Obj model pivot is not centered

[mjhassan]

Hi,
When I tried to scale and rotate a obj model I saw it doesn't transform around it's center. After opening that model in Blender I saw it's pivot is at right rather than center.
I searched GLView for any attribute that can change pivot, but found nothing.
Is there any way so I can change model's center? Specially, how do I transform (scale and rotation only) a model around it center?
Thank you.