Hierarchical Correlation Clustering in Multiple 2D Scalar Fields

Sets of multiple scalar fields can be used to model many types of variation in data, such as uncertainty in measurements and simulations or time‐dependent behavior of scalar quantities. Many structural properties of such fields can be explained by dependencies between different points in the scalar field. Although these dependencies can be of arbitrary complexity, correlation, i.e., the linear dependency, already provides significant structural information. Existing methods for correlation analysis are usually limited to positive correlation, handle only local dependencies, or use combinatorial approximations to this continuous problem. We present a new approach for computing and visualizing correlated regions in sets of 2‐dimensional scalar fields. This paper describes the following three main contributions: (i) An algorithm for hierarchical correlation clustering resulting in a dendrogram, (ii) a generalization of topological landscapes for dendrogram visualization, and (iii) a new method for incorporating negative correlation values in the clustering and visualization. All steps are designed to preserve the special properties of correlation coefficients. The results are visualized in two linked views, one showing the cluster hierarchy as 2D landscape and the other providing a spatial context in the scalar field's domain. Different coloring and texturing schemes coupled with interactive selection support an exploratory data analysis.     

Evaluation of interconnected production sites taking into account multidimensional uncertainties

The production sites of international companies are becoming increasingly interconnected. Due to the uncertainty of multiple factors, determining a location is a strategic choice entailing high financial risk. For this reason, a method for site evaluation was developed allowing multidimensional, i.e., both quantitative and qualitative, uncertainties to be taken into account. The uncertainties are modeled with both probability and fuzzy-set theory and integrated into a modular-structured monetary calculation model. For the analysis and interpretation of evaluation results, methods have been developed which allow risk assessment. The developed method provides a way to handle existing location risks and can thus ensure the success of manufacturing companies in the long term.     

Micro- and nanostructured Al2O3 surfaces for controlled vascular endothelial and smooth muscle cell adhesion and proliferation

The effect of the micro- and nanotopography on vascular cell-surface interaction is investigated using nano- and microstructured Al₂O₃ as model substrate. Two different nanostructured Al₂O₃ surfaces composed of low density (LD) and high density (HD) nanowires (NWs) were synthesized by chemical vapour deposition (CVD) and commercially available microstructured Al₂O₃ plates were used for comparison. A clear diverging response of human umbilical vein endothelial cells (HUVEC) and human umbilical vein smooth muscle cells (HUVSMC) was observed on these nano- and microstructured surfaces. LD Al₂O₃ NWs seem to enhance the proliferation of HUVECs selectively. This selective control of the cell-surface interaction by topography may represent a key issue for the future stent material design.     

A New Access to Piperidino-cyclopiperidinecarboxamides – constrained analogues of a pharmaceutical used diaminic building block

6-Piperidino-3-azabicyclo[3.1.0]hexane-6-carboxamide diastereomers 1a and 2a represent conformationally rigid analogues of 3a which is a building block in some pharmaceutical compounds. A new access to these compounds 1a and 2a was found via the cleavage of bicyclic N,N-acetal 6 with hydrocyanic acid as the stereodetermining step. Reaction of derivatives 1a and 2a with bromodiphenyl-butyronitrile 14 gave cyclopiritramide isomers 1c and 2c , respectively. Qualitative preliminary investigations showed different affinities of 1c and 2c to the opiate-μ receptor. These results were discussed on the basis of an X-ray structural analysis of cyclopiritramide isomer 2c . 1-Benzylcyclopiperidine derivatives 1d and 2d were used as model systems for studying the conformation of cyclopiritramide isomer 1c and 2c , respectively.     

Silicondioxide electret films prepared by the sol-gel process

Sol-gel silica electret films were coated on silicon substrates by a spin coating technique. The process of preparing the films is described and the electret behavior of the films is discussed. The films were corona charged at room temperature. Then, isothermal decay of the surface potential at room temperature and open-circuit thermally stimulated discharge (TSD) experiments were carried out. The results showed that the main peak of the TSD current spectra was situated at ~250°C and charge deposited in the film indicated good stability for the negative charged sample. After storage at room temperature for 50 days, the surface potential of the sample still retained at ~90% of the initial value. The authors found activation energies of 1.3 and 0.7 eV for negative and positive corona charged samples. Experimental results suggest that the sol-gel process could be useful in electret and electronic technique applications     

A place called HOPE: group psychotherapy for adolescents of parents with HIV/AIDS

Intraoperative ultrasound, whether during celiotomy or laparoscopy, plays an important role in assisting the surgeon in directing appropriate therapy for intra-abdominal diseases, particularly primary or metastatic malignancies involving the liver and primary malignancies of the pancreas and upper gastrointestinal tract. It is the most sensitive imaging technique for detecting small intraparenchymal lesions of the liver, pancreas, and other solid organs. Owing to its increased sensitivity over all commonly used preoperative imaging studies, it is responsible for changing the intraoperative treatment plan of these tumors in a significant percentage of cases. This is particularly true with respect to resectability. In the era of laparoscopic surgery, it replaces the surgeon's inability to palpate the liver and other organs during surgery. As surgeons use a laparoscopic approach with increasing frequency to treat intra-abdominal disease, they will have an increasing need to master the use of intraoperative ultrasound in order to render optimal care to their patients.     

Empirically Verified Thermodynamic Model of Gate Capacitance and Threshold Voltage of Nanoelectronic MOS Devices With Applications to HfO2 and ZrO2 Gate Insulators

A thermodynamic variational model derived by minimizing the Helmholtz free energy of the MOS device is presented. The model incorporates an anisotropic permittivity tensor and accommodates a correction for quantum-mechanical charge confinement at the dielectric/substrate interface. The energy associated with the fringe field that is adjacent to the oxide is of critical importance in the behavior of small devices. This feature is explicitly included in our model. The model is verified using empirical and technology-computer-aided-design-generated capacitance-voltage data obtained on MOS devices with ZrO₂, HfO₂, and SiO₂ gate insulators. The model includes considerations for an interfacial low-k interface layer between the silicon substrate and the high-k dielectric. This consideration enables the estimation of the equivalent oxide thickness. The significance of sidewall capacitance effects is apparent in our modeling of the threshold voltage (V_th) for MOS capacitors with effective channel length at 30 nm and below. In these devices, a variation in high-k permittivity produces large differences in V_th. This effect is also observed in the variance of V_th, due to dopant fluctuation under the gate.     

Integrating context-free and context-dependent attentional mechanisms for gestural object reference

We present a vision system for human-machine interaction based on a small wearable camera mounted on glasses. The camera views the area in front of the user, especially the hands. To evaluate hand movements for pointing gestures and to recognise object references, an approach to integrating bottom-up generated feature maps and top-down propagated recognition results is introduced. Modules for context-free focus of attention work in parallel with the hand gesture recognition. In contrast to other approaches, the fusion of the two branches is on the sub-symbolic level. This method facilitates both the integration of different modalities and the generation of auditory feedback.Published online: 5 October 2004Robert Rae: Now at PerFact Innovation, Lampingstr. 8, 33615 Bielefeld, Germany