http://smartech.gatech.edu/handle/1853/5985 For more than 110 years, Georgia Tech has been producing engineers. Today, we are recognized as one of the nation's top ranked engineering colleges. Search the Channel search http://smartech.gatech.edu/simple-search http://smartech.gatech.edu/handle/1853/24397 Title: Survivability and Resiliency of Spacecraft and Space-Based Networks: a Framework for Characterization and Analysis <br/> <br/>Authors: Castet, Jean-Francois; Saleh, Joseph H. <br/> <br/>Abstract: Considerations of survivability and resiliency have always been of importance in the design and analysis of military systems. Over the past two decades, the importance of survivability and resiliency has expanded beyond military systems to include public networks and infrastructure systems. The analysis and assessment of networked systems with respect to survivability has become particularly acute in recent years, as attested to by a growing technical literature on the subject. In this paper, we bring these considerations of survivability and resiliency to bear on spacecraft and space-based networks. We develop a framework for comparing the survivability and resiliency of different space architectures, namely that of a monolithic design and a distributed (or networked) space system architecture. There are multiple metrics along which different space architectures can be benchmarked and compared. We argue that if survivability and resiliency are not accounted for, then the evaluation process is likely to be biased in favor of monolithic spacecraft. We show that if in a given context survivability and resiliency are an important requirement for a particular customer, then a distributed architecture is more likely to satisfy this requirement than a monolithic spacecraft design. We discuss in the context of our framework different classes of threats, as well as the high-frequency and low-frequency system response to (or coping strategies with) these shocks or damaging events. We illustrate the importance of this characterization for a formal definition of survivability and resiliency and a proper quantitative analysis of the subject. Finally, we propose in future work to integrate our framework with a design tool that allows the exploration of the design trade-space of distributed space architecture and show how survivability can be “optimized” or traded against other system attributes. <br/> <br/>Description: AIAA 2008-7707, Space 2008 Conference & Exposition, San Diego, CA, Sept 2008. http://smartech.gatech.edu/handle/1853/24393 Title: Contextual Inquiry of a 50 Aircraft Regional Airline Systems Operation Center <br/> <br/>Authors: Feigh, Karen <br/> <br/>Abstract: A contextual inquiry was conducted at the Systems Operations Control (SOC) of a regional airline with approximately 50 aircraft from the 8th-11th of November 2006. A total of 35 hours of direct observation were conducted with various members of the SOC Staff including the System Operations Control Shift Manager (SOCSM), the System Customer Service Manager (SCSM), the Dispatchers, and the Line Maintenance Planners (LMP). During the inquiry a wide variety of situations occurred: unscheduled maintenance delays, estimated ready time slips, a lightning strike, aircraft damage from a ground vehicle, a system-wide gate printer outage during a departure push, ATC delays, internet and subsequent ACARS outage, an unruly passenger disruption and turn back, and a sick dispatcher. The vast majority of these situations were handled as if they were no different from routine operations; however, there were moments when the SOC personnel were fully involved in the situation, and other minor tasks were being ignored or transferred to other personnel. The majority of high impact problems faced by the the airline’s SOC on a daily basis came from unscheduled maintenance or IT glitches. Unlike other airlines, ATC restrictions are not often an issue for this airline, although station curfews in southern California do place an additional constraint on the schedule recovery process. Similarly, weather was also only a minor issue during the contextual interview. Beyond the inevitable weather and maintenance interruptions, the majority of problems stemmed from software tools which limited the efficiency of the SOC personnel, and from procedures that required the SOCSM to do certain steps multiple times. For example, in order to keep the non-SOC personnel informed about the state of the airline, the SOCSM is required to run reports after each routing change and paste them into both email and the shift log. Additionally, the SOCSM is required to manually enter flight data to create new flights or to maintain existing ones. Similarly, the SOCSM is also required to manually enter and maintain maintenance segments for aircraft. The solution to these problems includes making better use of the current software’s functionality, investigating the actual information needs of the routing change recipient list, and incorporating additional automation to automatically create routing change reports and shift logs. The current software includes a capability to create new flights or maintenance segments using a correctly formatted text file. Using this capability would save much time in manual entry and minimize the number of typographical errors. Additional software should also be created to transition the incident reporting system and the shift log to an electronic database to facilitate data analysis. The SOCSM is currently responsible for posting any routing changes to a preset list via email. The actual information needs of these recipients should be reviewed to determine how frequently this information is actually required and whether or not a more scheduled reporting of all routing changes during a given time period might be adequate. Depending on the outcome, it might be possible to consolidate reports to once or twice a shift. Regardless, additional software should be created to automate the reporting process. http://smartech.gatech.edu/handle/1853/24392 Title: Contextual Inquiry of a Major US Airline Systems Operation Center <br/> <br/>Authors: Feigh, Karen <br/> <br/>Abstract: A contextual inquiry was conducted at the airline’s Systems Operations Control (SOC) from the 13-15th of November 2006. A total of 26 hours of direct observation were conducted with various members of the SOC Staff including several of the Operations Coordinators, the ATC Coordinators, and the Operations Manager. During the inquiry a wide variety of situations occurred: unscheduled maintenance delays, estimated ready time slips, multiple hub ground delay programs, severely reduced arrival rates due to cross-directional winds, ground delay program revisions, and diversions of international flights. The vast majority of these situations were handled as if they were no different from routine operations; however, there were moments when the key SOC personnel were fully involved in the situation and the normal coordination and collaboration between the ATCCs, OCs, MOC and crew coordinators reverted to top down command and control. Thus the workload is not evenly distributed across all SOC personnel because of the geographic distribution of responsibilities. In addition to these observations this inquiry identified three issues with specific design implications, all centered around the OC’s work practices: overly involved coordination sessions with MOC, lack of control of printer output, and the use of schedule printouts as a primary source of solution information. All three of these issues lead to inefficiencies in the SOC operation, despite which, however, the SOC in general and the OCs in particular are able to remain effective. This report suggests that the OCs could become more efficient by shedding some of their printer maintenance tasks, extended MOC coordination sessions, and more effectively using software tools. In order to achieve this high level of effectiveness the SOC personnel actively adapt their roles and the balance of power depending on the level of operational disruption. With the addition of an MOC representative in the SOC or the availability of key maintenancerelated scheduling data, increased effectiveness may also be achievable under conditions of limited disruption. Changing the flow of messages from the printer to an on-screen system will help minimize the ‘busy’ work associated with maintaining the printer and keeping up with the printouts. Introducing new hardware and software tools to aid with the schedule sorting and filtering may also provide increased efficiency, especially for the more junior OCs. http://smartech.gatech.edu/handle/1853/24391 Title: Contextual Inquiry of a 100 Aircraft Regional Airline Systems Operation Center <br/> <br/>Authors: Feigh, Karen <br/> <br/>Abstract: A contextual inquiry was conducted at the Systems Operational Center (SOC) of a Regional Airline with approximately 100 aircraft from the 24-27th of July 2006. A total of 30 hours of direct observation were conducted with various members of the SOC Staff including the Director of Systems Operations (DSO), the Manager of Customer Operations (MCO) and the Line Maintenance Planner (LMP). During the inquiry a wide variety of situations occurred: unscheduled maintenance delays, estimated ready time slips, a bird strike, a disruptive passenger requiring a cabin lock-down, a declared emergency due to oil temperature, taxi delays, weather delays, and brake-cooling delays. The vast majority of these situations were handled as if they were no different from routine operations; however, there were moments when the SOC personnel were pushed to their professional limits and the introduction of any other, even minor, issue could have caused severe disruptions to the schedule. The majority of problems faced by the the airline’s SOC on a daily basis came from lack of resources (planes and flight crew) and from inclement weather. During the inquiry, between 4-12 planes ( 6-9% of the fleet) were consistently out for unscheduled maintenance. Additionally, one one day during the observations 241 flight crew who were scheduled to fly were unavailable. Unlike other airlines, ATC restrictions are not often an issue for this airline, although station curfews in southern California do place an additional constraint on the schedule recovery process. Beyond the resource shortages and the inevitable weather interruptions, the majority of problems stemmed from software tools which limited the effectiveness of the SOC personnel. For example, several of the major software tools depend on different databases with limited connectivity, creating discrepancies between systems and requiring information to be entered multiple times. Additionally, the VisOps tool, used a primary measure of airline schedule adherence, does not support the logging of problems/issues, solution generation through the use of either advanced sort and search features, optimization algorithms and solution sharing. To make best use of the software tools on hand, especially VisOps, larger computer monitors are needed. The resolution at which the software tools must be set for visibility limits their usefulness with 19 inch monitors. Finally, none of the staff interviewed could indicate to any consistent quantitative feedback regarding the relative merits of their decisions on overall system performance. Instead, they often faced inquires about specific decisions which may only make sense when viewed from the overall context of the situation. Appropriate feedback could be provided as summary statistics regarding number of fights canceled, average delay and daily operational costs, which could be generated and displayed to them automatically.