• Title, Summary, Keyword: trend analysis

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THE IMPLEMENTATION METHOD AND TEST OF TELEMETRY TREND ANALYSIS IN KOMPSAT-2

  • Kim Myungja;Jung Won-Chan;Kim Jae-Hoon
    • Bulletin of the Korean Space Science Society
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    • pp.235-238
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    • 2004
  • In this paper, we will present the implementation method of telemetry trend analysis in KOMPSAT-2 (KOrea Multi Purpose SATellite II), and then we will show the test result of trend analysis with telemetry data. Trend Analysis function is one of the module of Satellite Operations Subsystem and that analyzes the telemetry data of satellite state of health and telemetry trend for operation support. With this system many clients can analyze telemetry data simultaneously.

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Nano Technology Trend Analysis Using Google Trend and Data Mining Method for Nano-Informatics (나노 인포매틱스 기반 구축을 위한 구글 트렌드와 데이터 마이닝 기법을 활용한 나노 기술 트렌드 분석)

  • Shin, Minsoo;Park, Min-Gyu;Bae, Seong-Hun
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.40 no.4
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    • pp.237-245
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    • 2017
  • Our research is aimed at predicting recent trend and leading technology for the future and providing optimal Nano technology trend information by analyzing Nano technology trend. Under recent global market situation, Users' needs and the technology to meet these needs are changing in real time. At this point, Nano technology also needs measures to reduce cost and enhance efficiency in order not to fall behind the times. Therefore, research like trend analysis which uses search data to satisfy both aspects is required. This research consists of four steps. We collect data and select keywords in step 1, detect trends based on frequency and create visualization in step 2, and perform analysis using data mining in step 3. This research can be used to look for changes of trend from three perspectives. This research conducted analysis on changes of trend in terms of major classification, Nano technology of 30's, and key words which consist of relevant Nano technology. Second, it is possible to provide real-time information. Trend analysis using search data can provide information depending on the continuously changing market situation due to the real-time information which search data includes. Third, through comparative analysis it is possible to establish a useful corporate policy and strategy by apprehending the trend of the United States which has relatively advanced Nano technology. Therefore, trend analysis using search data like this research can suggest proper direction of policy which respond to market change in a real time, can be used as reference material, and can help reduce cost.

Trend analysis of aridity index for southeast of Korea

  • Ghafouri-Azar, Mona;Bae, Deg-Hyo
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.193-193
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    • 2017
  • Trend analysis can enhance our knowledge of the dominant processes in the area and contribute to the analysis of future climate projections. The results of previous studies in South Korea showed that southeast regions of Korea had the highest value of evapotranspiration. Thereby, it is of interest to determine the trend analysis in hydrological variables in this area. In this study, the recent 35 year trends of precipitation, reference evapotranspiration, and aridity index in monthly and annual time scale will be analyzed over three stations (Pohang, Daegu, and Pusan) of southeast Korea. After removing the significant Lag-1 serial correlation effect by pre-whitening, non-parametric statistical Mann-Kendall test was used to detect the trends. Also, the slope of trend of the Mann-Kendall test was determined by using Theil-Sen's estimator. The results of the trend analysis of reference evapotranspiration on the annual scale showed the increasing trend for the three mentioned stations, with significant increasing trend for Pusan station. The results obtained from this research can guide development if water management practices and cropping systems in the area that rely on this weather stations. The approaches use and the models fitted in this study can serve as a demonstration of how a time series trend can be analyzed.

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Nonstationary Frequency Analysis of Hydrologic Extreme Variables Considering of Seasonality and Trend (계절성과 경향성을 고려한 극치수문자료의 비정상성 빈도해석)

  • Lee, Jeong-Ju;Kwon, Hyun-Han;Moon, Young-Il
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.581-585
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    • 2010
  • This study introduced a Bayesian based frequency analysis in which the statistical trend seasonal analysis for hydrologic extreme series is incorporated. The proposed model employed Gumbel and GEV extreme distribution to characterize extreme events and a fully coupled bayesian frequency model was finally utilized to estimate design rainfalls in Seoul. Posterior distributions of the model parameters in both trend and seasonal analysis were updated through Markov Chain Monte Carlo Simulation mainly utilizing Gibbs sampler. This study proposed a way to make use of nonstationary frequency model for dynamic risk analysis, and showed an increase of hydrologic risk with time varying probability density functions. In addition, full annual cycle of the design rainfall through seasonal model could be applied to annual control such as dam operation, flood control, irrigation water management, and so on. The proposed study showed advantage in assessing statistical significance of parameters associated with trend analysis through statistical inference utilizing derived posterior distributions.

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Parametric and Non-parametric Trend Analyses for Water Levels of Groundwater Monitoring Wells in Jeju Island (제주도 지하수 관측망 수위에 대한 모수 및 비모수 변동경향 분석)

  • Choi, Hyun-Mi;Lee, Jin-Yong
    • Journal of Soil and Groundwater Environment
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    • v.14 no.5
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    • pp.41-50
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    • 2009
  • Water levels in groundwater monitoring wells of Jeju Island were analyzed using parametric and non-parametric trend analyses. Number of used monitoring wells in the analysis are 94 among totally 106 monitoring wells and the monitoring period is greater than single year, from 2001 to 2009. For the trend analysis, both parametric (linear regression) and nonparametric (Mann-Kendall trend test and Sen's trend test) methods were adopted. Results of the linear regression analysis on daily basis indicated that about 58.5% of the monitoring wells showed a decreasing trend, and analysis using monthly median indicated that about 79.8% showed a decreasing trend. The Mann-Kendall trend test and Sen's trend test with monthly median values in confidence levels of 95% and 99% showed the same analysis results. In confidence level of 95%, 32% were decreased, 3% were increased and the remains showed no trend. However, in confidence level of 99%, 16% were decreased, 2% were increased and the remains showed no trend. The largest decline rates of water levels were detected mainly at the coast of the northwestern and southwestern parts, which is expected to closely related to the increased pumping in the urban area and tourist resort.

A Study on the Water Quality Changes of TMDL Unit Watershed in Guem River Basin Using a Nonparametric Trend Analysis (비모수 경향분석법 적용을 통한 금강수계 총량관리 단위유역의 수질변화 연구)

  • Kim, Eunjung;Kim, Yongseok;Rhew, Doughee;Ryu, Jichul;Park, Baekyung
    • Journal of Korean Society on Water Environment
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    • v.30 no.2
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    • pp.148-158
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    • 2014
  • In order to assess the effect of TMDLs management and improve that in the future, it is necessary to analyze long-term changes in water quality during management period. Therefore, long term trend analysis of BOD was performed on thirty monitoring stations in Geum River TMDL unit watersheds. Nonparametric trend analysis method was used for analysis as the water quality data are generally not in normal distribution. The monthly median values of BOD during 2004~2010 were analyzed by Seasonal Mann-Kendall test and LOWESS(LOcally WEighted Scatter plot Smoother). And the effect of Total Maximum Daily Loads(TMDLs) management on water quality changes at each unit watershed was analyzed with the result of trend analysis. The Seasonal Mann-Kendall test results showed that BOD concentrations had the downward trend at 10 unit watersheds, upward trend at 4 unit watersheds and no significant trend at 16 unit watersheds. And the LOWESS analysis showed that BOD concentration began to decrease after mid-2009 at almost all of unit watersheds having no trend in implementation plan watershed. It was estimated that TMDLs improved water quality in Geum River water system and the improvement of water quality was made mainly in implementation plan unit watershed and tributaries.

Long-Term Trend Analyses of Water Qualities in Mangyung Watershed (비모수 통계기법을 이용한 만경강 유역의 장기간 수질 경향 분석)

  • Lee, Hye Won;Park, Seoksoon
    • Journal of Korean Society on Water Environment
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    • v.24 no.4
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    • pp.480-487
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    • 2008
  • Spatial and temporal analyses of water qualities were performed for 11 monitoring stations located in Mangyung watershed in order to analyze the trends of monthly water quality data of Biochemical Oxygen Demand (BOD), Total Nitrogen (TN) and Total Phosphorus (TP) measured from 1995 to 2004. The long-term trends were analyzed utilizing Seasonal Mann-Kendall test, LOWESS and three-dimensional graphs were constructed with respect to distance and time. The graph can visualize spatial and temporal trend of the long-term water quality in a large river system. The results of trend analysis indicated that water quality of BOD and TN showed the downward trend. This quantitive and quantitative analysis is the useful tool to analyze and display the long-term trend of water quality in a large river system.

The Study for Comparative Analysis of Software Failure Time Using EWMA Control Chart (지수 가중 이동 평균 관리도를 이용한 소프트웨어 고장 시간 비교분석에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.8 no.3
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    • pp.33-39
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    • 2008
  • Software failure time presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing. For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offer information of outline content. In this paper, we discuss exponentially weighted moving average chart, in measuring failure time. In control, exponentially weighted moving average chart's uses are efficiency case of analysis with knowing information, Using real software failure time, we are proposed to use exponentially weighted moving average chart and comparative analysis of software failure time.

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Suggestion of a Groundwater Quality Management Framework Using Threshold Values and Trend Analysis (문턱값과 추세분석을 이용한 지하수 수질관리체계 구축을 위한 연구)

  • An, Hyeonsil;Jee, Sung-Wook;Lee, Soo Jae;Hyun, Yunjung;Yoon, Heesung;Kim, Rak-Hyeon
    • Journal of Soil and Groundwater Environment
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    • v.20 no.7
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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.