SHARED: An information model for cooperative product development

One fundamental issue in developing collaborative engineering systems is the representation of product information which supports communication and coordination. This product information includes not only the geometric and physical properties of the product and its parts, but also information about functions, constraints and the design rationale. In this paper, we describe an information model, SHARED, which was developed for encoding product information in DICE, a distributed and integrated environment for computer-aided engineering. SHARED provides multiple levels of both functional and geometric abstractions, multiple views and techniques for maintaining consistency between the various abstractions and views. These elements are essential for a good representation model of product information. The use of the SHARED model is illustrated through an example, depicting the various representations of a product as it evolves through the design process. The SHARED model has been implemented over a distributed OODBMS as a toolkit/framework for developing environments which need to model, manipulate and communicate product information between distributed cooperating applications, while supporting coordination between them.     

Agent-based features for CAD browsers to foster engineering collaboration over the Internet

For distributed engineers, CAD browsers are very good tools to collaborate asynchronously over the Internet. Support for synchronous collaboration is well researched and developed. However, for asynchronous collaboration systems, the research is very limited. The purpose of this study is to identify the major factors that affect the efficiency of engineering collaboration over the Internet using CAD browsers and design-agent-based features to support engineering collaboration. Activity coordination, collaboration awareness, and communication support were identified as the major factors for efficient engineering collaboration using CAD browsers. The agent-based features of Comment Status, Communication Agent, Team Member Information Enhancement, and Task Information Enhancement were designed to support communication, activity coordination, and collaboration awareness issues for engineering collaboration. A prototype of the CAD browser was designed. Three experiments were conducted to test the efficiency of the new proposed features in the agent system. The experimental results indicate that (a) the Comment Status feature reduced the missing rates of comments and comment processing time, (b) the Communication Agent reduced delay time in processing comments, and (c) the features of Team Member Information and Task Information Enhancement improved collaboration efficiency and subject satisfaction.     

Variance plus bias optimal response surface designs with qualitative factors applied to stem choice modeling

This paper explores the issue of model misspecification, or bias, in the context of response surface design problems involving quantitative and qualitative factors. New designs are proposed specifically to address bias and compared with five types of alternatives ranging from types of composite to D‐optimal designs using four criteria including D‐efficiency and measured accuracy on test problems. Findings include that certain designs from the literature are expected to cause prediction errors that practitioners would likely find unacceptable. A case study relating to the selection of science, technology, engineering, or mathematics majors by college students confirms that the expected substantial improvements in prediction accuracy using the proposed designs can be realized in relevant situations. Copyright © 2011 John Wiley & Sons, Ltd.     

Ferroelectric polymer gates for non-volatile field effect control of ferromagnetism in (Ga, Mn)As layers

(Ga, Mn)As and other diluted magnetic semiconductors (DMS) attract a great deal of attention for potential spintronic applications because of the possibility of controlling the magnetic properties via electrical gating. Integration of a ferroelectric gate on the DMS channel adds to the system a non-volatile memory functionality and permits nanopatterning via the polarization domain engineering. This topical review is focused on the multiferroic system, where the ferromagnetism in the (Ga, Mn)As DMS channel is controlled by the non-volatile field effect of the spontaneous polarization. Use of ferroelectric polymer gates in such heterostructures offers a viable alternative to the traditional oxide ferroelectrics generally incompatible with DMS. Here we review the proof-of-concept experiments demonstrating the ferroelectric control of ferromagnetism, analyze the performance issues of the ferroelectric gates and discuss prospects for further development of the ferroelectric/DMS heterostructures toward the multiferroic field effect transistor.     

A distributed multi-agent environment for product design and manufacturing planning

This paper describes a multi-agent approach to the integration of product design, manufacturability analysis, and process planning in a distributed manner. The objective is to develop a distributed concurrent engineering system to allow geographically dispersed entities to work cooperatively towards overall system goals. In the paper, an agent-based concurrent engineering system concerning product design and manufacturing planning, and its fundamental framework and functions are presented. The proposed model considers constraints and requirements from the different product development cycles in the early development phases and fully supports the concept of design-for-manufacturability. This methodology uses conflict resolution (CR) techniques and design-improvement suggestions to refine the initial product design. The model comprises a facilitator agent, a console agent and six service agents. Each service agent is used to model different product development phases, and the console agent acts as an interacting interface between designers and the system, while the facilitator is responsible for the decomposition and dispatch of tasks, and resolving conflicts of poor designs. A prototype system for part design, manufacturability analysis, and process planning has been implemented. The performance of the prototype system shows that it could be extended to include other service agents, such as assemblability analysis, to become a comprehensive distributed concurrent engineering system for geographically dispersed customers and suppliers.     

Multi-objective analysis of a component-based representation within an interactive evolutionary design system

This article describes research relating to a user-centered evolutionary design system that evaluates both engineering and aesthetic aspects of design solutions during early-stage conceptual design. The experimental system comprises several components relating to user interaction, problem representation, evolutionary search and exploration and online learning. The main focus of the article is the evolutionary aspect of the system when using a single quantitative objective function plus subjective judgment of the user. Additionally, the manner in which the user-interaction aspect affects system output is assessed by comparing Pareto frontiers generated with and without user interaction via a multi-objective evolutionary algorithm (MOEA). A solution clustering component is also introduced and it is shown how this can improve the level of support to the designer when dealing with a complex design problem involving multiple objectives. Supporting results are from the application of the system to the design of urban furniture which, in this case, largely relates to seating design.     

Characterization of gas-phase molecular interactions on differential mobility ion behavior utilizing an electrospray ionization-differential mobility-mass spectrometer system

Differential mobility spectrometry (DMS) is a rapidly advancing technology for gas-phase ion separation. The interfacing of DMS with mass spectrometry (MS) offers potential advantages over the use of mass spectrometry alone. Such advantages include improvements to mass spectral signal/noise ratios, orthogonal/complementary ion separation to mass spectrometry, enhanced ion and complexation structural analysis, and potential for rapid analyte quantitation. The introduction of a new ESI-DMS-MS system and its utilization to aid in the understanding of DMS separation theory is described. A current contribution to DMS separation theory is one of an association/dissociation process between ions/molecules in the gas phase during the differential mobility separation. A model study was designed to investigate the molecular dynamics and chemical factors influencing the theorized association/dissociation process, and the mechanisms by which these gas-phase interactions affect an ion's DM behavior. Five piperidine analogues were selected as model analytes, and three alcohol drift gas dopants/modifiers were used to interrogate the analyte ions in the gas phase. Two proposed DMS separation mechanisms, introduced as Core and Fa?ade, corresponding to strong and weak attractions between ions/molecules in the gas phase, are detailed. The proposed mechanisms provide explanation for the observed changes in analyte separation by the various drift gas modifiers. Molecular modeling of the proposed mechanisms provides supportive data and demonstrates the potential for predictive optimization of analyte separation based on drift gas modifier effects.     

计算机支持的工程设计和工业设计的协同工作

随着信息技术的快速发展，设计自动化越来越为工业界所接受。与此同时，产品设计正日益朝着更强功能和更加和谐的人机关系方向发展。如何对上述多元关系进行协调，使产品设计建立在完整的信息模型基础之上，并在计算机支持下进行协同设计，成为产品设计的一个新焦点。本文分析并讨论了工程设计和工业设计两种方法在产品设计中的作用及其协同的可能性，并进一步探讨信息技术环境下产品设计新体系，最后给出了计算机支持的产品协同设计过程。     

Event oriented system analysis

This article presents an attempt towards a probabilistic event oriented system analysis in engineering. Engineering systems are represented as either complete or incomplete systems of events and as compounds of various subsystems of events. The event oriented system analysis investigates important subsystems in engineering systems, such as operational modes and failure modes and their interrelations. The analysis is also applicable to engineering systems with various relations among the sets of events, such as mutually exclusive and inclusive sets. Further, the systems and subsystems are subjected to probability and uncertainty analysis. The system uncertainty analysis is based on entropy. General relations among the probability, uncertainty of the system and uncertainties of the subsystems are derived by using information theory. Specific mathematical aspects and available methods in the uncertainty modelling of systems and subsystems are summarised. Numerical examples confirm the relevance of the event oriented system analysis and indicate potential improvements in system design.     

Magnetic charged system search: a new meta-heuristic algorithm for optimization

An improved version of the charged system search (CSS) algorithm is introduced which is called magnetic charged system search (MCSS). In the new algorithm, magnetic forces are considered in addition to electrical forces, using the Biot–Savart law. Each charged particle (CP), as a search agent, exerts magnetic forces on other CPs based on the variation of its objective function value during its last movement and its distance between other CPs. This additional force provides useful information for the optimization process and enhances the performance of the CSS algorithm. The efficiency of the MCSS is examined by application of this algorithm to well-known mathematical benchmarks and three well-studied engineering design problems. The results are compared to those of the CSS, and the improvements are highlighted.     

Adaptive One-Factor-at-a-Time Experimentation and Expected Value of Improvement

This article concerns adaptive experimentation as a means for making improvements in design of engineering systems. A simple method for experimentation, called “adaptive one-factor-at-a-time,” is described. A mathematical model is proposed and theorems are proven concerning the expected value of the improvement provided and the probability that factor effects will be exploited. It is shown that adaptive one-factor-at-a-time provides a large fraction of the potential improvements if experimental error is not large compared with the main effects and that this degree of improvement is more than that provided by resolution III fractional factorial designs if interactions are not small compared with main effects. The theorems also establish that the method exploits two-factor interactions when they are large and exploits main effects if interactions are small. A case study on design of electric-powered aircraft supports these results.     

Project Management and Coordination of Distributed Cooperative Product Design in a Virtual Enterprise

The architecture of project management of distributed concurrent product design in a virtual enterprise is put forward. The process of project management and its functions are presented. Product design process coordination is also discussed. First, based on the analysis of traditional project management, project management and coordination of distributed cooperative product design in the virtual enterprise is put forward. Then, aiming at the characteristics of a distributed concurrent product design process, the inherent rules and complex interrelations in product development are studied. Accordingly, the architecture of project management of distributed cooperative product design in a virtual enterprise is presented to adapt to distributed concurrent development of complex products. The main advantages of the architecture are also discussed. Finally, the emphasis is placed on the project management process. Its main functions are set forth, such as projectdefinition, task decomposition and distribution, resource cortstraints and dynamic resource scheduling, process fusion, task scheduling and monitoring, project plan, cost and quality evaluation, etc.     

Rapid separation and quantitative analysis of peptides using a new nanoelectrospray- differential mobility spectrometer-mass spectrometer system

Differential mobility spectrometry (DMS) (see Buryakov, I. A.; Krylov, E. V.; Nazarov, E. G.; Rasulev, U. Kh. Int. J. Mass Spectrom. Ion Processes 1993, 128, 143-148), also commonly referred to as high-field asymmetric waveform ion mobility spectrometry (FAIMS) (see Purves, R. W.; Guevremont, R.; Day, S.; Pipich, C. W.; Matyjaszcyk, M. S. Rev. Sci. Instrum. 1998, 69, 4094-4105), is a rapidly advancing technology for gas-phase ion separation. The interfacing of DMS with mass spectrometry (MS) offers potential advantages over the use of mass spectrometry alone. Such advantages include improvements to mass spectral signal-to-noise, orthogonal/complementary ion separation to mass spectrometry, enhanced ion and complexation structural analysis, and the potential for rapid analyte quantitation. In this report, we investigate the use of our nanoESI-DMS-MS system to demonstrate differential mobility separation of peptides. The formation of higher order peptide aggregate ions (ion complexes) via electrospray ionization and the negative impact this has on DMS peptide separation are examined. The successful use of differential mobility drift gas modifiers (dopants) to reduce aggregate ion size and improve DMS peptide ion separation is presented. Following optimization of DMS peptide separation conditions, we examined next the feasibility of a new analytical platform which uses direct sample infusion with nanoESI-DMS-MS for ultrarapid analyte quantitation. Quantitation of a selected peptide from a semicomplex peptide mixture is presented. Initial feasibility results with this new approach demonstrate good accuracy and reproducibility, as well as an absolute mass sensitivity of 6.8 amol and a minimum dynamic range of 2500 for the peptide of interest. This report offers a first look at utilizing nanoESI-DMS-MS to create an ultrarapid (under 5 s) quantitative analysis platform and its potential in the high-throughput arena. Each ion separation technique, DMS and MS, offers orthogonal ion separation to one another, enhancing the overall specificity for this quantitative approach.     

具有分布质量的双层隔振系统隔振特性分析

研究了分布质量对双层隔振系统隔振特性的影响，得到了质量对称分布时六自由度双层隔振系统固有频率及对谐波激励响应的解析表达式，提出了考虑摆动影响时确定隔振参数的实用设计方法并进行了实例计算。     

Improving the performance of mobile broadcasting systems using multiple base stations and distributed space?time codes

Error performance of distributed space-time codes used for mobile broadcasting systems consisting of multiple base stations is analysed. The base stations are assumed to operate in a simulcast mode, that is they simultaneously transmit the same message using the same carrier frequency. Mobile users within the intersection of the coverage areas, thus, enjoy a small probability of shadowing and a high probability of at least one line-of-sight (LOS) link. In effect, the base stations establish a virtual multiple-antenna system. The use of a distributed space-time code offers an additional spatial diversity gain. Considering a single user with a fixed (random) position, the impact of shadowing and LOS components on the error performance of the system is analysed and compared with a conventional multiple-antenna system with co-located transmit antennas. Specifically, the analysis shows that already a single LOS link significantly improves the overall system performance. In the case of shadowing, huge diversity gains are obtained in the distributed system. In a system with co-located transmitters, however, the performance improvements compared with a single-antenna system are rather small, when shadowing is taken into account. Altogether, it can be concluded that systems with distributed transmitters are typically superior to conventional multiple-antenna systems (due to macroscopic diversity), and that distributed space-time codes are superior to conventional simulcasting (due to microscopic diversity)     

Characterizing Design Learning: A Mixed‐Methods Study of Engineering Designers' Use of Language

Using multiple quantitative and qualitative methods to examine engineering design learning, we found that students taking a course in engineering design and/or studying engineering for four years acquired engineering design language that is common to a larger community of practice as well as common to their own programs and institutions of higher learning. The study also suggests that engineering design language shapes the knowledge that students have about engineering design. Finally, students did not always put their design knowledge into practice, suggesting the need for educational improvements and research to bridge this gap.     

Harmonization of individual dosimetry quality control within metrology system of a small country

A programme of harmonization of individual dosimetry quality control organized in the framework of a distributed metrology system is presented as seen from the experiences gained in Slovenia. As a part of the programme intercomparison of dosimetry services was organized and basic characteristics of dosimetry systems compared. Results are discussed with suggestions for further improvements of quality assurance.     

Unified structural–procedural approach for designing integrated manufacturing systems

A manufacturing system consists of a structure and distributed working procedures that include operating parameters. A new approach named unified structural–procedural approach (USPA) for designing the integrated structure and the distributed but integrated working procedures of a manufacturing system is included in this paper. The designed structure and working procedures bring about the efficiency desired by the target market on the ordered products even when the desired efficiency is turbulent. Here, the USPA approach is applied to redesign a real apparel factory. The USPA includes identification of the target market requirements, conception of the target manufacturing system, design of the system structure and working procedures. Conception of the target manufacturing system is done using pseudo-neural networks that exploit the improvements introduced by the higher performing firms throughout the industry. Design of the system structure is done using simulation models that bring forth building structural improvements whose implementation investments equate the saved inefficiency costs because the system structure is improved. The distributed working procedures are specified using flowcharts that include integrated values of the procedural parameters. The nature of these parameters are identified from available non-integrated operations management models and their integrated values obtained by using simulation models that evaluate their joint effect on product efficiency.