Eun Suk Suh

PRODUCT FAMILY AND PLATFORM PORTFOLIO OPTIMIZATION

In this paper, a methodology is presented to determine the optimum number of product platforms to maximize overall product family profit with simplifying assumptions. This methodology is attempting to aid various manufacturing industries who are seeking ways to reduce product family manufacturing costs and development times through implementation of platform strategies. The methodology is based on a target market segment analysis, market leader’s performance vs. price position, and a two-level optimization approach for platform and variant designs. The proposed methodology is demonstrated for a hypothetical automotive vehicle family that attempts to serve seven different vehicle market segments. It is found that the use of three distinct platforms maximizes overall profit by pursuing primarily a horizontal leveraging strategy.Copyright

Level of modularity and different levels of system granularity

All complex system development projects involve analysis of the system architecture. Thus far it has been assumed that there is some correct system decomposition that can be used in the architectural analysis without consideration of the sensitivity of the results to the chosen level of decomposition. We represent 88 idealized system architectures and a real complex system as a design structure matrix at two different levels of decomposition. We analyze these architectures for their degree of modularity. We find that the degree of modularity can vary for the same system when the system is represented at the two different levels of granularity. For example, the printing system used in the case study is considered slightly integral at a higher level of decomposition and quite modular at a lower level of decomposition. We further find that even though the overall results can be different depending on the level of decomposition, the direction of change toward more modular or more integral can be calculated the same regardless of the level of decomposition. We conclude that the level of decomposition can distort the results of architectural analysis and care must be taken in defining the system decomposition for any analysis.

Flexible platform component design under uncertainty

Incorporating flexibility into product platforms allows manufacturers to respond to changing market needs with a minimal increase in product family complexity and investment cost. To successfully design a flexible product platform, proper design of flexible platform components is critical. These components can be described as “cousin” parts as they are neither completely unique nor completely common among variants. In this paper, a multidisciplinary process for designing flexible product platform components is introduced, assuming the platform component is decided a priori. The design process starts with identification of uncertainties and generation of multiple design alternatives for embedding flexibility into the component. Design alternatives are then optimized for minimum cost, while satisfying the component performance requirements. The flexible designs are then evaluated for economic profitability under identified uncertainty, using Monte Carlo simulation. At the end, the most profitable flexible component design is selected. The proposed design process is demonstrated through a case study, in which different flexible designs are generated and optimized for an automotive floor pan, an essential element of most vehicle product platforms. Results suggest that the way in which the flexibility is incorporated in the component, production volume trends, and the degree of built-in flexibility are important factors to consider when designing flexible product platforms.

System Architecture and Mathematical Models of Electric Transit Bus System Utilizing Wireless Power Transfer Technology

We introduce a new type of electric transit bus (ETB) system that uses the innovative wireless power transfer technology developed by the Korea Advanced Institute of Technology (KAIST), which is called on-line electric vehicle (OLEV). In the ETB system, the wireless-charging infrastructure installed under the road charges the fleet of electric buses that are operative over that road. The technology is innovative in that the battery in the bus is charged while it is moving over the charging infrastructure. Unlike conventional electric vehicles, the OLEV-based ETB system is a road-vehicle integrated system. Since charging occurs while the vehicle is operational, the performance of the operation depends on the system integration of the vehicle and the road in which the charging infrastructure is embedded. In this paper, we qualitatively analyze the benefits of the OLEV-based ETB system from the energy logistics perspective. We then present two analytical economic design optimization models. The first model is for an ETB system operating in a “closed environment” with no traffic and no heavy vehicle interactions. The OLEV-based shuttle bus currently operating on the KAIST campus constitutes such a case. The second model is the “open environment model” and considers an ETB system operating in normal traffic conditions. We also present the result of numerical case studies for the optimization models. The goal of this paper is to present an innovative ETB system and a logical design framework for commercializing and deploying that system.

Comparative analysis of coupling modularity metrics

Modular design has become a widely accepted developmental strategy to create products and systems that can be easily manufactured, upgraded and maintained. In order to achieve these benefits through improvement of a systems modularity, it must be measured. An ideal measure ought to capture modularity while being independent of other architectural factors such as size, system coupling density or the number of modules. In this work, we review past research on modularity measures. Eight modularity measures are selected for a detailed analysis. We use a design of experiments approach to analyse which metrics best measure the degree of modularity independent of other irrelevant factors. To do this, we conduct a factorial analysis of 24 canonical architectures with idealised modularity, including precisely integral, modular and bus architectures. We find that most measures produce inconsistent results, especially if the system architecture contains a bus or modules with loose internal coupling. We identify the metrics that are able to capture the degree of modularity in the most consistent manner.

Flexible Product Platforms: Framework and Case Study

Customization and market uncertainty require increased functional and physical bandwidth in product platforms. This paper presents a platform design process in response to such future uncertainty. The process consists of seven iterative steps and is applied to an automotive body-in-white (BIW) where 10 out of 21 components are identified as potential candidates for embedding flexibility. The method shows how to systematically pinpoint and value flexible elements in platforms. This allows increased product family profit despite uncertain variant demand and specification changes. We show how embedding flexibility suppresses change propagation and lowers switch costs, despite an increase of 34% in initial investment for equipment and tooling. Monte Carlo simulation results for 12 future scenarios reveal the value of embedding flexibility.Copyright

Seeing Complex System through Different Lenses: Impact of Decomposition Perspective on System Architecture Analysis

Creating a representation of the base system architecture is one of the first and most critical steps for system development. Typically, the system architect would start by decomposing the existing or proposed system into smaller subsystems or modules. It is widely recognized that at the overall systems level a system can be viewed from different viewpoints. However, unlike often assumed, also when focusing on a single view, such as a systems view, the system decomposition can be done in many alternative ways thus resulting in a different base architecture every time. Depending on the system architects perspective, representation of system can vary widely, having a profound impact on subsequent system architecture development. In this paper, quantitative analysis of system architecture representation, using a design structure matrix (DSM), and its effect on system modularity is presented. The analysis reveals that the results of the system analysis, namely modularity, are different for the same system, depending on the system architects perspective. This work highlights the need for more structured approaches to system decomposition and system analysis based on that decomposition.

Technology Infusion: An Assessment Framework and Case Study

Many product manufacturing companies in today’s environment constantly need to develop new technologies and infuse them into their line of products to stay ahead of the competition. Most new technologies only deliver value once they are successfully infused into a parent system. However, there has been very little research done to develop formal methodologies to assess the impact and implication of new technology infusion into existing products. In this paper, a systematic process framework to quantify and assess the impact of technology infusion early in the product planning cycle is proposed. The proposed methodology quantitatively estimates the impact of technology infusion through the use of a Design Structure Matrix (DSM) and the creation of a Delta DSM (ΔDSM) describing the changes to the original system based on the infused technology. The cost for technology infusion is then estimated from the ΔDSM, and the market impact of the technology is calculated using customer value (utility) curves for customer relevant system performance measures. Finally, the probabilistic ΔNPV of a newly infused technology is obtained using Monte Carlo simulation. The proposed methodology was demonstrated on a complex printing system, represented as an 84 element DSM with a density of 3.7%, where a newly developed value enhancing technology was infused into the existing product. The result shows that a positive marginal net present value ΔNPV can be expected, despite the new technology causing an invasiveness of 8.5% to the existing design. The methodology can be applied in a rigorous and repeatable manner, opening up possibilities for further implementation of the proposed framework, including analysis of the interactions amongst technologies.Copyright

Design for Flexibility: Performance and Economic Optimization of Product Platform Components

Embedding flexibility into physical products or manufacturing processes has been a research topic of great interest. Embedding such flexibility allows manufacturers to respond to changing market preferences or regulations with minimum increase in product complexity and investment cost. In this paper, a multidisciplinary optimization design process for embedding and evaluating flexibility in product components is introduced. The components are assumed to be part of an existing or planned product platform. The design process starts with generation of multiple design alternatives for embedding flexibility into product components. The generated flexible designs are then optimized for component performance maximization and cost minimization. The optimized designs are then evaluated for economic profitability using a Monte Carlo simulation. At the end, the most profitable flexible component design is selected. The proposed design process is demonstrated through a detailed case study, where flexible design alternatives for an automotive floor pan are generated and optimized.

Architectural Decomposition: The Role of Granularity and Decomposition Viewpoint

Before any platform development, one must create the representation of the products’ architectures. Typically, one would start by decomposing the existing or proposed systems into smaller subsystems or modules. This is a critical step since the remainder of the platform development will depend on the choices made at the decomposition phase. This chapter will discuss how to decompose a product architecture. Specifically we will address the decomposition choices such as level of granularity and different decomposition viewpoints and how they affect the final resulting architecture.