Forecasting unstable processes

Previous analysis on forecasting theory either assume knowing the true parameters or assume the stationarity of the series. Not much are known on the forecasting theory for nonstationary process with estimated parameters. This paper investigates the recursive least square forecast for stationary and nonstationary processes with unit roots. We first prove that the accumulated forecast mean square error can be decomposed into two components, one of which arises from estimation uncertainty and the other from the disturbance term. The former, of the order of $\log(T)$, is of second order importance to the latter term, of the order T. However, since the latter is common for all predictors, it is the former that determines the property of each predictor. Our theorem implies that the improvement of forecasting precision is of the order of $\log(T)$ when existence of unit root is properly detected and taken into account. Also, our theorem leads to a new proof of strong consistency of predictive least squares in model selection and a new test of unit root where no regression is needed. The simulation results confirm our theoretical findings. In addition, we find that while mis-specification of AR order and under-specification of the number of unit root have marginal impact on forecasting precision, over-specification of the number of unit root strongly deteriorates the quality of long term forecast. As for the empirical study using Taiwanese data, the results are mixed. Adaptive forecast and imposing unit root improve forecast precision for some cases but deteriorate forecasting precision for other cases.Comment: Published at http://dx.doi.org/10.1214/074921706000000969 in the IMS Lecture Notes Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

Fabrication of GaN-Based White Light-Emitting Diodes on Yttrium Aluminum Garnet-Polydimethylsiloxane Flexible Substrates

This study concerns the characteristics of white GaN-based light-emitting diode (LED) on flexible substrates. The thin film GaN-based blue LEDs were directly transferred from sapphire onto the flexible polydimethylsiloxane (PDMS) substrates by laser lift-off (LLO) process. The PDMS substrates were incorporated 10–40% cerium doped yttrium aluminum garnet phosphor, YAG:Ce3+, and formed the GaN-based white LEDs. The white LEDs prepared by the GaN-based LEDs on the YAG-PDMS substrates reveal one peak at 470 nm corresponding to the emission of the GaN-based LED and a broadband included five weak peaks caused by YAG:Ce3+ phosphors

The Intellectual Core Of Electronic Commerce Research From 2006 To 2010

The purpose of this paper is to explore the intellectual core of electronic commerce (e-commerce) research. Data was collected from the top six e-commerce journals (Lowry, Romans, & Curtis, 2004), the International Journal of Electronic Commerce, MIS Quarterly, Electronic Market, Journal of MIS, Information Systems Research, Management Sciences from 2006-2010. A total of 1056 electronic commerce related articles and 33036 references were identified. There were 47 high value research articles identified using a citation and co-citation analysis. Using factor analysis we identified five research areas: trust, technology acceptance and technology application, e-commerce task-related application, e-markets, and information systems success. The findings of this study provide core knowledge and directions for researchers and practitioners interested in the electronic commerce field

Superplastic Forming of SiAlON Ceramics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66409/1/j.1151-2916.1994.tb04645.x.pd

Maximizing analytical precision: exploring the advantages of ratiometric strategy in fluorescence, Raman, electrochemical, and mass spectrometry detection

Ratiometric strategy are an invaluable method that helps to detect and quantify analytes. This approach relies on measuring changes in the ratio of two or more signals to improve the accuracy and sensitivity of the results. Ratiometric strategies are widely used in a variety of fields including biomedical, environmental monitoring and food safety. It is particularly popular when traditional single-signal based detection methods are not feasible, especially when interfering substances severely affect the detection. In addition, ratiometric methods have the potential to improve the accuracy and reliability of analyte detection, leading to better results in a variety of complex environments. The article provides a comprehensive review of ratiometric strategy, focusing on ratiometric fluorescent nanoprobes for the visual detection of analytes. This paper also discusses the design of ratiometric two-photon fluorescent probes for biomedical imaging, the synthesis of ratiometric surface-enhanced Raman scattering nanoprobes for the imaging of intracellular analytes, the development of ratiometric molecularly imprinted electrochemical sensors for detection of electroactive species, and the use of isotopically-labeled internal standards in matrix-assisted laser desorption/ionization for ratiometric analysis. The article not only discusses each technique in detail, including its principles, advantages, potential applications, and limitations, but also highlights recent advances in each method and possible future directions

Washington Households’ Expected Responses to the Volcanic Threat of Mt. Rainier

This study examines households’ knowledge, attitudes and adjustments toward volcanic threat through an investigation of the population at risk from Mt. Rainier. To bridge the gaps of previous volcano research, I first explored the effects of demographic variables, locational variables (i.e., crater proximity, lahar zone location and community bondedness), and past information search on three sets of psychological variables—risk perception, hazard intrusiveness, and affective response. In turn, I examined the effects of these psychological variables along with locational and demographic variables on three measures of hazard adjustments—emergency preparedness, future information search, and evacuation preparedness—made by the households. The analysis of variance (ANOVA) results show that there were significantly mean differences in five variables—risk perception, hazard intrusiveness, affective response, evacuation plan effectiveness, and community bondedness—among nine communities; however, no significant differences were found in the other four variables—future information search, adequacy of official lahar evacuation routes, school evacuation plan compliance, and adequate preparedness. In addition, the results of ordinary least squares (OLS) regression analyses indicate that two psychological factors (e.g., risk perception and hazard intrusiveness), two demographic factors (e.g., female gender and income), community bondedness, past information search, and hazard proximity (e.g., lahar zone location and crater proximity), all had significant effects on the three measures of hazard adjustments—emergency preparedness, future information search, and evacuation preparedness. The findings also reveal that most respondents had low levels of hazard intrusiveness and few engaged in volcano-specific emergency preparedness actions. This makes it essential for local emergency managers to increase residents’ volcano hazard awareness and preparedness. Due to the report of high percent of car usage (74.3%) and an increasing population growth in the Puyallup River valley, the local emergency managers should collaborate with transportation engineers to conduct evacuation analyses to determine if the evacuation routes have adequate capacity for the likely evacuation demand. They should also work with land use planners to conduct land use analyses to manage residential and commercial development, as well as the siting of essential facilities such as schools and hospitals

Acute aortic dissection mimicking as ureteral calculus

AbstractAcute aortic dissection is an uncommon but life-threatening emergency, which is often missed in up to 38% of patients on initial evaluation, and in up to 28% of patients the diagnosis is made at autopsy. Painless aortic dissection has been reported, but is relatively uncommon. The mortality rates are estimated at 50% by 48 hours and increase by 1% per hour if undiagnosed. We report a case of atypical aortic dissection who presented to ER with subtle unspecific renal colicky like pain as a primary symptom, which had made the prompt diagnosis very challenging and difficult

The relationship between the waste recycling fee and subsidy of due recyclable waste

This study employs a life-cycle evaluation model of due recyclable waste (DRW) to analyze its optimal waste recycling fee (WRF) and subsidy. The results suggest that the government could set the optimal WRF and subsidy of DRW under the assumptions of the relationship that exist between the WRF and the subsidy for the budgetary constraints, but not set for the externality of DRW, and the environmental consciousness of individuals. And the different purposes of the WRF and subsidy are the reasons why a life-cycle evaluation model of due recyclable waste (DRW) is necessary to analyze its optimal waste recycling fee (WRF) and subsid

THE EFFECTS OF FUNGAL MEDIUM ON HATCHING RATE OF BITING MIDGE

The little black mosquitos, Forcipomyia taiwana, bite human and become one of the most annoying pests in Taiwan. Recently, the population of F. taiwana increases and invades urban and countryside. In order to effectively prevent the harassment of F. taiwana, develop control strategy is urgent and necessary. Our study found that the fungal medium influenced the length and width of the F. taiwana eggs. It also significantly decreased the hatching rate of F. taiwana. Besides, this artificial diet was more non-toxic and environment-friendly than general chemical pesticides. Thus, this study provided critical information to develop potentially useful bait of F. taiwana in the future