried subjects and organizing system(p<.05), inadequate compensation(p<.01). In the results of multivariate regression analysis, adjusted $R^2$ value was 0.567. The model fit was 56.7%. Job satisfaction was low in the insufficient job control and inadequate organizing system. It is hospital policies for the reduction of job stress(particularly, insufficient job control, and organizing system stress).

• The Journal of the Korean bone and joint tumor society
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• v.16 no.1
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• pp.14-20
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• 2010

Purpose: To investigate prognostic factors influencing on local recurrence, distant metastasis and event-free survival of liposarcomas. Materials and Methods: Fifty-two patients managed for liposarcomas since 1993 were analyzed respectively in the view of prognostic influence of patient age, tumor size, location, histologic type, histologic grade, resection type, surgical margin, chemotherapy and radiation therapy on local recurrence, distant metastasis and event-free survival. The mean follow up period was 39 months. The univariate and multivariate regression analysis were performed for statistical evaluation. Results: The local recurrences occurred in 11 patients (21.2%) and distant metastasis in 4 patients (8%), Event-free survival rate at 4 year follow up was 67%. In univariate analysis, histologic grade, surgical margin, chemotherapy and radiation therapy were significant prognostic factors on local recurrence (p<0.05). However, histologic grade lost its significance in muitivariate analysis. Trunk location revealed higher rate of distant metastasis than extremity location. In univariate analysis on event-free survival. histologic grade and chemotherapy were significant factors (p<0.05). No factor remained significant in multivariate analysis. Conclusion: Considering selection bias, positive surgical margin was negative prognostic factor on local recurrence. Liposarcomas arisen in trunk revealed higher rate of distant metastasis. There was no independent prognostic factor on event-free survival of patients with liposarcomas.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.250-256
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• 2006

Purpose: Recently, interest in peroxisome-proliferator-activated receptors (PPAR) has increased, although clinical studies of the effect of $PPAR-{\gamma}$ expression on gastric cancer have not been reported yet. In this study, we investigated the role of $PPAR-{\gamma}$ expression in gastric cancer patients. Materials and Methods: One hundred twenty-eight (128) samples of both gastric cancer and normal tissues were obtained from 128 patients who had undergone at a curative gastrectomy at Seoul Medical Center from Jan. 2001 to Dec. 2005. $PPAR-{\gamma}$ expression was determined by using immunohistochemical staining, and the results were analyzed. The statistical analysis was based on clinicopathological findings and the differences in survival rates. Results: The mean age of the patients was 6n, and the male : female ratio was 1.9 : 1. $PPAR-{\gamma}$ expression was significantly higher in cancer tissues than in normal tissue (81.3% vs. 57.0%, p<0.001). There was insignificant difference between well and moderately differentiated types and poorly differentiated types in terms of the expression of $PPAR-{\gamma}$ (87.0% vs. 74.6%, P=0.074). In the univariate analysis the survival rate was significantly increased when $PPAR-{\gamma}$ was expressed in normal tissue (P=0.003). In the multivariate analysis, only the UICC TNM staging had significance related to the survival rate. Conclusion: The rate of $PPAR-{\gamma}$ expression was higher in cancer tissue than it was in normal tissue from gastric cancer patients. In the univariate analysis, $PPAR-{\gamma}$ expression in normal tissue had significance with respect to survival, but the multivariate analysis showed no such significance. Thus, we should further evaluate more cases to determine whether or not such a significance exists.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.9-21
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• 2019

This study aimed to compare the prosodic characteristics of North Korean defectors and South Koreans in three types of sentences (declarative, interrogative, and negative) in two reading tasks (short and dialogue) through acoustic analysis and auditory-perceptual evaluation. In addition, this study examined the relationship between the auditory-perceptual evaluation scores and self-assessment questionnaires on intonation for North Korean defectors. The participants were 15 North Korean defectors and 15 Korean speakers with standard Seoul accents. For statistical analysis, three-way mixed ANOVA and multivariate analysis were performed within the three types of sentences in the reading tasks through acoustic analysis and the Mann-Whitney U Test for auditory-perceptual evaluation. Pearson's product-moment correlation coefficients were also used to identify the correlations between the results of the self-assessment questionnaire on intonation and the auditory-perceptual evaluation. The North Korean defectors were found to have a significantly lower pitch range and auditory-perceptual evaluation score than South Koreans in reading tasks. Moreover, there was a significant correlation between their auditory-perceptual evaluations and self-assessment questionnaires on intonation. The study findings suggest that North Korean defectors, who face many challenges with intonation, showed a tendency to think that their intonation differed from the standard Korean intonation and showed better auditory evaluation results for interrogative sentences.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.53-59
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• 2014

In this study, we suggest a system to build the monitoring model for compressed natural gas (CNG) stations, operated in only non-stationary modes, and perform the real-time monitoring and the abnormality diagnosis using principal component analysis (PCA) that is suitable for processing large amounts of multi-dimensional data among multivariate statistical analysis methods. We build the model by the calculation of the new characteristic variables, called as the major components, finding the factors representing the trend of process operation, or a combination of variables among 7 pressure sensor data and 5 temperature sensor data collected from a CNG station at every second. The real-time monitoring is performed reflecting the data of process operation measured in real-time against the built model. As a result of conducting the test of monitoring in order to improve the accuracy of the system and verification, all data in the normal operation were distinguished as normal. The cause of abnormality could be refined, when abnormality was detected successfully, by tracking the variables out of the score plot.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.522-526
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• 2007

Since newly emerged disease, the Severe Acute Respiratory Syndrome (SARS), spread from Asia to North America and Europe rapidly in 2003, many researchers have tried to determine where the virus came from. In the phylogenetic point of view, SARS virus has been known to be one of the genus Coronavirus, but, the overall conservation of SARS virus sequence was not highly similar to that of known coronaviruses. The natural reservoirs of SARS-CoV are not clearly determined, yet. In the present study, the genomic sequences of SARS-CoV were analyzed by bioinformatics techniques such as multiple sequence alignment and phylogenetic analysis methods as well multivariate statistical analysis. All the calculating processes, including calculations of the relative synonymous codon usage (RSCU) and other genomic parameters using 30,305 coding sequences from the two genera, Coronavirus, and Lentivirus, and one family, Orthomyxoviridae, were performed on SMP cluster in KISTI, Supercomputing Center. As a result, SARS_CoV showed very similar RSCU patterns with feline coronavirus on the both axes of the correspondence analysis, and this result showed more agreeable results with serological results for SARS_CoV than that of phylogenetic result itself. In addition, SARS_CoV, human immunodeficiency virus, and influenza A virus commonly showed the very low RSCU differences among each synonymous codon group, and this low RSCU bias might provide some advantages for them to be transmitted from other species into human beings more successfully. Large-scale genomic analysis using bioinformatics techniques may be useful in genetic epidemiology field effectively.