• Communications for Statistical Applications and Methods
• /
• 제16권3호
• /
• pp.511-518
• /
• 2009

We consider the problem of testing for change and estimating the unknown change-point in a sequence of time-ordered observations from the binomial and Poisson distributions. Including the likelihood ratio test, Gombay and Horvath (1990) tests are studied and the proposed change-point estimator is derived from their test statistic. A power study of tests and a comparison study of change-point estimators are done via simulation.

• 대한환경공학회지
• /
• 제30권12호
• /
• pp.1183-1189
• /
• 2008

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2023년도 춘계학술대회
• /
• pp.59-59
• /
• 2023

• 산업기술연구
• /
• 제35권
• /
• pp.23-30
• /
• 2015

In recent, the various methods to predict the hydrological impacts due to climate change have been developed and applied. Especially, the variability of the meteorological factors such as rainfall, temperature, and evaporation can impact on the ecosystem in a basin. The variability caused by climate change on the meteorological factors can be divided by a gradual and abrupt change. Therefore, in this study, the gradual change is detected by simple linear regression and Mann-Kendall trend test. Also, the abrupt change is detected by Bayesian change point analysis. Finally, the result using these methods can identify the meteorological threats in the Cheongmicheon basin.

• Communications for Statistical Applications and Methods
• /
• 제9권1호
• /
• pp.75-86
• /
• 2002

We consider the problem of estimating the change-point in mean change model with one change-point. Gombay and Huskova(1998) derived a class of change-point estimators with the score function of rank. A change-point estimator with the log score function of rank is suggested and is shown to be involved in the class of Gombay and Huskova(1988). The simulation results show that the proposed estimator has smaller rose, larger proportion of matching the true change-point than the other estimators considered in the experiment when the change-point occurs in the middle of the sample.

• 한국경영과학회지
• /
• 제31권2호
• /
• pp.1-13
• /
• 2006

To rapidly respond to uncertainties in the business environment whilst remaining competitive, every organization needs to be able to successfully introduce and manage organizational change. Cognizant of the role of information systems (IS) as an enabler of organizational change, many organizations have paid attention to Enterprise Resource Planning (ERP) systems for successful organizational change primarily because of their change-driving forces across organizations. This study focuses attention on the role of readiness for change in the ERP systems adoption. Readiness for change described as views about the need for organizational change is posited to be an antecedent of two expectancies about the system, performance expectancy and effort expectancy, which lead to actual system use. Based on data gathered from the users of the ERP systems, structural equation analysis using LISREL provides significant support for the proposed relationships.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.1099-1101
• /
• 2003

Change detection technology, which discovers the change information on the surface of the earth by comparing and analyzing multi-temporal satellite images, can be usefully applied to the various fields, such as environmental inspection, urban planning, forest policy, updating of geographical information and the military usage. In this paper, we introduce a change detection system that can extract and analyze change elements from high-resolution satellite imagery as well as low- or middle-resolution satellite imagery. The developed system provides not only 7 pixelbased methods that can be used to detect change from low- or middle-resolution satellite images but also a float window concept that can be used in manual change detection from highresolution satellite images. This system enables fast access to the very large image, because it is constituted by OGC grid coverage components. Also new change detection algorithms can be easily added into this system if once they are made into grid coverage components.

• Asian Journal of Business Environment
• /
• 제11권4호
• /
• pp.39-45
• /
• 2021

Purpose: This study is designed to investigate the extent and nature of climate change disclosure of listed pharmaceutical companies of Bangladesh. Research design, data and methodology: In order to perform this research, a content analysis methodology is used. A climate change disclosure index is constructed to examine 12 different climate change disclosure issues. Information is collected from the annual reports of 29 pharmaceutical companies listed on the Dhaka Stock Exchange for the year 2019. Results: This study finds that only 48.28% of the sample companies provided disclosure on at least one issue regarding climate change. 'Energy savings' is the mostly disclosed issue whereas 'Pollution control expenditure', 'Biodiversity conservation initiatives' are the least disclosed issues. Research implication: This study concludes 64.29% of the companies examined, use less than five sentences for climate change disclosure, which depicts unsatisfactory disclosure practices regarding climate change issues. Study findings would be helpful for different industries of Bangladesh to implement efficient climate change reporting Practice. Future studies can be conducted on other industries to obtain more comprehensive result.

• Communications for Statistical Applications and Methods
• /
• 제28권5호
• /
• pp.511-520
• /
• 2021

Over the last decade, Bitcoin has attracted a great deal of public interest and Bitcoin market has grown rapidly. One of the main characteristics of the market is that it often undergoes some events or incidents that cause outlying observations. To obtain reliable results in the statistical analysis of Bitcoin data, these outlying observations need to be carefully treated. In this study, we are interested in change point analysis for Bitcoin return series having such outlying observations. Since these outlying observations can affect change point analysis undesirably, we use a robust test for parameter change to locate change points. We report some significant change points that are not detected by the existing tests and demonstrate that the model allowing for parameter changes is better fitted to the data. Finally, we show that the model with parameter change can improve the forecasting performance of Value-at-Risk.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.622-624
• /
• 2015

As uncertain factors are latent in a construction project by nature, a change order occurs frequently. The occurrence of change orders in construction projects conducted during construction phase is known to cause unexpected negative impacts such as cost overrun, schedule delay, quality problem, and claims in the post-process. Thus, an efficient management method is necessary to prevent and minimize change orders during construction phase when they occur frequently. This paper analyzed the causes of change orders and the impact factors that occur during the construction phase of a construction project and suggested a direction for change order database building.