Closed-form design equations for decoupling networks of small arrays

Small element spacing in compact arrays results in strong mutual coupling between the array elements. A decoupling network consisting of reactive cross-coupling elements can alleviate problems associated with the coupling. Closed-form design equations for the decoupling networks of symmetrical arrays with two or three elements are presented.

Microassembly fabrication of tissue engineering scaffolds with customized design

Browse > Journals> Automation Science and Enginee ...> Volume: 5 Issue: 3 Microassembly Fabrication of Tissue Engineering Scaffolds With Customized Design 4468741 abstract Han Zhang; Burdet, E.; Poo, A.N.; Hutmacher, D.W.; GE Global Res. Center Ltd., Shanghai This paper appears in: Automation Science and Engineering, IEEE Transactions on Issue Date: July 2008 Volume: 5 Issue:3 On page(s): 446 - 456 ISSN: 1545-5955 Digital Object Identifier: 10.1109/TASE.2008.917011 Date of Current Version: 02 July 2008 Sponsored by: IEEE Robotics and Automation Society Abstract This paper presents a novel technique to fabricate scaffold/cell constructs for tissue engineering by robotic assembly of microscopic building blocks (of volume 0.5$,times,$0.5$,times,$0.2 ${hbox{mm}}^{3}$ and 60 $mu {hbox{m}}$ thickness). In this way, it becomes possible to build scaffolds with freedom in the design of architecture, surface morphology, and chemistry. Biocompatible microparts with complex 3-D shapes were first designed and mass produced using MEMS techniques. Semi-automatic assembly was then realized using a robotic workstation with four degrees of freedom integrating a dedicated microgripper and two optical microscopes. Coarse movement of the gripper is determined by pattern matching in the microscopes images, while the operator controls fine positioning and accurate insertion of the microparts. Successful microassembly was demonstrated using SU-8 and acrylic resin microparts. Taking advantage of parts distortion and adhesion forces, which dominate at micro-level, the parts cleave together after assembly. In contrast to many current scaffold fabrication techniques, no heat, pressure, electrical effect, or toxic chemical reaction is involved, a critical condition for creating scaffolds with biological agents.

Computer profiling for forensic purposes

Computer forensics is the process of gathering and analysing evidence from computer systems to aid in the investigation of a crime. Typically, such investigations are undertaken by human forensic examiners using purpose-built software to discover evidence from a computer disk. This process is a manual one, and the time it takes for a forensic examiner to conduct such an investigation is proportional to the storage capacity of the computer's disk drives. The heterogeneity and complexity of various data formats stored on modern computer systems compounds the problems posed by the sheer volume of data. The decision to undertake a computer forensic examination of a computer system is a decision to commit significant quantities of a human examiner's time. Where there is no prior knowledge of the information contained on a computer system, this commitment of time and energy occurs with little idea of the potential benefit to the investigation. The key contribution of this research is the design and development of an automated process to describe a computer system and its activity for the purposes of a computer forensic investigation. The term proposed for this process is computer profiling. A model of a computer system and its activity has been developed over the course of this research. Using this model a computer system, which is the subj ect of investigation, can be automatically described in terms useful to a forensic investigator. The computer profiling process IS resilient to attempts to disguise malicious computer activity. This resilience is achieved by detecting inconsistencies in the information used to infer the apparent activity of the computer. The practicality of the computer profiling process has been demonstrated by a proof-of concept software implementation. The model and the prototype implementation utilising the model were tested with data from real computer systems. The resilience of the process to attempts to disguise malicious activity has also been demonstrated with practical experiments conducted with the same prototype software implementation.

Hungry 24/7? HCI design for sustainable food culture workshop

This workshop proposes to explore new approaches to cultivate and support sustainable food culture in urban environments via human computer interaction design and ubiquitous technologies. Food is a challenging issue in urban contexts: while food consumption decisions are made many times a day, most food interaction for urbanites occurs based on convenience and habitual practices. This situation is contrasting to the fact that food is at the centre of global environment, health, and social issues that are becoming increasingly immanent and imminent. As such, it is timely and crucial to ask: what are feasible, effective, and innovative ways to improve human-food-interaction through human-computer-interaction in order to contribute to environmental, health, and social sustainability in urban environments? This workshop brings together insights across disciplines to discuss this question, and plan and promote individual, local, and global change for sustainable food culture.

Object-centric process models and the design of flexible processes

Mainstream business process modelling techniques promote a design paradigm wherein the activities to be performed within a case, together with their usual execution order, form the backbone of a process model, on top of which other aspects are anchored. This paradigm, while eective in standardised and production-oriented domains, shows some limitations when confronted with processes where case-by-case variations and exceptions are the norm. In this thesis we develop the idea that the eective design of exible process models calls for an alternative modelling paradigm, one in which process models are modularised along key business objects, rather than along activity decompositions. The research follows a design science method, starting from the formulation of a research problem expressed in terms of requirements, and culminating in a set of artifacts that have been devised to satisfy these requirements. The main contributions of the thesis are: (i) a meta-model for object-centric process modelling incorporating constructs for capturing exible processes; (ii) a transformation from this meta-model to an existing activity-centric process modelling language, namely YAWL, showing the relation between object-centric and activity-centric process modelling approaches; and (iii) a Coloured Petri Net that captures the semantics of the proposed meta-model. The meta-model has been evaluated using a framework consisting of a set of work ow patterns. Moreover, the meta-model has been embodied in a modelling tool that has been used to capture two industrial scenarios.

Design of automatic vision-based inspection system for solder joint segmentation

Purpose: Computer vision has been widely used in the inspection of electronic components. This paper proposes a computer vision system for the automatic detection, localisation, and segmentation of solder joints on Printed Circuit Boards (PCBs) under different illumination conditions. Design/methodology/approach: An illumination normalization approach is applied to an image, which can effectively and efficiently eliminate the effect of uneven illumination while keeping the properties of the processed image the same as in the corresponding image under normal lighting conditions. Consequently special lighting and instrumental setup can be reduced in order to detect solder joints. These normalised images are insensitive to illumination variations and are used for the subsequent solder joint detection stages. In the segmentation approach, the PCB image is transformed from an RGB color space to a YIQ color space for the effective detection of solder joints from the background. Findings: The segmentation results show that the proposed approach improves the performance significantly for images under varying illumination conditions. Research limitations/implications: This paper proposes a front-end system for the automatic detection, localisation, and segmentation of solder joint defects. Further research is required to complete the full system including the classification of solder joint defects. Practical implications: The methodology presented in this paper can be an effective method to reduce cost and improve quality in production of PCBs in the manufacturing industry. Originality/value: This research proposes the automatic location, identification and segmentation of solder joints under different illumination conditions.

Blogs, wikis and podcasts : collaborative knowledge building tools in a design and technology course

Design and Technology has become an important part of the school curriculum. In Queensland, Australia, Technology (which encompasses Design) is one of the Key Learning Areas (KLAs) for students in the first ten years of schooling. This KLA adopts a student-centred, hands-on constructivist approach to teaching and learning. The ability to conceptualise and implement appropriate learning experiences, however, has been a challenge for some early career teachers. This paper describes how Design and Technology is being taught to pre-service primary teachers at an Australian University through their involvement in a range of authentic problem-solving activities supported by social learning tools such as wikis and blogs. An interview with a sample from this group (N=5) provides an insight into how these social software tools enhanced their knowledge and learning. This paper will describe how these social learning tools impact on the agency of learning.