• Journal of Korean Society on Water Environment
• /
• v.28 no.6
• /
• pp.933-942
• /
• 2012

The purpose of this study is to evaluate the degree of waterbody impairment according to the flow conditions and present to the appropriate water quality improvement alternatives using observed water quality and flow for Total Maximum Daily Load (TMDL) implementation at 39 unit watersheds the nakdong river basin. Observed water quality data for 7 years are divided into five cumulative flow frequency group and comparing the each observed water quality data and TMDL Target water quality (TWQ) the last evaluate the water quality is impaired group. We found that the cumulative flow frequency group-specific the average excess rate of V group was the highest (32.86%), followed by the IV group (26.04%), group III (23.36%), II group (22.67%), I group (20.70%), the degree of impaired waterbody tended to be inversely proportional to the flow rate. Resulted from cumulative flow frequency group of impaired water quality assessment, 13 unit watersheds are impaired from a group IV and group V affected by point sources. Therefore, improvement of sewage discharge and the initial composition of the riparian buffer zone are needed. Nakbon F, Namkang D and Namkang E within 13 unit watersheds are impaired from group II and III affected by non-point sources. Therefore, application of Best Management Practices (BMPs) is needed for these watersheds. Evaluation of impaired waterbody using Cumulative flow frequency group is able to determine the extent of the judgment to TWQ exceeded by the flow conditions and helps proper setting Standard flow and planning pollutant reduction for TMDL.

• Archives of Plastic Surgery
• /
• v.35 no.5
• /
• pp.514-520
• /
• 2008

Purpose: Many attempts have been made to describe ideal facial proportions for over two thousands year and constantly lasted till now. Dr. Marquardt has derived supposedly ideal facial proportions from the facial golden mask using golden ratio of 1 : 1.618. On the other hand, facial reducing surgeries such as mandible angle reduction are popularized in Asia because the width of mid and lower face of Korean is recognized to be wider. The purpose is to analyze characters of Korean university students' faces in horizontal plane and establish the objective data for facial width distributions and clinical applications. Methods: We applied the facial golden mask to the photographs in 1000 cases, compared the width of mid and lower face between the facial golden mask and Korean university students' faces. And we first calculated the horizontal ratio(HR) of middle and lower face each for using comparative scale of width, facial golden mask. We divided 1,000 cases into 3 groups by degrees of HR and analyzed data of HR on each groups. Using calculated horizontal ratio, we newly invented the cumulative frequency of distribution graphs in Korean university students' faces. Results: Mean data of HR were over 1.0 in all groups, which means that Korean university students' faces are typically wider than facial golden mask in horizontal planes. And this study was statistically significant(p- value < 0.05). Clinically using the cumulative frequency distributions of Korean university students' face width, we can easily explain changes of facial width to patient after facial reducing surgery and describe the changes into objective data. Conclusion: This study concludes thatKorean university students' faces are wider than facial golden mask is significantly true and the cumulative frequency of distribution graphs are expected to be widely used for comparison of results in facial reducing surgery.

• The Korean Journal of Applied Statistics
• /
• v.20 no.2
• /
• pp.357-371
• /
• 2007

For the time-to-failure data with competing risks, cumulative incidence functions (CIFs) are commonly estimated using nonparametric methods. If the cases of events due to the cause of primary interest are infrequent relative to other cause of failure, nonparametric methods may result in rather imprecise estimates for CIF. In such cases, Bryant et al. (2004) suggested to model the cause-specific hazard of primary interest parametrically, while accounting for the other modes of failure using nonparametric estimator. We represented the semiparametric cumulative incidence estimator and extended to the model of Weibull and log-normal distribution. We also conducted simulations to access the performance of the semiparametric cumulative incidence estimators and to investigate the impact of model misspecification in log-normal cause-specific hazard model.

• Journal of the Korean Society for Railway
• /
• v.17 no.1
• /
• pp.52-58
• /
• 2014

Plastic deformation of roadbed influences the stability and maintenance of concrete slab track. Long-term plastic deformation in a railway roadbed is generated primarily due to accumulated inelastic strains caused by repeated passing of trains. Prediction of cumulative plastic deformation is important in cost-effective maintenance of railway tracks as well as for the safe operation of trains. In this study, the vertical displacements in railway roadbeds with different thicknesses of reinforced roadbed were computed. Parameters of the power model for cumulative plastic strain were calibrated by using the data from triaxial tests and full-scale loading tests. Results of three-dimensional finite element analyses of standard roadbed sections provide us with design guidelines for the selection of the thickness of reinforced roadbed.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.4
• /
• pp.1-9
• /
• 2002

The distribution characteristics of data retention time for DRAM was studied in connection with the probability distribution of the cell parameters. Using the cell parameters and the transient characteristics of cell node voltage, data retention time was investigated. The activation energy for dielectric layer growth on cell capacitance, the recombination trap energy for leakage current in the junction depletion region, and the sensitivity characteristics of sense amplifier were used as the random variables to perform the Monte Carlo simulation, and the probability distributions of cell parameters and distribution characteristics of cumulative failure bit on data retention time in DRAM cells were calculated. we found that the sensitivity characteristics of sense amplifier strongly affected on the tail bit distribution of data retention time.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.6
• /
• pp.137-143
• /
• 2010

A method for improving prediction accuracy through processing time series data has been studied in this research. We have designed techniques to model multiple similar time series data and avoided the shortcomings of single prediction model. We predicted the future changes by effective rules derived from these models. The methods for testing prediction accuracy consists of three types: fixed interval, sliding, and cumulative method. Among the three, cumulative method produced the highest accuracy.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.382-384
• /
• 2004

In this parer, we propose a clustering that perform algorithm using new convergence properties. For detection and optimization of cluster, we use to similarity measure with cumulative probability and to inference the its parameters with MLE. A merits of using the cumulative probability in our method is very effectiveness that robust to noise or unnecessary data for inference the parameters. And we adopt similarity threshold to converge the number of cluster that is enable to past convergence and delete the other influence for this learning algorithm. In the simulation, we show effectiveness of our algorithm for convergence and optimization of cluster in riven data set.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.2
• /
• pp.523-530
• /
• 2016

Most classical control charts assume that processes are serially independent, and autocorrelation among variables makes them unreliable. To address this issue, a variety of statistical approaches has been employed to estimate the serial structure of the process. In this paper, we propose a multioutput least squares support vector regression and apply it to construct a residual multivariate cumulative sum control chart for detecting changes in the process mean vector. Numerical studies demonstrate that the proposed multioutput least squares support vector regression based control chart provides more satisfying results in detecting small shifts in the process mean vector.

• Journal of the Korean Data and Information Science Society
• /
• v.13 no.2
• /
• pp.21-29
• /
• 2002

Several different control statistics to simultaneously monitor dispersion matrix of several quality variables are presented since different control statistics can be used to describe variability. Multivariare cumulative sum (CUSUM) control charts are proposed and the performances of the proposed CUSUM charts are evaluated in terms of average run length (ARL). Multivariate Shewhart charts are also proposed to compare the properties of the proposed CUSUM charts. The numerical results show that multivariate CUSUM charts are more efficient than multivariate Shewhart charts for small or moderate shifts. And we also found that small reference value of the CUSUM chart is more efficient for small shift.

• Journal of Soil and Groundwater Environment
• /
• v.6 no.1
• /
• pp.33-43
• /
• 2001

A calculation technique which estimates natural recharge using groundwater level change was proposed and prepared with the existing techniques using groundwater recession curve during dry days. As a part of estimating natural groundwater recharge nation wide, the reliable data from the national groundwater monitoring network were used and the methodology was applied to the three sites which have enough data (Chungju, Jinju and Kwangju). For this study, seasonal variation of groundwater level change, an analysis of lagging time on groundwater level and cumulative precipitation, and a comparative study for groundwater recharge were conducted.