Over the past four years, the Submarine Warfare Federated Tactical Systems (SWFTS) Systems Engineering & Integration (SE&I) program has shifted from traditional document‐centric systems engineering to a model‐based systems engineering (MBSE) process for managing the evolution and support of the common combat system used by most submarines in the U.S. and Royal Australian Navies. At the beginning of this transition a pilot study established technical feasibility, and projected a 13% reduction in the cost of processing a baseline if MBSE were applied to support the SWFTS system of systems baseline development process. Over the course of two years of development new modeling techniques were invented, and a large‐scale system of systems model was designed, implemented, and populated. Now the transition to operations has begun. In early 2012 SWFTS SE&I produced its first new generation of combat system interface baselines using MBSE. The technical foundation has been established, and the workforce transition is under way. Anticipated cost reductions are still a year away as the workforce ascends the learning curve, but the program is already seeing improvements in the quality and consistency of engineering products. This paper summarizes this document‐centric to model‐based SE transition, describes the accomplishments and observations to date, and describes the metrics being collected to quantify the achieved return on investment once the transition is complete.
The Submarine Warfare Federated Tactical Systems (SWFTS) is a rapidly evolving combat system of systems (SoS) product family. Managing the annual baseline updates requires processing thousands of baseline change requests, then coordinating and verifying their implementation. The complexity of this effort, which involves well over ten million source-lines-of-code (SLOC) as well as Commercial-Off-the-Shelf (COTS) and military-unique hardware, is compounded by being deployed in ten variants.After a feasibility study in 2010 the SWFTS systems engineering and integration program started a transition from traditional requirements database and documentcentric systems engineering (DCSE) to a model-based systems engineering (MBSE) process. At that time there was little solid evidence in the literature for a positive Return on Investment (ROI) for moving from DCSE to MBSE.Applying MBSE to this program has resulted in measurable monetary and operational benefits. We 1) summarize the DCSE to MBSE transition, 2) describe the accomplishments and observations to date, 3) define the metrics collected, and 4) quantify the achieved ROI. Background on the systems engineering and integration (SE&I) process and an apples-to-apples comparison of SE quality and efficiency are provided. The raw SE&I efficiencies of the DCSE and MBSE approaches are documented, along with conclusions showing that the MBSE approach delivers a positive ROI through higher quality SE products at significantly less cost-per-change, enables managing more baselines and SoS complexity using constant resources, and reduces the cost of the downstream integration effort.
Hazardous events, both natural and human-made, present tremendous risks to communities throughout the world. These events typically necessitate the evacuation of local or regional populations to safe destinations or shelters and have warning times ranging from minutes to hours or even days. The size and scope of these events present a challenge to the emergency management or agency personnel who must see to the health and safety of those living or working in their jurisdiction. This study evaluated various heuristic strategies to improve evacuation of an at-risk region by using a representative traffic roadway network. Finding evacuation strategies that reduce clearance time would lead to saving lives, time, and money. For the given test network, population density, or total number of trips, has an effect on overall clearance times; as densities (trips) increase, a greater potential for improved clearance time is indicated. Six different shift strategies were evaluated, each strategy based on origin-to-destination distances. For departure volumes greater than five vehicles per acre (approximately 12 vehicles per hectare), clearance times showed statistically significant improvements when departure times were shifted for groups within the network. In addition, the amount of the departure shift has an effect on clearance time.
The development of contemporary systems is an extremely complex process. One approach to modeling system behavior uses activity diagrams from Unified Modeling Language (UML)/System Modeling Language (SysML), providing a standard object‐oriented graphical notation and enhancing reusability. However, UML/SysML activity diagrams do not directly support the kind of analysis needed to verify the system behavior, such as might be available with a Petri net (PN) model. We show that a behavior model represented by a set of fUML‐compliant modeling elements in UML/SysML activity diagrams can be transformed into an equivalent PN, so that the analysis capability of PN can be applied. We define a formal mathematical notation for a set of modeling elements in activity diagrams, show the mapping rules between PN and activity diagrams, and propose a formal transformation algorithm. Two example system behavior models represented by UML/SysML activity diagrams are used for illustration.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.