Conceptual Modeling for Design Formulation

A design methodology is developed for the preliminary stage of building design. The methodology applies a theory of conceptual structure to model building design processes and incorporates the top-down approach of design decisions from a total system point of view. This design approach accounts for the uncertainties in the structural design processes and information, and provides a vehicle for formulating complex engineering decisions. The computing aspects of the design processes are categorised as arithmetic and reasoning formulations for capturing design information. The computing formulations are represented and manipulated, in the present study, using fuzzy logic, and their applications are illustrated with examples of building component design. The research results enable the implementation of a computer-aided tool for structural engineers to enhance their design decisions.     

Function in Device Representation

We explore the meanings of the terms ‘structure’, ‘behaviour’, and, especially, ‘function’ in engineering practice. Computers provide great assistance in calculation tasks in engineering practice, but they also have great potential for helping with reasoning tasks. However, realising this vision requires precision in representing engineering knowledge, in which the terms mentioned above play a central role. We start with a simple ontology for representing objects and causal interactions between objects. Using this ontology, we investigate a range of meanings for the terms of interest. Specifically, we distinguish between function as effect on the environment, and a device-centred view of device function. In the former view, function is seen as an intended or desired role that an artifact plays in its environment. We identify an important concept called mode of deployment that is often left implicit, but whose explicit representation is necessary for correct and complete reasoning. We discuss the task of design and design verification in this framework. We end with a discussion that relates needs in the world to functions of artifacts created to satisfy the needs.     

Modular Design of Real-Time Systems Using Hierarchical Communicating Real-time State Machines

This paper proposes a methodology for the development of distributed real-time systems. The methodology consists of the Hierarchical Communicating Real-Time State Machines (H-CRSM) modelling language, and the Violin toolset. H-CRSM combines Statecharts constructs with CSP-like timed communications. Violin provides a visual environment supporting in a seamless way all the life-cycle development phases of an H-CRSM system. Temporal validation rests on assertion checking during system simulation. Code generation is based on Java and a customizable runtime. The practical use of H-CRSM/Violin is shown by an example. A preliminary version of this paper appears in Proc. of Joint Modular Languages Conference (JMLC'2003), Klagenfurt, Austria, August 2003, LNCS 2789, Springer, pp. 110–121. Angelo Furfaro, Phd, is a computer science assistant professor at Unical, DEIS, teaching object-oriented programming. His research interests include: multiagent systems, Petri nets, parallel simulation, verification of time-dependent systems, distributed measurement systems. He is a member of ACM. Libero Nigro is a full professor of computer science at Unical, DEIS, where he teaches object-oriented programming, software engineering and real-time systems courses. He is the responsible of Software Engineering Laboratory (www.lis.deis.unical.it). His current research interests include: software engineering of time-dependent and distributed systems, real-time systems, Petri nets, modeling and parallel simulation of complex systems, distributed measurement systems. Prof. Nigro is a member of ACM and IEEE. Francesco Pupo, Phd, is a computer science assistant professor at Unical, DEIS, teaching introductory programming and computer architecture courses. His research interests include: Petri nets, discrete-event simulation, real-time systems, distributed measurement systems.     

Modular software system for computer aided design of microsystems

A modular software system to assist engineers in designing microsystems is presented. The different modules support both the system and the component design and are linked with each other by a workflow management system. In particular, this paper presents the co-operation of the modules rumtopf, suzana and μ-toast. They assist the designer in the definition and validation of process sequences, the simulation of wet chemical etching of silicon and the tolerance management. The usage and usefulness of the presented software system is illustrated by an example showing the design of an acceleration sensor.     

Automated generation of multiphysics simulation models to support multidisciplinary design optimization

To ensure a consistent design representation for serving multidisciplinary analysis, this research study proposes an intelligent modeling system to automatically generate multiphysics simulation models to support multidisciplinary design optimization processes by using a knowledge based engineering approach. A key element of this system is a multiphysics information model (MIM), which integrates the design and simulation knowledge from multiple engineering domains. The intelligent modeling system defines classes with attributes to represent various aspects of physical entities. Moreover, it uses functions to capture the non-physical information, such as control architecture, simulation test maneuvers and simulation procedures. The challenge of system coupling and the interactions among the disciplines are taken into account during the process of knowledge acquisition. Depending on the domain requirements, the intelligent modeling system extracts the required knowledge from the MIM and uses this first to instantiate submodels and second to construct the multiphysics simulation model by combining all submodels. The objective of this research is to reduce the time and effort for modeling complex systems and to provide a consistent and concurrent design environment to support multidisciplinary design optimization. The development of an unstable and unmanned aerial vehicle, a multirotor UAV, is selected as test case. The intelligent modeling system is demonstrated by modeling thirty-thousand multirotor UAV designs with different topologies and by ensuring the automatic development of a consistent control system dedicated for each individual design. Moreover, the resulting multiphysics simulation model of the multirotor UAV is validated by comparing with the flight data of an actual quadrotor UAV. The results show that the multiphysics simulation model matches test data well and indicate that high fidelity models can be generated with the automatic model generation process.     

ASPECS: an agent-oriented software process for engineering complex systems

Holonic multiagent systems (HMAS) offer a promising software engineering approach for developing complex open software systems. However the process of building Multi-Agent Systems (MAS) and HMAS is mostly different from the process of building more traditional software systems as it introduces new design and development challenges. This paper introduces an agent-oriented software process for engineering complex systems called ASPECS. ASPECS is based on a holonic organisational metamodel and provides a step-by-step guide from requirements to code allowing the modelling of a system at different levels of details using a set of refinement methods. This paper details the entire ASPECS development process and provides a set of methodological guidelines for each process activity. A complete case study is also used to illustrate the design process and the associated notations. ASPECS uses UML as a modelling language. Because of the specific needs of agents and holonic organisational design, the UML semantics and notation are used as reference points, but they have been extended by introducing new specific profiles.     

Application of 3D Solid Modeling and Simulation Programs to a Bridge Structure

. This paper presents our work on the integrated use of computational methods (e.g. geometric modeling, simulation, visualization and optimization) for structural analysis and design. The focus in this paper is on 3D solid modeling and dynamic simulation. The paper describes our program system comprising the in-house program FEM90 integrated with commercial CAD and optimization programs. The program system is tested on a major bridge structure example. The example shows that 3D solid modeling and simulation are versatile tools for design of structures.     

Expanding bottleneck management from manufacturing to product design and engineering processes

Bottlenecks inhibit the performance of companies. Up to now, bottleneck management research has concentrated on manufacturing processes, while neglecting product design and engineering processes. This research fills this gap through developing and testing of a new bottleneck management concept for product design and engineering processes. The new concept is developed using a system theory modelling approach and comprises of four bottleneck management counter measures. Two propositions were developed to test the concept through an event-discrete simulation model. The simulation is grounded on empirical data from three design-driven companies and tests the impact of the four bottleneck management counter measures on the performance of product design and engineering processes. The findings from the simulation confirm the applicability of the newly developed bottleneck concept to improve the performance of product design and engineering processes. In doing so, this research study expands bottleneck management for the first time from manufacturing to product design and engineering processes.     

PACT: an experiment in integrating concurrent engineering systems

The Palo Alto Collaborative Testbed (PACT), a concurrent engineering infrastructure that encompasses multiple sites, subsystems, and disciplines, is discussed. The PACT systems include NVisage, a distributed knowledge-based integration environment for design tools; DME (Device Modeling Environment), a model formulation and simulation environment; Next-Cut, a mechanical design and process planning system; and Designworld, a digital electronics design, simulation, assembly, and testing system. The motivations for PACT and the significance of the approach for concurrent engineering is discussed. Initial experiments in distributed simulation and incremental redesign are reviewed, and PACT's agent-based architecture and lessons learned from the PACT experiments are described     

Metamodels for Computer-based Engineering Design: Survey and recommendations

The use of statistical techniques to build approximations of expensive computer analysis codes pervades much of today’s engineering design. These statistical approximations, or metamodels, are used to replace the actual expensive computer analyses, facilitating multidisciplinary, multiobjective optimization and concept exploration. In this paper, we review several of these techniques, including design of experiments, response surface methodology, Taguchi methods, neural networks, inductive learning and kriging. We survey their existing application in engineering design, and then address the dangers of applying traditional statistical techniques to approximate deterministic computer analysis codes. We conclude with recommendations for the appropriate use of statistical approximation techniques in given situations, and how common pitfalls can be avoided.     

safeDpi: a language for controlling mobile code

safeDpi is a distributed version of the Picalculus, in which processes are located at dynamically created sites. Parametrised code may be sent between sites using so-called ports, which are essentially higher-order versions of Picalculus communication channels. A host location may protect itself by only accepting code which conforms to a given type associated to the incoming port. We define a sophisticated static type system for these ports, which restrict the capabilities and access rights of any processes launched by incoming code. Dependent and existential types are used to add flexibility, allowing the behaviour of these launched processes, encoded as process types, to depend on the host's instantiation of the incoming code. We also show that a natural contextually defined behavioural equivalence can be characterised coinductively, using bisimulations based on typed actions. The characterisation is based on the idea of knowledge acquisition by a testing environment and makes explicit some of the subtleties of determining equivalence in this language of highly constrained distributed code.     

Modeling and simulating software acquisition process architectures

In this paper, we describe our efforts to support the modeling and simulation of processes associated with software system acquisition activities. Software acquisition is generally a multi-organization endeavor concerned with the funding, management, engineering, system integration, deployment and long-term support of large software systems. We first describe our approach supporting the modeling and simulation of software acquisition processes using a software process architecture (SPA). We then introduce how we support the distribution, concurrent execution and interoperation of multiple software process simulations using the high-level architecture (HLA) and run-time infrastructure (RTI) to address the complexity of software acquisition process architectures. To illustrate this, we provide examples from the design and prototyping of a Web-based environment that supports the modeling and simulation of acquisition process architectures. This environment thus serves as a new kind of software process test-bed that can demonstrate and support experiments incorporating multiple software process simulation systems that interoperate in a distributed and concurrent manner across a network.     

EFDEX: A Knowledge-Based Expert System for Functional Design of Engineering Systems

This paper presents a knowledge-based system, ‘EFDEX’, the Engineering Functional Design Expert, which was developed using an expert system shell, CLIPS 6.1, to perform intelligent functional design of engineering systems. On the basis of a flexible, causal and hierarchical functional modeling framework, we propose a knowledge-based functional reasoning methodology. By using this intelligent functional reasoning strategy, physical behavior can be reasoned out from a desired function or desired behavior, and inter-connection of these behaviors is possible when there is compatibility between the functional output of one and the corresponding functional requirement (e.g. driving input) of the next one. In addition, a complicated, desired function which cannot be matched with the functional output of any behavior after searching the object-oriented behavior base, will be automatically decomposed into less complex sub-functions by means of relevant function decomposition rules. An intelligent system for the functional design of an automatic assembly system provides an application of this intelligent design environment, and a demonstration of its methodology. In this paper, a knowledge-based functional representation scheme which integrates two popular AI representation techniques (object-oriented representation and rule-based representation) is also proposed as a prelude to a knowledge-based functional design system     

基于仿真的C4ISR系统设计方法及其支持环境研究

C4ISR系统的分析与设计是一项非常复杂的系统工程,而建模和仿真技术(M&S)作为系统分析与设计的一种关键技术有着广泛地应用.该文在对C4ISR系统的分析与设计过程进行研究的基础上,结合基于仿真的设计(SBD)方法,提出了基于仿真的C4ISR系统设计方法,深入探讨了在C4ISR系统分析设计全生命周期中运用SBD方法进行辅助设计的过程,并对其支持环境的设计进行了研究.     

Parallel programming inPanda

Distributed systems are an alternative to shared-memory multiprocessors for the execution of parallel applications.Panda is a run-time system that provides architectural support for efficient parallel and distributed programming. It supplies fast user-level threads and a means for transparent and coordinated sharing of objects across a homogeneous network. The paper motivates the major architectural choices that guided our design. The problem of sharing data in a distributed environment is discussed, and the performance of the mechanisms provided by thePanda prototype implementation is assessed.     

Attribute Management System for Engineering Analysis

. This paper presents the design and implementation of an attribute management system that supports the specification of information, past that of the domain definition, needed to qualify an engineering analysis. The information anaged by this system includes various order tensors eeded to specify the analysis attributes of material properties, oads, and boundary conditions as well as additional data constructs used by the analysis such as strings, and references to either other attributes or model entities. The system supports general dependencies and variations of this attribute information as well as its association with the various geometric entities which constitute the geometric domain being analyzed. In addition, since the information is coupled with the model entities themselves, the system can be used to store information needed to control the discretization process of the geometric domain. Since the information can be both spatially and temporally varying, an expression subsystem was also designed into the system. The framework was designed using object-oriented techniques, implemented in C++, and can be easily maintained and extended.     

Computational origami environment on the web

We present a computing environment for origami on the web. The environment consists of the computational origami engine Eos for origami construction, visualization, and geometrical reasoning, WebEos for providing web interface to the functionalities of Eos, and web service system Scorum for symbolic computing web services. WebEos is developed using Web2.0 technologies, and provides a graphical interactive web interface for origami construction and proving. In Scorum, we are preparing web services for a wide range of symbolic computing systems, and are using these services in our origami environment. We explain the functionalities of this environment, and discuss its architectural and technological features.     

Emergence of Collective Behavior in Evolving Populations of Flying Agents

We demonstrate the emergence of collective behavior in two evolutionary computation systems, one an evolutionary extension of a classic (highly constrained) flocking algorithm and the other a relatively un-constrained system in which the behavior of agents is governed by evolved computer programs. The first system demonstrates the evolution of a form of multicellular organization, while the second demonstrates the evolution of a form of altruistic food sharing. In this article we describe both systems in detail, document the emergence of collective behavior, and argue that these systems present new opportunities for the study of group dynamics in an evolutionary context. We also provide a brief overview of the breve simulation environment in which the systems were produced, and of breve’s facilities for the rapid, exploratory development of visualization strategies for artificial life.