Innovative Projects Realized

Glass micro-machining by glow discharge electrolysis

Beside silicon, glass is the most important material used in the constantly growing field of micro-devices. Several applications need glass because of its unique properties: chemical resistance, transparency, low electrical and thermal conductivity, and biocompatibility. Some of these devices are: micro-accelerometers, micro-reactors, micro-pumps, and medical devices. The limiting factor for increasing the usage of glass in micro-devices is its limited structuring possibility. Chemical etching technologies (such as with hydrogen fluoride) are well established, but remain too slow and expensive for many industrial applications. Other technologies are available, such as laser machining or mechanical machining (ultra-sonic or powder blasting). Both are hampered by the difficulty in obtaining good surface quality and the potential for structural damage. In general, high aspect-ratio structures are a challenging problem. A possible answer is Spark Assisted Chemical Engraving (SACE).

SACE, also known in the literature as Electro Chemical Discharge Machining, or ECDM (not to be confused with Electro Discharge Machining and Electro Chemical Machining for Conductive Materials, two processes that are also referred to as ECDM in combination), is based on electrochemical discharges. The principle is simple: the work-sample and two electrodes are dipped into an electrolyte (typically aqueous NaOH). The cathode is used as a tool. When applying a voltage higher than a critical value (typically 30V) a gas film around the tool is formed by coalescence of the bubbles growing on its surface. Electrochemical discharges occur between the tool and the electrolyte. The heat generated locally promotes etching of the work-sample. SACE needs neither clean-room facilities nor mask fabrication, unlike most micro-machining technologies.
Today, one-dimensional SACE drilling is well characterized in open loop operation. However, no control strategy has been reported. Developing feedback strategies would open new possibilities for SACE machining, helping to overcome its main limitations.

The aim of the proposed project is to develop drilling strategies based on force-feedback control.

Sensor fusion for robust pose tracking using a combined accelerometer-magnetometer-gyroscope device

High-accuracy optical and electromagnetic trackers are commonly used for image-guided interventions for tracking the position and orientation (pose) of surgical tools and target objets. In certain applications these tracking devices could be replaced by small, low-cost inertial measurement units (IMU), which contains integrated accelerometer-magnetometer-gyroscope sensors. Typical size of the sensor is a few centimeters by a few centimeters and it costs about $150. This allows new applications that have not be possible to implement with optical or electromagnetic sensors.

Contour interpolation in medical imaging

Planning of medical procedures, such as radiation therapy or minimally invasive interventions, almost always require delineation of organs and other important structures by closed curves. Most frequently this is performed manually, by drawing contours around the objects on several two-dimensional cross-sectional images.

Typically the contours change smoothly between adjacent image slices, therefore it could be possible to speed up the contouring process by drawing contours manually only on a limited subset of images and generating contours between the manually contoursed slices by interpolation.

The contour interpolation method could be also used for generating visually appealing and accurate surface models from sparse manually defined contour sets.

Visualization of deformation fields in medical imaging

Image registration methods are often used in image-guided medical interventions to determine dislocation of the target organ. Advanced registration methods can determine not just a rigid transformation, but also organ deformations. Performance assessment of deformable image registration algorithms requires visualization of the resulting deformation fields, by means of colored image slices, isolines, arrows, deformed grids, etc.

3D Slicer (www.slicer.org) is an open-source medical image analysis and visualization application that is used extensively in the Perk Lab. This application contains deformable image registration algorithms, but unfortunately it cannot visualize deformation fields.

Fault-Handling in Chemical Process Systems

The need for a comprehensive framework to diagnose and handle actuator and sensor faults has been well recognized. This project will strive to develop rigorous first principles and data-based fault-detection and isolation filters and fault-tolerant control designs.

Constrained Control Lyapunov-function construction

One of the fundamental unsolved problems in control theory is the choice of a constrained control Lyapunov-function for nonlinear systems-a problem that goes to the heart of defining and understanding what stability means. In our group we have used results on null controllable regions for linear systems to address this problem for linear systems. This project will focus on a class of nonlinear systems.

Evolution of High Latitude Birds

Current research projects focus on resident and short distance migrants. Using molecular markers (e.g., DNA sequence data), we can look at historical biogeography and how glaciations have shaped current populations. We have a number of species that can be worked on to look at population genetic structure.

Divergence Preserving Approximation of Vector Fields

Fluids are often simulated on regular grids. At each grid point, the fluid velocity is stored as a vector. In order to analyze the flow, most flow-visualization algorithms interpolate the vector field at non-grid points in a component-wise fashion. This straightforward approach is not conservative i.e., the interpolated vector-field is no longer divergence-free.

The aim of this research project is two fold:

1) Quantify the error introduced due to this component-wise treatment.

2) Investigate efficient strategies that attempt to lower the error with little or no overhead. Such strategies include: using alternate sampling lattices, prefiltering the vector data so as to minimize the divergence, and using alternate flow-field representations that are inherently divergence-free.

Improved Simulation of Shockwaves in Compressible Fluid Flows

The reliable simulation of shockwaves is critical in the prediction and study of many physical phenomena, where abrupt changes in material properties due to shockwaves can greatly affect regions of interest and activate physical mechanisms. The predominant method for simulating flows with shockwaves, shock-capturing has been around for more than sixty years.and have been successfully applied to a wide range of problems. However, often, in compressible fluid flow simulations, large errors appear as a result of the presence of shockwaves. These errors do not disappear with grid refinement or higher-order schemes and cast doubt on this otherwise robust and reliable class of methods.

A summer intern is sought to analyze and improve performance of a new class of schemes which do not suffer from these problems. Currently, this new class of schemes is not reliable and new analysis and numerical testing is required to better understand these new developments. The intern will use existing codes to test schemes on simple test problems before utilizing mathematical and numerical analysis. The student will gain an understanding of shockwaves and shock-capturing methods as well as learning basic analysis techniques and improved understanding of partial differential equations.

Implementation of an Engine Control Unit for Automotive Fuel Injection

The objective of the research project is to implement an engine control unit (ECU) that we acquired recently to an automotive engine test bench for the fuel injection control purpose. The engine system to be used is a Sunbird engine (port-fuel-injection gasoline engine) that UBC Mechanical Engineering has. The ECU is a MotoHawk microcontroller which determines the amount of fuel to be injected based on sensor measurements. To measure the air-to-fuel ratio in real time, a wide-band oxygen sensor will be installed before the three-way catalytic converter in the exhaust pipe. Both a simple PID controller and an advanced robust controller will be tested, and the closed-loop system performances will be compared over various operating conditions (engine speed and air flow). These controllers will be realized in Matlab/Simulink, and transferred to the ECU microcontroller.

A Fuzzy Expert System on Qualitative Mineralogy

This project involves the evolution of an existing computer software system designed to teach mineralogy and assist in the identification of a mineral specimen. The current system operates in a proprietary hypertext-based software environment that needs to be upgraded to run in a Windows-based browser such as Firefox or MS-Explorer.

The system uses a fuzzy expert system to present information on over 250 minerals and to assist a student in learning how to identify an unknown specimen. It uses observations made by the user to increase or decrease the degree of belief in a particular mineral name that is initially chosen by the user. In this way the user acquires the ability to make observations about the properties of rocks and minerals such as colour, streak, luster, S.G., hardness, crystal structure and habit, cleavage, twinning, and numerous unique characteristics such as twinning and fluorescence; and apply these facts to identify minerals.

The research involves evolving the existing rules and fuzzy logic structure into a form compatible with web-based programming. Some of the existing rules can be made to operate in a more efficient manner using an Agent-based approach to reuse rules and apply them across the different properties rather than being applied as separate entities. The system uses a number of Fuzzy Associative Memory maps to take input information and determine the degree of belief in an output. Input and output is typically of a linguistic nature except where measurements have been made such as S.G. and hardness. The method of Defuzzification uses a Weighted Average approach although some rules use Weighted Inferencing similar to an Artificial Neural Network. Examination of ways to streamline these two alternatives will occur during the research. The ability to easily add new minerals into the system will also be examined.

The research plan for this work is as follows:

Week 01 – Familiarization with the existing system
Week 02 – Learning the AI elements in the system
Week 03 – Transferring the hypertext documents into HTML/XML
Week 04 – Continuing with hypertext documents and database
Week 05 – Creating rules for on-line application/manipulation of data
Week 06 – Continuing to create rules
Week 07 – Continuing to create rules
Week 08 – Testing the system
Week 09 – Testing the system
Week 10 – Developing the User Interface
Week 11 – Final clean-up and write-up of a brief report
Week 12 – Presentation of the new system to our department

The ideal candidate for this project would possess knowledge in web-based programming, data management systems, and would wish to learn more about AI techniques such as fuzzy logic, expert systems, and artificial neural networks. An interest in minerals and earth sciences would be an asset, but expertise in this area is not required to do this research.

Scalable Pervasive Games for Natural Disaster Preparation

Pervasive games are a new genre of computer game played on mobile devices in the everyday locations we inhabit. With them come a new way for people to socialize, interact, understand places and locations, and engage in various aspects of community. The challenge, however, is we still do not know how to best design pervasive games to fully engage game players such that they can find new ways of exploring and understanding aspects of their culture and geographical situation.
One specific challenge that exists with many pervasive games is the creation and orchestration of game content and activities. By creation, we mean the construction and placement of game content. By orchestration, we are referring to the monitoring of players’ activities in the game, and the quality and continued availability of game content, to ensure that play proceeds smoothly for players. Orchestration involves actively monitoring players to ensure they stay out of harm’s way and continue to participate in the game. Here the orchestration needs are highly dynamic as the physical constraints of the game appear unbounded to the player, as do the rules (i.e., who to interact with). In general, game creation and orchestration in pervasive games is crucial to a game’s success. If it is done poorly, players may not enjoy the game or may be at risk; perhaps, even worse, non-players who do not realize they are part of a game as bystanders may be at risk. Pragmatically, challenges with creation and orchestration also mean that pervasive games are often “one offs” and only available in a single location or conducted over a short period of time, never to be run again. As a result, participation is limited or game players cannot continue to play like they might computer or online games. Our interest is in understanding how pervasive games can be designed to be scalable. By scalable, we are referring to a game’s ability to be: 1) played and orchestrated over long periods of time in a variety of locations, and 2) played by a large number of players (e.g., hundreds or thousands of people).
This project explores how scalable pervasive games can be designed for players to learn about and share knowledge between family, friends, and community members related to impending and potential natural disasters. For example, it looks at how Vancouver residents can learn about emergency preparedness for a potential major earthquake and how they can share their knowledge with family and friends to help them prepare as well. We will design a prototype of a pervasive game that utilizes design elements that will potentially make the game scalable and then evaluate the game through actual play by end users. The outcome will be a broader understanding of what game elements promote scalability (e.g., narrative, game mechanics, group play) and how these aspects affect game play experiences in the setting of natural disaster preparedness.