Perception-based visualization of manifold-valued medical images using distance-preserving dimensionality reduction

A method for visualizing manifold-valued medical image data is proposed. The method operates on images in which each pixel is assumed to be sampled from an underlying manifold. For example, each pixel may contain a high dimensional vector, such as the time activity curve (TAC) in a dynamic positron emission tomography (dPET) or a dynamic single photon emission computed tomography (dSPECT) image, or the positive semi-definite tensor in a diffusion tensor magnetic resonance image (DTMRI). A nonlinear mapping reduces the dimensionality of the pixel data to achieve two goals: distance preservation and embedding into a perceptual color space. We use multidimensional scaling distance-preserving mapping to render similar pixels (e.g., DT or TAC pixels) with perceptually similar colors. The 3D CIELAB perceptual color space is adopted as the range of the distance preserving mapping, with a final similarity transform mapping colors to a maximum gamut size. Similarity between pixels is either determined analytically as geodesics on the manifold of pixels or is approximated using manifold learning techniques. In particular, dissimilarity between DTMRI pixels is evaluated via a Log-Euclidean Riemannian metric respecting the manifold of the rank 3, second-order positive semi-definite DTs, whereas the dissimilarity between TACs is approximated via ISOMAP. We demonstrate our approach via artificial high-dimensional, manifold-valued data, as well as case studies of normal and pathological clinical brain and heart DTMRI, dPET, and dSPECT images. Our results demonstrate the effectiveness of our approach in capturing, in a perceptually meaningful way, important features in the data.     

HYDROCARBON LOADS FROM STREET CLEANING PRACTICES: COMPARISON WITH DRY AND WET WEATHER FLOWS IN A PARISIAN COMBINED SEWER SYSTEM

Abstract

So far, little attention has been given to the effect of the street cleaning waters (SCW) load on the sewer systems during dry-weather periods. However, the knowledge of this pollution is needed to better understand the contribution of SCW to dry weather flow (DWF) pollution within combined sewers. Therefore, hydrocarbon loads conveyed by SCW were analyzed for two different sites of the Paris agglomeration. Median n-alkane, Unresolved Complex Mixture (UCM) and Polycyclic Aromatic Hydrocarbon (PAH) concentrations have been estimated at 19, 628 and 1.4 μ g · l^{? 1}for the Marais catchment (or 4th district), and at 8, 249, and 2.1 μ g · l^{? 1}for the 13th district, respectively. The observed contamination was mainly attributed to road traffic. Moreover, a comparison between SCW and street runoff showed that street cleaning removes a higher PAH stock than street runoff. In addition, SCW hydrocarbon fluxes evaluated at 5.4, 178 and 0.4 g · d^{? 1}for n-alkanes, UCM and PAH, respectively, were compared to the hydrocarbon fluxes of the DWF pollutant load at the combined sewer outlet of the Marais catchment. Hydrocarbon loads conveyed by SCW into Paris combined sewers appeared to be a minor source of DWF pollution for n-alkane and UCM, but represented a significant source for PAHs.     

Effectiveness of the earth tube heat exchanger system coupled to a space model in achieving thermal comfort in rural areas

The aim of this work is to investigate by modelling the possibility of reducing the operational energy of a typical house without negatively affecting its embodied energy. This is done through consideration of different building materials coupled with the use of an earth to air heat exchanger (EAHE) for fresh air supply and cooling. For known indoor and outdoor conditions and for given building materials (thermal capacity and conductance), a ventilation controller determines the amount of flow rate needed to temperate the indoor air temperature to achieve thermal comfort. Different wall configurations are assumed for each of the living zone and the bedroom zone of the apartment. It is found that the use of an optimal wall configuration in each zone coupled with the EAHE results in 76.7% energy savings compared with the reference case with conventional cooling.     

Evolving performance control systems for digital puppetry

We describe a new approach for creating performance control systems for digital puppetry. Genetic programming with fitness values specified directly by the puppeteer is used. A generic device and model representation combined with the inherent domain independence of the genetic programming paradigm allows this approach to create control systems for arbitrary combinations of input devices and models. In addition, a number of unique interaction techniques have been developed to support the user‐directed search. In this paper we introduce the approach, describe the implementation and user interface and present the results from a comprehensive evaluation with expert users. We show that a search‐based approach can provide an effective alternative to manually designing performance control systems and an elegant mechanism for unifying low‐level input devices with a broad range of model control modes. Copyright © 2000 John Wiley & Sons, Ltd.     

Magnetic Field-Assisted Laser Ablation of Titanium Dioxide Nanoparticles in Water for Anti-Bacterial Applications

Journal of Inorganic and Organometallic Polymers and Materials - Titanium oxide nanoparticles (TiO2) were produced by pulsed Nd:YAG laser ablation in water under the effect of an external magnetic...     

Performance investigation of a new renewable energy-based carbon dioxide capturing system with aqueous ammonia

In this study, a novel wind energy-based carbon dioxide (CO₂) capturing system is developed and investigated for practical applications to reduce environmental emissions. The aqueous ammonia-based capturing technology is utilized. Wind turbines are used to operate the onsite ammonia synthesis as well as hydrogen production. The proton exchange membrane electrolysis system is considered for hydrogen production and the Haber-Bosch ammonia synthesis technique is utilized. The developed system is modeled in Aspen Plus software. The system performance for CO₂ capture is studied through economic, energy, and exergy perspectives. The CO₂ capture cost is evaluated to be between 0.1 and 0.23 $/kg CO₂. Furthermore, the system CO₂ capture rate is determined to be 3.5 kg/s. Moreover, for a unit mass of CO₂ captured, the energy consumption is found to be 640.1 kg CO₂/MWh. Several parametric studies are also conducted to analyze the effects of varying operating conditions on the system performance.     

Solar energy harvesting and self-cleaning of surfaces by an impacting water droplet

The self-cleaning of surfaces via impacting water droplets is examined pertinent to solar energy applications. The mechanism of spreading and retraction of the impacting droplet onto the dust and cleaned hydrophobic surfaces is considered in the analysis. The spreading factor of the impacting droplet is formulated incorporating the energy balance on the hydrophobic surface. High-speed photography is used to monitor the impacting droplet behavior. The functionalized silica particles coating is introduced towards generating hydrophobic wetting state on the glass surfaces. Environmental dust particles are characterized prior to self-cleaning impacting tests. It is found that spreading rate predicted for the impacting droplet agrees well with that obtained from the experiments. The droplet Weber number incorporated in the experiments does not result in droplet breaking on the surface upon impacting. The dusts are dissimilar in shapes and consist of several elements. Impacting droplet gives rise to cloaking of the dust on the surface during spreading and retraction. Almost all the dusts are removed from the surface through the impacting droplets; however, few dust residues are left on the impacting surface, which cover only 0.03% of the total surface area. Hence, we have demonstrated that self-cleaning of a surface can be achieved by an impacting droplet for renewable energy applications.