Abstract: In a paper by Willems et al., it was shown that persistently exciting data can be used to represent the input-output behavior of a linear system. Based on this fundamental result, we derive ...

Will Kenton is an expert on the economy and investing laws and regulations. He previously held senior editorial roles at Investopedia and Kapitall Wire and holds a MA in Economics from The New School ...

Julia Kagan is a financial/consumer journalist and former senior editor, personal finance, of Investopedia. Erika Rasure is globally-recognized as a leading consumer economics subject matter expert, ...