Frequently Asked Questions (FAQs)

General SPI2 Questions

Q1. What is a SPI2 system?

A SPI2 system:    [See this page for specific examples of SPI2 systems.]

  • Is fundamentally 3-dimensional and involves interconnected heterogeneous physical subsystems and components with complex geometry and topology that functions within often complex, irregularly-shaped enclosing volumes;
  • Includes interconnects of various types (ducts, pipes and/or wires, etc.), sizes, shapes, and requirements (curvature, proximity, temperature, electromagnetic interference (EMI), etc.) as well as various levels of spatial and topological complexity;
  • Is governed by strongly-coupled physical interactions (e.g., thermal, hydraulic pressure, electromagnetic, thermo-mechanical, etc.) and by the influence of the spatial arrangement on system behavior and performance;
  • Is characterized in 3D by solid components (casings, bays, etc) that may have holes or spatial-access ports. This, in turn, makes the topological considerations more subtle and complex.
  • Must meet a diverse set of constraints that depend on a variety of functionally-related considerations, such as geometry (for ensuring both feasibility and connectivity), physics, material behavior, failure mechanisms, manufacturing, and repair.
  • Must attain desired value metrics: spatial packaging density, volumetric power density,   product life-cycle costs, system efficiency, system reliability, etc.

Real-world SPI2 applications cut across a wide swath of engineering domains that are vital to society such as mobile transportation systems (aircraft, ships, automotive), medical devices, spacecraft, microelectronics, etc. In addition, SPI2 system scale varies widely (e.g., system-level, cabinet-level, or device level, as well as geometric scales ranging from microelectronics to ships and buildings). 

Q2. What is a SPI2 design problem?

An engineering design problem can be defined as the set of design decisions to be made, as well as a means of determining which decisions are preferred (such as figures of merit). A SPI2 design problem involves making design decisions about a SPI2 system, including elements such as: 

  • Component/subsystem geometric placement and orientation;
  • Interconnect routing (both continuous placement/path decisions and topological routing choices such as over/under/through decisions);
  • Component or system parametric decisions, such as sizing or control, that influence system functionality and performance for a given set of placement and routing decisions.

Factors that may be considered in determining what SPI2 system designs are preferred may include:

  • Predicted system behavior within an anticipated physical environment and operating conditions;
  • Satisfaction of geometric constraints, such as the operating spatial envelope, assembly/disassembly constraints, non-interference …..
  • Satisfaction of system failure modes, such as thermal, voltage, or mechanical stress limits, that depend on physical system behavior, spatial arrangement, and control or operating decisions;
  • Enhancement of system performance metrics, such as density, energy efficiency, or other objectives, as well as navigation of the often conflicting tradeoffs between these metrics. 
  • System manufacturability and maintainability (and other holistic lifecycle considerations).

Q3. What is a SPI2 design method?

SPI2 design methods are techniques or procedures for designing real-world SPI2 systems. These methods are comprised of 1) a strategy for defining (formulating) the SPI2 design problem, and 2) a method for solving the SPI2 design problem. Both design method elements may vary in formality or fidelity. Three examples of SPI2 design methods, with increasing levels of formality, follow:

  • Current SPI2 design practice relies upon engineers manually making layout and routing decisions to satisfy system requirements. These engineers can utilize support from CAD and MBSE tools, but component placement and interconnect routing is largely performed manually. In this case, the problem formulation may have a high level of formality embodied in rigorously-defined requirements, but the solution method is less formal, relying heavily upon human expertise. This reliance on human cognition limits the complexity of SPI2 designs that may be designed successfully, as well as increases the time and resources required for SPI2 design. 
  • Previous design automation research efforts have focused on formalizing both the problem formulation and solution methods for very specific elements of the SPI2 system design problem. For example, design optimization methods have been used to maximize geometric packing density for SPI2 systems, but largely without concurrent consideration of interconnect routing decisions or physics-based performance metrics or constraints. These are examples of increased formality in SPI2 design methods, but opportunities for significant improvement exist through more holistic treatment of SPI2 design considerations.
  • Recent work in SPI2 design methods research have focused on strategies that support simultaneous consideration of all classes of SPI2 design decisions, while explicitly satisfying not only geometric constraints, but also physical failure modes and other design considerations that require prediction of physical behavior and the dependence of this behavior on spatial arrangement. Such efforts are the focus of the current SPI2 research activities being conducted by UIUC researchers and partners. These efforts are increasing the formality, fidelity, and integrated treatment of SPI2 design, with the objective of expanding the complexity of SPI2 systems that can be designed, as well as reducing the time and resources required.   

Q4. Who are SPI2 system design stakeholders?

Numerous individuals and organizations stand to benefit from fundamental improvements in SPI2 system design capabilities. Companies or other institutions who design, manufacture, or operate SPI2 systems may benefit from the potential sea change in SPI2 system design and analysis capability. Users of SPI2 systems, which include a very large portion of humanity, stand to reap benefits from new SPI2 technical capabilities, reduced cost, and enhanced reliability and sustainability. SPI2 design method researchers and SPI2 design tool creators are also key stakeholders. 

Breakthroughs in SPI2 Design

Q1. How is the SPI2 system design currently performed, and why does it need to be improved?

The SPI2 design problems entail especially large design spaces (combining complex combinatorial/topological, geometric, parametric, and time-dependent decisions) that are difficult to navigate either via expert human cognition or computational search. These have resisted holistic treatment by potentially powerful design automation methods, and still rely largely on manual, and sub-optimal spatial placement by designers supported by computer-aided design (CAD) tools or MSBE capabilities. Designing SPI2 systems still requires highly skilled engineers who understand the engineering operation, manufacturing, assembly, testing, maintenance, and repair requirements. Moreover, the design and maintenance of large-scale systems such as aircraft and ships requires thousands of man-hours. During maintenance many of these high-impact systems are unavailable for use, thus increasing the required sizes of fleets and the associated cost. Any advancement to overcome this bottleneck has the potential for significant technical and economic impact.

Q2. What has changed recently to indicate that a fundamentally new SPI2 system design capability is on the horizon?

Recent discoveries by our SPI2 research team, based on a new framing of existing spatial graph and braid theories, indicate that, for the first time, holistic treatment of SPI2 design problems is viable through fundamentally new mathematical design representation. Precedent exists for the precipitation of completely new engineering research disciplines from novel mathematical representation breakthroughs (e.g., material distribution topology optimization, or MDTO). While important factors relating to the rise of MDTO research are due to the technical genius and creativity of many individuals, other elements, such as the later advent of practical additive manufacturing and its natural fit with MDTO, were serendipitous. This immediate moment presents a similar opportunity for impact. Instead of relying upon chance for the remaining pieces to come together in the right way to transform SPI2 design practice, we propose a more deliberate strategy in this research.

SPI2 Software Tools and Application

Q1. What is the difference between a SPI2 design method and a SPI2 tool? 

SPI2 design tools are specific pieces of software that enable a SPI2 system design method. A SPI2 design method is a broader entity that comprises both how a SPI2 design problem is formulated and how it is solved. A SPI2 design tool may assist engineers with either problem formulation or problem solution.  

Q2. Who are potential SPI2 design tool users?

SPI2 tool users include individuals at companies or other institutions who are involved with the design, development, operation, or diagnosis of SPI2 systems. SPI2 system researchers may also benefit from the application of SPI2 tools and methods.  

Opportunities for SPI2 Design Tool Creation

Q1. Who are potential SPI2 tool creators?

Potential SPI2 tool creators include commercial engineering software tool companies, in-house support teams for institutions that design SPI2 systems, as well as applied research teams. Advanced SPI2 tool creation will need to leverage close collaboration with SPI2 design method researchers and designers.