• Title/Summary/Keyword: Time trend analysis

Search Result 1,585, Processing Time 0.037 seconds

A Study of Discriminant Analysis about Korean Quick Response System Adoption (국내(國內) 신속대응(迅速對應)시스템 도입업체(導入業體)의 판별분석(判別分析) 연구(硏究))

  • Ko, Eun-Ju
    • Journal of Fashion Business
    • /
    • v.4 no.3
    • /
    • pp.103-114
    • /
    • 2000
  • The purpose of this study was to test the discriminant analysis model of Quick Response system and to examine the detailed relationship between each discriminant factor and Quick Response adoption. In this discriminant analysis model of Quick Response system, firm size, strategic type, product category, fashion trend, selling time and the Quick Response benefits were included as discriminant factors. Onehundred and two subjects were randomly selected for the survey study and discriminant analysis, descriptive analysis, t-test, and x square test were used for the data analysis. The results of this study were: 1. Wilks Lambda and F value support the discriminant analysis model that, taken together firm size, strategic type, product category, fashion trend, selling time and the Quick Response benefits significantly help to explain Quick Response adoption. 2. The importance of discriminant ability was, in order, firm size, the Quick Response benefits, women's wear, fashion trend, analyzer, selling time, reactor, defender and men's wear. 3. The discriminant function had the high hit ratio, so this can be well used for the classification of Quick Response adoption/nonadoption.

  • PDF

Power Test of Trend Analysis using Simulation Experiment (모의실험을 이용한 경향성 분석기법의 검정력 평가)

  • Ryu, Yongjun;Shin, Hongjoon;Kim, Sooyoung;Heo, Jun-Haeng
    • Journal of Korea Water Resources Association
    • /
    • v.46 no.3
    • /
    • pp.219-227
    • /
    • 2013
  • Time series data including change, jump, trend and periodicity generally have nonstationarity. Especially, various methods have been proposed to identify the trend about hydrological time series data. However, among various methods, evaluation about capability of each trend test has not been done a lot. Even for the same data, each method may show the different result. In this study, the simulation was performed for identification about the changes in trend analysis according to the statistical characteristics and the capability in the trend analysis. For this purpose, power test for the trend analysis is conducted using Men-Kendall test, Hotelling-Pabst test, t test and Sen test according to the slope, sample size, standard deviation and significance level. As a result, t test has higher statistical power than the others, while Mann-Kendall, Hotelling-Pabst, and Sen tests were similar results.

The Study for Process Capability Analysis of Software Failure Interval Time (소프트웨어 고장 간격 시간에 대한 공정능력분석에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
    • /
    • v.7 no.2
    • /
    • pp.49-55
    • /
    • 2007
  • 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. From the subdivision of this analysis, new attemp needs the side of the quality control. In this paper, we discuss process capability analysis using process capability indexs. Because of software failure interval time is pattern of nonnegative value, instead of capability analysis of suppose to normal distribution, capability analysis of process distribution using to Box-Cox transformation is attermpted. The used software failure time data for capability analysis of process is SS3, the result of analysis listed on this chapter 4 and 5. The practical use is presented.

  • PDF

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
    • /
    • 2010.05a
    • /
    • pp.581-585
    • /
    • 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.

  • PDF

Dynamic Simple Correspondence Analysis

  • Choi Yong-Seok;Hyun Gee Hong;Seo Myung Rok
    • Communications for Statistical Applications and Methods
    • /
    • v.12 no.1
    • /
    • pp.199-205
    • /
    • 2005
  • In general, simple correspondence analysis has handled mainly correspondence relations between the row and column categories but can not display the trends of their change over the time. For solving this problem, we will propose DSCA(Dynamic Simple Correspondence Analysis) of transition matrix data using supplementary categories in this study, Moreover, DSCA provides its trend of the change for the future by predicting and displaying trend toward the change from a standard point of time to the next.

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
    • /
    • v.24 no.4
    • /
    • pp.480-487
    • /
    • 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.

Confounding of Time Trend with Dropout Process in Longitudinal Data Analysis

  • Kim, Ji-Hyun;Choi, Hye-Hyun
    • Communications for Statistical Applications and Methods
    • /
    • v.9 no.3
    • /
    • pp.703-713
    • /
    • 2002
  • In longitudinal studies, outcomes are repeatedly measured over time for each subject. It is common to have missing values or dropouts for longitudinal data. In this study time trend in longitudinal data with dropouts is of concern. The confounding of time trend with dropout process is investigated through simulation studies. Some simulation results are reported for binary responses as well as continuous responses with patterns of dropouts varying. It has been found that time trend is not confounded with random dropout process for binary responses when it is estimated using GEE.

The Trend on the Change of the Cherry Blossom Flowering Time due to the Temperature Change (기온 변화에 따른 벚꽃 개화시기의 변화 경향)

  • Lee, Seungho;Lee, Kyoungmi
    • Journal of Environmental Impact Assessment
    • /
    • v.12 no.1
    • /
    • pp.45-54
    • /
    • 2003
  • The purpose of this paper is to examine the trend on the change of the cherry blossom flowering time due to the temperature change by selecting regions that have long periods of cherry blossom flowering time data as cases. With the flowering time data, the distribution of cherry blossom flowering time, time series change and change rate of cherry blossom flowering time were analyzed. Also, the correlation between the cherry blossom flowering time and the temperature was analyzed. The flowering of cherry blossom is earlier in metropolitan areas, and in the east coastal region than the west coastal region. The trend on the change of the cherry blossom flowering time is very similar to change the temperature. The change rate of the cherry blossom flowering time is rising up in the whole regions under study, and is relatively high in metropolitan areas. Especially, the cherry blossom flowering time festinated greatly in Pohang that is one of the heavily industrialized cities. From the analysis of correlation analysis between cherry blossom flowering time and temperature elements, the cherry blossom flowering time is highly related with mean temperature of March, which the month is just before the beginning of flowering.

Trend Analysis Service using a Temporal Web Ontology Language in News Domains (시간 웹 온톨로지 언어를 이용한 뉴스 동향 분석 서비스)

  • Kim, Sang-Kyun;Lee, Kyu-Chul
    • The Journal of Society for e-Business Studies
    • /
    • v.12 no.3
    • /
    • pp.133-150
    • /
    • 2007
  • In this paper we investigate a trend analysis service using Semantic Web technology in a news domain. The trend analysis service can provide more intelligent answers rather than the answer given In current news search engines since it can analyze the passage of time and the relation among news. In order to provide the trend analysis service, the capability of temporal reasoning is required, but the Semantic Web language such as OWL does not support the reasoning capability. Therefore, we propose a language TL-OWL(Temporal Web Ontology Language) extending OWL with the temporal reasoning.

  • PDF

A Study of Non-parametric Statistical Tests to Analyze Trend in Water Quality Data (수질자료의 추세분석을 위한 비모수적 통계검정에 관한 연구)

  • Lee, Sang-Hoon
    • Journal of Environmental Impact Assessment
    • /
    • v.4 no.2
    • /
    • pp.93-103
    • /
    • 1995
  • This study was carried out to suggest the best statistical test to analyze the trend in monthly water quality data. Traditional parametric tests such as t-test and regression analysis are based on the assumption that the underlying population has a normal distribution and regression analysis additionally assumes that residual errors are independent. Analyzing 9-years monthly COD data collected at Paldang in Han River, the underlying population was found to be neither normal nor independent. Therefore parametric tests are invalid for trend detection. Four Kinds of nonparametric statistical tests, such as Run Test, Daniel test, Mann-Kendall test, and Time Series Residual Analysis were applied to analyze the trend in the COD data, Daniel test and Mann-Kendall test indicated upward trend in COD data. The best nonparametric test was suggested to be Daniel test, which is simple in computation and easy to understand the intuitive meaning.

  • PDF