902 resultados para Analog electronic systems -- Design
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The research, which was given the terms of reference, "To cut the lead time for getting new products into volume production", was sponsored by a company which develops and manufactures telecommunications equipment. The research described was based on studies made of the development of two processors which were designed to control telephone exchanges in the public network. It was shown that for each of these products, which were large electronic systems containing both hardware and software, most of their lead time was taken up with development. About half of this time was consumed by activities associated with redesign resulting from changes found to be necessary after the original design had been built. Analysing the causes of design changes showed the most significant to be Design Faults. The reasons why these predominated were investigated by seeking the collective opinion from design staff and their management using a questionnaire. Using the results from these studies to build upon the works of other authors, a model of the development process of large hierarchical systems is derived. An important feature of this model is its representation of iterative loops due to design changes. In order to reduce the development time, two closely related philosophies are proposed: By spending more time at the early stages of development (detecting and remedying faults in the design) even greater savings can be made later on, The collective performance of the development organisation would be improved by increasing the amount and speed of feedback about that performance. A trial was performed to test these philosophies using readily available techniques for design verification. It showed that about an 11 per cent saving would be made on the development time and that the philosophies might be equally successfully applied to other products and techniques.
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This study is concerned with several proposals concerning multiprocessor systems and with the various possible methods of evaluating such proposals. After a discussion of the advantages and disadvantages of several performance evaluation tools, the author decides that simulation is the only tool powerful enough to develop a model which would be of practical use, in the design, comparison and extension of systems. The main aims of the simulation package developed as part of this study are cost effectiveness, ease of use and generality. The methodology on which the simulation package is based is described in detail. The fundamental principles are that model design should reflect actual systems design, that measuring procedures should be carried out alongside design that models should be well documented and easily adaptable and that models should be dynamic. The simulation package itself is modular, and in this way reflects current design trends. This approach also aids documentation and ensures that the model is easily adaptable. It contains a skeleton structure and a library of segments which can be added to or directly swapped with segments of the skeleton structure, to form a model which fits a user's requirements. The study also contains the results of some experimental work carried out using the model, the first part of which tests• the model's capabilities by simulating a large operating system, the ICL George 3 system; the second part deals with general questions and some of the many proposals concerning multiprocessor systems.
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The work described was carried out as part of a collaborative Alvey software engineering project (project number SE057). The project collaborators were the Inter-Disciplinary Higher Degrees Scheme of the University of Aston in Birmingham, BIS Applied Systems Ltd. (BIS) and the British Steel Corporation. The aim of the project was to investigate the potential application of knowledge-based systems (KBSs) to the design of commercial data processing (DP) systems. The work was primarily concerned with BIS's Structured Systems Design (SSD) methodology for DP systems development and how users of this methodology could be supported using KBS tools. The problems encountered by users of SSD are discussed and potential forms of computer-based support for inexpert designers are identified. The architecture for a support environment for SSD is proposed based on the integration of KBS and non-KBS tools for individual design tasks within SSD - The Intellipse system. The Intellipse system has two modes of operation - Advisor and Designer. The design, implementation and user-evaluation of Advisor are discussed. The results of a Designer feasibility study, the aim of which was to analyse major design tasks in SSD to assess their suitability for KBS support, are reported. The potential role of KBS tools in the domain of database design is discussed. The project involved extensive knowledge engineering sessions with expert DP systems designers. Some practical lessons in relation to KBS development are derived from this experience. The nature of the expertise possessed by expert designers is discussed. The need for operational KBSs to be built to the same standards as other commercial and industrial software is identified. A comparison between current KBS and conventional DP systems development is made. On the basis of this analysis, a structured development method for KBSs in proposed - the POLITE model. Some initial results of applying this method to KBS development are discussed. Several areas for further research and development are identified.
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As a new medium for questionnaire delivery, the Internet has the potential to revolutionize the survey process. Online-questionnaires can provide many capabilities not found in traditional paper-based questionnaires. Despite this, and the introduction of a plethora of tools to support online-questionnaire creation, current electronic survey design typically replicates the look-and-feel of paper-based questionnaires, thus failing to harness the full power of the electronic delivery medium. A recent environmental scan of online-questionnaire design tools found that little, if any, support is incorporated within these tools to guide questionnaire designers according to best-practice [Lumsden & Morgan 2005]. This paper briefly introduces a comprehensive set of guidelines for the design of online-questionnaires. Drawn from relevant disparate sources, all the guidelines incorporated within the set are proven in their own right; as an initial assessment of the value of the set of guidelines as a practical reference guide, we undertook an informal study to observe the effect of introducing the guidelines into the design process for a complex online-questionnaire. The paper discusses the qualitative findings — which are encouraging for the role of the guidelines in the ‘bigger picture’ of online survey delivery across many domains such as e-government, e-business, and e-health — of this case study.
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As a new medium for questionnaire delivery, the internet has the potential to revolutionise the survey process. Online (web-based) questionnaires provide several advantages over traditional survey methods in terms of cost, speed, appearance, flexibility, functionality, and usability (Bandilla et al., 2003; Dillman, 2000; Kwak and Radler, 2002). Online-questionnaires can also provide many capabilities not found in traditional paper-based questionnaires: they can include pop-up instructions and error messages; they can incorporate links; and it is possible to encode difficult skip patterns making such patterns virtually invisible to respondents. Despite this, and the introduction of numerous tools to support online-questionnaire creation, current electronic survey design typically replicates that of paper-based questionnaires, failing to harness the full power of the electronic delivery medium. Worse, a recent environmental scan of online-questionnaire design tools found that little, if any, support is incorporated within these tools to guide questionnaire designers according to best-practice (Lumsden and Morgan, 2005). This article introduces a comprehensive set of guidelines - a practical reference guide - for the design of online-questionnaires.
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The chapter discusses both the complementary factors and contradictions of adoption ERP-based systems with Enterprise 2.0. ERP is well known as IT's efficient business process management. Enterprise 2.0 supports flexible business process management, informal, and less structured interactions. Traditional studies indicate efficiency and flexibility may seem incompatible because they are different business objectives and may exist in different organizational environments. However, the chapter breaks traditional norms that combine ERP and Enterprise 2.0 in a single enterprise to improve both efficient and flexible operations simultaneously. Based on multiple case studies, the chapter analyzes the benefits and risks of the combination of ERP with Enterprise 2.0 from process, organization, and people paradigms. © 2013 by IGI Global.
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A new original method and CASE-tool of system analysis and modelling are represented. They are for the first time consistent with the requirements of object-oriented technology of informational systems design. They essentially facilitate the construction of organisational systems models and increase the quality of the organisational designing and basic technological processes of object application developing.
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The paper deals with a problem of intelligent system’s design for complex environments. There is discussed a possibility to integrate several technologies into one basic structure. One possible structure is proposed in order to form a basis for intelligent system that would be able to operate in complex environments. The basic elements of the proposed structure have found their implemented in software system. This software system is shortly presented in the paper. The most important results of experiments are outlined and discussed at the end of the paper. Some possible directions of further research are sketched.
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It has been years since the introduction of the Dynamic Network Optimization (DNO) concept, yet the DNO development is still at its infant stage, largely due to a lack of breakthrough in minimizing the lengthy optimization runtime. Our previous work, a distributed parallel solution, has achieved a significant speed gain. To cater for the increased optimization complexity pressed by the uptake of smartphones and tablets, however, this paper examines the potential areas for further improvement and presents a novel asynchronous distributed parallel design that minimizes the inter-process communications. The new approach is implemented and applied to real-life projects whose results demonstrate an augmented acceleration of 7.5 times on a 16-core distributed system compared to 6.1 of our previous solution. Moreover, there is no degradation in the optimization outcome. This is a solid sprint towards the realization of DNO.
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Modern manufacturing systems should satisfy emerging needs related to sustainable development. The design of sustainable manufacturing systems can be valuably supported by simulation, traditionally employed mainly for time and cost reduction. In this paper, a multi-purpose digital simulation approach is proposed to deal with sustainable manufacturing systems design through Discrete Event Simulation (DES) and 3D digital human modelling. DES models integrated with data on power consumption of the manufacturing equipment are utilized to simulate different scenarios with the aim to improve productivity as well as energy efficiency, avoiding resource and energy waste. 3D simulation based on digital human modelling is employed to assess human factors issues related to ergonomics and safety of manufacturing systems. The approach is implemented for the sustainability enhancement of a real manufacturing cell of the aerospace industry, automated by robotic deburring. Alternative scenarios are proposed and simulated, obtaining a significant improvement in terms of energy efficiency (−87%) for the new deburring cell, and a reduction of energy consumption around −69% for the coordinate measuring machine, with high potential annual energy cost savings and increased energy efficiency. Moreover, the simulation-based ergonomic assessment of human operator postures allows 25% improvement of the workcell ergonomic index.
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Permanent magnet synchronous motors (PMSMs) provide a competitive technology for EV traction drives owing to their high power density and high efficiency. In this paper, three types of interior PMSMs with different PM arrangements are modeled by the finite element method (FEM). For a given amount of permanent magnet materials, the V-shape interior PMSM is found better than the U-shape and the conventional rotor topologies for EV traction drives. Then the V-shape interior PMSM is further analyzed with the effects of stator slot opening and the permanent magnet pole chamfering on cogging torque and output torque performance. A vector-controlled flux-weakening method is developed and simulated in Matlab to expand the motor speed range for EV drive system. The results show good dynamic and steady-state performance with a capability of expanding speed up to four times of the rated. A prototype of the V-shape interior PMSM is also manufactured and tested to validate the numerical models built by the FEM.
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Thesis (Ph.D.)--University of Washington, 2016-08
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This article introduces the idea of asking people to create instructions for others, as a way of exploring their mental models of designed systems. An example exercise run at the 2012 Brighton Maker Faire provides context. Article part of the 'On Modelling' forum edited by Hugh Dubberly.
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Design influences behaviour, whether it's planned or not. Service Design has a great opportunity to lead the emerging field of design for behavioural change, helping guide and shape experiences to benefit users, service providers and wider society. In this article, presented as an evolving conversation between research and practice, Nick Marsh (EMC Consulting) and Dan Lockton (Brunel University) discuss and explore design patterns for influencing behaviour through Service Design, and how Service Designers and academics can work together for social benefit.
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As unmanned autonomous vehicles (UAVs) are being widely utilized in military and civil applications, concerns are growing about mission safety and how to integrate dierent phases of mission design. One important barrier to a coste ective and timely safety certication process for UAVs is the lack of a systematic approach for bridging the gap between understanding high-level commander/pilot intent and implementation of intent through low-level UAV behaviors. In this thesis we demonstrate an entire systems design process for a representative UAV mission, beginning from an operational concept and requirements and ending with a simulation framework for segments of the mission design, such as path planning and decision making in collision avoidance. In this thesis, we divided this complex system into sub-systems; path planning, collision detection and collision avoidance. We then developed software modules for each sub-system