• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.469-475
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• 2017

Software reliability is one of the most basic and essential problems in software development. In order to detect the software failure phenomenon, the intensity function, which is the instantaneous failure rate in the non-homogeneous Poisson process, can have the property that it is constant, non-increasing or non-decreasing independently at the failure time. In this study, was compared the reliability performance of the software reliability model using the Landely lifetime distribution with the intensity function decreasing pattern and Erlang lifetime distribution from increasing to decreasing pattern in the software product testing process. In order to identify the software failure phenomenon, the parametric estimation was applied to the maximum likelihood estimation method. Therefore, in this paper, was compared and evaluated software reliability using software failure interval time data. As a result, the reliability of the Landely model is higher than that of the Erlang distribution model. But, in the Erlang distribution model, the higher the shape parameter, the higher the reliability. Through this study, the software design department will be able to help the software design by applying various life distribution and shape parameters, and providing software reliability attributes data and basic knowledge to software reliability model using software failure analysis.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.723-729
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• 2017

Objective : Acute subdural hematoma (ASDH) is generally considered a condition that should be managed surgically. However, some patients initially receive conservative treatment, a subset of whom require surgical intervention later. This study aimed to evaluate the predictors of delayed surgical intervention in ASDH patients who are initially managed conservatively. Methods : From January 2007 to December 2015, 842 patients diagnosed with ASDH were treated at our institution. Among them, 158 patients with convexity ASDH were initially treated conservatively. Patients were divided into a delayed surgery group and a conservative group. Demographic characteristics, past medication and medical histories, and radiological and laboratory data were collected by retrospective chart review. Independent risk factors were identified with univariate and multivariate analyses. Results : Twenty-eight patients (17.7%) underwent delayed surgical intervention. Their mean age was 69.0 years, and 82.1% were male. Hypertension, diabetes mellitus, and heart disease prevalence and use of anti-platelet agents did not significantly differ from the conservative group. However, age (p=0.024), previous cerebral infarction history (p=0.026), increased maximal hematoma thickness (p<0.001), midline shifting (p=0.001) and accompanying subarachnoid hemorrhage (p=0.022) on initial brain computed tomography (CT) scan, low hemoglobin level (p<0.001), high leukocyte count (p=0.004), and low glucose level (p=0.002) were significantly associated with delayed surgical intervention. In multivariate analysis, increased maximal hematoma thickness (odds ratio [OR]=1.279, 95% confidence interval [CI] 1.075-1.521; p=0.006), low hemoglobin level (OR=0.673, 95% CI 0.467-0.970; p=0.034), and high leukocyte count (OR=1.142, 95% CI 1.024-1.272; p=0.017) were independent risk factors for delayed surgical intervention. Conclusion : Due to the high likelihood of delayed surgical intervention among minimal ASDH patients with a thicker hematoma on initial brain CT, lower hemoglobin level, and higher leukocyte count, these patients should receive more careful observation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.2
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• pp.127-135
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• 1983

A new approach is developed to analyze the reliability of the earth retaining wall using the concept of probability of failure, instead of conventional factor of safety. Many uncertainties, which are included in the conventional stability analysis, can be excluded by using the stochastic approach. And the reliability, more consistent with the reality, can be obtained by the simulation. The strength parameters of soil properties are assumed to be random variables to follow a generalized beta distribution. The interval [A, B] of the random variables could be determined using the maximum likelihood estimation. The pseudo-random values corresponding to the proposed beta distribution are generated using the rejection method. The probability of failure defined as follows, is obtained by using the Monte Carlo Method. $$P_f=\frac{M}{N}$$ where, $P_f$ : Probability of failure N : Total number of trials M : Total number of failure out of N A computer program is developed for the computation procedure mentioned above. Finally, a numerical example is solved using the developed program.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.3
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• pp.75-83
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• 1984

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; $P_f=M/N$ N: Total number of trials M: Total number of failures Some of the conclusions derived. from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The $F_3/F_2$ ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. From the two models (normal, beta) considered for the distribution of the factor of safety, the beta distribution generally provides lager than normal distribution. 4. Results obtained using the beta and normal models are presented in a nomgraph relating slope height and slop angle to probability of failure.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1550-1556
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• 2017

Objective: This study estimated the genetic parameters for productive and reproductive traits. Methods: The data included production and reproduction records of animals that have calved between 1979 and 2013. The genetic parameters were estimated using multivariate mixed models (DMU) package, fitting univariate and multivariate mixed models with average information restricted maximum likelihood algorithm. Results: The estimates of heritability for milk production traits from the first three lactation records were $0.03{\pm}0.03$ for lactation length (LL), $0.17{\pm}0.04$ for lactation milk yield (LMY), and $0.15{\pm}0.04$ for 305 days milk yield (305-d MY). For reproductive traits the heritability estimates were, $0.09{\pm}0.03$ for days open (DO), $0.11{\pm}0.04$ for calving interval (CI), and $0.47{\pm}0.06$ for age at first calving (AFC). The repeatability estimates for production traits were $0.12{\pm}0.02$, for LL, $0.39{\pm}0.02$ for LMY, and $0.25{\pm}0.02$ for 305-d MY. For reproductive traits the estimates of repeatability were $0.19{\pm}0.02$ for DO, and to $0.23{\pm}0.02$ for CI. The phenotypic correlations between production and reproduction traits ranged from $0.08{\pm}0.04$ for LL and AFC to $0.42{\pm}0.02$ for LL and DO. The genetic correlation among production traits were generally high (>0.7) and between reproductive traits the estimates ranged from $0.06{\pm}0.13$ for AFC and DO to $0.99{\pm}0.01$ between CI and DO. Genetic correlations of productive traits with reproductive traits were ranged from -0.02 to 0.99. Conclusion: The high heritability estimates observed for AFC indicated that reasonable genetic improvement for this trait might be possible through selection. The $h^2$ and r estimates for reproductive traits were slightly different from single versus multi-trait analyses of reproductive traits with production traits. As single-trait method is biased due to selection on milk yield, a multi-trait evaluation of fertility with milk yield is recommended.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.241-253
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• 2009

This study performs the investigation of a long-term variation of annual maximum surge heights(AMSH) and main characteristics of high surge events, and the statistical evaluation of the AMSH using sea level data at Yeosu and Tongyeong tidal stations over more than 30 years. It is found that the long-term uptrends based on the linear regression in the AMSH are 34.5 cm/34 yr at Yeosu and 33.6 cm/31 yr at Tongyeong, which are relatively much higher than those at Sokcho and Mukho in the Eastern Coast. 71% and 68% of the AMSH occur during typhoon's event in Yeosu and Tongyeong tidal stations, respectively, and the highest surge records are mostly produced by the typhoon. The generalized extreme value distribution taking into account of the time variable is applied to detect time trend in annual maximum surge heights. In addition, Gumbel distribution is checked to find which one is best fitted to the data using likelihood ratio test. The return level and its 90% confidence interval are obtained for the statistical prediction of the future trend. The prevention of the growing storm surge damage by the intensified typhoon requires the steady analysis and prediction of the surge events associated with the climate change.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.1
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• pp.31-37
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• 2018

Objective: To evaluate the pregnancy rate and time to pregnancy after timed coitus with or without superovulation in infertile young women younger than 35 years old with low serum $anti-M{\ddot{u}}llerian$ hormone (AMH) levels ( < 25th percentile). Methods: A total of 202 patients younger than 35 years old were recruited retrospectively between 2010 and 2012. Ninety-eight women had normal serum AMH levels (25-75th percentile), 75 women had low serum AMH levels (5th ${\leq}$ & < 25th percentile) and 29 women had very low serum AMH levels ( < 5th percentile), according to reference values for their age group. Results: The clinical pregnancy rate was positively associated with AMH levels, but this trend did not reach statistical significance (43.9% vs. 41.3% vs. 27.6% in the normal, low, and very low AMH groups, respectively). The time to pregnancy was longer in the very low AMH group than in the normal AMH group ($13.1{\pm}10.9months$ vs. $6.9{\pm}6.1months$, p= 0.030). The cumulative live birth rate over 18 months was lower in the very low AMH group than in the normal AMH group, with marginal significance (20.0% vs. 55.9%, p= 0.051). The duration of infertility was negatively correlated with achieving pregnancy (odds ratio, 0.953; 95% confidence interval, 0.914-0.994; p= 0.026). Conclusion: Conservative management, such as timed coitus with or without superovulation, should be considered in young patients who have low ovarian reserve without any infertility factors. However, for women with a long duration of infertility or very low serum AMH levels, active infertility treatment should be considered.

• The Journal of the Korea Contents Association
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• v.13 no.7
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• pp.463-472
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• 2013

The purpose of this study is to examine the relationships among three factors such as the family health, school adjustment and internet addiction, and their subordinated factors. The research is going to clarify if school adjustment has mediating effect in the relationship between the family health and internet addiction. 371 of elementary school students resideing in Dadjeon-city completed questionnaires assessing family health, school adjustment and internet addiction. The sample variance-covariance matrix was analyzed using SPSS 18.0 and AMOS 20.0, the mazimum likelihood minimization function. The goodness of fit was evaluated using the SRMR, RMSEA and its 90% confidence interval, CFI, and TLI. The results are as follows: First, there were significant correlations among family health, school adjustment and internet addiction. Second, the subordinated factors in the family health, school adjustment, and internet addiction regulation are also closely related in the statistically significant positive relationship excepting school adjustment. After conducting the Covariance Structure Analysis to verify the mediating effect of school adjustment in the relationship between the family health and internet addiction, we found that it was appropriate to explain our findings with the structural equation model. when the family health has an effect on internet addiction, the school adjustment partially influences this process. Finally, educational implications and suggestions for future studies are addressed.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.363-369
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• 2015

Chronic pain is one of the leading causes of hospital visits. It not only affects the patients themselves but also has a major negative impact on their families and society. In this study, we investigated epidemiology of musculoskeletal disorders induced chronic pain among general population based on Korea National Health and Nutrition Examination Survey database and also analysed how it influenced on the use of medical services. This study was done by using the data of 5th Korea National Health and Nutrition Examination Survey (KNHANES V), taking aged 20 years and over adults as research subjects. The EuroQoL-5 Dimension Index(EQ-5D) was used as a survey instrument. T-test, chi-square test and multivariate logistic regression were used for statistical analysis. Subjects with chronic pain had a higher likelihood than control group to use medical services(odds ratio : 5.858, confidence interval 3.636-9.438). Controlling for existence of chronic pain, more women were likely to use medical services than men(1.156, 0.707-1.889). Age, gender and household income level did not affect the use of medical services. Proper control of chronic pain is very helpful in improving patient's quality of life and it also accounts for a large proportion in suppressing excessive consumption of medical services. Anesthesia and pain medicine specialists have superior knowledge about analgesics and anticonvulsants than other physicians do and also have specialized skills to perform procedures like nerve blocks in treating chronic pain. Therefore Anesthesia and pain medicine specialists need to play a leading role in managing chronic pain.

• Korean Journal of Clinical Pharmacy
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• v.29 no.2
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• pp.125-132
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• 2019

Objective: To examine the perceptions and attitudes toward spontaneous adverse drug reaction (ADR) reporting system among community pharmacists and identify factors that influence reporting, by implementing a survey. Methods: A structured questionnaire was developed and distributed online. Request for the survey was posted on the website of pharmacy's billing program, and the survey was conducted for 8 days. We collected the participants' response on their work environment, experience of ADR reporting, and their perception and attitude on the reporting system. Multivariate logistic regression was used to evaluate factors influencing ADR reporting. Results: A total of 382 pharmacists participated in the survey. Significant contributing factors for reporting level were age (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.84-0.96), knowledge of reporting method (OR, 53.56; 95% CI, 9.10-315.41), installation of reporting program (OR, 31.92; 95% CI, 4.16-244.75), and encouragement from the Korean pharmaceutical association (OR, 4.13; 95% CI, 1.11-15.35). Regarding the attitude toward spontaneous ADR reporting system, 'lack of time for reporting' (OR, 0.29; 95% CI, 0.15-0.53) and 'complexity of reporting procedure' (OR, 0.51; 95% CI, 0.31-0.84), were associated with a low likelihood of reporting. Conclusion: Our results indicated that the knowledge of ADR reporting method, installation of the reporting program, and encouragement from the Korean Pharmaceutical Association contribute to active reporting. It is necessary to simplify the reporting method, make the ADR reporting program user-friendly, and provide educational interventions to increase participation in spontaneous reporting by the community pharmacists.