1. An integrated security event management system (ISEMS), based on service-oriented architecture, comprising one or more computers connected to one or more service-providing devices that transmit state information notifications, the one or more computers comprising one or more modules adapted to perform: a) tasks to dynamically discover the service-providing devices and their services within a transit security domain in about real-time, wherein the service-oriented architecture allows for a uniform means of discovery; b) tasks to acquire asynchronous state information notifications in about real-time from the discovered services, wherein the service-oriented architecture allows for a uniform means of sending and receiving the notifications; c) tasks to determine one or more Boolean outcomes from the asynchronous state information in about real-time via a configurable rules engine, wherein the configurable rules engine is based on at least one of a Boolean, mathematical, statistical or combinational logic; and d) tasks to evaluate the one or more Boolean outcomes in about real-time via a configurable policy engine to determine state changes of one or more security policies, wherein a security policy state change indicates a security event, and wherein the policy engine associates rules with the one or more security policy states and defines actions to be followed when a security policy state change occurs.