Design tool

About: Design tool is a research topic. Over the lifetime, 3864 publications have been published within this topic receiving 46401 citations.

Embedded Algorithms Within an FPGA to Classify Nonlinear Single-Degree-of-Freedom Systems

Abstract: This study is a significant advancement of this team's proof-of-concept study on using field-programmable gate arrays (FPGAs) in wireless sensing for structural health monitoring. Compared with traditional microprocessor-based systems, fast growing FPGA technology offers a more powerful, efficient, and flexible hardware platform. An effort is presented herein to embed algorithms to process nonlinear time series by entirely using an FPGA, while an ongoing effort is to pursue the development of an FPGA and microprocessor co-design for a more extended and robust version of this study. The Hilbert transform (HT) and a backbone curve technique are the centerpiece to extract instantaneous characteristics of a displacement time history from a under free vibration. Critical design issues are carefully considered including required approximation accuracy, constraints imposed by limited hardware resources, timing in the execution of the hardware design, and data representations in a fixed-point design environment. An automation of the classification of three basic types of SDOF systems (including linear, hardening and softening) are implemented for wireless transmission of processed results. An off-the-shelf high-level abstraction tool along with the MATLAB/Simulink environment is utilized to program the FPGA, rather than coding the hardware description language (HDL) manually. Extensive validation using simulated data is conducted for every step/stage of the design as well as major built-in functions adopted from the hardware design tool. The contribution of this study includes (1) enabling the functionality of a full hardware design for an enhanced computational efficiency in wireless structural health monitoring and (2) achieving balance between computational efficiency and resource utilization for onboard data processing especially when non-high-end FPGA products are targeted for practical consideration in structural health monitoring.

Classification of Analysis Techniques for Wireless Sensor Networks

Abstract: Analysis techniques study the trade-offs in wireless sensor networks (WSNs) using mathematical results. This is a new research area and relatively few analytical results exist in the literature. In this paper, we conduct a survey of some existing analysis techniques for WSNs and classify them to establish possible taxonomies for analysis techniques. Such a taxonomy for analysis techniques is especially helpful when developing an analysis-based design tool. We have developed such a tool, ANDES (ANalysis-based Design tool for wireless Sensor networks), which we describe briefly in this paper. We also discuss how tools like ANDES can benefit from a taxonomy for analysis techniques.

Chrono : A conceptual design framework for temporal entities

Abstract: Database applications are frequently faced with the necessity of representing time varying information and, particularly in the management of information systems, a few kinds of behavior in time can characterize a wide class of applications. A great amount of work in the area of temporal databases aiming at the definition of standard representation and manipulation of time, mainly in relational database environment, has been presented in the last years. Nevertheless, conceptual design of databases with temporal aspects has not yet received sufficient attention. The purpose of this paper is twofold: to propose a simple temporal treatment of information at the initial conceptual phase of database design; to show how the chosen temporal treatment can he exploited in time integrity enforcement by using standard DBMS tools, such as referential integrity and triggers. Furthermore, we present a design tool implementing our data model and constraint generation technique, obtained by extending a commercial design tool.

Cascade Optimization Strategy for Aircraft and Air-Breathing Propulsion System Concepts

Abstract: Design optimization for subsonic and supersonic aircraft and for air-breathing propulsion engine concepts has been accomplished by soft-coupling the Flight Optimization System (FLOPS) and the NASA Engine Performance Program analyzer (NEPP), to the NASA Lewis multidisciplinary optimization tool COMETBOARDS. Aircraft and engine design problems, with their associated constraints and design variables, were cast as nonlinear optimization problems with aircraft weight and engine thrust as the respective merit functions. Because of the diversity of constraint types and the overall distortion of the design space, the most reliable single optimization algorithm available in COMETBOARDS could not produce a satisfactory feasible optimum solution. Some of COMETBOARDS' unique features, which include a cascade strategy, variable and constraint formulations, and scaling devised especially for difficult multidisciplinary applications, successfully optimized the performance of both aircraft and engines. The cascade method has two principal steps: In the first, the solution initiates from a user-specified design and optimizer, in the second, the optimum design obtained in the first step with some random perturbation is used to begin the next specified optimizer. The second step is repeated for a specified sequence of optimizers or until a successful solution of the problem is achieved. A successful solution should satisfy the specified convergence criteria and have several active constraints but no violated constraints. The cascade strategy available in the combined COMETBOARDS, FLOPS, and NEPP design tool converges to the same global optimum solution even when it starts from different design points. This reliable and robust design tool eliminates manual intervention in the design of aircraft and of air-breathing propulsion engines where it eases the cycle analysis procedures. The combined code is also much easier to use, which is an added benefit. This paper describes COMETBOARDS and its cascade strategy and illustrates the capability of the combined design tool through the optimization of a subsonic aircraft and a high-bypass-turbofan wave-rotor-topped engine.

Automated Hull Optimisation of Offshore Structures Based on Rational Seakeeping Criteria

Abstract: Hydrodynamic shape optimization is one of the key tools for the development of new system concepts in offshore engineering. Especially in system concepts where the design team can not rely on data and experiences of previous tasks automated hull optimisation is a valuable design tool, which significantly speeds up the hull design process. This paper presents a fully automated numerical procedure for optimum adjustment of shapes to environmental conditions. Optimisation algorithms vary the free variables to find a minimum of the objective function within a few iterations. The resulting hull shapes are characterized by minimized wave loads and motions. Rational design criteria like maximum forces and expected downtime are minimized applying spectral analysis in combination with standard wave spectra and long-term wave scatter diagrams. The paper presents the optimization of a fixed structure and a semisubmersible to illustrate the efficiency of the proposed procedure.