Execution Monitoring and Replanning with Incremental and Collaborative Scheduling

We describe the Flight Manager Assistant (FMA), a prototype system, designed to support real-time management of airlift operations at the USAF Air Mobility Command (AMC). In current practice, AMC flight managers are assigned to manage individual air missions. They tend to be overburdened with associated data monitoring and constraint checking, and generally react to detected problems in a local, myopic fashion. Consequently, decisions taken for one mission can often have deleterious effects on others. FMA combines two key capabilities for overcoming these problems: (1) intelligent monitoring of incoming information (for example, weather, airport operations, aircraft status) and recognizing those situations that require corrective action, and (2) dynamic rescheduling of missions in response to detected problems, both to understand the global implications of changed circumstances and to determine appropriate rescheduling actions. FMA builds on two of our existing technologies: an execution-monitoring framework previously applied to small-unit operations and control of robots, and a dynamic scheduling tool that is transitioning into operational use in AMC's Tanker/Airlift Control Center. FMA's dynamic mediation module provides for collaborative mission management by different planning and execution offices by structuring communication for decision making. Introduction and Problem Statement Management of flight operations at the United States Air Force Air Mobility Command (AMC) is a challenging problem. AMC typically flies several thousand missions worldwide on a weekly basis (more in a crisis situation), involving several hundreds of aircraft and comparable numbers of aircrews. The execution of any given mission requires attention to a broad range of constraints relating to the mission’s requirements (e.g., delivery dates, cargo type and weight), resource availability (e.g., aircraft, aircrews, airports, diplomatic clearances), and usage constraints (e.g., crew duty day restrictions and scheduled return dates, aircraft speed, range, and capacity, airspace restrictions). Although missions are planned and globally scheduled to satisfy such constraints, the dynamics of execution regularly forces changes. Aircraft break down, airports become unavailable due to weather, missions become delayed due to diplomatic clearance problems, and so on, and all such events can warrant reassessment of previous allocation decisions. In such execution-driven rescheduling contexts, it is important to weigh potential recovery options against their prospective impact on future operations, and to take actions that continue to make the most effective global use of AMC assets. In current practice, management of flight operations at AMC is a stovepiped process, where planning and execution are treated as sequential steps and information flows in one direction (from planning to execution). New mission requirements flow into AMC’s planning offices on a continuous basis, and as they do aircraft and aircrews are incrementally allocated to support new missions in accordance with associated priorities and as resource availability allows. When a mission gets to within 24 hours of execution, it is “pushed” from the planning side of AMC to the execution office, and becomes the responsibility of an individual flight manager. AMC flight managers take responsibility for checking to ensure that all mission constraints remain satisfied before and during execution, and as problems are detected, they diagnose and revise mission plans to facilitate mission continuation and/or recovery. Unfortunately, AMC flight managers are not well supported in this execution management task. Some alerting tools do exist for signaling certain kinds of problems, but there is generally no ability to differentiate routine checks from exceptional events (i.e., everything shows up red), and no ability to detect more complex, compound conditions. Flight managers are typically overburdened by the data monitoring and constraint checking activities that are required to ensure the continuing viability of executing missions. Furthermore, when problematic situations are detected, flight managers have no visibility of the larger AMC operating picture, and must take recovery actions without regard to potential interactions with other missions. As a result, execution management often proceeds in fire-fighting mode, where putting out one fire ignites the next one. For the past several years, we have been engaged in the development of technologies that we believe can provide a basis for more effective flight management. At Carnegie Mellon University (CMU) we have been developing the AMC Allocator, a dynamic scheduling tool for day-to-day management of airlift and tanker schedules [Kramer & Smith 2002, Smith et al. 2004]. The AMC Allocator provides a range of capabilities for incrementally revising schedules to accommodate new or changed requirements, with continued emphasis on efficient resource utilization. It is currently transitioning into use as a “planning” tool in the Tanker/Airlift Control center at AMC. At SRI, we have been developing the Small Unit Operations Execution Assistant (SUO-EA), which monitors large volumes of situational data and gets urgent, plan-aware alerts to the right users [Wilkins et al. 2003]. SUO-EA has been successfully demonstrated in both the DARPA SUO program and ONR UCAV program. Also at SRI, we have developed technologies for incremental negotiation and coalition formation technology within the DARPA Autonomous Negotiating Teams program and the ONR UCAV program [Ortiz et al. 2003]. Finally, SRI's Open Agent Architecture (OAA) [Cheyer & Martin 2001] provides a robust integration infrastructure that has been used in dozens of programs and applications. In this paper, we describe the Flight Manager Assistant (FMA), a system that integrates the above set of technology components to provide a flexible, mixedinitiative tool for real-time flight management. Through a coupling of execution monitoring capabilities with a global dynamic scheduler, the FMA is designed to promote a more integrated, and hence more informed, basis for detecting and responding to exceptional execution events. The FMA actively monitors data information sources for expectations it derives from the current schedule, recognizes deviations immediately, and applies policies for responding to deviations. Responses to significant deviations may alert the user to take control. Other options might include automated responses (when permitted by policy), or invoking the scheduler to explore alternative rescheduling options. By integrating status update information with the current schedule, the FMA indicates the important consequences of detected events on current and future operations. Through generation and comparison of alternative schedule repair options (either through interaction with the user or automatically), the FMA supports determination of globally coherent recovery actions while also promoting schedule changes that minimize disruption to other missions whenever possible. A given schedule repair process may also initiate and assist a collaboration between the user responsible for execution and the users who planned the missions. Finally, the FMA can provide automated support for implementing the human-selected response. The FMA continuously reacts to new information while interspersing its proactive pursuit of response procedures. The broad goal of the FMA project has been to develop technology that enables increased organizational responsiveness and effectiveness in managing the dynamics of mission operations. In our view, there are two key factors to realizing this goal: • Increased automation. Ubiquitous computers, data sources, and reliable, high-bandwidth communication networks are providing too much information for humans to monitor. In our vision, flight managers will rely on an automated execution aid to monitor the large (and ever increasing) volume of incoming information. By understanding the plan and situation, such an execution aid will consider the outputs of multiple monitoring techniques and tools, and then judge when the user should be alerted. Good judgment avoids overalerting. There may be many exceptions noted in the current plan by various AMC monitoring tools – the FMA recognizes which are most important, focuses the human on those, and assists with developing responses. • Closing the loop between planning and execution. The ability to effectively respond to important alerts requires access to the global state of current and planned future operations, and to the rationale that underlies current mission plans/schedules. In our vision, flight managers will utilize dynamic scheduling tools to understand the consequences of detected events, to generate alternative reactions and evaluate the impact of each, and to provide a basis for negotiating mission requirements—the FMA provides these sorts of capabilities and enables a flight manager to apply a more global perspective in determining how to respond. The FMA also alerts originating planners to problems with their missions and provides support for them to contribute information relevant to execution decisions and achieve globally beneficial changes to individual mission plans. The current FMA prototype is composed of two principal components: a Flight Manager Executive (built from SRI’s SUO-EA system) and a Dynamic Scheduler (derived from CMU’s AMC Allocator system). We have demonstrated this prototype on a series of execution management vignettes, using actual (full scale) AMC schedules pulled from AMC’s Consolidated Air Mobility Planning System (CAMPS), and representative (but scripted) execution data streams. A third Dynamic Mediation component (based on SRI’s incremental negotiation techniques) has undergone preliminary proof-of-concept testing. In the sections below we describe these components in more detail,