Manipulation of mental models of anatomy in interventional radiology and its consequences for design of human–computer interaction

Interventional radiology procedures require extensive cognitive processing from the physician. A set of these cognitive functions are aimed to be replaced by technology in order to reduce the cognitive load. However, limited knowledge is available regarding mental processes in interventional radiology. This research focuses on identifying mental model–related processes, in particular during percutaneous procedures, useful to improve image guidance during interventions. Ethnographic studies and a prototype-based study were conducted in order to perform a task analysis and to identify working strategies and cognitive processes. Data were compared to theories from visual imagery. The results indicate a high level of complexity of mental model construction and manipulation, in particular when mentally comparing mental model knowledge with radiology images on screen (e.g., to steer a needle correctly). Regarding current interface support, most difficult is the interpretation and selection of oblique views. New interface principles are needed to bring cognitive demands within reasonable human range, and also accompanying cognitive work strategies should be developed.     

The cluster scanning system

Users with severe physical impairment often use computers with one or two switches using a scanning system. Scanning is a technique of successively highlighting portions of screen. This paper presents a new scanning system that works through clustering screen objects. The system is initially calibrated through simulation and later validated through a user trial. Results show that it outperforms existing block scanning systems.     

Integrated SMD pressure/flow/temperature multisensor for compressed air in LTCC technology: Thermal flow and temperature sensing

In this work, we present and analyse the flow-sensing part of a recently-developed multisensor in LTCC (low-temperature co-fired ceramic) technology; this device integrates flow/pressure/temperature sensing and is designed for diagnostics monitoring of standard industrial compressed air circuits and devices such as valves and actuators. In this prototype, flow is sensed using the constant-temperature anemometric principle, with temperature-sensing active and reference thermistors placed in the fluidic channel integrated within the LTCC structure. The LTCC bridge structuration technology and electronics are analysed, and possible improvements in fabrication yield and efficiency outlined.     

Flexible electronics: Prediction of substrate deformation during different steps of the lithography process

A numerical model was developed to simulate the micro-deformations of a polymeric substrate due to lithographic processing of different layers of a transistor-like structure. The results of the model were validated with the results from experiments. The model, a mechanical-thermal-hygroscopic model, takes into account the dimensional effects of temperature, moisture and stresses. It also includes the temperature dependent visco-elastic behaviour of the polymer substrate. The model can be used to predict overlay accuracies between different functional layers introduced by the lithographic process. It can also be used to understand the underlying processes such that it provides a tool to improve the overlay accuracy during actual processing.     

Study on conductivity and redox stability of iron orthovanadate

FeVO₄ was synthesised by conventional solid state technique. Impedance measurements using a silver electrode were unsuccessful due to a solid state reaction between FeVO₄ and Ag, forming α-AgVO₃ and α-Fe₂O₃ at the interface. Impedance measurements, with a platinum electrode, reaffirmed that FeVO₄ exhibits semiconductor behaviour in air. In a reducing atmosphere, 5% H₂/Ar, high electronic conductivity, from 1 S cm⁻¹ at 300 °C to 2 S cm⁻¹ at 700 °C, was observed with an activation energy of 0.13(1) eV. X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry data determined that the change in electronic conductivity was due to the degradation of the material into FeV₂O₄ and α-Fe₂O₃. It is believed that the conduction was due to electron hopping between vanadium d-orbitals. Neither FeVO₄ nor FeV₂O₄ are deemed suitable as anode materials for solid oxide fuel cells, due to redox instability.