The article is an extended version of the verbal summary presented at the concluding lunch of the workshop on “Computing Futures in Engineering Design.” In the paper, the first person is used to differentiate my observations or reactions from the summaries of the speakers' presentations. The common themes that emerge during the workshop are: the need to set the discipline-specific context before computational tools are used; the incompatibilities between point tools that hinder their use; the paramount importance of teamwork; and the need to understand and treat design as a social process.

Meertens number is a number with a very peculiar property. I had the idea in 1991, when I was invited to celebrate the occasion of Lambert Meertens' 25 years at the CWI, Amsterdam. Lambert has been a good friend and colleague for a number of years, and rather than bring the usual bottle of Glenlivet as a gift, I decided to give him a number.

The intellectual content and social activity of engineering product development are a constant source of surprise, excitement, and challenge for engineers. When our students experience product-based-learning (PBL), they experience this excitement (Brereton et al., 1995). They also have fun and perform beyond the limits required for simple grades. We, their teachers, experience these things too. Why, then, are so few students and faculty getting the PBL message? How, then, can we put the excitement back in engineering education? In part, we think this is because of three persistent mistakes in engineering education:

1. We focus on individual students.

2. We focus on engineering analysis versus communication between engineers.

3. We fail to integrate thinking skills in engineering science and engineering practice.

One of the biggest problems in pneumatic system design is over design. Thus, the results are excessive in costs of the initial investment and it requires too much energy. This article describes the development of expert system based pneumatic design system, PNEUDES (PNEUmatic Design Expert System), prototype that enables the user the optimal design of pneumatic system. Once the design requirements such as cylinder type and work load, etc. are input to the system, optimal cylinder specifications with standardized order-based size, valves types, and necessary accessories are all determined. Also the configuration information such as the connectivity among components and cylinder image data are supplied to the user. It can also help the novice of pneumatic design. The rule-based reasoning approach is used as a reasoning strategy with Intelligent Rule Element shell.

As manufacturing systems become more sophisticated and complicated, effective managers know how they play a crucial role in managing an enterprise and managers know how to deal with their dynamics and uncertainty. In this article, a formalism based on the computer-integrated manufacturing open-system architecture (CIMOSA) reference model is presented to specify the business processes and enterprise activities at the knowledge level. The formalism uses an integration of multiple types of knowledge, including precise, muddy, and random symbolic and numerical knowledge to systematically represent enterprise behavior and functionality. To support the modelling process, a prototype is developed and an example for a maintenance activity is presented to demonstrate the effectiveness of the proposed method.

This position paper proposes the P5BL initiative and vision, that is, Problem-, Project-, Product-, Process-, People-Based Learning. A definition is proposed for the P5BL teaching and learning approach. The discussion identifies key pedagogical issues and innovative roles of computing for each of the five critical Ps in a multisite, cross-disciplinary, project-centered, and team-oriented Architecture/Engineering/Construction environment.

Expansion postponement is a tantalisingly simple conjecture about pure type systems which has so far resisted all attempts to prove it for any interesting class of systems. We prove the property for all normalising pure type systems, and discuss the connection with typechecking.

Manipulators with some flexible links are attractive because they avoid the severe control problems associated with the large inertia forces generated when the large-mass, rigid links in conventional robot manipulators move at high speed. In fact only two of the links within a typical six degrees of freedom revolute-geometry industrial robot cause significant inertia forces, and so only these two links need to be flexible. The development of a two-flexible-link system controller is therefore very relevant to larger manipulators, because it can be readily expanded by adding simple controllers for the other rigid links. Two alternative controllers are developed in this paper, a computed-torque controller and a quadratic optimal controller. Simulations confirm the superior performance of the latter.

An efficient algorithm for generating an optimal plan for part-bringing tasks, using robotic manipulators, is introduced. The task of transporting a micro-part in a partially unstructured environment, that includes obstacles whose locations are not initially known, is introduced with the optimal plan formulated on the basis of the observed environmental conditions. Fuzzy set theory, well-suited to the management of uncertainty, is introduced to address the uncertainty associated with the part-bringing procedure. A part-bringing algorithm for generating the optimal plan related to a part assembly, despite existing obstacles, is presented. It is shown that the machine organizer using a sensor system can intelligently determine an optimal plan, based on explicit performance criteria, to overcome environmental uncertainty. The algorithm utilizes knowledge processing functions such as machine reasoning, planning, memory, and decision-making. Simulation results show the effectiveness of the proposed approach. The proposed algorithm is applicable not only to a wide range of robotic tasks including pick and place operations and maneuvering mobile based robots around obstacles, but also to the control of unmanned aircraft.

In the late 1980s someone in the CAD software arena coined the phrase in the main title. A decade passed by and the appealing idea is still not realized. Is it ever going to be or is there an inherent fallacy in the idea? The following is the author's position on the subject, admittedly biased by a structural engineering background.

In this paper, nine adaptive control algorithms are compared. The best two of them are tested experimentally. It is shown that the Adaptive FeedForward Controller AFFC) is well suited for learning the parameters of the dynamic equation, even in the presence of friction and noise. The resulting control performance is better than with measured parameters for any trajectory in the workspace. When the task consists of repeating the same trajectory, an adaptive look-up-table MEMory, introduced and analyzed in this paper, is simpler to implement and results in even better control performance.

The important questions for instructors to address concern what skills the student is to learn and how the student is to be motivated to acquire those skills. Questions about simulations, graphics tools, and the like are unimportant until the first two questions have been answered adequately. We discuss the role of explanation by students and describe a mechanism for motivating students to learn.

By exploiting an important property of the time optimal control law structure, this paper introduces a new dynamic programming approach for X-Y robot minimum time path following problem. Compared with the conventional dynamic programming method, the proposed approach significantly reduces the computational cost. The efficiency and effectiveness of the proposed approach are demonstrated via computer simulations. In addition, via experimental studies, this paper also addresses practical difficulties in implementing the minimum-time control law.

Lazy functional languages seem to be unsuitable for programming embedded computers because their implementations require so much memory for program code and graph. In this paper we describe a new abstract machine for the implementation of lazy functional languages on embedded computers called the X-machine. The X-machine has been designed so that program code can be stored compactly as byte code, yet run quickly using dynamic compilation. Our first results are promising – programs typically require only 33% of the code space of an ordinary implementation, but run at 75% of the speed. Future work needs to concentrate on reducing the size of statically-allocated data and the run-time system, and on developing a more detailed understanding of throw-away compilation.

This article contains a description of a constraint solver that determines complete solution spaces. These spaces are defined by sets of constraints in continuous variables. Interactive design is supported through improvements to existing algorithms that have increased system performance. In addition, heuristics for activating the best set of preferred constraints for a design task are presented, and two ways are proposed for interactively exploring design alternatives. IDIOM is an application framework that has successfully tested these algorithms for interactive apartment layout design.

Functional programming languages are informally classified into pure and impure languages. The precise meaning of this distinction has been a matter of controversy. We therefore investigate a formal definition of purity. We begin by showing that some proposed definitions which rely on confluence, soundness of the beta axiom, preservation of pure observational equivalences and independence of the order of evaluation, do not withstand close scrutiny. We propose instead a definition based on parameter-passing independence. Intuitively, the definition implies that functions are pure mappings from arguments to results; the operational decision of how to pass the arguments is irrelevant. In the context of Haskell, our definition is consistent with the fact that the traditional call-by-name denotational semantics coincides with the traditional call-by-need implementation. Furthermore, our definition is compatible with the stream-based, continuation-based and monad-based integration of computational effects in Haskell. Finally, we observe that call-by-name reasoning principles are unsound in compilers for monadic Haskell.

The collection of papers that follow this Editorial (beginning on page 43) come from the symposium “Computing Futures in Engineering Design” that was held on the campus of Harvey Mudd College in Claremont, California, on May 2–3, 1997. The symposium focused on future roles of computing in doing design and engineering and in the teaching of design and engineering. The intention of the symposium organizer, Clive Dym, was to provide useful insight, advice, and information to educators about how they might think about the future of design in engineering education.