• Title/Summary/Keyword: Probability of survival

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A Study on The Assesment of Power Improvement Effectiveness of Corps Level C4I System Applied to Integrated Fire Operation (지상전술 C4I체계의 통합화력운용간 전투력 상승효과 평가에 관한 연구)

  • 박송기;이재영
    • Journal of the military operations research society of Korea
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    • v.29 no.1
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    • pp.8-27
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    • 2003
  • This paper develops a methodology that can be used to quantify the assesment of power improvement effectiveness of corps level C4I system applied to integrated fire operation by adapting Schuzer's C2 theory. This paper first describes how C4I systers can enhance the battle outcome in three way. : (1) Enhanced unit probability of survival; (2) Enhanced unit's individual effectiveness; improved exchange ratios; (3) Improved task force allocations : increased percentage of assets that can be assigned to a given engagement These enhancements are then show to result from improved probability of detection through information sharing; improved survivability and lethality through battle force coordination; and enhanced force allocation and prepositioning through improved timeliness of information(more advanced warning). It demonstrates that well-designed C4I systems can be shown to represent a significant force multiplier on the outcome of the battle.

Seedling Plug and Cutting Method for Multi-propagation of Ornamental Miscanthus Spp. (조경용 억새의 대량번식을 위한 플러그묘와 삽목번식법)

  • Hwang, Kyung Sik;Joo, Song Tak;Ha, Soo Sung;Kim, Ki Dong;Joo, Young Kyoo
    • Weed & Turfgrass Science
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    • v.7 no.3
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    • pp.275-282
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    • 2018
  • Miscanthus species are known as a genus of eco-friendly and low-maintenance cost ornamental grasses. Plug and cutting methods were tested for multi-propagation of most promising ornamental Miscanthus species in greenhouse and field plot. The plug formation period with three different cell sizes with four cultivars (M. sinensis 'Andersson', 'Strictus', 'Gracillimus', 'Variegatus') were evaluated the seedling development stages with two irrigation types of the over-head and the bottom watering in greenhouse and field plot afterward during 2015-2016 season. In seedling plug test, the size of tray cell affected the plug formation. Bottom irrigation resulted positively on plant height, weight, root and tiller development compared with the over-head irrigation. Plug cell size affected the plant growth in the field after transplanting. All of the 3 Miscanthus species showed higher rates of successful propagation at the lower nodes before inflorescence formation (vegetative growth stage). To analyze the survival factors of M. xgiganteus cutting, the cutting time, node part, and culm diameter were tested as independent variables with the binary logistic model. The survival probability was influenced by node part and culm diameter significantly. The third and fifth node parts showed 0.12 (8X higher failure probability) and 0.02 (50X higher failure probability) times less survival probability. It means the survival probability will be increased by using older and lower part of cuttings during a vegetative growth stage before inflorescences of M. xgiganteus.

Survival analysis of bank loan repayment rate for customers of Hawassa commercial bank of Ethiopaia

  • Kitabo, Cheru Atsmegiorgis;Kim, Jong Tae
    • Journal of the Korean Data and Information Science Society
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    • v.25 no.6
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    • pp.1591-1598
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    • 2014
  • The reviews of the balance sheet of commercial banks showed that loan item constitutes the largest portion of bank's assets. Although the sector has highest rate of profit, it possesses the greatest risk. Identifying factors that can contribute in lifting-up the loan repayment rate of customers of Hawassa district commercial bank is the major goal of this study. A sample of 183 customers who took loan from October, 2005 to April, 2012 was taken from the bank record. Kaplan-Meier estimation method and univariate Cox proportional hazard model were applied to identify factors affecting bank loan repayment rate. The result from Kaplan-Meier survival estimation revealed that the loan repayment rate is significantly related with loan type, and previous loan experience, educational level and mode of repayment. The log-rank test indicates that the survival probability of loan customers is not statistically different in repaying the loan among groups classified by sex. Moreover, the univariate Cox proportional hazard model result portrayed that educational level, having previous loan experience, mode of repayment, collateral type and purpose of loan are significantly related with loan repayment rate of customers commercial bank. Hence, banks should design loan strategies giving special emphasis on the significant factors while they are giving loans to their customers.

Analysis of Factors Affecting First Job Exit (첫 일자리 이탈 영향요인 분석)

  • Hwang, Kwanghoon
    • Journal of Labour Economics
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    • v.43 no.2
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    • pp.41-74
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    • 2020
  • In this study, using the job history data of the Youth Panel(1-12th year: 2007 ~ 2018) of the Korea Employment Information Service, it is found that characteristics and duration distribution of first jobs of wage and salary worker, and estimated the factors of first job exit by utilizing survival analysis. As a result of the analysis, regular workers are less likely to leave their first jobs than temporary/daily workers. In addition, the group with a high degree of major congruence was found to have a lower chance of leaving the first job than the group with a major mismatch. And the higher the income level, the lower the probability of departure, which shows that the possibility of leaving low-income workers is very high.

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Application of the Weibull-Poisson long-term survival model

  • Vigas, Valdemiro Piedade;Mazucheli, Josmar;Louzada, Francisco
    • Communications for Statistical Applications and Methods
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    • v.24 no.4
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    • pp.325-337
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    • 2017
  • In this paper, we proposed a new long-term lifetime distribution with four parameters inserted in a risk competitive scenario with decreasing, increasing and unimodal hazard rate functions, namely the Weibull-Poisson long-term distribution. This new distribution arises from a scenario of competitive latent risk, in which the lifetime associated to the particular risk is not observable, and where only the minimum lifetime value among all risks is noticed in a long-term context. However, it can also be used in any other situation as long as it fits the data well. The Weibull-Poisson long-term distribution is presented as a particular case for the new exponential-Poisson long-term distribution and Weibull long-term distribution. The properties of the proposed distribution were discussed, including its probability density, survival and hazard functions and explicit algebraic formulas for its order statistics. Assuming censored data, we considered the maximum likelihood approach for parameter estimation. For different parameter settings, sample sizes, and censoring percentages various simulation studies were performed to study the mean square error of the maximum likelihood estimative, and compare the performance of the model proposed with the particular cases. The selection criteria Akaike information criterion, Bayesian information criterion, and likelihood ratio test were used for the model selection. The relevance of the approach was illustrated on two real datasets of where the new model was compared with its particular cases observing its potential and competitiveness.

Probabilistic failure analysis of underground flexible pipes

  • Tee, Kong Fah;Khan, Lutfor Rahman;Chen, Hua-Peng
    • Structural Engineering and Mechanics
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    • v.47 no.2
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    • pp.167-183
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    • 2013
  • Methods for estimating structural reliability using probability ideas are well established. When the residual ultimate strength of a buried pipeline is exceeded the limit, breakage becomes imminent and the overall reliability of the pipe distribution network is reduced. This paper is concerned with estimating structural failure of underground flexible pipes due to corrosion induced excessive deflection, buckling, wall thrust and bending stress subject to externally applied loading. With changes of pipe wall thickness due to corrosion, the moment of inertia and the cross-sectional area of pipe wall are directly changed with time. Consequently, the chance of survival or the reliability of the pipe material is decreased over time. One numerical example has been presented for a buried steel pipe to predict the probability of failure using Hasofer-Lind and Rackwitz-Fiessler algorithm and Monte Carlo simulation. Then the parametric study and sensitivity analysis have been conducted on the reliability of pipeline with different influencing factors, e.g. pipe thickness, diameter, backfill height etc.

Ovarian Malignancy Probability Score (OMPS) for Appropriate Referral of Adnexal Masses

  • Arab, Maliheh;Honarvar, Zahra;Hosseini-Zijoud, Seyed-Mostafa
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.20
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    • pp.8647-8650
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    • 2014
  • Background: Ovarian cancer is the most common cancer cause of gynecologic cancer deaths. In order to increase the likelihood of patient survival through primary operation by gyneco-oncologists, an appropriate algorithm for referral is considered here. Materials and Methods: Suspicious adnexal mass cases including ovarian malignancy probability score-1 (OMPS1) scores between 2.3-3.65 are re-evaluated by OMPS2. Sensitivity and specificity of each score were determined. Results: Sensitivity and specificity with a 3.82 score of OMPS2 in the studied subgroup (OMPS1 scores between 2.3-3.65) were 64% and 76.9% respectively. Conclusions: Management of OMPS1 scores of below 2.3 with sensitivity of 100% and above 3.65 with specificity of 72.9% is clear. In the subgroup of cases with OMPS1 score between 2.3-3.65, OMPS2 is helpful for triage with a cutoff score of 3.82.

Fitting Cure Rate Model to Breast Cancer Data of Cancer Research Center

  • Baghestani, Ahmad Reza;Zayeri, Farid;Akbari, Mohammad Esmaeil;Shojaee, Leyla;Khadembashi, Naghmeh;Shahmirzalou, Parviz
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7923-7927
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    • 2015
  • Background: The Cox PH model is one of the most significant statistical models in studying survival of patients. But, in the case of patients with long-term survival, it may not be the most appropriate. In such cases, a cure rate model seems more suitable. The purpose of this study was to determine clinical factors associated with cure rate of patients with breast cancer. Materials and Methods: In order to find factors affecting cure rate (response), a non-mixed cure rate model with negative binomial distribution for latent variable was used. Variables selected were recurrence cancer, status for HER2, estrogen receptor (ER) and progesterone receptor (PR), size of tumor, grade of cancer, stage of cancer, type of surgery, age at the diagnosis time and number of removed positive lymph nodes. All analyses were performed using PROC MCMC processes in the SAS 9.2 program. Results: The mean (SD) age of patients was equal to 48.9 (11.1) months. For these patients, 1, 5 and 10-year survival rates were 95, 79 and 50 percent respectively. All of the mentioned variables were effective in cure fraction. Kaplan-Meier curve showed cure model's use competence. Conclusions: Unlike other variables, existence of ER and PR positivity will increase probability of cure in patients. In the present study, Weibull distribution was used for the purpose of analysing survival times. Model fitness with other distributions such as log-N and log-logistic and other distributions for latent variable is recommended.

Analysis of the Shell Height Frequencies on the Fresh-Water Cockle, Corbicula elatior, by Means of Probability Graph (확률도에 의한 재첩(Corbicula elatior) 각고빈도의 분석)

  • PARK Sing Won;LEE Sung Hun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.1 no.1
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    • pp.31-43
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    • 1968
  • 1. Shell height frequencies of the fresh-water cockle, Corbicula elatior, sampled in the period of 1960 to 1963, are analyzed to assess the age composition and average growth pattern. Cumulative frequencies in a sample are traced on a probability scale, and the points of inflection on a probability graph are assumed to dissect age groups. 2. Seasonal growth of Corbicula elatior in the Naktong River ill as follows: Young cockles settle down on river-bed by June and grow rapidly during the summer season, reaching 14mm in shell height by October. From October to April the growth is very slow. The rapid growth in the second year starts around in May. 3. Survival rate per year for Corbicula elatior in the Naktong River is estimated to be $5\~10\%$ by age composition.

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Retrospective analysis of 8th edition American Joint Cancer Classification: Distal cholangiocarcinoma

  • Atish Darshan Bajracharya;Suniti Shrestha;Hyung Sun Kim;Ji Hae Nahm;Kwanhoon Park;Joon Seong Park
    • Annals of Hepato-Biliary-Pancreatic Surgery
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    • v.27 no.3
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    • pp.251-257
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    • 2023
  • Backgrounds/Aims: This is a retrospective analysis of whether the 8th edition American Joint Committee on Cancer (AJCC) was a significant improvement over the 7th AJCC distal extrahepatic cholangiocarcinoma classification. Methods: In total, 111 patients who underwent curative resection of mid-distal bile duct cancer from 2002 to 2019 were included. Cases were re-classified into 7th and 8th AJCC as well as clinicopathological univariate and multivariate, and Kaplan-Meier survival curve and log rank were calculated using R software. Results: In patient characteristics, pancreaticoduodenectomy/pylorus preserving pancreaticoduodenectomy had better survival than segmental resection. Only lymphovascular invasion was found to be significant (hazard ratio 2.01, p = 0.039) among all clinicopathological variables. The 8th edition AJCC Kaplan Meier survival curve showed an inability to properly segregate stage I and IIA, while there was a large difference in survival probability between IIA and IIB. Conclusions: The 8th distal AJCC classification did resolve the anatomical issue with the T stage, as T1 and T3 showed improvement over the 7th AJCC, and the N stage division of the N1 and N2 category was found to be justified, with poorer survival in N2 than N1. Meanwhile, in TMN staging, the 8th AJCC was able differentiate between early stage (I and IIA) and late stage (IIB and III) to better explain the patient prognosis.