We present an updated catalog of 4680 northern eclipsing binaries ( EBs ) with Algol-type light curve morphology ( i.e. , with well-defined beginning and end of primary and secondary eclipses ) , using data from the Catalina Sky Surveys .
Our work includes revised period determinations , phenomenological parameters of the light curves , and system morphology classification based on machine learning techniques .
While most of the new periods are in excellent agreement with those provided in the original Catalina catalogs , improved values are now available for \sim 10 \% of the stars .
A total of 3456 EBs were classified as detached and 449 as semi-detached , while 145 can not be classified unambiguously into either subtype .
The majority of the SD systems seems to be comprised of short-period Algols .
By applying color criteria , we searched for K- and M-type dwarfs in these data , and present a subsample of 609 EB candidates for further investigation .
We report 119 EBs ( 2.5 \% of the total sample ) that show maximum quadrature light variations over long timescales , with periods bracketing the range 4.5 - 18 yrs and fractional luminosity variance of 0.04 - 0.13 .
We discuss possible causes for this , making use of models of variable starspot activity in our interpretation of the results .