Context :

Aims : This program originated as the north pole region extension of the established exoplanet survey using 1.8 m telescope at Bohyunsan Optical Astronomy Observatory ( BOAO ) .
The aim of our paper is to find exoplanets in northern circumpolar stars with a precise radial velocity ( RV ) survey .

Methods : We have selected about 200 northern circumpolar stars with the following criteria : \delta \geq 70 ^ { \circ } , 0.6 ¡ B - V ¡ 1.6 , HIPPARCOS _ { scat } ¡ 0.05 magnitude , and 5.0 ¡ m _ { v } ¡ 7.0 .
The high-resolution , fiber-fed Bohyunsan Observatory Echelle Spectrograph ( BOES ) was used for the RV survey .
Chromospheric activities , the HIPPARCOS photometry , and line bisectors were analyzed to exclude other causes for the RV variations .

Results : In 2010 , we started to monitor the candidates and have completed initial screening for all stars for the last five years .
We present the detection of four new exoplanets .
Stars HD 11755 , HD 12648 , HD 24064 , and 8 UMi all show evidence for giant planets in Keplerian motion .
The companion to HD 11755 has a minimum mass of 6.5 \it M _ { \mathrm { Jup } } in a 433-day orbit with an eccentricity of 0.19 .
HD 12648 is orbited by a companion of minimum mass of 2.9 \it M _ { \mathrm { Jup } } having a period of 133 days and an eccentricity of 0.04 .
Weak surface activity was suspected in HD 24064 .
However , no evidence was found to be associated with the RV variations .
Its companion has a minimum mass of 9.4 \it M _ { \mathrm { Jup } } , a period of 535 days , and an eccentricity of 0.35 .
Finally , 8 UMi has a minimum mass of 1.5 \it M _ { \mathrm { Jup } } , a period of 93 days with an eccentricity of 0.06 .

Conclusions :