• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.112-120
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• 2015

Statistical trend analysis using the data from the National Groundwater Quality Monitoring Network (NGQMN) of Korea was conducted to establish a new groundwater quality management framework. Sen’s test, a non-parametric statistical method for trend analysis, was used to determine the linear trend of the groundwater quality data. The analysis was conducted at different confidence levels (i.e., at 70, 80, 90, 95, and 99% confidence levels) for three of groundwater quality parameters, i.e., nitrate-nitrogen, chloride, and pH, which have sufficient time series of the NGQMN data between 2007 and 2013. The results showed that different trends can be determined for different depths even for the same monitoring site and the numbers of wells having significant trends vary with different confidence levels. The wells with increasing or decreasing trends were far less than the wells with no trend. Chloride had more wells with increasing trend than other parameters. On the other hand, nitrate-nitrogen had the most wells with increasing trend and concentration exceeding 75% of the threshold values (TVs). Based on the methodology used for this study, we suggest including groundwater TVs and trend analysis to evaluate groundwater quality and to establish an advanced groundwater quality management framework.

• 한국군사과학기술학회지
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• 제14권5호
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• pp.859-870
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• 2011

The purpose of this paper is to develop reliability analysis procedures for repairable systems with interval failure time data and apply the procedures for assessing the storage reliability of a subsystem of a certain type of guided missile. In the procedures, the interval failure time data are converted to pseudo failure times using the uniform random generation method, mid-point method or equispaced intervals method. Then, such analytic trend tests as Laplace, Lewis-Robinson, Pair-wise Comparison Nonparametric tests are used to determine whether the failure process follows a renewal or non-renewal process. Monte Carlo simulation experiments are conducted to compare the three conversion methods in terms of the statistical performance for each trend test when the underlying process is homogeneous Poisson, renewal, or non-homogeneous Poisson. The simulation results show that the uniform random generation method is best among the three. These results are applied to actual field data collected for a subsystem of a certain type of guided missile to identify its failure process and to estimate its mean time to failure and annual mean repair cost.

• International Journal of Advanced Culture Technology
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• 제8권3호
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• pp.216-222
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• 2020

The purpose of this study was to predict the performance of female weightlifters using time series analysis. Based on this purpose, a time series analysis was used to calculate the performance prediction model for women(58kg) among the domestic women weightlifters who participated in the Olympics. As a result of creating time series data based on 10 years of record and then evaluating the sequential charts of each athlete group, the female athletes' records did not show any seasonality or difference. In addition, after examining the independence of the data through the creation of a time series model, it was shown that the models produced conformed to the criteria for compliance and that there was no difference in the data, but there was a trend. Accordingly, Holt linear trend analysis of the exponential smoothing model was applied. As a result of deriving the prediction model of the athletes through this process, it was found that the women (58kg) who participated in the Olympics continued to improve within the range of 166.11kg to 184.1kg.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2010년도 춘계 학술발표회 및 심포지엄
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• pp.200-201
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• 2010

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3673-3676
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• 2015

To observe and analyze the characteristic trend of cancer patients hospitalized for the first time in Shanxi Tumor Hospital from 2001 to 2010, clinical data including case number, age, gender, and frequency of different tumor occurrences were collected and statistically analyzed. Results: (i) From 2001 to 2010, the number of cancer patients hospitalized for the first time increased by 1.3-fold; (ii) The patient overall average age also increased from 51.8 to 54.4, for males from 55.5 to 58.7 and females from 48.4 to 51.1, respectively. (iii) Male patients accounted for 43-48% and females accounted for 52-57% of the total. The percentage of female patients was higher than that of male patients in every year and showed an upward trend over the years, while that of the males showed a downward trend (${\chi}^2=7.031$, p=0.008); (iv) Among the top 6 most common cancers, lung, cervical, esophageal, colorectal and breast cancers tended to increase over the years (p<0.05), but not gastric cancer (p=0.423). Conclusions: (i) The number of cancer patients hospitalized for the first time during the past 10 years increased year by year, and was higher for female than male; (ii) the average age of patients increased year after year and was greater for male than female; (iii) the number of patients with lung cancer, cervical cancer, esophageal cancer, colorectal cancer and breast cancer increased over years.

• 대한공간정보학회지
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• 제18권4호
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• pp.109-117
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• 2010

본 논문은 용수공급 2축의 한방향인 공급관리의 효율화를 개선하는 한 방안을 제시하는데 그 궁극적인 목적을 두고 있다. 그 총체적 접근의 일환으로 생활용수 중 상업용수를 대상으로 공간분석 대상지 선정, 센서 설치위치 선정, 센서 및 서버시스템의 설치, 실시간 데이터 모니터링 등의 일련의 과정을 시도했다. 이러한 과정을 거쳐 수집된 실시간 데이터 분석을 통해 요일별, 월별 용수사용 추세패턴 모형을 개발하였다. 또한 개발된 추세패턴 모형과 GIS시스템의 연계방안을 제안하였다. 모형의 신뢰도 향상과 더불어 상기 제시된 접근 및 결과는 물사용 예측행정 및 관리를 위한 주요한 도구의 역할을 수행할 수 있을 것으로 기대된다.

• 한국정보전자통신기술학회논문지
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• 제15권5호
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• pp.423-432
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• 2022

본 논문은 학술연구자들이 COVID-19 관련 논문의 전체적인 연구 동향을 파악할 수 있도록 한다. KCI 사이트에서 수집한 2020년 1월부터 2022년 7월까지 총 10,599편의 COVID-19 관련 논문 정보를 LDA 토픽 모델링으로 분석한 결과를 제시한다. 또한 학술연구자들이 자신의 관심 연구분야의 토픽을 쉽게 파악할 수 있도록 LDA 토픽 모델링의 결과를 주요 연구 카테고리별로 분석하고, 토픽별로 연구가 많이 이루어지는 세부 연구 카테고리 정보를 분석한다. 학술연구자들이 시간의 흐름에 따른 연구 토픽의 추세(trend)를 파악하는 것은 연구 동향을 파악하는데 매우 중요하다. 따라서 이를 위해 본 논문에서는 시계열 분해를 사용하여 토픽들의 추세(trend)를 분석하여 제시한다.

• 한국농공학회논문집
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• 제57권6호
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• pp.153-162
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• 2015

In this study, we analyzed the trends of water quality along the main stream in Nakdong river basin using the recent data and seasonal Mann-Kendall test. Monthly averaged values of DO, BOD, SS, COD, TN, and TP from 1989 to 2014 for 14 stations (including 2 TMDLs stations) were used in the study. The trend analysis results showed that BOD and TP at most stations has decreasing temporal trend except a few stations while COD and SS showed increasing trend at most stations. Temporal trends in TN at 8 stations were found to be statistically significant and 5 of them showed increasing temporal trend. Temporally averaged BOD, COD, TN and TP were generally increasing as going downstream and the worst water quality were found at Goryeong and Hyunpung station. Overall, water quality of Nakdong river especially in COD, SS, and TN getting worse in time at most stations and as going downstream.

• 한국멀티미디어학회논문지
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• 제6권7호
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• pp.1266-1276
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• 2003

인터넷 환경에서는 일반 정보에 비해 수십 배 또는 수백 배가 큰 음성과 영상을 포함한 멀티미디어 정보가 전송된다. 네트워크 관리를 위한 분석 유형들은 실시간 분석, 기본분석과 심화분석으로 구성되며, 심화분석은 특정 object들에 대해 일정기간 주기 적으로 경향정보를 수집하여 네트워크 상태를 분석하는데 유용하다. 심화분석 용 경향정보 수집을 위해 SNMP 적용 시 관리자의 폴링에 대해 에이전트가 매번 응답해야 하기 때문에 네트워크 부하 증가, 응답시간 지연, 데이터 수집의 정확성 감소를 초래한다. 본 논문에서는 기존 SNMP PDU에 시간변수를 추가하여 심화분석 시에 관리자와 에이전트간 불필요한 트래픽 발생을 최소화하고, 보다 정확하게 경향정보를 수집할 수 있는 효율적인 방안을 제안하고 구현하였다. 시험 분석 결과 기존 SNMP와 호환성을 유지하면서 네트워크 트래픽 부하가 감소하였으며, 정보수집의 정확도가 증가하였다.

• Communications for Statistical Applications and Methods
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• 제7권2호
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• pp.513-523
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• 2000

The X-12-ARIMA program was utilized on the analysis of the time series trend on 76 Korean industrial activities data in order to ensure that the trading day effect adjustment as well as the seasonal effect adjustment is needed to extract the fundamental trend-cycle factors from various economic time series data. The trading day effect is strongly correlated with the activity of production and shipping but not with the activity of inventory. Furthermore, the industrial activities were classified with respect to the sensitivity on the tranding day effect.