First of all, Intrusion Detection is the process or techniques used to detect attacks on a specific network, system or application. Most intrusion detection tools not only detect attacks, but also software misuse, policy violations and other forms of inappropriate activities.

A Host-based IDS performs intrusion detection from within the systems you want to protect. Some of these tools perform log analysis, others spyware detection, while others perform virus detection.

LIDS (Log-based intrusion detection systems) is just a fancy term for tools that perform security log analysis (specified above). It’s goal is to detect misuse (or attacks) using logs as the primary source of information. It is not a replacement for NIDS (Network-based IDS) or any other security solution, but an addition to them.