CONCURRENT MULTI-PART MULTI-EVENT DESIGN REFRESH PLANNING MODELS INCORPORATING SOLUTION REQUIREMENTS AND PART-UNIQUE TEMPORAL CONSTRAINTS

Technology obsolescence, also known as DMSMS (Diminishing Manufacturing Sources and Material Shortages), is a significant problem for systems whose operational life is much longer than the procurement lifetimes of their constitute components. The most severely affected systems are sustainment-dominated, which means their long-term sustainment (life-cycle) costs significantly exceed the procurement cost for the system. Unlike high-volume commercial products, these sustainment-dominated systems may require design refreshes to simply remain manufacturable and supportable. A strategic method for reducing the life-cycle cost impact of DMSMS is called refresh planning. The goal of refresh planning is to determine when design refreshes should occur (or what the frequency of refreshes should be) and how to manage the system components that are obsolete or soon to be obsolete at the design refreshes. Existing strategic management approaches focus on methods for determining design refresh dates. While creating a set of feasible design refresh plans is achievable using existing design refresh planning methodologies, the generated refresh plans may not satisfy the needs of the designers (sustainers and customers) because they do not conform to the constraints imposed on the system. This dissertation develops a new refresh planning model that satisfies refresh structure requirements (i.e., requirements that constrain the form of the refresh plan to be periodic) and develops and presents the definition, generalization, synthesis and application of part-unique temporal constraints in the design refresh planning process for systems impacted by DMSMS-type obsolescence. Periodic refresh plans are required by applications that are refresh deployment constrained such as ships and submarines (e.g., only a finite number of dry docks are available to refresh systems). The new refresh planning model developed in this dissertation requires 50% less data and runs 50% faster than the existing state-of-the-art discrete event simulation solutions for problems where a periodic refresh solution is required

An Evaluation of End of Maintenance Dates and Lifetime Buy Estimations for Electronic Systems Facing Obsolescence

The business of supporting legacy electronic systems is challenging due to mismatches between the system support life and the procurement lives of the systems' constituent components. Legacy electronic systems are threatened with Diminishing Manufacturing Sources and Material Shortages (DMSMS)-type obsolescence, and the extent of their system support lives based on existing replenishable and non-replenishable resources may be unknown. This thesis describes the development of the End of Repair/End of Maintenance (EOR/EOM) model, which is a stochastic discrete-event simulation that follows the life history of a population of parts and cards and operates from time-to-failure distributions that are either user-defined, or synthesized from observed failures to date. The model determines the support life (and support costs) of the system based on existing inventories of spare parts and cards, and optionally harvesting parts from existing cards to further extend the life of the system. The model includes: part inventory segregation, modeling of part inventory degradation and periodic inventory inspections, and design refresh planning. A case study using a real legacy system comprised of 117,000 instances of 70 unique cards and 4.5 million unique parts is presented. The case study was used to evaluate the system support life (and support costs) through a series of different scenarios: obsolete parts with no failure history and never failing, obsolete parts with no failure history but immediately incurring their first failures with and without the use of part harvesting. The case study also includes analyses for recording subsequent EOM and EOR dates, sensitivity analyses for selected design refreshes that maximize system sustainment, and design refresh planning to ensure system sustainment to an end of support date. Lifetime buys refer to buying enough parts from the original manufacturer prior to the part's discontinuance in order to support all forecasted future part needs throughout the system's required support life. This thesis describes the development of the Lifetime Buy (LTB) model, a reverse-application of the EOR/EOM model, that follows the life history of an electronic system and determines the number of spares required to ensure system sustainment. The LTB model can generate optimum lifetime buy quantities of parts that minimizes the total life-cycle cost associated with the estimated lifetime buy quantity

FORECASTING TECHNOLOGY INSERTION CONCURRENT WITH DESIGN REFRESH PLANNING FOR COTS-BASED OBSOLESCENCE SENSITIVE SUSTAINMENT-DOMINATED SYSTEMS

There are many types of products and systems that have lifecycles longer than their constituent parts (specifically COTS - Commercial Off The Shelf parts). These lifecycle mismatches often result in high sustainment* costs for long field life systems (e.g., avionics, military systems, etc.) due to part obsolescence problems. While there are a number of ways to mitigate obsolescence, e.g., lifetime buys, aftermarket sources, etc., ultimately systems are redesigned one or more times during their lives to update functionality and manage obsolescence. Unfortunately, redesign of sustainment-dominated systems like those mentioned above often entails very large non-recurring engineering and system re-qualification costs. Ideally, a methodology that determines the best dates for design refreshes, and the optimum mixture of actions to take at those design refreshes is needed. The goal of refresh planning is to determine: When to refresh the design Which obsolete parts should be replaced at a specific design refresh (versus continuing with some other obsolescence mitigation strategy) Which non-obsolete parts should be replaced at a specific design refresh Which parts should be functionally upgraded. To address the refresh planning goals above, a methodology called MOCA (Mitigation of Obsolescence Cost Analysis) has been developed. MOCA determines the electronic part obsolescence impact on lifecycle sustainment costs for long field life electronic systems based on future production projections, maintenance requirements and part obsolescence forecasts. The methodology determines the optimal design refresh plan to be implemented during the system's lifetime in order to minimize the system's lifecycle cost. For technology insertion decision making, MOCA uses a Monte Carlo/multi-criteria decision making hybrid computational technique in which a Monte Carlo is used to accommodate input uncertainties and Bayesian networks are used to make part upgrade decisions at design refreshes. A case study is performed to demonstrate MOCA's capabilities on a NDU (Navigation Data Unit) that resides on a US Navy class of ships known as the LPD-17. * Sustainment in this context means all activities necessary to: keep an existing system operational, and continue to manufacture and field versions of the system that satisfy the original and evolving requirements

Selection of obsolescence resolution strategy based on a multi criteria decision model

A component becomes obsolete when it is no longer available from its original manufacturer in its original form. Component obsolescence is a significant problem in the electronics industry. There are different strategies employed to address this problem, for example, using an alternative part, life time buy, redesign etc. Often, techniques used in industry select one of these options based on the most economical solution as determined by minimizing direct costs. However, there are factors other than cost, such as the number of suppliers, time constraints, reliability of the solution etc., which may play a crucial role in determining an overall best decision. In addition, there are multiple stakeholders like design, operations, manufacturing, sales, service etc., who might have different opinions when it comes to obsolescence management. This research provides a multi criteria decision model that will consider the trade-offs among multiple factors and provide the decision maker solution that will be acceptable to a wide variety of stakeholders as well as being viable from the company\u27s perspective. The model is based on multi attribute utility theory. It will provide the stakeholders a platform to express their preferences and experience in the decision process. And, based on the overall utility value, the most suitable obsolescence resolution strategy for a specific application will be provided. The research provides a hypothetical case study in order to illustrate the application and usage of the model

A Hierarchical Core Reference Ontology for New Technology Insertion Design in Long Life Cycle, Complex Mission Critical Systems

Organizations, including government, commercial and others, face numerous challenges in maintaining and upgrading long life-cycle, complex, mission critical systems. Maintaining and upgrading these systems requires the insertion and integration of new technology to avoid obsolescence of hardware software, and human skills, to improve performance, to maintain and improve security, and to extend useful life. This is particularly true of information technology (IT) intensive systems. The lack of a coherent body of knowledge to organize new technology insertion theory and practice is a significant contributor to this difficulty. This research organized the existing design, technology road mapping, obsolescence, and sustainability literature into an ontology of theory and application as the foundation for a technology design and technology insertion design hierarchical core reference ontology and laid the foundation for body of knowledge that better integrates the new technology insertion problem into the technology design architecture

INTEGRATION OF TECHNOLOGY ROADMAPPING INFORMATION INTO DMSMS-DRIVEN DESIGN REFRESH PLANNING OF THE V-22 ADVANCED MISSION COMPUTER

As the pace of technological progress increases, technology obsolescence problems will have a greater effect on traditionally sustainment-dominated industries. Many organizations rely solely on reactive approaches to manage obsolescence events as they occur, often employing lifetime buys, aftermarket sources and other mitigation approaches to ensure that they have enough parts to last through the system's lifecycle. Strategically planned design refreshes coupled with various mitigation approaches can, in many cases, lead to greater cost avoidance than reactive mitigation alone. Design refresh planning is performed by organizations that wish to avoid the high costs of purely reactive obsolescence solutions. Planning to phase-out specific parts at certain times lessens the reliance on reactive solutions (and the resulting quest for obsolete parts) and, in turn, lessens the total cost of sustaining a system. However, design refreshing solely to manage obsolescence is not practical for many systems, and therefore, obsolescence management refresh activities need to be coordinated with the technology insertion roadmap. Technology insertion roadmaps are developed to dictate how the system's functionality and performance must be changed over time. Technology roadmaps reflect an organization's internal technology goals and budget cycles, and give insight into the organization's inherent modus operandi. The MOCA (Mitigation of Obsolescence Cost Analysis) software tool has been designed to generate and select an optimum design refresh plan for a system. This thesis describes an extension to MOCA that allows information from technology roadmaps to be used as constraints in MOCA. The integration of technology roadmap information into MOCA's decision analysis ensures that selected refresh plans meet roadmap imposed timing constraints, and that the costs of roadmap specified actions are included within relevant refreshes. These new developments in MOCA are discussed in the context of the V-22 Advanced Mission Computer (AMC) system. The mechanics of the MOCA tool's optimization analysis with roadmapping considerations are described and the cost avoidance resulting from the optimum refresh plan is articulated in business case terms

Identifying and Managing Asset Obsolescence within the Built Environment

Obsolescence in practice commonly occurs in two forms; the asset in question is no longer suitable for current demands, or is no longer available from manufacturers. Most research surrounding obsolescence has targeted short lifecycle components such as electronics or software (2-5 years). There is little consideration of low volume, long-life assets (20+ years) that are commonplace within the built environment (e.g. Uninterruptable Power Supply Systems, Building Management Systems and Fire Alarm Systems). This paper evidences the importance of identifying asset obsolescence within the built environment by observing 'lifecycle mismatches' within a live case study of a ten year old UK Private Finance Initiative (PFI). This paper develops and proposes an original assessment tool, identifying obsolescence within the built environment and empirically tests it within the case study. The methodology and results combine to evidence the importance of obsolescence and the contractual and financial risk it poses. The model is transferrable and scalable thus allowing larger portfolios to be considered. The levels of identifying obsolescence within long-life assets are increasing, whilst the lifecycles of certain component groups are decreasing; posing a growing problem for future Facility Managers

Design For Longevity and Design For X: Concepts, Applications, and Perspectives

The scientific development of Design For X is very rapid. The definition of Design For X in question is Design for specific purposes. Starting from Design For Manufacture, Design For Sustainability developed into Design For Longevity. The goal of Design For Longevity is design to extend product lifetime.Design For Longevity is a concept where products with a short lifespan are strived for a longer life. As a new concept that develops in a fast-paced era and products shift with short trends, the DfL application is indispensable.This study used a bibliometric study approach using NVIVO analysis and combined with a descriptive qualitative study the relationship between Design For Longevity and Design For X