The rise of online social media is providing a wealth of social network data. Data mining techniques provide researchers and practitioners the tools needed to analyze large, complex, and frequently changing social media data. This chapter introduces the basics of data mining, reviews social media, discusses how to mine social media data, and highlights some illustrative examples with an emphasi...

Differential 2.2μm (K-band) luminosity functions are presented for a complete sample of 1570 nearby (Vgsr ≤ 3000 km/s, where Vgsr is the velocity measured with respect to the Galactic standard of rest), bright (K ≤ 10 mag), galaxies segregated by visible morphology. The K-band luminosity function for late-type spirals follows a power law that rises towards low luminosities whereas the K-band lu...