1. An integrated security event management system (ISEMS), based on service-oriented architecture, comprising one or more computers connected to a combination of different types of service-providing devices that advertise services and transmit state information notifications, the one or more computers comprising one or more program modules adapted to perform: a) tasks which issue commands to the service-providing devices and allow the service-providing devices to define and advertise their one or more services b) tasks which dynamically discover the service-providing devices and their services within a transit security domain in real-time, wherein the service-oriented architecture allows for a uniform means of discovery; c) tasks which acquire asynchronous state information notifications in real-time from the discovered services, wherein the service-oriented architecture allows for a uniform means of sending and receiving the notifications; d) tasks which determine one or more Boolean outcomes from the asynchronous state information in 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 e) tasks which 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.