• Title/Summary/Keyword: Multivariate Statistical Analysis

Search Result 632, Processing Time 0.035 seconds

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
    • /
    • v.29 no.1
    • /
    • pp.20-27
    • /
    • 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.

The Structure of Plant Community in Jungdaesa-Birobong Area, Odaesan National Park (오대산국립공원 중대사-비로봉 구간 식물군집구조)

  • Han, Bong-ho;Choi, Jin-woo;Noh, Tai-hwan;Kim, Dong-wook
    • Korean Journal of Environment and Ecology
    • /
    • v.29 no.5
    • /
    • pp.764-776
    • /
    • 2015
  • This study aims to identify the structure of the plant community, and the ecological succession sere and the change in the forest ecosystem in Jungdaesa-Birobong area, Odaesan National Park_(i._e., located at high altitudes(over 1,000m)). It seeks to offer the basic data for the planning of vegetation management. In order to verify the status of the forest vegetation between Jungdaesa-Birobong, seventeen plots(size is $20m{\times}20m$) were set up as research sites at high altitudes. Importance value, distribution by diameter at breast height(DBH), the growth volume and age of the sample trees, similarity index and species diversity index of each survey plot were analysed. According to the results of DCA(Detrended Correspondence Analysis), one of the multivariate statistical techniques. It was found that the plant communities were classified into five groups: community I_(Quercus mongolica-Tilia amurensis community), community II_(Q. mongolica-Deciduous broad-leaved community), community III_(Q. mongolica-Pinus koraiensis community), community IV_(Abies holophylla-Q. mongolica community) and community V_(A. holophylla-Deciduous broad-leaved community). Community I which is dominated by Quercus mongolica and Deciduous broad-leaved communities is located at an altitude of over 1,300 meters(ranging from 1,335m to 1,495m), the community IV and V which are dominated by Abies holophylla are located at an altitude of under 1,200 meters(ranging from 1,115m to 1,175m) and the community II and III which include the main species of Quercus mongolica, Pinus koraiensis and Abies holophylla are located at an altitude of between 1,160 meters and 1,300 meters. The results showed that Quercus mongolica tends to have a higher importance value of woody species at a higher altitude while Abies holophylla tends to have higher importance value at a lower altitude. For the importance value woody species and -DBH class distribution, the communites I, II and III are expected to continuously maintain the present status. Whereas, for the influence of communities IV and V, Q. mongolica is predicted to be weakened. The age of sample trees was between 85 and 161; the average age was 123. The index of Shannon's Species diversity (H') showed heterogeneity was found among community I_(i._e., located at high altitude) and communities IV and V_(i._e., located at low altitude). As a results of analysing the index of Shannon's Species diversity (H': unit: $400m^2$), community III showed the highest diversity intex with 1.1109 followed by community II with 1.0475, community I with 1.0125, community IV with 0.9918 and community V with 0.8686. This study verified that the index of Shannon's species was significantly different by plant communities. For instance, when comparing the index of Shannon's species diversity in Quercus mongolica communities of this study and that of past relevant research, the value of index is very similar. However, the diversity index for the community which is dominated by Abies holophylla showed lower value when compared to the results from past relevant research.

The Role of Immunohistochemical Biomarkers as Prognostic Factors by the Use of a Tissue Microarray in Breast Cancer Patients Under 45-years-old (45세 이하의 유방암환자에서 조직미세배열법을 이용한 면역조직화학적 생체표지자의 역할)

  • Kim, Eun-Seog;Choi, Doo-Ho;Jin, So-Young;Lee, Dong-Wha;Park, Hee-Sook;Lee, Min-Hyuk;Won, Jong-Ho;Kim, Yong-Ho;Lee, Kyu-Taek;Kim, Sung-Yong
    • Radiation Oncology Journal
    • /
    • v.26 no.1
    • /
    • pp.45-55
    • /
    • 2008
  • Purpose: This study evaluates the association of estrogen receptor(ER), progesterone receptor(PR), Her-2, COX-2, and survivin with the clinicopathological features and outcomes in young Korean women with breast cancer using recently developed tissue microarray(TMA) technology. Materials and Methods: A cohort of 212 young patients with breast cancer diagnosed at the age of 45 years or younger from March 1994 to August 2005, were enrolled in this study. The age range of patients was $23{\sim}45$ years(median age, 39 years). The minimum and median follow-up periods were 24 months and 60 months, respectively. Serial sections of primary tumors were processed by the use of a TMA for immunohistochemical staining for five biomarkers. The correlation of these five biomarkers and the clinicopathological features and outcomes were analyzed by statistical methods. Results: The majority of the patients were stage T1(90 patients) or T2(101 patients), and 105 patients(49.5%) had an axillary node metastasis. The 5-year overall and relapse free survival rates for all of the patients were 90.4% and 82.3%, respectively, and 36 patients had a locoregional or distant metastasis as a first event. Positive expression of ER, PR, Her-2, COX-2, and survivin was determined in 38.2%, 45.3%, 25.9%, 41.5%, and 43.4%, of the tumor samples, respectively. Tumor stage, nodal status, age, as well as expression of ER, PR, and HER-2 status were significantly associated with the disease free survival rate. Tumor stage, nodal status, as well as expression of ER, PR, and HER-2 were significantly related with the overall survival rate. Expression of COX-2 and survivin were not single independent prognostic factors for the disease free and overall survival rate although co-expression of HER-2 and COX-2 had a tendency as a poor prognostic factor. By multivariate analysis, only T stage and lymph node status were significant prognostic factors, and ER status was a marginally significant prognostic factor(p=0.075). Conclusion: Expression of ER, PR and HER-2 were significant prognostic factors for the relapse free and overall survival rate. Expression of COX-2 and survivin were not prognostic factors for young women with breast cancer.

Expression of Hypoxia-inducible Factor-1 $\alpha$ in Esophageal Squamous Cell Carcinoma: Relationship to Prognosis and Tumor Biomarkers (식도 편평세포암에시 Hypoxia-inducible Factor-1 $\alpha$의 발현: 예후와 종양표지자와의 상관성)

  • 양일종;김종인;이해영;천봉권;조성래
    • Journal of Chest Surgery
    • /
    • v.37 no.8
    • /
    • pp.691-701
    • /
    • 2004
  • Background: Tissue hypoxia is a characteristic of many human malignant neoplasms, and hypoxia inducible factor-1 (HIF-1) plays a pivotal role in essential adaptive response to hypoxia, and activates a signal pathway for the expression of the hypoxia-regulated genes, resulting in increased oxygen delivery or facilitating metabolic adaptation to hypoxia. Increased level of HIF-1 a has been reported in many human malignancies, but in esophageal squamous cell carcinoma, the influence of HIF-1 a on tumor biology, including neovascularization, is not still defined. Material and Method: The influence of HIF-1 a expression on angiogenic factors, correlation between the tumor proliferation and HIF-1 a expression, interaction of HIF-1 a expression and p53, and correlation between HIF-1 a expression and clinicopathological prognostic parameters were investigated, using immunohistochemical stains for HIF-1 a, VEGF, CD34, p53, and Ki-67 on 77 cases of resected esophageal squamous cell carcinoma. Result: HIF-1 a expression in cancer cells was found in 33 of 77 esophageal squamous cell carcinoma cases. The 33 cases (42.9%) showed positive stain for HIF-1 a. High HIF-1 a expression was significantly associated with several pathological parameters, such as histologic grade (p=0.032), pathological TMN stage (p=0.002), the depth of tumor invasion (p=0.022), regional lymph node metastasis (p=0.002), distant metastasis (p=0.049), and lymphatic invasion (p=0.004). High HIF-1 a expression had significant VEGF immunoreactivity (p=0.008) and Ki-67 labeling index (p<0.001), but was not correlated with microvascular density within tumors (p=0.088). The high HIF-1 a expression was correlated with aberrant p53 accumulation with a marginal significance (p=0.056). The overall 5-year survival rate was 34.9%. The survival rate of patients with a high HIF-1 a expression was worse than that of patients with low-expression tumors (log-rank test, p=0.0001). High HIF-1 a expression was independent unfavorable factors although statistical significance is marginal in multivariate analysis. Conclusion: It is suggested that (1) high HIF-1 a expression in esophageal squamous cell carcinoma is associated with tumor hypoxia, or with genetic alteration in early carcinogenesis and progressive stages, (2) high HIF-1 a expression may be associated with intratumoral neovascularization through HIF-VEGF pathway, and (3) high HIF-1 a expression is associated with poor prognosis in patients with esophageal squamous cell carcinoma and may playa role as biomarker for regional lymph node metastasis.

The Association between Types of Smoking and Periodontal Disease according to the Survey Year Using the Fourth and Fifth Korea National Health and Nutrition Examination Surveys (조사연도에 따른 흡연 유형과 치주질환의 관련성 분석: 제4기, 제5기 국민건강영양조사를 이용하여)

  • Kim, Myoung-Hee;Yoon, Mi-Sook;Lim, Youn-Hee;Lee, Sae-Rom;Kim, So-Yeon;Park, Seon-Ju;Shin, Sun-Jung
    • Journal of dental hygiene science
    • /
    • v.17 no.6
    • /
    • pp.487-494
    • /
    • 2017
  • There is little evidence on the effects of environmental tobacco smoke (ETS) on prevalence of periodontal disease. The aims of this study were to explore the trends of prevalence of periodontal disease and types of exposure to smoke, including ETS according to the survey year, identify factors affecting periodontal disease, and compare the effect size of periodontal disease between active smokers and secondhand smokers. Data on 11,643 individuals were obtained from the fourth and fifth Korean National Health and Nutritional Examination Surveys. Information on exposure to ETS at home and work was self-reported. Severity of periodontal disease was evaluated using the community periodontal index. A multivariate logistic regression analysis was performed to model periodontal disease using types of smoking and the survey year. Overall, the prevalence of periodontal disease was 26.0% (n=3,029) and about 9% of the study population were secondhand smokers. The prevalence of periodontal disease among smokers was significantly increased according to smoking types by year. Active smokers showed a statistically significant adjusted odds ratio (aOR) for having periodontal disease except in the year 2007, whereas secondhand smokers had significant associations only in 2010 (aOR, 1.68; 95% confidence interval, 1.05 to 2.70) compared to non-smokers. For secondhand smokers, the statistical relationship of predicting periodontal disease was weaker than that of active smokers. However, ETS should separately be considered as an important risk factor for periodontal disease. This study suggested the need for further investigation of the impact of ETS on prevalence of periodontal disease using in-depth research designs and objective measurements for assessing periodontal disease and ETS.

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
    • /
    • v.42 no.3
    • /
    • pp.192-200
    • /
    • 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.

The effects of adjuvant therapy and prognostic factors in completely resected stage IIIa non-small cell lung cancer (비소세포 폐암의 근치적 절제술 후 예후 인자 분석 및 IIIa 병기에서의 보조 요법의 효과에 대한 연구)

  • Cho, Se Haeng;Chung, Kyung Young;Kim, Joo Hang;Kim, Byung Soo;Chang, Joon;Kim, Sung Kyu;Lee, Won Young
    • Tuberculosis and Respiratory Diseases
    • /
    • v.43 no.5
    • /
    • pp.709-719
    • /
    • 1996
  • Background: Surgical resection is the only way to cure non-small cell lung cancer(NSCLC) and the prognosis of NSCLC in patients who undergo a complete resection is largely influenced by the pathologic stage. After surgical resection, recurrences in distant sites is more common than local recurrences. An effective postoperative adjuvant therapy which can prevent recurrences is necessary to improve long tenn survival Although chemotherapy and radiotherapy are still the mainstay in adjuvant therapy, the benefits of such therapies are still controversial. We initiated this retrospective study to evaluate the effects of adjuvant therapies and analyze the prognostic factors for survival after curative resection. Method: From 1990 to 1995, curative resection was perfomled in 282 NSCLC patients with stage I, II, IIIa, Survival analysis of 282 patients was perfonned by Kaplan-Meier method. The prognostic factors, affecting survival of patients were analyzed by Cox regression model. Results: Squamous cell carcinoma was present in 166 patients(59%) ; adenocarcinoma in 86 pmients(30%) ; adenosquamous carcinoma in II parients(3.9%); and large cell undifferentiated carcinoma in 19 patients(7.1%). By TNM staging system, 93 patients were in stage I; 58 patients in stage II ; and 131 patients in stage rna. There were 139 postoperative recurrences which include 28 local and 111 distant failures(20.1% vs 79.9%). The five year survival rate was 50.1% in stage I ; 31.3% in stage II ; and 24.1% in stage IIIa(p <0.0001). The median survival duration was 55 months in stage I ; 27 months in stage II ; and 16 months in stage rna. Among 131 patients with stage rna, the median survival duration was 19 months for 81 patients who received postoperative adjuvant chemotherapy only or cherne-radiotherapy and 14 months for the other 50 patients who received surgery only or surgery with adjuvant radiotherapy(p=0.2982). Among 131 patients with stage IIIa, the median disease free survival duration was 16 months for 21 patients who received postop. adjuvant chemotherapy only and 4 months for 11 patients who received surgery only(p=0.0494). In 131 patients with stage IIIa, 92 cases were in N2 stage. The five year survival rate of the 92 patients with N2 was 25% and their median survival duration was 15 months. The median survival duration in patients with N2 stage was 18 months for those 62 patients who received adjuvant chemotherapy and 14 months for the other 30 patients who did not(p=0.3988). The median survival duration was 16 months for those 66 patients who received irradiation and 14 months for the other 26 patients who did not(p=0.6588). We performed multivariate analysis to identify the factors affecting prognosis after complete surgical resection, using the Cox multiple regression model. Only age(p=0.0093) and the pathologic stage(p<0.0001) were significam prognostic indicators. Conclusion: The age and pathologic stage of the NSCLC parients are the significant prognostic factors in our study. Disease free survival duration was prolonged with statistical significance in patients who received postoperative adjuvant chemotherapy but overall survival duration was not affected according to adjuvant therapy after surgical resection.

  • PDF

The Etiologies and Initial Antimicrobial Therapy Outcomes in One Tertiary Hospital ICU-admitted Patient with Severe Community-acquired Pneumonia (국내 한 3차 병원 중환자실에 입원한 중증지역획득폐렴 환자의 원인 미생물과 경험적 항균제 치료 성적의 고찰)

  • Lee, Jae Seung;Chung, Joo Won;Koh, Yunsuck;Lim, Chae-Man;Jung, Young Joo;Oh, Youn Mok;Shim, Tae Sun;Lee, Sang Do;Kim, Woo Sung;Kim, Dong-Soon;Kim, Won Dong;Hong, Sang-Bum
    • Tuberculosis and Respiratory Diseases
    • /
    • v.59 no.5
    • /
    • pp.522-529
    • /
    • 2005
  • Background : Several national societies have published guidelines for empirical antimicrobial therapy in patients with severe community-acquired pneumonia (SCAP). This study investigated the etiologies of SCAP in the Asan Medical Center and assessed the relationship between the initial empirical antimicrobial regimen and 30 day mortality rate. Method : retrospective analysis was performed on patients with SCAP admitted to the ICU between March 2002 and February 2004 in the Asan Medical Center. The basic demographic data, bacteriologic study results and initial antimicrobial regimen were examined for all patients. The clinical outcomes including the ICU length of stay, the ICU mortality rate, and 30 days mortality rates were assessed by the initial antimicrobial regimen. Results : One hundred sixteen consecutive patients were admitted to the ICU (mean age 66.5 years, 81.9 % male, 30 days mortality 28.4 %). The microbiologic diagnosis was established in 58 patients (50 %). The most common pathogens were S. pneumoniae (n=12), P. aeruginosae (n=9), K. pneumonia (n=9) and S. aureus (n=8). The initial empirical antimicrobial regimens were classified as: ${\beta}$-lactam plus macrolide; ${\beta}$-lactam plus fluoroquinolone; anti-Pseudomonal ${\beta}$-lactam plus fluoroquinolone; Aminoglycoside combination regimen; ${\beta}$-lactam plus clindamycin; and ${\beta}$-lactam alone. There were no statistical significant differences in the 30-day mortality rate according to the initial antimicrobial regimen (p = 0.682). Multivariate analysis revealed that acute renal failure, acute respiratory distress syndrome and K. pneumonae were independent risk factors related to the 30 day mortality rate. Conclusion : S. pneumoniae, P. aeruginosae, K. pneumonia and S. aureus were the most common causative pathogens in patients with SCAP and K. pneumoniae was an independent risk factor for 30 day mortality. The initial antimicrobial regimen was not associated with the 30-day mortality.

Prospective Study on Preoperative Evaluation for the Prediction of Mortality and Morbidity after Lung Cancer Resection (폐암절제술후 발생하는 사망 및 합병증의 예측인자 평가에 관한 전향적 연구)

  • Park, Jeong-Woong;Suh, Gee-Young;Kim, Ho-Cheol;Cheon, Eun-Mee;Chung, Man-Pyo;Kim, Ho-Joong;Kwon, O-Jung;Kim, Kwan-Min;Kim, Jin-Kook;Shim, Young-Mok;Rhee, Chong-H.;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
    • /
    • v.45 no.1
    • /
    • pp.57-67
    • /
    • 1998
  • Purpose : This study was undertaken to determine the preoperative predictors of mortality and morbidity after lung cancer resection. Method: During the period from October 1, 1995 to August 31, 1996, a prospective study was conducted in 92 lung resection candidates diagnosed as lung cancer. For preoperative predictors of nonpulmonary factors, we considered age, sex, weight loss, hematocrit, serum albumin, EKG and concomitant illness, and for those of pulmonary factors, smoking history, presence of pneumonia, dyspnea scale(1 to 4), arterial blood gas analysis with room air breathing, routine pulmonary function test. And predicted postoperative(ppo) pulmonary factors such as PPO-$FEV_1$, ppo-diffusing capacity(DLco), predicted postoperative product(PPP) of ppo-$FEV_1%{\times}ppo$-DLco% and ppo-maximal $O_2$ uptake($VO_2$max) were also considered. Results: There were 78 men and 14 women with a median age of 62 years(range 42 to 82) and a mean $FEV_1$ of $2.37\pm0.06L$. Twenty nine patients had a decreased $FEV_1$ less than 2.0L. Pneumonectomy was performed in 26 patients, bilobectomy in 12, lobectomy in 54. Pulmonary complications developed in 10 patients, cardiac complications in 9, other complications(empyema, air leak, bleeding) in 11, and 16 patients were managed in intensive care unit for more than 48hours. Three patients died within 30 days after operation. The ppo-$VO_2$max was less than 10ml/kg/min in these three patients, but its statistical significance could not be determined due to small number of patients. In multivariate analysis, the predictor related to postoperative death was weight loss(p<0.05), and as for pulmonary complications, weight loss, dyspnea scale, ppo-DLco and extent of resection(p<0.05). Conclusions: Based on this study, preoperative nonpulmonary factors such as weight loss and dyspnea scale are more important than the pulmonary factors in the prediction of postoperative mortality and/or morbodity in lung resection candidates, but exercise pulmonary fuction test may be useful Our study suggests that ppo-$VO_2$max value less than 10ml/kg/min is associated with death after lung cancer resection but further studies are needed to validate this result.

  • PDF

Studies on Development of Prediction Model of Landslide Hazard and Its Utilization (산지사면(山地斜面)의 붕괴위험도(崩壞危險度) 예측(豫測)모델의 개발(開發) 및 실용화(實用化) 방안(方案))

  • Ma, Ho-Seop
    • Journal of Korean Society of Forest Science
    • /
    • v.83 no.2
    • /
    • pp.175-190
    • /
    • 1994
  • In order to get fundamental information for prediction of landslide hazard, both forest and site factors affecting slope stability were investigated in many areas of active landslides. Twelve descriptors were identified and quantified to develop the prediction model by multivariate statistical analysis. The main results obtained could be summarized as follows : The main factors influencing a large scale of landslide were shown in order of precipitation, age group of forest trees, altitude, soil texture, slope gradient, position of slope, vegetation, stream order, vertical slope, bed rock, soil depth and aspect. According to partial correlation coefficient, it was shown in order of age group of forest trees, precipitation, soil texture, bed rock, slope gradient, position of slope, altitude, vertical slope, stream order, vegetation, soil depth and aspect. The main factors influencing a landslide occurrence were shown in order of age group of forest trees, altitude, soil texture, slope gradient, precipitation, vertical slope, stream order, bed rock and soil depth. Two prediction models were developed by magnitude and frequency of landslide. Particularly, a prediction method by magnitude of landslide was changed the score for the convenience of use. If the total store of the various factors mark over 9.1636, it is evaluated as a very dangerous area. The mean score of landslide and non-landslide group was 0.1977 and -0.1977, and variance was 0.1100 and 0.1250, respectively. The boundary value between the two groups related to slope stability was -0.02, and its predicted rate of discrimination was 73%. In the score range of the degree of landslide hazard based on the boundary value of discrimination, class A was 0.3132 over, class B was 0.3132 to -0.1050, class C was -0.1050 to -0.4196, class D was -0.4195 below. The rank of landslide hazard could be divided into classes A, B, C and D by the boundary value. In the number of slope, class A was 68, class B was 115, class C was 65, and class D was 52. The rate of landslide occurrence in class A and class B was shown at the hige prediction of 83%. Therefore, dangerous areas selected by the prediction method of landslide could be mapped for land-use planning and criterion of disaster district. And also, it could be applied to an administration index for disaster prevention.

  • PDF