We consider an optimal design of composite hydrophones consisting of parallel piezoelectric PZT rods that are embedded in a porous polymer matrix. Given the material properties of the polymer and PZT ceramic, we have optimally designed the piezocomposite to maximize the hydrostatic coupling factor, hydrophone figure of merit, or electromechanical coupling factor, using the methods of homogeniza...

The Design Structure Matrix (DSM) methodology and the Net Option Value (NOV) model have been used before to show how aspects can add value to a design. Following with an in-depth analysis of that study, this paper demonstrates how aspects can be beneficial as well as detrimental. The structural transformations involved in aspect modularizations are carefully analyzed in the context of DSMs. Thi...

This paper presents the development and testing of two techniques of texture analysis based on different mathematical tools: the semi-variogram and the Fourier spectra. Three series of experiments are presented where these techniques are compared against a bench mark technique: the Grey-Tone Dependency Matrix. Results, their interpretation and conclusions are presented.

One of the most challenging issues in ship design is developing a system that meets the current, and future, needs of your customer. Failing to comprehensively define requirements often results in a costly and lengthy redesign effort that reduces the availability of the ship. Designing modularity into a system can lessen the impact of modifications to future mission requirements, because the sy...

We discuss the object-oriented design of a software package for solving sparse, symmetric systems of equations (positive definite and indefinite) by direct methods. At the highest layers, we decouple data structure classes from algorithmic classes for flexibility. We describe the important structural and algorithmic classes in our design, and discuss the trade-offs we made for high performance....

This paper presents results from an investigation regarding the use of the Design Structure Matrix (DSM) as a means to guide a designer through the calculation of numerical relationships within the early design system Designer. Characteristics, relationships and goals are used within Designer to enable the evaluation and approximation of the design model and are represented within the system as...

Charles Dodgson (1866) introduced a method to calculate matrices determinant, in asimple way. The method was highly attractive, however, if the sub-matrix or the mainmatrix determination is divided by zero, it would not provide the correct answer. Thispaper explains the Dodgson method's structure and provides a solution for the problemof "dividing by zero" called "virtua...

introduction the urban population experienced rapid growth in the recent decades, particularly between 1975 and 2000 when it has reached from 1.5 to more than 2 billion people. by turn of the century; half of the world's populations are concentrated in cities. this would severely affect the quality of life in urban areas. accordingly, cities will be faced with significant challenges in inf...

This paper examines design iteration and its modelling in the simulation of New Product Development (NPD) processes. A framework comprising six perspectives of iteration is proposed and it is argued that the importance of each perspective depends upon domain-specific factors. Key challenges of modelling iteration in process simulation frameworks such as the Design Structure Matrix are discussed...

In this work, a defect based photonic crystal (PC) structure presented for design of tunable infrared photodetector. Absorption response was investigated under the effects of various structural parameters. Using straight transfer matrix method, PC band edge effect was studied on absorption and a significant absorption enhancement up to %96 was achieved for defect-based structure.