Design and development of automatic visual inspection system for PCB manufacturing

Inspection of solder joints has been a critical process in the electronic manufacturing industry to reduce manufacturing cost, improve yield, and ensure product quality and reliability. This paper proposes two inspection modules for an automatic solder joint classification system. The “front-end” inspection system includes illumination normalisation, localisation and segmentation. The “back-end” inspection involves the classification of solder joints using the Log Gabor filter and classifier fusion. Five different levels of solder quality with respect to the amount of solder paste have been defined. The Log Gabor filter has been demonstrated to achieve high recognition rates and is resistant to misalignment. This proposed system does not need any special illumination system, and the images are acquired by an ordinary digital camera. This system could contribute to the development of automated non-contact, non-destructive and low cost solder joint quality inspection systems.

Fault diagnosis of induction motor based on decision trees and adaptive neuro-fuzzy inference

This paper presents a fault diagnosis method based on adaptive neuro-fuzzy inference system (ANFIS) in combination with decision trees. Classification and regression tree (CART) which is one of the decision tree methods is used as a feature selection procedure to select pertinent features from data set. The crisp rules obtained from the decision tree are then converted to fuzzy if-then rules that are employed to identify the structure of ANFIS classifier. The hybrid of back-propagation and least squares algorithm are utilized to tune the parameters of the membership functions. In order to evaluate the proposed algorithm, the data sets obtained from vibration signals and current signals of the induction motors are used. The results indicate that the CART–ANFIS model has potential for fault diagnosis of induction motors.

Design of experiments for bivariate binary responses modelled by Copula functions

Optimal design for generalized linear models has primarily focused on univariate data. Often experiments are performed that have multiple dependent responses described by regression type models, and it is of interest and of value to design the experiment for all these responses. This requires a multivariate distribution underlying a pre-chosen model for the data. Here, we consider the design of experiments for bivariate binary data which are dependent. We explore Copula functions which provide a rich and flexible class of structures to derive joint distributions for bivariate binary data. We present methods for deriving optimal experimental designs for dependent bivariate binary data using Copulas, and demonstrate that, by including the dependence between responses in the design process, more efficient parameter estimates are obtained than by the usual practice of simply designing for a single variable only. Further, we investigate the robustness of designs with respect to initial parameter estimates and Copula function, and also show the performance of compound criteria within this bivariate binary setting.

Collaborative destination branding : planning for tourism development through design in the Waterfall Way, NSW, Australia

This thesis develops, applies and analyses a collaborative design methodology for branding a tourism destination. The area between the Northern Tablelands and the Mid-North Coast of New South Wales, Australia, was used as a case study for this research. The study applies theoretical concepts of systems thinking and complexity to the real world, and tests the use of design as a social tool to engage multiple stakeholders in planning. In this research I acknowledge that places (and destinations) are socially constructed through people's interactions with their physical and social environments. This study explores a methodology that is explicit about the uncertainties of the destination’s system, and that helps to elicit knowledge and system trends. The collective design process used the creation of brand concepts, elements and strategies as instruments to directly engage stakeholders in the process of reflecting about their places and the issues related to tourism activity in the region. The methods applied included individual conversations and collaborative design sessions to elicit knowledge from local stakeholders. Concept maps were used to register and interpret information released throughout the process. An important aspect of the methodology was to bring together different stakeholder groups and translate the information into a common language that was understandable by all participants. This work helped release significant information as to what kind of tourism activity local stakeholders are prepared to receive and support. It also helped the emergence of a more unified regional identity. The outcomes delivered by the project (brand, communication material and strategies) were of high quality and in line with the desires and expectation of the local hosts. The process also reinforced local sense of pride, belonging and conservation. Furthermore, interaction between participants from different parts of the region triggered some self organising activity around the brand they created together. A major contribution of the present work is the articulation of an inclusive methodology to facilitate the involvement of locals into the decision-making process related to tourism planning. Of particular significance is the focus on the social construction of meaning in and through design, showing that design exercises can have significant social impact – not only on the final product, but also on the realities of the people involved in the creative process.

Design, fabrication and characterization of PCL electrospun scaffolds—a review

The expanding interest in electrospinning fibers for bioengineering includes a significant use of polyesters, including poly(3-caprolactone) (PCL). This review summarizes literature on PCL and selected blends, and provides extensive descriptions of the broad range of parameters used in manufacturing such electrospun fibers. Furthermore the chemical, physical and biological approaches for characterizing the electrospun material are described and opinions offered on important information to include in future publications with this electrospun material.

Dangers of the after-dark wonderlands : Part A - A review of the impact of physical environment design on nightclub violence

Nightclubs are businesses. Their business is pleasure; however pleasure has its price. People have become increasingly concerned about the problems of violence in society but why do higher levels of violence occur in nightclubs despite the established patterns of behaviour that dictates how we socialise and act? In response, researchers have focused on identifying social and situational factors that may contribute to violence from a government perspective, focusing on a variety of specific issues ranging from financial standpoints with effective target marketing strategies to legal obligations of supplying alcohol and abiding regulatory conditions. There is little research into specific design properties that can determine design standards to ensure/improve the physical design of nightclub environments to reduce patron violence. To address this gap, this current article aims to understand how people experience and respond to the physical environment of nightclubs and how these spaces influence their behaviour. The first section of this paper examines the background on nightclubs and theories concerning the influence of pleasure. The second section of this paper details the findings of existing studies that have examined the nightlife context and the various factors that influence patron violence. The main finding of this paper is that although alcohol likely plays a contributing role in aggressive patron behaviour, there is evidence that the relationship is moderated by a number of significant factors relating to the characteristics of the drinking environment such as: physical comfort; the degree of overall 'permissiveness‘ in the establishment; crowding; and physical environmental elements most influenced by day to-day management practices such as lighting, ventilation, cleanliness and seating arrangements. The findings from this paper have been used to develop a framework to guide exploratory research on how specific elements of the physical environment of nightclubs have an impact on elevated patron aggression and assault (Koleczko & Garcia Hansen, 2011).

Dangers of the after-dark wonderlands : Part B - A review of the impact of the physical environment design on nightclub violence

Violence in nightclubs is a serious problem that has the Australian government launching multimillion dollar drinking campaigns. Research on nightclub violence has focused on identifying contributing social and environmental factors, with many concentrating on a variety of specific issues ranging from financial standpoints with effective target marketing strategies to legal obligations of supplying alcohol and abiding regulatory conditions. Moreover, existing research suggests that there is no single factor that directly affects the rate violence in licensed venues. As detailed in the review paper of Koleczko and Garcia Hansen (2011), there is little research about the physical environment of nightclubs and which specific design properties can be used to determine design standards to ensure/improve the physical design of nightclub environments to reduce patron violence. This current study seeks to address this omission by reporting on a series of interviews with participants from management and design domains. Featured case studies are both located in Fortitude Valley, a Mecca for party-goers and the busiest nightclub district in Queensland. The results and analysis support the conclusions that a number of elements of the physical environment influence elevated patron aggression and assault.

Digital signal processing

Signal Processing (SP) is a subject of central importance in engineering and the applied sciences. Signals are information-bearing functions, and SP deals with the analysis and processing of signals (by dedicated systems) to extract or modify information. Signal processing is necessary because signals normally contain information that is not readily usable or understandable, or which might be disturbed by unwanted sources such as noise. Although many signals are non-electrical, it is common to convert them into electrical signals for processing. Most natural signals (such as acoustic and biomedical signals) are continuous functions of time, with these signals being referred to as analog signals. Prior to the onset of digital computers, Analog Signal Processing (ASP) and analog systems were the only tool to deal with analog signals. Although ASP and analog systems are still widely used, Digital Signal Processing (DSP) and digital systems are attracting more attention, due in large part to the significant advantages of digital systems over the analog counterparts. These advantages include superiority in performance,s peed, reliability, efficiency of storage, size and cost. In addition, DSP can solve problems that cannot be solved using ASP, like the spectral analysis of multicomonent signals, adaptive filtering, and operations at very low frequencies. Following the recent developments in engineering which occurred in the 1980's and 1990's, DSP became one of the world's fastest growing industries. Since that time DSP has not only impacted on traditional areas of electrical engineering, but has had far reaching effects on other domains that deal with information such as economics, meteorology, seismology, bioengineering, oceanology, communications, astronomy, radar engineering, control engineering and various other applications. This book is based on the Lecture Notes of Associate Professor Zahir M. Hussain at RMIT University (Melbourne, 2001-2009), the research of Dr. Amin Z. Sadik (at QUT & RMIT, 2005-2008), and the Note of Professor Peter O'Shea at Queensland University of Technology. Part I of the book addresses the representation of analog and digital signals and systems in the time domain and in the frequency domain. The core topics covered are convolution, transforms (Fourier, Laplace, Z. Discrete-time Fourier, and Discrete Fourier), filters, and random signal analysis. There is also a treatment of some important applications of DSP, including signal detection in noise, radar range estimation, banking and financial applications, and audio effects production. Design and implementation of digital systems (such as integrators, differentiators, resonators and oscillators are also considered, along with the design of conventional digital filters. Part I is suitable for an elementary course in DSP. Part II (which is suitable for an advanced signal processing course), considers selected signal processing systems and techniques. Core topics covered are the Hilbert transformer, binary signal transmission, phase-locked loops, sigma-delta modulation, noise shaping, quantization, adaptive filters, and non-stationary signal analysis. Part III presents some selected advanced DSP topics. We hope that this book will contribute to the advancement of engineering education and that it will serve as a general reference book on digital signal processing.