Heiko Rudolph

A virtual tabletop workspace for the assessment of upper limb function in Traumatic Brain Injury (TBI)

Traditional methods of movement assessment in clinical rehab are often labor intensive and provide a limited number of outcome variables for tracking recovery. Entry level virtual reality (VR) systems afford new possibilities for systematic assessment and treatment. This paper describes the development of a virtual tabletop environment for the assessment of upper limb function in Traumatic Brain Injury (TBI). The system is designed to present realistic virtual workspaces and to measure performance at both a functional and kinematic level. In addition, we incorporate the use of Tangible User Interfaces (TUIs) as a means of integrating performance with the workspace. Unlike top-end movement analysis systems, the experimental system utilizes readily available computing technologies: mid-range PC, LCD panels, stereo camera, Virtools software, and TUI enabled by Wii Remote, Wii Sensor Bar (Nintendo¿) and passive markers. The combination of vision-based marker tracking with a low cost game controller (viz Wii system) provides a stable and accurate means of tracking the TUI on the virtual workspace, and for interactivity within this space. The system provides a compelling sense of realism for the performer and an innovative means of assessing movement capabilities over time.

A virtual tabletop workspace for upper-limb rehabilitation in Traumatic Brain Injury (TBI): A multiple case study evaluation

Deficits in upper limb function are common among patients with traumatic brain injury (TBI). Accordingly, new technologies, such as virtual reality (VR), are being developed to further upper limb rehabilitation. The study described here successfully trialed a table-top VR-based system (called Elements). Two patients with TBI participated in case-studies using a multiple-baseline, AB time-sequence design; the intervention consisted of 12 1-hour sessions. Performance was measured on both system-rated measures and standardized tests of functional skill. Time-sequence plots for each patient were first sight inspected for trends; this was followed by split-middle trend analysis. Participants demonstrated significant improvements in their movement accuracy, efficiency, and bimanual dexterity; and mixed improvement on speed and other measures of movement skill. Taken together, these findings demonstrate that the Elements system facilitated motor learning in both TBI patients. Larger scale clinical trials are now deemed a viable step in further validating the system.

Stereo Vision for Unrestricted Human-Computer Interaction

Since the advent of the electronic computer there have been constant developments in human-computer interaction. Researchers strive towards creating an input method that is natural, compelling and most of all effective. The ideal computer interface would interpret natural human interactions in much the same way another human would. As humans we are used to giving instructions with our voice, body language and gestures: i.e. pointing at objects of interest, looking at things we interact with and using our hands to move objects. The ideal visual input device, the “holy grail” of human computer interfaces would be capable of accepting visual cues and gestures much as another human being would. Although this theoretical ideal is not feasible with current technologies it serves to guide research in the field. Stereo vision has been researched for the purpose of studying human motion for many years (Aggarwal & Cai 1997; Cappozzo et al. 2005). Much effort has gone into achieving full body motion capture with multiple cameras, in order to overcome the need for artificial markers. This allows for unrestricted movement for the user, improves flexibility and overcomes occlusion problems with marker based approaches. However the processor time required to locate and track arbitrary objects in 3D has until recently been prohibitive for use in interactive scenarios. Faster processors, memory, bus/interface speeds are helping overcome a significant constraint in using stereo vision for human-computer interaction (HCI), that of: producing real-time refresh rates and low latency response. Now that interactive 3D human motion capture is becoming a reality, its necessary to take stock of what can be achieved with this approach. This chapter will not cover the theory behind stereo vision. Nor will we be considering technologies such as motion capture, as these are not intended for everyday computer usage. We are interested in applications that allow unencumbered interactions and operate without requiring the user to attach special devices to their body. We will be looking the current state of the art and where the next could be taken. O pe n A cc es s D at ab as e w w w .ite ch on lin e. co m

Improved Background Removal through Polarisation in Vision-Based Tabletop Interface

This paper presents a novel method of enhancing computer assisted motor rehabilitation for brain injury patients by detailing a method of overcoming a significant technical constraint. The focus of our system is three dimen- sional(3D) tracking of upper limb movements on a horizontal tabletop system. We describe a new horizontal table- top system that utilises real-time stereo vision for 3D tracking of user interaction in the workspace. An overview of existing background removal techniques is presented, and their strengths and weaknesses discussed. We then present a novel approach that utilises polarisation of light for background removal. The system uses an LCD panel for the display device, which achieves a more portable system, and also allows for total removal of screen interference by utilising the polarising nature of LCD technology. Initial testing of this approach has proved highly successful. Key benefits are outlined.

Haptic Eyes: Mapping Visual Information in to Haptic Displays

This paper presents a method of mapping visual data into haptic cues for the blind to support them in navigation. Employing auditory cues alone to support blind navigation may help some extent but too much information to the ear may lead to confusion so important information such as dangers from the obstacles, stairs, potholes, sharp edges etc given through haptic signals not only reduce the over load on the auditory channel but also improves the speed of navigation by enabling quicker reaction. The proposed system for representing visual information intuitively and easily using haptic signals may assist the visually impaired in their navigation. This technique translates the images captured from digital cameras, extracts the required information and converts it into tactile signals. The use of the haptic channel is suggested in order to prevent overload of the auditory system and to use the special qualities of the haptic sense to convey important messages of danger and hazards. This paper presents a tactile display design and discusses the application framework for using these displays for tactile information design experimentation.

Runtime Control of Subthreshold Current using DoubleGate Device Technology

The close link between power and performance represents a significant hurdle to the design of portable embedded systems. As supply voltage falls, thereby saving dynamic power, the impact of threshold voltage on delay becomes greater so that it will become increasingly difficult to set a fixed threshold voltage that optimizes both performance and static power. This paper proposes a method around these conflicting requirements by allowing threshold voltages to be dynamically adjusted at run time via back–gate control on thin–body double–gate Silicon on Insulator (TBDGSOI) transistors. Using a multi–level simulation approach, with SPICE and VHDL-AMS, and using a small RISC microprocessor architecture as an example, it is shown that reductions in subthreshold leakage of between 6X and 11X can be achieved using this run-time control technique under a number of small software workloads.

Interpretations of corruption in intercultural bargaining

There is a fine line in business negotiations between being perceived as corrupt and having proper engagement with the natural tension and excitement of the business bargaining process. Combining literature review and experiential observation we provide a framework that will assist global business managers to more successfully negotiate cross-cultural business transactions. We identify some archetypal underpinnings of bargaining in a business context and question the established perceptions of corruption in intercultural business dealings. We conclude that different cultural systems produce variations of negotiating behaviour that need to be judged with a deeper local knowledge to avoid simply transferring inappropriate labels.

Design and trial of a low cost inspection graded Portable Emission Measurement System (PEMS): for in-the field exhaust emission measurement in Hong Kong

This paper describes the rationale and background for a low cost Portable Emission Measurement System in Hong Kong. We describe an accurate and portable system design which makes emissions testing feasible and applicable for a broad range of applications. By using industry standard components the test results are comparable to certified laboratory systems. The low cost system takes emissions testing out of the laboratory into a larger range of applications making emissions testing more viable and available in locations previously very hard to test. The added benefits of deploying such systems lie in better data collection, for systems previously too difficult to measure due to location and or cost.

New energy efficient routing algorithm for Wireless Sensor Network

Energy efficiency is the most challenging topic in Wireless Sensor Networks (WSN). Because of the increasing demands of various applications, and the constraints of energy, memory and computational power of the WSN nodes, many studies have focused on these areas in recent years. Researchers have proposed a variety of protocols such as LEACH, PEGASIS, HEED, TEEN, etc. In this paper, we will discuss how energy efficiency is affected by scaling, i.e. different network sizes, and by different routing algorithms. With the increasing applications of large scale WSNs, such as smart grid and environmental monitoring. We will propose a new routing algorithm to optimize the energy efficiency by reducing the number and total transmissions distance in order to save energy. Simulations suggest that the proposed algorithm will be more energy efficient in medium to large scale wireless sensor networks.

Surface Electromyogram for Gait Analysis of Low Back Pain subjects

This paper describes surface electromyogram (sEMG) recordings of the lumbar muscles during walking. The intent of these pilot trials was to evaluate the usefulness of the sEMG in differentiating between two groups of subjects: healthy subjects and those with lower back pain. An analysis of the features of the sEMG was performed for clearly defined walking activities for both subject groups. The results showed no significant variance of amplitude between the subject groups. It is proposed to extend the same methodology to running in order to expose any underlying difference.