measuring the requirements allocation capacity within a system of systems
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Measuring the Requirements Allocation Capacity within a System of Systems. David Flanigan The Johns Hopkins University Applied Physics Laboratory Dr Peggy Brouse George Mason University August 21, 2014. Outline. Objective Literature Review - PowerPoint PPT PresentationTRANSCRIPT
Measuring the Requirements Allocation Capacity within a System of Systems
David FlaniganThe Johns Hopkins University Applied Physics Laboratory
Dr Peggy BrouseGeorge Mason University
April 22, 2023
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Outline
Objective Literature Review Steps in the SoS Requirements Allocation
Process Case Study Next Steps
Objective
During initial development of a System of Systems (SoS), many SoS do not have authority over the systems and need to work with developers and stakeholders to identify and allocate requirements to the system level
Traditional Systems Engineering techniques do not have the ability to allocate SoS requirements and determine if this they are satisfactory or not
A process and series of metrics are offered to develop SoS requirements allocation
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Literature Review We examine existing requirements allocation processes for
any methods / metrics applicabile to SoS: Multi-attribute optimization process (Sutton) Decomposition of top-level requirements (Kusiak and Qin) Martin et al. studies three Requirements Engineering (RE)
process models: • Linear incremental model (Kotonya & Sommerville)• Purely linear model (Macaulay)• Iterative and cyclical model (Loucopoulos and Karakostas)
Interaction matrix to identify system – system interactions (Fry and DeLaurenitis)
We are motivated to develop a SoS requirements allocation method since there is currently no process to ensure this SoS allocation is
successfully conducted
SoS Requirements Allocation Process
• Define the SoS problem space and scope• Inventory existing system objectives and
requirements• Allocate SoS requirements to system
requirements• Assess the SoS requirements allocation
Case Study An illustrative case study involving a US Navy Carrier Strike
Group (CSG) will conduct Surface Warfare (SUW), e.g. identifying and engaging hostile surface platforms
Enterprise Command and Control Requirements and Common Architecture on US Navy Surface Combatants, Naval Postgraduate School, NPS-SE-09-003, June 2009.
Step 1: Define the SoS problem space and scope
Limited to a US Carrier Strike Group – with only the organic platforms and not external systems (e.g. satellites, joint forces, other systems)
Our SoS scope
Enterprise Command and Control Requirements and Common Architecture on US Navy Surface Combatants, Naval Postgraduate School, NPS-SE-09-003, June 2009.
Step 2: Inventory existing system objectives and requirements
For our example, we look at three specific systems and their missions from various sources
O'Rourke, R. "Unmanned Vehicles for US Naval Forces: Background and Issues for Congress". DTIC Document , 2005.
US Navy. 2011. "Destroyers - DDG." Last modified 31 January 2011. http://www.navy.mil/navydata/fact_display.asp?cid=4200&tid=900&ct=4.
US Navy. 2009. "F/A-18 Hornet strike fighter." Last modified 26 May 2009. http://www.navy.mil/navydata/fact_display.asp?cid=1100&tid=1200&ct=1.
Platform Missions
F/A-18E/F Super Hornet
Air superiority, fighter escort, reconnaissance, aerial refueling, close air support, air defense suppression and day/night precision strike
Guided missile destroyersAnti-Air Warfare (AAW), Anti-Submarine Warfare (ASW), and Anti-Surface Warfare (ASUW)
Naval Unmanned Aerial Vehicle (UAV) Intelligence, Surveillance, and Reconnaissance (ISR)
Step 3: Allocate SoS requirements to system requirements
Step 3a: Decompose SoS objective to SoS phases Step 3b: Identify frequency of use of each SoS phase Step 3c: Catalog the system-system interfaces within
each SoS phase
Step 3a: Decompose SoS objective to SoS phases
For our example, we focus on one SoS mission• Surface Warfare (SuW) mission: the detection, tracking,
and engagement of hostile surface platforms We use the SuW kill chain to functionally describe
the mission in six distinct phases: find, fix, track, target, engage, and assess
We leverage an example from NPS that describes a generic SuW kill chain and develop an activity diagram to map to our specific systems
Step 3a: Decompose SoS objective to SoS phases
Enterprise Command and Control Requirements and Common Architecture on US Navy Surface Combatants, Naval Postgraduate School, NPS-SE-09-003, June 2009.
For this example, we derive the given SUW kill chain and convert into a SoS activity diagram that contains SoS phases and intra/inter-phase interfaces
Step 3b: Identify frequency of use of each SoS phase
For this example, we can solve the frequency based on simple assumptions and a 4-hour air wing event time constraint; future work would develop a full-
scale discrete event simulation to calculate percentages
Step 3c: Catalog the system-system interfaces within each SoS phase
Identify the system-system interactions within each SoS phase transition• Extending Fry and
DeLaurentis’ research on adjacency matrices to define SoS interactions
• We must look at each SoS phase since there may be different systems interacting and differing levels of effort
Find/Fix to Track/Target
C2 Aircraft Surface Ship UAVC2 0 0 0 0
Aircraft 1 0 0 0Surface Ship 0 0 0 0
UAV 1 0 0 0Track/Target
to EngageC2 Aircraft Surface Ship UAV
C2 0 1 1 0Aircraft 0 0 1 0
Surface Ship 0 0 0 0UAV 0 0 0 0
Engage to Assess
C2 Aircraft Surface Ship UAVC2 0 0 0 0
Aircraft 1 0 0 0Surface Ship 0 1 0 1
UAV 1 0 0 0
Fry, D. N., and D. A. DeLaurentis. "Measuring Net-Centricity". Paper presented at System of Systems Engineering (SoSE), 2011 6th International Conference on. IEEE, 27-30 June. 264-269.
Step 4: Assess the SoS requirements allocation
Total Network Capacity Requirements• Using our series of adjacency matrices, calculate
the amount of network capacity that each system would require for the SoS mission
System contribution throughout the SoS• Since we know the frequency of each SoS phase
and the number of activities that are used within each phase, we can calculate the contribution of each system within the entire SoS mission
The airborne platforms have the greatest network usage and contribute most to the SoS mission, which helps to identify & allocate system-level requirements
PlatformNetwork usage
C2 11%Aircraft 40%Surface
Ship 14%UAV 35%
PlatformSystem
contributionC2 9%
Aircraft 44%
Surface Ship 5%UAV 42%
Our calculations are intuitive: for a mission that heavily relies on the find/fix phase to search out a target (this often happens in SuW missions to detect and identify a
single ship in a large body of water)
Next Steps Add multiple missions for the SoS to simultaneously
execute• Identify where adding more missions would compete and
adversely affect other missions• Where does the over-allocation of particular systems
occur? Quantify the reallocation process of system
contributions to SoS requirements• What happens to different SoS configurations? (e.g. have a
more ship-centric activity flow)
Questions