{"title":"Severe Testing and Characterization of Change Points in Climate Time Series","authors":"James Ricketts, Roger N. Jones","doi":"10.5772/intechopen.98364","DOIUrl":"https://doi.org/10.5772/intechopen.98364","url":null,"abstract":"This paper applies misspecification (M-S) testing to the detection of abrupt changes in climate regimes as part of undertaking severe testing of climate shifts versus trends. Severe testing, proposed by Mayo and Spanos, provides severity criteria for evaluating statistical inference using probative criteria, requiring tests that would find any flaws present. Applying M-S testing increases the severity of hypothesis testing. We utilize a systematic approach, based on well-founded principles that combines the development of probative criteria with error statistical testing. Given the widespread acceptance of trend-like change in climate, especially temperature, tests that produce counter-examples need proper specification. Reasoning about abrupt shifts embedded within a complex times series requires detection methods sensitive to level changes, accurate in timing, and tolerant of simultaneous changes of trend, variance, autocorrelation, and red-drift, given that many of these measures may shift together. Our preference is to analyse the raw data to avoid pre-emptive assumptions and test the results for robustness. We use a simple detection method, based on the Maronna-Yohai (MY) test, then re-assess nominated shift-points using tests with varied null hypotheses guided by M-S testing. Doing so sharpens conclusions while avoiding an over-reliance on data manipulation, which carries its own assumptions.","PeriodicalId":126776,"journal":{"name":"Recent Advances in Numerical Simulations","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125459667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Femtosecond Laser Pulses: Generation, Measurement and Propagation","authors":"M. Khelladi","doi":"10.5772/intechopen.95978","DOIUrl":"https://doi.org/10.5772/intechopen.95978","url":null,"abstract":"In this contribution some basic properties of femtosecond laser pulse are summarized. In sections 2.1–2.5 the generation of femtosecond laser pulses via mode locking is described in simple physical terms. In section 2.6 we deal with measurement of ultrashort laser pulses. The characterization of ultrashort pulses with respect to amplitude and phase is therefore based on optical correlation techniques that make of the short pulse itself. In section 3 we start with the linear properties of ultrashort light pulses. However, due to the large bandwidth, the linear dispersion is responsible for dramatic effects. To describe and manage such dispersion effects a mathematical description of an ultrashort laser pulse is given first before we continue with methods how to change the temporal shape via the frequency domain. The chapter ends with a paragraph of the wavelet representation of an ultrashort laser pulse.","PeriodicalId":126776,"journal":{"name":"Recent Advances in Numerical Simulations","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114764139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}