• 산업경영시스템학회지
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• 제32권1호
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• pp.11-19
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• 2009

A number of trend test methods, i.e., Military Handbook test and Laplace test etc., have been applied to investigate recurrent failures trend in repairable systems. Existing methods provide information about only existence of trend in the system. In this paper, we propose a new change-point test based on the Schwarz Information Criterion(SIC). The change-point approach is more informative than other trend test methods in that it provides the number of change-points and the location of change-points if it exists, as well as the existence of change-point for recurrent failures. The change-point test is applied to nine 300MW generating units operated in East China. We confirm that the change-point test has a potential for establishing optimal preventive maintenance policy by detecting change-point of failure rate.

• 한국생활과학회지
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• 제15권2호
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• pp.261-274
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• 2006

The purpose of this study was to explore the well-being behaviors and the consciousness toward well-being trend. The well-being behaviors were composed of 4 dimensions such as regular exercise, purchase the organic agricultural products, use of the air cleaner, and diet for health. The consumer consciousness toward well-being trend was composed of 3 factors such as the marketing criticism, the pursuit of mental richness and orientation for rural life. Especially, the differences of well-being behavior and consumer consciousness toward well-being trend according to socio-demographic variables. The main results were as follows: 1. The well-being trend was extended every consumer, but consumers were not after well-being trends or goods. In addition to consumers thought that well-being trend was stoked by marketers. 2. The well-being behaviors and consumer consciousness were statistically different among groups by the socio-demographic variables.

• 한국조리학회지
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• 제14권3호
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• pp.45-57
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• 2008

The purpose of this study is to initiate a systematic approach to maximize profits through continuous development of menu and build a strong image of Western restaurants located inside hotels by identifying their guests' knowledge and concern and menu selection behavior in well being trend. Findings from the analysis are as follows. First, among the Western menu selection behavior, organic grain and seafood, seasonal event menu, less spicy and more natural cooking methods are favored as the most important consideration. Second, customers' knowledge and concern in well being trend and menu selection behavior were found to be statistically significant. Third, customers' awareness in health and obesity were found to be statistically significant to the concern in well being trend. Fourth, demographical characteristics of customers such as gender, marital status, age, income level and education were tested for their relationships with knowledge and concern in well being trend.

• 한국농촌생활과학회지
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• 제6권1호
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• pp.11-24
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• 1995

The new textile materials may be defined as textile materials different from already existing ones in the physical and chemical structure, manufacturing process, or end-use property. The present time what is called the post-industrial society is characterized by rapid change and new technology. Also, textile materials have been changed rapidly and diversely in the post-industrial society than in any other periods. The study aimed to analyze the trend of new tektite materials development in Korea and to forecast the development trend in the future. To investigate the trend of new textile materials, various written materials and informations were collected from the manufacturers, textile related periodicals, and research journals, and they were analyzed. The period of analysis was from January 1992 to May 1995. The results of this research are as followings : (1) Mixed textile materiasl such as bicomponent fiber, blended yam and blended fabric were increased. (2) High technology has an important effect upon new textile material development. (3) functional textile materials were increased (4) The high value-added products were increased. (5) The naturalized textile materials were increased.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2004년도 추계 학술발표대회 논문집
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• pp.136-137
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• 2004

• 패션정보와 기술
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• 제2권
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• pp.3-13
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• 2005

• 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.

• 한국물환경학회지
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• 제26권6호
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• pp.895-902
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• 2010

The effect of seasonality on water quality variation is very significant. Generally, it reduce the power of the trend extraction. A parametric time-series model was used for detecting trends in historic constituent concentration data. The effect of seasonality is able to remove from time series decomposition technique. According to such statistic methode, long-term water quality trend analysis system (NTrend 1.0) was developed by Nakdong River Water Environmental Research Center. The trend analysis of BOD variation was conducted with NTrend 1.0 at Goreong and Moolkum site in Nakdong river to show the effect of water quality management action plan. Power test of trend extraction was tried each case of 'deseasonalized and deannulized' data and 'deseasonalized' data. Analysis period was from 1989 to 2006, and it's period was divided again three times, 1989~1993, 1994~1999 and 2000~2006 according to action plan period. The BOD trend was downward in Goreong site during three times and it's trend slope was very steep, and upward in Moolkum during 1989~1993, but it was turned downward during 1994~1999 and 2000~2006. It was revealed that it's very effective to reduce the concentration of BOD by water quality management action plan in that watershed. The result of power test was shown that it is high for trend extraction power in case of 'deseasonalized' data.

• KDI Journal of Economic Policy
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• 제35권2호
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• pp.107-131
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• 2013

본고는 글로벌 금융위기 이후 자산가격 버블의 이해에 대한 관심이 높아지고 있는 여건을 감안하여 우리나라 주가에 펀더멘털과 무관한 I(1)인 비정상 확률적 추세(stochastic trend)가 존재하는지의 여부를 주가 배당금의 2변수 VAR 모형에서 검정하고 이를 추정하여 보았다. 이 추세는 주가의 합리적 버블을 추정하기 어려운 점을 감안하여 도입한 것으로, 공적분 및 오차수정모형을 해석하는 경우 양자 간에 유사성이 있음을 설명한다. 한편, 분석 모형에서 주가와 배당은 모두 I(1)인 시계열이며 서로 Engle-Granger 공적분 관계인 것으로 가정한다. 이런 이론적 틀에서 배당금 충격(펀더멘털)의 추세와 통계적으로 상관관계가 없는 주가 내 추세의 추정이 잘 알려진 베버리지-넬슨 분해(Beveridge-Nelson decomposition)를 통해 가능함을 보인다. 또한 이의 검정은 표준적인 t-검정을 통해 쉽게 수행될 수 있음도 보인다. 이러한 추세가 주가에 존재할 경우 일단 발생한 충격은 영구히 지속되며 경제적 영향 역시 항구적일 수 있다. 실증분석에서 1976~2012년 중 연간 실질 KOSPI 지수와 배당 자료를 분석한 결과, 한국주가에 '펀더멘털과 무관한 추세가 존재하지 않는다'는 귀무가설을 기각할 수 없는 것으로 나타났으나, 올림픽 이후 기간의 경우에는 부분적으로 주가변동을 견인하는 것으로 추정된다.

• 한국물환경학회지
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• 제30권2호
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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.