finding robot posture

I have joint 3D positions of the robot.
num tJoint
{
JOINT_HEAD,
JOINT_NECK,

JOINT_LEFT_SHOULDER,
JOINT_RIGHT_SHOULDER,
JOINT_LEFT_ELBOW,
JOINT_RIGHT_ELBOW,
JOINT_LEFT_HAND,
JOINT_RIGHT_HAND,

JOINT_TORSO,

JOINT_LEFT_HIP,
JOINT_RIGHT_HIP,
JOINT_LEFT_KNEE,
JOINT_RIGHT_KNEE,
JOINT_LEFT_FOOT,
JOINT_RIGHT_FOOT,
};
And i need to find the posture like { standing, sitting, laying, bending} from the joint positions. Could you suggest me something. Thank you.

Create a specific example for each of the poses you are interested in, e.g. every joint angle 0 for standing, hips, knees, and ankles bent to PI half for sitting and so on. And then take the euklidean distance between the query pose and the recorded poses in joint space and if one is near enough, then return that as the estimated posture.