Modeling adaptation of breast cancer treatment decision protocols in the <Emphasis Type="SmallCaps">Kasimir</Emphasis> project

Medical decision protocols constitute theories for health-care decision making that are applicable for “standard” medical cases but have to be adapted for the other cases. This holds in particular for the breast cancer treatment protocol studied in the Kasimir research project. Protocol adaptations can be seen as knowledge-intensive case-based decision support processes. Some examples of adaptations that have been performed by oncologists are presented in this paper. Several issues are then identified that need to be addressed while trying to model such processes, namely: the complexity of adaptations, the lack of relevant information about the patient, the necessity to take into account the applicability and the consequences of a decision, the closeness to decision thresholds, and the necessity to consider some patients according to different viewpoints. As handling these issues requires some additional knowledge, which has to be acquired, different methods are presented that perform adaptation knowledge acquisition either from experts, or in a semi-automatic manner. A discussion and a conclusion end the paper.     

The Dynamics of Spreading of Oils on Hydrophilic and Hydrophobic Surfaces Revisited Using Computational Fluid Dynamics

The dynamics of drop spreading on horizontal smooth surfaces of different wettabilities is revisited using computational fluid dynamics （CFD）. For this purpose, a recently developed CFD model, based on the volume of fluid technique （VOF）, with piecewise linear interface calculations method （PLIC） for interface reconstruction, is generalized and applied to simulate the time evolution of spreading drops on solid surfaces （drop base radius and dynamic contact angle）. The CFD simulations are quantitatively compared with previously published experimental results from other research groups. The influence of different factors, such as oils nature （silicone, mineral, peanut and coconut）, viscosity （0.02-1 Pa.s）, drop volume （0.3-38 μL） and type of surfaces （hydrophilic glass, stainless steel and hydrophobic glass） on the temporal evolution of the drop base radius and contact angle is investigated. For hydrophilic surfaces, the predictions of the CFD model agree remarkably well with the measurements. For hydrophobic surfaces, a small deviation between calculated and experimental results occurs because the model does not consider the partial slippage which can take place on hydrophobic materials. Despite neglecting this aspect, the simulations are found to capture the key features of drop spreading on hydrophobic surface. The fact that we obtain a good agreement between the proposed theory and the experimental results for a large range of oils and surfaces over five decades of time is a strong argument in favor of the model. The accuracy of the model demonstrates also that the influence of the surface wettabity （partial wetting and complete wetting） can be successfully simulated. The numerical results reproduce perfectly the spreading regimes which occur during the time course of the drop. The succession of two different regimes takes place in the following order： a hydrodynamic regime followed by a gravity regime.     

Adaptive link layer strategies for asymmetric high-speed wirelesscommunications

A forward error correction (FEC) strategy and a medium access control (MAC) protocol that are thoroughly tailored to complement and support a high-speed asymmetric physical layer design based on equalization and precoding is presented and fully discussed. Both proposals exhibit a high degree of adaptability and flexibility, which allows for increased data throughput while providing a wide range of quality-of-service requirements. Fast link layer adaptation is made possible through the joint design of link and physical layers. The adaptive FEC algorithm is based on the use of variable-rate trellis coded modulation with fast channel estimation, while the MAC protocol employs a centralized, dynamic slot allocation technique. The overall system design is shown to achieve high spectral efficiency, while minimizing energy consumption at the portable unit     

Asymmetric physical layer design for high-speed wireless digitalcommunications

High data rates and portability are conflicting requirements in the design of reliable indoor wireless data communication systems. Asymmetric system design addresses this problem by exploiting the major differences in the availability of resources (i.e., energy, space) that exist between base stations and portable units. Such an approach seeks to concentrate most of the signal processing tasks involved in the operation of the two-way wireless link at the base station. This paper presents and discusses the implications of a set of techniques for asymmetric physical layer system design based on the use of channel precoding for forward transmission. System performance is assessed via simulations using a realistic time-varying channel model. Simplified two-way antenna diversity implemented exclusively at the base station and the key issue of automatic gain control at the receive side of the precoded link are also addressed and evaluated. Simulation results confirm that the adoption of these techniques enables reliable digital communication at a data rate of 20 Mbit/s on both links while significantly reducing the power consumption of the portable unit     

Catalytic combustion of selected hydrocarbon fuels on platinum: Reactivity and hetero–homogeneous interactions

This paper addresses the interactions between homogeneous and heterogeneous reactions for different hydrocarbons namely, compressed natural gas (CNG), liquefied petroleum gas (LPG), butane and dimethyl ether (DME) over platinum. Experiments are performed to study the effects of varying the temperature of the incoming mixture (T_jet), its equivalence ratio (Ø) and the Reynolds number (Re), on the reactivity limits. Computational fluid dynamic (CFD) calculations using detailed chemical kinetics for both the platinum surface and gas phase are completed for a range of methane–air mixtures to resolve the impact of varying T_jet, Ø and Re on the compositional structure of the flow. Comparison between numerical and experimental results is performed where relevant.For flameless conditions (defined by the presence of reactions on the plate without a gaseous flame), it is found for all fuels studied here that the temperature of the platinum plate, resulting from reactions with the co-flowing fuel–air mixture, increases with increasing T_jet and Re. However, with CNG, the temperature of the plate peaks near stoichiometry while for LPG, butane and DME the peak occurred at richer mixtures of Ø ≈ 1.5. The reactive limits for CNG, propane and DME are found to broaden significantly. Numerical simulations show very good agreement with the measured plate temperature at different equivalence ratios. The computed compositional structure confirms the existence of a flame inhibition effect due to the presence of the catalyst and shows interesting trends of some species at different Re, T_jet and Ø. Gas and surface chemistries seem to affect a few species such as CO, CO₂, H₂, and H₂O depending on the conditions of the co-flowing mixture. Minor species such as CH₃, CH₂O, O, HCO, and OH are largely controlled by gas-phase chemistry.     

Effect of alkali roasting and sulfatization on the extraction of different metal oxides from waste alum sludge

Water treatment plants (WTP) generate a significant amount of sludge as byproducts with environmentally harmful elements. Thus, this work focused on the recycling of alum sludge through the extraction of different metal oxides, i.e., Al₂O₃, Fe₂O₃ and SiO₂, for use in different applications, such as ceramics, cement, and agriculture. The extraction of Al₂O₃, Fe₂O₃, and SiO₂ from alum sludge was performed using sulfatization and roasting to compare which of the two processes could produce the metal oxides of the highest purity. Precipitated powders were calcined at 700°, 900° and 1100 °C. Moreover, the obtained prepared and calcined powders were characterized by studying their phase compositions, microstructure, particle size, and surface area. Results indicated that roasting achieved the highest yield of alumina. Iron oxide was extracted mostly in maghemite form through roasting after calcination at 1100 °C. Further, silica was obtained in cristobalite and quartz phases after calcination at 1100 °C for the samples prepared through sulfatization. However, these phases of silica were combined with albite and obtained after calcination at 1100 °C for the samples prepared through roasting method.     

A Web-based virtual environment for operator training [for powersystems]

The wide accessibility and low cost of virtual reality (VR) on the World Wide Web with the advent of the Virtual Reality Modelling Language (VRML) and VRML interpreters makes it ideal for use in providing cost-effective training for operators in selected complex technical environments. This paper presents SEDA-VRML, a VR-based learn-by-doing system developed for the training of maintenance workers in the troubleshooting and inspection of power transformers at Hydro-Quebec that is accessible from a Web browser. SEDA-VRML is a prototype application of a reuse-driven design incorporating VRML, Java and an expert system within a user interface system (UIS) architecture. The paper describes the functionality and design principles of SEDA-VRML, with key implementation results, to show how SEDA-VRML's design can indeed answer to the limitations of VRML to act as a cost-effective alternative to traditional operator training systems for operator training in VR, as well as a basis for the rapid development of future operator training systems     

Enhanced Transient Heat Transfer From Arrays of Jets Impinging on a Moving Plate

This article addresses the numerical analysis of single and multiple circular jets impinging perpendicularly on a flat plate for heating and cooling purposes. Computational fluid dynamics (CFD) is used to evaluate heat transfer calculations for different configurations and different flow boundary conditions. The commercial CFD package FLUENT is employed with various turbulence models. Results for a single jet are validated against experimental data. The SST k ? ω turbulence model is compared with the elliptic V2F model, and both were validated against experimental data. Results were obtained for a range of jet Reynolds numbers and jet-to-target distances. Optimization results for the single jet case are validated against experimental data. The SST k ? ω and V2F turbulence models succeeded with a reasonable accuracy (within 20% error) in reproducing experimental results. The heat transfer rates from the use of multijet configurations are discussed in the article. Transient heat transfer between multiple jets and a moving plate is more difficult to study due to the changing boundaries but is also very relevant in engineering applications. This article presents full CFD calculations of the transient heat transfer between a bank of circular jets and a moving plate. Design optimization has also been achieved for the single- and multiple-jet configurations.     

A simple low-cost laboratory hardware for noise generation

Circuit hardware for custom noise generation is presented, described, and explained. Its very low circuit complexity, along with the spectral and statistical features of the noise signal obtained, make it specially suitable for student use in laboratory sessions related to digital and analog communications systems