• Title/Summary/Keyword: multivariate statistical methods

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Use of Discriminant Analysis to Identify Soil Quality Variation by Land Use (판별분석을 이용한 토지이용별 토양 특성 변화 연구)

  • Ko Kyung-Seok;Kim Jae Gon;Lee Jin-Soo;Kim Tack Hyun;Lee Gyoo Ho;Cho Choon Hee;Oh In Suk;Cheong Young Wook
    • Economic and Environmental Geology
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    • v.38 no.3 s.172
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    • pp.207-219
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    • 2005
  • The physical and chemical characteristics of soils in a small watershed were investigated and the effect of geology and land use on soil quality were examined by using multivariate statistical methods, principal components analysis and discriminant analysis. The soil developed from andesite had finer texture and higher contents of water extractable inorganic components, clay, and mafic minerals than the soil developed from granite. It is considered that the accumulation of salts in the farmland soils indicated by electrical conductivity, contents of cations and anions and pH was caused by fertilizer input during cultivation. The low contents of organic matter in the farmland soils was due to the enhanced oxidation of organic matter by tillage and by the harvest of crops. The contents of inorganic components are increased as following order: upland > orchard > paddy field > forest. The high contents of water soluble $SO_4\;^{2-}$ of paddy soils is due to the oxidation of sulfides mineral formed during the flooding period during the air-dry and extraction. The results of principal components analysis show the difference of soil quality was controlled by geology and land use. PCI indicate the input of fertilizer, mineral weathering and ion exchange reaction by application of nitrogenous fertilizers. The results of two discriminant analyses using water extractable inorganic components and their ratios by land use were also clearly classified by discriminant function 1 and 2. In discriminant analysis by components, discriminant function 1 indicated the effect of fertilizer application and increased as following order: upland > orchard > paddy field > forest soil. The investigated and predicted data for land use from discriminant analysis showed similar results. The discriminant analysis can be used as a useful method certifying the change of land use.

Irradiation Alone in Stage IB, IIA, and IIB Cervix Cancer : I Analysis of Survival and Failure Patterns (자궁경부암 병기 IB, IIA, IIB에서 방사선 단독치료성적 : I 생존기간 및 재발양상에 관한 분석)

  • Ahn Sung Ja;Chung Woong Ki;Nah Byung Sik;Nam Taek Keun;Choi Ho Sun;Byun Ji Soo
    • Radiation Oncology Journal
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    • v.15 no.2
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    • pp.129-136
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    • 1997
  • Purpose : We analyzed the survival and failure patterns of cervix cancer patients treated with irradiation alone to evaluate our treatment method and to compare with the others Methods and Materials : Two hundred and twenty cervical cancer patients, Stage IB, II A, and II B who completed the planned treatment between Mar 1987 and December 1991 were analyzed retrospectively. The Stage IB patients were restaged to the Stage IB1 and IB2 by the recently revised FIGO classification, Patients were treated with a combination of external irradiation and the intracavitary brachytherapy Determination of the tumor control was done at the time of 6 months Postirradiation. The follow-up time was ranged from 3 to 115 months and the mean was 62 months and the follow-up rate was $93.6\%$(206/220) Results : The overall 5-year survival rate of Stage IB1 (N=50), IB2(N: 15). II A(N=58), and II B(N=97) was $94\%,\;87\%,\;69\%,\;and\;56\%$. respectively. In the univariate analysis of prognostic factors, stage(0.00), initial Hg level (P=0.00), initial TA-4(tumor-associated) antigen level(p= 0.02), initial CEA level(p=0.02), barrel-shaped tumor(p=0.02), whole cervical involvement (0.00), pelvic tyrnphadenopathy(LAP) in CT(p=0.04), and Post-irradiation adiuvant chemotherapy(P=0.00) were statistically significant in survival analysis. In a while multivariate analysis showed that the stage was the most powerful Prognostic indicator and the Post-irradiation chemotherapy factor also showed the statistical significance. The overall local control rate was $81\%$ and by the stage, $100\%$ in Stage IBI, $86.7\%$ in Stage IBS, $84.5\%$ in Stage IIA, and $68.1\%$ in Stage IIB, respectively The overall tumor recurrence rate was $15.5\%$(27/174) and by the stage, $8\%$(4/50) in Stage IB1, $0\%$(0/l3) in Stage IB2, $22.4\%$(l1/49) in Stage II A, and $19.4\%$(12/62) in Stage II B, respectively. Conclusions : We obtained the similar treatment results to the other's ones in early stage cervical cancer patients. But in Stage II B, the local control rate was lower than that of the other institutes and also the survival was poorer. So it seems to be necessary to reevaluate the treatment method in advanced cervical cancer patients.

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Relationship between Blood Pressure and Impairment of Cognitive Function In Some Rural Residents Aged 60-64 (일부 60-64세 농촌 거주자에서 혈압과 인지기능 장애와의 관계)

  • Lee, Moo-Sik;Chun, Jong-Chan;Lee, Choong-Won
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.2
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    • pp.208-214
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    • 2000
  • Objectives : Face-to-face interviews were conducted to investigate the relationship between blood pressure and the impairment of cognitive function in rural elderly (N=932) aged 60-64 in Dalsung County, April to September in 1996 Methods : Impairment of cognitive function was defined as a score of less than 23 by the Korean version of the Mini-Mental State Examination (MMSEK). Blood pressure was measured once in each subject using a portable automatic sphygmomanometer. Results : By univariate logistic regression on males, no category of systolic blood pressure bore statistical significance. Groups with diastolic blood pressures of, less than 80 mmHg, 90-94 mmHg, and more than 95mmHg had odds ratios of more than one compared with the reference group (80-89 mmHg). This was most significant in the group with blood pressures lower than 80 mmHg, which had a statistically significant odds ratio of 1.68 (95% confidence interval CI; 1.02-2.75). No category of blood pressure was statistically significant in females. Multivariate logistic regression for males, with adjustment for age, educational attainment, smoking, alcoholic drinking, body mass index, atherosclerotic disease, and antihypertensive medication use, did not alter the odds ratios significantly in terms of systolic blood pressure. However, the group with diastolic blood pressure of less than 80 mmHg had an increased odds ratio of 2.01 (95% CI; 1.15-3.52) compared with the reference group. In females, systolic blood pressure did not alter the odds ratio, but the group with a diastolic blood pressure of less than 80 mmHg had a statistically significant odds ratio of 0.57 (95% CI; 0.37-0.89). Conclusions : These results suggest that the relationship between blood pressure and cognitive function status is stronger diastolic than systolic blood pressure and that there is a complex relationship between blood pressure and cognitive function by sex.

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The Relation of Dampness-Phlegm and Metabolic Syndrome in Acute Stroke Patients (중풍(中風)환자의 습담변증(濕痰辨證) 대사증후군과의 관련성 연구)

  • Min, In-Kyu;Kim, Chang-Hyun;Hwang, Jae-Woong;Park, Joo-Young;Lee, Seung-Yeop;Choi, Won-Woo;Na, Byong-Jo;Park, Sung-Wook;Jung, Woo-Sang;Moon, Sang-Kwan;Park, Jung-Mi;Ko, Chang-Nam;Cho, Ki-Ho;Kim, Young-Suk;Bae, Hyung-Sup
    • The Journal of Korean Medicine
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    • v.30 no.1
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    • pp.109-119
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    • 2009
  • Objectives: This study was aimed to clarity the relationship between the pattern of dampness-phlegm and metabolic syndrome in acute stroke patients. Methods: Three hundred fifty-nine subjects were recruited from the patients admitted to the Internal Medical Department at Kyunghee University Oriental Medical Center, Donggnk University Ilsan Oriental Medical Center, Kyungwon University Songpa Oriental Medical Center and Kyungwon University Incheon Oriental Medical Center from April 2007 to March 2008. We diagnosed dampness-phlegm by Oriental medical diagnosis and analyzed their characteristics with type of stroke, blood test result, Sasang constitution, lifestyle and metabolic syndrome. Results: I. On the demographic variables of the patients, the weight and body mass index, the rate of hypertension, diabetes mellitus, hyperlipidemia, silent infarction were significantly higher in dampness-phlegm group than in the control. 2. There was no significant difference of stroke type between the dampness-phlegm group and the control. 3. According to the blood test, the dampness-phlegm group showed higher total cholesterol, triglyceride, fasting blood sugar and lower high density lipoprotein cholesterol than the control group with statistical significance. 4. According to the Sasang constitution distribution, the rate of Tae-Eum was significantly higher in dampness-phlegm group than in the control. 5. According to lifestyle, smoking and drinking were significantly lower in the dampness-phlegm group than in the control. Otherwise, exercise and dietary habits showed no significant difference between the two groups. 6. There were much more patients diagnosed with metabolic syndrome in the dampness-phlegm group than in the control. 7. Metabolic syndrome, silent infarction and obesity showed close relationship with dampness-phlegm pattern in multivariate analysis. Conclusions: According to the analysis, the relationship between the patterns of dampness-phlegm and metabolic syndrome in acute stroke patients were clarified. These results can be utilized in the future as a basis material.

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Evaluation of Correlation between Chlorophyll-a and Multiple Parameters by Multiple Linear Regression Analysis (다중회귀분석을 이용한 낙동강 하류의 Chlorophyll-a 농도와 복합 영향인자들의 상관관계 분석)

  • Lim, Ji-Sung;Kim, Young-Woo;Lee, Jae-Ho;Park, Tae-Joo;Byun, Im-Gyu
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.5
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    • pp.253-261
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    • 2015
  • In this study, Chlorophyll-a (chl-a) prediction model and multiple parameters affecting algae occurrence in Mulgeum site were evaluated by statistical analysis using water quality, hydraulic and climate data at Mulgeum site (1998~2008). Before the analysis, control chart method and effect period of typhoon were adopted for improving reliability of the data. After data preprocessing step two methods were used in this study. In method 1, chl-a prediction model was developed using preprocessed data. Another model was developed by Method 2 using significant parameters affecting chl-a after data preprocessing step. As a result of correlation analysis, water temperature, pH, DO, BOD, COD, T-N, $NO_3-N$, $PO_4-P$, flow rate, flow velocity and water depth were revealed as significant multiple parameters affecting chl-a concentration. Chl-a prediction model from Method 1 and 2 showed high $R^2$ value with 0.799 and 0.790 respectively. Validation for each prediction model was conducted with the data from 2009 to 2010. Training period and validation period of Method 1 showed 20.912 and 24.423 respectively. And Method 2 showed 21.422 and 26.277 in each period. Especially BOD, DO and $PO_4-P$ played important role in both model. So it is considered that analysis of algae occurrence at Mulgeum site need to focus on BOD, DO and $PO_4-P$.

Influencing Factors on Suicide Ideation among High School Students (고등학생들의 자살생각에 영향을 미치는 관련요인)

  • Song, Sung-Ho;Kang, Chang-Yeol;Lee, Tae-Yong;Kwon, In-Sun
    • Journal of agricultural medicine and community health
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    • v.36 no.1
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    • pp.1-12
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    • 2011
  • Objectives: The purpose of this study was to find out the suicide ideation of high school students in urban and rural areas, and especially to research the relationship between suicide ideation, and general characteristics, characteristics of school life, and empirical characteristics of suicide. Methods: This research targeted four urban and four rural high schools in two cities. The study subjects were 1,114 students in urban area and 968 students in rural area, total 2,082 students. The survey was conducted from July 1, 2009 to July 31, 2009. For statistical analysis, chi-square test, t-test and ANOVA were used for investigating related factors with suicide ideation in urban and rural areas, respectively, with multiple logistic regression for multivariate analysis. Results: The results showed that 38.8% of respondents had suicide ideation within 1 year. The percentage of female students (44.8%) was significantly higher than that of male students (33.4%). However, there was no significant difference between urban (38.0%) and rural area (39.9%). The significant influencing factors on suicide ideation in multiple logistic regression were gender [female student OR(odds ratio)=1.80 (95% CI 1.31-2.47) compared with male student] and grade [second year OR=1.40 (95% CI 0.98-2.00), third year OR=2.15 (95% CI 1.49-3.12) compared with first year] in urban area. Those in rural area were gender [female student OR(odds ratio)=2.71 (95% CI 1.23-2.38) compared with male student], economic deterioration [yes OR=1.81 (95% CI 1.24-2.64) compared with no], and grade [second year OR=2.80 (95% CI 1.82-4.32), third year OR=3.84 (95% CI 2.52-5.87) compared with first year]. Conclusions: This study showed about 40% of high school students had suicide ideation within 1 year. A suicide prevention program may be implemented considering factors related with suicide ideation identified in this study.

Concurrent Chemoradiotherapy in Locally Advanced Esophageal Cancer (국소적으로 진행된 식도암에서 동시항암화학방사선치료의 결과)

  • Byun, Sang-Jun;Kim, Jin-Hee;Kim, Ok-Bae;Song, Hong-Suk
    • Radiation Oncology Journal
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    • v.29 no.1
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    • pp.20-27
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    • 2011
  • Purpose: This study was designed to evaluate the results of local control, survival rate, prognostic factors, and failure pattern in locally advanced esophageal cancer. Materials and Methods: We retrospectively studied 50 patients with locally advanced esophageal cancer treated with concurrent chemoradiotherapy at Keimyung University Dongsan Medical Center from June of 1999 to August of 2008. Seven patients with inappropriate data were excluded, and 43 patients were analyzed. There were 39 males and four female patients ranging in age from 43 to 78 years (median, 63 years). There were seven patients with stage IIA and 36 with stage III. Irradiation from 46 Gy to 63 Gy (median, 54 Gy) was carried out 5 days per week, 1.8 Gy once a day. There were eight patients with neo-adjuvant chemotherapy, and we mostly used 5-fluorouracil, cisplatin with 3 cycles for concurrent chemotherapy. The range of follow up periods was from 2 to 82 months (median, 15.5). Results: There were nine patients that exhibited a cornplete response, 23 that exhibited a partial response, 9 that exhibited no response, and 2 that exhibited disease progression. The median survival time was 15 months. Two-year and 5-year survival rates were 36.5% and 17.3%, respectively. Two-year and 5-year disease-free survival rates were 32.4% and 16%, respectively. Treatment failure occurred in 22 patients (51.2%). Patterns of failure were categorized as local failure in 18 patients and distant metastasis in four patients. In a univariate analysis for prognostic factors related to overall survival and disease-free survival, the hemoglobin levels during chemoradiotherapy (${\geq}$ 12 vs. <12, p=0.02(p=0.1) and the response to the treatments (CR/PR vs. NR/PD, p=0.002/p< 0.0001) were statistically significant. In a multivariate analysis, only response to the treatments was revealed to be statistically significant. There was no statistical significance associated with patient age, gender, disease stage, T-stage, smoking history, tumor location, or neo-adjuvant chemotherapy. Conclusion: Our survival rate was similar to those of other institutions. Local recurrence was the main reason for failure. It is suggested that further prospective studies should be performed to improve local control.

Effect of Thermal Method on the Activation of Brown Adipose Tissue (온열 요법이 갈색지방세포 활성화에 미치는 영향)

  • You, Yeon Wook;Lee, Chung Wun;Seon, Ahn Jeong;Lee, Dong Eun;Moon, Jong Wun;Kim, Yun Cheol;Park, So Hyeon;Kim, Tae-Sung
    • The Korean Journal of Nuclear Medicine Technology
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    • v.25 no.2
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    • pp.48-54
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    • 2021
  • Purpose In 18F-FDG PET/CT, the absorption of 18F-FDG due to the activation of Brown Adipose Tissue (BAT) greatly interferes with the discrimination of lymph node malignant metastasis. Warming the patient's body temperature before and after injection of 18F-FDG to prevent FDG absorption by BAT is a safe and non-pharmacological approach. The purpose of this study was to identify and select patients with a high potential for BAT activation in advance, and to investigate whether BAT can inhibit FDG absorption when the body temperature is raised for a short time by directly applying heat to the target patient. Materials and Methods Among the patients who underwent 18F-FDG PET/CT at the National Cancer Center from January 2020 to December 2020, 825 female patients (415 in the thermal group, 410 in the non-thermal group) under 50 years old were included. The thermal group was administered heat for 10 minutes before injection of 18F-FDG. For statistical analysis, the Z test comparing the ratios between the two groups was used, and logistic regression analysis was performed to correct for important variables (BMI, outdoor temperature, blood sugar) according to the results of the previous retrospective study. Results Among 825 patients, 19 patients with BAT activated (Thermal group: 5(1.2%), Non-thermal group: 14(3.41%)) accounted for 2.3% of the total. As a result of performing the Z test to compare the ratios between the two groups, the activation of BAT in the thermal group was significantly decreased (P=0.034). In the univariate logistic regression analysis, the activation of BAT was also decreased in the thermal group (OR: 0.34, P<0.05). In the multivariate results, BAT activation increased in patients younger than 45 years old (OR: 4.46, P<0.05) and outdoor temperature less than 13.2 degrees (OR: 9.97, P<0.05). BAT activation tended to decrease in the thermal group, but there was no significant difference (OR: 0.37, P=0.066). Conclusion We confirmed that the activation of BAT tends to decrease by 62.5% in the group subjected to the thermal method, and it will be of great help in preventing FDG absorption of BAT more effectively in the future.

Assessment of Cerebral Hemodynamic Changes in Pediatric Patients with Moyamoya Disease Using Probabilistic Maps on Analysis of Basal/Acetazolamide Stress Brain Perfusion SPECT (소아 모야모야병에서 뇌확률지도를 이용한 수술전후 혈역학적 변화 분석)

  • Lee, Ho-Young;Lee, Jae-Sung;Kim, Seung-Ki;Wang, Kyu-Chang;Cho, Byung-Kyu;Chung, June-Key;Lee, Myung-Chul;Lee, Dong-Soo
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.3
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    • pp.192-200
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    • 2008
  • To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Methods: Total fifty six (M:F = 33:24, age $6.7{\pm}3.2$ years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was $33{\pm}21$ months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. Results: In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal lobe of the hemispheres with EDAS and frontal EGS, the post-operative CVRI, and ${\Delta}CVRI$ showed a significant difference between patients with a good and poor clinical outcome (p<0.05). In a multivariate logistic regression analysis, the ${\Delta}CVRI$ and the post-operative CVRI of medial frontal gyrus on the hemispheres where EDAS with frontal EGS was performed were the significant predictive factors for the clinical outcome (p =0.002, p =0.015), Conclusion: With probabilistic map, we could objectively evaluate pre/post-operative hemodynamic changes of pediatric patients with moyamoya disease. Specifically the post-operative CVRI and the post-operative CVRI of medial frontal gyrus where EDAS with frontal EGS was done were the significant predictive factors for further clinical outcomes.