Visualization Method (visualization + method)

Distribution by Scientific Domains


Selected Abstracts


DTI in Context: Illustrating Brain Fiber Tracts In Situ

COMPUTER GRAPHICS FORUM, Issue 3 2010
Pjotr Svetachov
Abstract We present an interactive illustrative visualization method inspired by traditional pen-and-ink illustration styles. Specifically, we explore how to provide context around DTI fiber tracts in the form of surfaces of the brain, the skull, or other objects such as tumors. These contextual surfaces are derived from either segmentation data or generated using interactive iso-surface extraction and are rendered with a flexible, slice-based hatching technique, controlled with ambient occlusion. This technique allows us to produce a consistent and frame-coherent appearance with precise control over the lines. In addition, we provide context through cutting planes onto which we render gray matter with stippling. Together, our methods not only facilitate the interactive exploration and illustration of brain fibers within their anatomical context but also allow us to produce high-quality images for print reproduction. We provide evidence for the success of our approach with an informal evaluation with domain experts. [source]


Illustrative Hybrid Visualization and Exploration of Anatomical and Functional Brain Data

COMPUTER GRAPHICS FORUM, Issue 3 2008
W. M. Jainek
Abstract Common practice in brain research and brain surgery involves the multi-modal acquisition of brain anatomy and brain activation data. These highly complex three-dimensional data have to be displayed simultaneously in order to convey spatial relationships. Unique challenges in information and interaction design have to be solved in order to keep the visualization sufficiently complete and uncluttered at the same time. The visualization method presented in this paper addresses these issues by using a hybrid combination of polygonal rendering of brain structures and direct volume rendering of activation data. Advanced rendering techniques including illustrative display styles and ambient occlusion calculations enhance the clarity of the visual output. The presented rendering pipeline produces real-time frame rates and offers a high degree of configurability. Newly designed interaction and measurement tools are provided, which enable the user to explore the data at large, but also to inspect specific features closely. We demonstrate the system in the context of a cognitive neurosciences dataset. An initial informal evaluation shows that our visualization method is deemed useful for clinical research. [source]


Rapid Geometric Modeling for Unstructured Construction Workspaces

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2003
Yong-Kwon Cho
Most automated and semi-automated construction tasks require real-time information about the local workspace in the form of 3D geometric models. This article describes and demonstrates a new rapid, local area, geometric data extraction and 3D visualization method for unstructured construction workspaces that combines human perception, simple sensors, and descriptive CAD models. The rapid approach will be useful in construction to optimize automated equipment tasks and to significantly improve safety and a remote operator's spatial perception of the workspace. [source]


Visualized Sclerotherapy of Varicose Veins

DERMATOLOGIC SURGERY, Issue 2010
MAMORU KIKUCHI MD
BACKGROUND The spread and movement of sclerosant after injection during sclerotherapy is difficult to monitor. OBJECTIVE To develop a new visualization method that allows monitoring of sclerosant dosage and flow during sclerotherapy. METHODS We used a photodynamic eye (PDE) to perform indocyanine green (ICG) imaging. ICG produces strong fluorescence detectable using PDE and allows monitoring of sclerosant spread through blood vessels in real time. We performed visualized sclerotherapy on 50 limbs, comprising high ligation and sclerotherapy (35 limbs), stripping and sclerotherapy (10 limbs), and sclerotherapy alone (5 limbs). RESULTS In all cases, fluorescence imaging of the injected sclerosant was possible. No complications resulted from combining ICG and polidocanol in any of the patients, all of whom received follow-up evaluations at 1 week, 1 month, and 3 months after treatment. CONCLUSIONS Our new method not only avoids the risk of radiation exposure, but also allows for simple observation of sclerosant range of access, determination of the dosage for each lesion, and accurate administration of therapy to target lesions. This method will contribute to further advances in sclerotherapy, given that it allows administration of sclerosant and visual confirmation of optimal injection dosage, speed, and movement of sclerosant after injection. The authors have indicated no significant interest with commercial supporters. [source]


Visualization of material stiffness in geomechanics analysis

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2006
Donald C. Wotring
Abstract This paper presents novel visualization techniques to simplify representation of the fourth-order material stiffness tensor as a set of three-dimensional geometric objects. Stiffness visualization aids in understanding the complex stiffness characteristics of highly non-linear constitutive models including modelled material anisotropy and loading path dependent stiffness variation. Stiffness visualization is relevant for understanding the relationship of material stiffness to global behaviour in the analysis of a boundary value problem. The spherical pulse stiffness visualization method, developed in the acoustics field, is extended to visualize stiffness of geomaterials using three three-dimensional objects. This method is limited to relatively simple constitutive models with symmetric stiffness matrices insensitive to loading magnitude and direction. A strain dependent stiffness visualization method is developed that allows the examination of material stiffness for a range of loading directions and is suitable for highly non-linear and path dependent material models. The proposed stiffness visualization can be represented as 3-D, 2-D and 1-D objects. The visualization technique is used to represent material stiffness and its evolution during simulated soil laboratory tests and deep excavation construction. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Discovering Emerging Topics from WWW

JOURNAL OF CONTINGENCIES AND CRISIS MANAGEMENT, Issue 2 2002
Naohiro Matsumura
Discovering emerging topics from WWW has been attracting attention of business professionals, especially marketing researchers. For this purpose, WWW can be a valuable source of information because it reflects the dynamics of human society. In this paper we aim at revealing the structure of WWW by using KeyGraph, a visualization method of hidden structure behind data, for understanding emerging topics. [source]


Protein partitioning and transport in supported cationic acrylamide-based hydrogels

AICHE JOURNAL, Issue 5 2003
Shawn M. Russell
The partitioning and transport of myoglobin in cationic, acrylamide-based hydrogels are studied by a microscopic visualization method. Homogeneous cationic gels are synthesized inside fused-silica capillaries with a square section, which allow a direct determination of protein concentration profiles during transient adsorption and desorption. Diffuse, self-similar profiles are observed and used to determine the equilibrium protein binding capacity and the protein diffusivity in the gel. Mass-transfer rates are found to be essentially independent of the external solution concentration, but to vary dramatically with the gel polymer concentration. A Fickian diffusion model with a flux based on the adsorbed-phase concentration gradient is consistent with the experimentally determined concentration profiles for both positive and negative protein concentration steps. The equilibrium and rate parameters determined for the capillary-supported gels also compare favorably with those obtained from macroscopic measurements using composite ion-exchange media comprising similar gels held within the pores of porous silica particles. [source]


Study on conical columns for semi-preparative liquid chromatography

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 3-4 2003
Ma Jiping
Abstract The dynamic flow profiles and column efficiencies in conically shaped semi-preparative liquid chromatographic columns (inlet ID larger than outlet ID) with two different conical angles (7° and 15°) were studied. The dynamic flow profiles were studied by an on-column visualization method. Conical columns were compared with cylindrical column of the same length and internal volume. The results showed that the flow profile of a sample band in the conical column of 7° (50 mm×17 mm , 11 mm ID) was parabolic in shape. The sample band migrated slower in the wall region than in the central region, as in the cylindrical column (50 mm×14 mm ID). However, the sample band in the conical column of 15° (50 mm×20 mm , 7 mm ID) migrated slower in the central region than in the wall region, resulting in a reverse parabolic flow profile, in contrast to that in cylindrical column. This indicated that a flat flow profile might be realized in a conical column with a conical angle between 7° and 15°. The conical column of 15° had the highest column efficiency among the three columns under the same conditions. Compared with the cylindrical column packed with identical packing material, the conical column of 15° had 22%,45% higher column efficiency and 11%,27% higher peak height. [source]


Developing a new collection-evaluation method: Mapping and the user-side h-index

JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 11 2009
Pan Jun Kim
This study proposes a new visualization method and index for collection evaluation. Specifically, it develops a network-based mapping technique and a user-focused Hirsch index (user-side h-index) given the lack of previous studies on collection evaluation methods that have used the h-index. A user-side h-index is developed and compared with previous indices (use factor, difference of percentages, collection-side h-index) that represent the strengths of the subject classes of a library collection. The mapping procedure includes the subject-usage profiling of 63 subject classes and collection-usage map generations through the pathfinder network algorithm. Cluster analyses are then conducted upon the pathfinder network to generate 5 large and 14 small clusters. The nodes represent the strengths of the subject-class usages reflected by the user-side h-index. The user-side h-index was found to have advantages (e.g., better demonstrating the real utility of each subject class) over the other indices. It also can more clearly distinguish the strengths between the subject classes than can collection-side h-index. These results may help to identify actual usage and strengths of subject classes in library collections through visualized maps. This may be a useful rationale for the establishment of the collection-development plan. [source]


Detection of the anoxic depolarization of focal ischemia using manganese-enhanced MRI

MAGNETIC RESONANCE IN MEDICINE, Issue 1 2003
Ichio Aoki
Abstract Mismatch between diffusion- and perfusion-weighted MRI was used to indicate a treatable area following focal ischemia, called the penumbra. Activity-induced manganese contrast MRI has been reported as a new visualization method for neural activation using manganese ions as a depolarization-dependent contrast agent. It is well known that energy failure induced by cerebral ischemia produces anoxic depolarization. The purpose of this study was to detect manganese accumulation caused by permanent middle cerebral artery occlusion (MCAO) of rat brain and to compare regional differences between manganese accumulation and decreased apparent diffusion coefficient (ADC). The ratios of signal intensity of manganese-enhanced MRI in the ipsilateral cortex to that in the contralateral cortex were 171.0 ± 17.5% in MCAO group and 108.4 ± 13.2% in the sham group. In addition, the enhanced region was much smaller than the area which was detected as having a reduced ADC. Magn Reson Med 50:7,12, 2003. © 2003 Wiley-Liss, Inc. [source]


Design of electronic systems based on functional capability

QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 1 2008
James M. Gilbert
Abstract An important measure of design quality is the extent to which a circuit design is able to meets its specification in the presence of component parameter variations. Of equal importance is knowing how to improve this capability most effectively. This paper presents an analysis technique and visualization method which give the designer information about design quality and possible routes to improved quality. The paper introduces two new measures of functional capability, based on the process capability measure Cpk, and shows how these may be linked to the statistical variations in individual component parameters. It then shows how this information may be used to assess the effectiveness of altering the nominal value and variability in each of the component parameters in order to improve circuit performance capability. The analysis required is straightforward and the information is presented in a clear manner which can readily be interpreted by the designer. The effectiveness of the technique has been evaluated through analysis of a number of printed circuit board level analogue and mixed signal circuits and the results of a case study are shown. Copyright © 2007 John Wiley & Sons, Ltd. [source]


LDA Velocity Measurements of High-Viscosity Fluids in Mixing Vessel with Vane Geometry Impeller

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2007
Lidija Slemenik Perse
Abstract The object of this work was to measure the velocity field in non-Newtonian fluids inside mixing vessel. The six-bladed vane rotor used for mixing was designed from rotating vane geometry of a sensor system, commonly used for rheometrical measurements of complex fluids (Barnes and Nguyen, J. Non-Newtonian Fluid Mech. 98, 1-14 (2001); Schramm, 1994). During mixing, the viscosity was determined by measuring the torque at different impeller speeds, and compared to rheologically obtained shear dependent viscosity. The velocity field was determined by LDA measurements at twelve places inside mixing vessel. It was observed that axial and radial component of the velocity were insignificant at all measurement points. On the other hand, the results showed the periodic nature of tangential component of the velocity, which was confirmed with computer-aided visualization method. Ce travail avait pour objectif de mesurer le champ de vitesse dans des fluides non newtoniens dans un réservoir de mélange. Le rotor à six pales utilisé pour le mélange a été conçu d'après la géométrie des ailettes rotatives d'un système de senseurs, communément utilisés dans les mesures rhéométriques de fluides complexes (Barnes and Nguyen, J. Non-Newtonian Fluid Mech. 98, 1-14 (2001); Schramm, 1994). Lors du mélange, on a déterminé la viscosité en mesurant le couple à différentes vitesses de turbine, puis on l'a comparée à la viscosité de cisaillement obtenue rhéologiquement. Le champ de vitesse a été déterminé par des mesures LDA à douze positions dans le réservoir de mélange. On a observé que la composante axiale et radiale de la vitesse était négligeable pour tous les points de mesure. Par ailleurs, les résultats montrent la nature périodique de la composante tangentielle de la vitesse, ce qui est confirmé par une méthode de visualisation assistée par ordinateur. [source]


Recent Progress in Artificial Organ Research at Tohoku University

ARTIFICIAL ORGANS, Issue 1 2003
Tomoyuki Yambe
Abstract: Tohoku University has developed various artificial organs over the last 30 years. Pneumatic driven ventricular assist devices with a silicone ball valve have been designed by the flow visualization method, and clinical trials have been performed in Tohoku University Hospital. On the basis of these developments, a pneumatic driven total artificial heart has been developed and an animal experimental evaluation was conducted. The development of artificial organs in Tohoku University has now progressed to the totally implantable type using the transcutaneous energy transmission system with amorphous fibers for magnetic shielding. Examples of implantable systems include a vibrating flow pump for ventricular assist device, an artificial myocardium by the use of shape memory alloy with Peltier elements, and an artificial sphincter for patients with a stoma. An automatic control system for artificial organs had been developed for the ventricular assist devices including a rotary blood pump to avoid suction and to maintain left and right heart balance. Based upon the technology of automatic control algorithm, a new diagnostic tool for evaluating autonomic nerve function has been developed as a branch of artificial organ research and this new machine has been tested in Tohoku University Hospital. Tohoku University is following a variety of approaches aimed at innovation in artificial organs and medical engineering fields. [source]