By electron microscopy, the intensity of an electron beam transmitted through an object is observed. While by electron holography, the whole information, i. e. both intensity and phase of the electron beam can be observed. Therefore, higher resolution images are obtained by compensating for the lens aberrations, and hitherto-unobservable objects can be also observed using the phase information of an electron beam.
A new approach, Multi-Objective Design Exploration (MODE), is presented to address aerospace design problems. MODE reveals the structure of the design space from the trade-off information and visualizes it as a panorama for Decision Maker. The present form of MODE consists of Kriging Model, Adaptive Range Multi Objective Genetic Algorithms, Analysis of Variance and Self-Organizing Map. The main emphasis of this approach is visual data mining. Design example using high fidelity simulation codes is presented for four-objective aerodynamic optimization for the fly-back booster.
Robot Contest started 17 years ago. The aim of the contest is aimed to tell to students the importance of love, free thinking and creativity. The present situation of NHK Robocons and some probrems in them are discussed.
I'm going to tell how we use a visual technology on the development of sports wear. Since the beginning of 1980, we have investigated the effect of athletic wear, such as ski-jump, downhill race, using the flow visualization technique in the wind tunnel. This was our first step of the visualization. Since then, we've done the visualization of water-flow in the flume to develop swim suite. And we've visualized a heat transport characteristic using thermograph to assess temperature & heat characteristics of sports wear. In resent years, we have visualized heat production characteristic of a new material. In last, I'll talk about visualization for new apparel planning technique, using three-dimensional computer graphic (3DCG).
Although the phenomena related to the multiphase flow can be found in many kinds of industrial and engineering applications, the physical mechanism of the multiphase flow has not been investigated in detail. The major reason for the lack of data in the multiphase flow lies in the difficulties in measuring the flow quantities of the multiple phases simultaneously. Presently, the simultaneous visualization and the PIV measurement have been carried out about the both phases of the liquid-liquid two-phase flow. The difference in the refractive indices makes the visualization in the vicinity of the boundary of the multiple phases almost impossible. In this study, the refractive index of the aqueous phase has been equalized to that of the oil phase by adjusting the concentration of aqueous solution. The results show the flow structure both outside and inside of a falling water droplet in the stationary oil simultaneously.
The field of two-phase flows has been interested in the interfacial flow of a dispersed phase such as bubble and water drop. The interface is contaminated by the contaminant included in surrounding liquid. The contaminant is carried backward by the interfacial flow. The contaminant accumulates in a rear region of the dispersed phase. The interface in a rear region becomes like the solid wall by the accumulated contaminant. Previous studies could measure the interfacial flow of a spherical water drop in this condition. The interfacial velocities in a rear region were 0. This result is the same as the solid wall. However, the value of velocity gradient in a rear region was larger than theoretical value of the rigid sphere which is Stokes flow. The difference of this value has possibility of the influence by the contamination and the wake region behind the water drop. This study aims to measure the velocity gradient distribution around a rigid sphere. Our experimental results show that the velocity gradient distribution in the wake region is lager value than the theoretical value.
To measure local instantaneous velocity and velocity gradients, a molecular tagging velocimetry based on photobleaching reaction was developed in this study. The photobleaching is an irreversible photodegradation of a fluorescent dye, and therefore the velocity and its gradient can be measured from the translation and deformation of photobleached tag, respectively. The method was applied to a laminar pipe flow, laminar suction flow, and a turbulent flow in a square duct. It was confirmed that the method can accurately measure radial distributions of liquid velocity and shear stress in the pipe flow and that the method is applicable to turbulent flows.
This paper described about flow visualization of a gas-liquid two-phase flow in vertical channel with contraction. We have found that the pulsation for void fraction and pressure are occurred by the contraction. However, the mechanism of pulsation is not cleared. Therefore, we construct Dynamic PIV/IST (Infrared Shadow Technique) system using high-speed camera and laser systems to visualize a two-phase flow. We use the system and analyze the profiles of bubble segments and flow structure of liquid phase around bubble segments.
In this paper, interesting transient phenomena that happen at the nozzle exit region are reported. When bubbles leave a nozzle, the bubbles form various complicated shapes. The processes of bubble generation from a nozzle were pictured using a high-speed video camera. In order to suppress unnecessary reflection at bubble surfaces, laser sheet illumination was polarized by a wire-grid filter. PTV measurement of flow adjacent to bubble surface were done simultaneously with observation of bubble surface by the present illumination system. As the result, local sudden acceleration and deceleration induced by complex deformation of a bubble can be measured.
Skin frictional drag of the gas-liquid two-phase flow is investigated using silicon oil in a horizontal channel. The silicon oil has three characteristics, i.e. stable interfacial property, high viscosity, and low surface tension in comparison to water. The present study is planned to grasp the skin friction characteristics modified with bubbles in the oil. The measurement and the visulization results show increment of the frictional drag by bubbles because of promotion of the laminar to turbulent flow transition. Bubble shapes changing with the transition is also discussed.
The wall turbulence in a horizontal channel flow is visualized by platelet type of tracer particles. The tracer is around 5-50 micrometer in size and has a glossy interfacial property reflecting light dependent on the orientation of local shear strain. The present study aims to find out the difference of the wall turbulence in the channel caused by inclusion of various sizes of bubbles. The visualization results newly confirm that streamwise vortices remain in the case of large bubbles mixed while it does not emerge clearly in the case of small bubbles, implying that frictional drag reduction occurs more effectively by use of small bubbles.
Authors pointed out that the optimum conditions existed by the influence of the bubble of between electrodes, and did the modeling for the hydrogen production by the alkaline water electrolysis of natural convection. This research aims to obtain the optimum conditions when the alkaline water was pumped to flow between electrodes. As a result, it has been found that the optimum condition with forced convection qualitatively agrees with that of natural convection by replacing the bubble rising velocity in the model equation with the average velocity of electrolyte of forced convection, yet quantitative matching has not been achieved.
Volatilizing of the molten salt is one of factors, that control the life performance of Molten Carbonate Fuel Cell (MCFC). Volatilizing of the molten salt promotes the cross-leak and the corrosion of the metallic component. Moreover, the piping blockage is caused by volatile matter's solidifying. Especially, because the reforming catalysts filled to the anode channel are polluted by volatile matter of the molten salt in Direct Internal Reforming Molten Carbonate Fuel Cells (DIR-MCFC), volatilizing of the molten salt is a weighty subject. However, neither the behaviour nor the volatilization volume of molten salt volatile matter has been elucidated. These reasons are that molten salt volatile matter that has the strong alkalinity cannot be supplied directly to the analyzer, and as its volatilization volume is a small amount, the analysis accuracy is bad. Therefore, we tried to elucidate the behaviour of vaporized alkali hydroxide by using the image measurement technique that is a non-contact measurement method. As a result, we succeed visualization for the three-phase interface and could measure the volatile phenomenon of MCFC electrolyte. This result proves an actual polluted phenomenon.
The liquid water generated controls a performance of Polymer Electrolyte Fuel Cell (PEFC) by preventing the drying of polymer electrolyte, but on the other hand the liquid water can hinder transport of the reactant species by blocking the pores in the porous gas diffusion layer. In order to clarify the behavior of liquid water generated in the cathode of PEFC, a single cell image measurement model has been designed. Image measurement clears the three points below. (1) The effectiveness of 3-serpentine channel, has the merit of serpentine and parallel, is judged. (2) The effectiveness of a new channel, has the WAL (Water Absorption Layer) and waste channel, is confirmed. (3) We propose the installation angle of the cell for efficient drainage of the condensate in the cathode channel. The results show that 3-serpentine channel and WAL are verified.
This paper presents an experimental study of Leidenfrost conditions on stainless plate in high-pressure environment. By utilizing a pressure vessel, Leidenfrost conditions of water droplets were measured up to 2.1 MPa of ambient pressure. The results revealed that the wetting limit temperature increased with the ambient pressure. The theoretical equations regarding to the wall temperature at onset of liquid contact in pool boiling predicted well the present results.
Accurate prediction of the interfacial area concentration is essential to successful development of the interfacial transfer terms in the two-fluid model. Mechanistic modeling of the interfacial area concentration entirely relies on accurate local flow measurements over extensive flow conditions and channel geometries. From this point of view, accurate measurements of flow parameters such as void fraction, interfacial area concentration, gas velocity, bubble Sauter mean diameter, and bubble number density were performed by the image processing method at five axial locations in vertical upward bubbly flows using 0.55 mm and 1.02 mm-diameter pipes. The frictional pressure loss was also measured by a differential pressure cell. In the experiments, the obtained data give near complete information on the time-averaged local hydrodynamic parameters of two-phase flow. These data can be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow. As the first step to understand the flow characteristics in micro- and mini-channels, the applicability of the existing drift-flux model, interfacial area correlation, and frictional pressure correlation was examined by the data obtained in the mini-channel.
In order to predict the stock market price, modified Grandville law based on the wavelet analysis were developed. The present method improved profit of the stock trading. Since the conventional Grandville-law is not suitable to estimate the turnover period in the collapse region, we cannot estimate the suitable time for the stock trading. The wavelet analysis estimates the higest and lowest price in the long period. However the wavelet analyses are sometimes misreading the turnover. The present method modified theses weak points of Grandville and wavelet method. This new method can be controlled stock trading in the collapse period. Moreover, the stock was purchased in the lowest price with this method. The simulated data showed the market price was increasing after the stock buying. The simulation result showed that the average profit of 7 descriptions was over 35% of the capital. It was 10% larger than that of the conventional Grandville law.
By using the methods of the flow visualization and the PIV, the effects of chemical reaction on the diffusion of jet have been investigated. In this paper, a simple irreversible chemical reaction has selected. This reaction is negligible small heat. Moreover, the large and middle scale structures of the jet have been investigated by applying the wavelet multi-resolution analysis to the images of mixing dye obtained from the LIF method. As a result, it has been found that the jet diffusion is largely affected by the chemical reaction and the difference of the flow structure is recognized between the jet with chemical reaction and that without chemical one.
A method for image hiding based on Multi-Resolution Analysis(MRA) with image cordinate transformation as a preprocessing is proposed. The method allows hide key images in the most efficient manner in terms of invisibility of the key images as well as information content point of view. Such efficiency is shown with the experimental images.
The Complexity of religion in Faust has been clarified by the multi-resolution analysis of wavelets. The Author, Johann Wolfgang von Goethe expressed his broader aspects to the religion in Maximen and Reflexionen. The aspects for analysis has employed following three elements; pantheism as a natural scientist, polytheist as a poet, and monotheist as a moralist. The wavelets analysis has visualized his religious elements fluctuation in Faust. The main element is the monotheist as moralist. The diversity in Goethe's religion consists on the sense of balance for harmony. Furthermore, it is evident the element of pantheism as natural scientist is a main plot of this work.
After Newton mechanics had been established, major effort of human innovation had been devoted to amplify the human physical power, such as hand, foot and fighting power by many physical tools and mechanical devices. After widely spreading use of digital computers, most of the human innovative efforts are now devoting to work out the artificial human brain or compensative tool of human brain works. In the present paper, one of the methodologies to carry out the line signal diagnosis is proposed based on the some assumptions in natural phenomena.
Most of the conventional image cognition methodologies are based on the geometrical singular points extraction of an image. This method has problem that requires the definition what is the singular point of image also the way how to extract the singular point. To remove this difficulty, we have proposed the Eigen pattern method that was based on color information of images. Even though Eigen pattern method has been successfully applied the image cognition, image diagnosis and so on, it has been pointed out that the Eigen pattern method lost the original geometrical information of target image, i.e., geometrical complexity. To overcome this problem, this paper proposes that the geometrical information or complexity of image is represented by means of the modified Fourier power spectrum histogram.
In recent years, advanced transport system such as high speed rail ways in the town and expressways connecting among big towns strongly requires to install the various sensors in particular velocity and acceleration sensors on their ways to govern and monitor the flow of traffic stream. Up to now, it is possible to use various types of velocity and acceleration sensors. We have employed two typical sensors in this paper. One is a fixed type to the way and is possible to measure the exact speed as well as acceleration vectors. The other is a removable type to any location and is available to measure the instantaneous speed as well as acceleration vectors. The fixed type is a magnetic sensor, which equips the sensing or picking up coils, and has reasonable tough property to the mechanical and environmental conditions, but does not have high sensibility at low speed. The other is a CCD camera, which makes it possible to measure any low speed but is difficult to measure high speed over the frame rate speed limitation. To visualize the speed and acceleration vectors under any conditions, we propose a hybrid measuring system combining both magnetic and CCD image sensors. Initial experiments demonstrate the usefulness of our system.
Most of the natural phenomena include a time fluctuating component. Frequency analysis of this time fluctuation component leads to the famous "1/f fluctuation" characteristic that gives mental as well as psychological relaxation effects to human. Because of wide spreading electrical power supply, modern residence removes the combustion utilities and installs much electricity. Our target in this paper is to propose the method of frequency characteristic extraction from dynamic burning flame image of candle. As a result, one of the methods proposed in this paper enables us to extract major frequency characteristic of lighting sources. The other one makes it possible to visualize the precise frequency characteristic of lighting sources.
In this study, the wavelet-based JPEG2000, the next generation image compression technique was applied to PIV for efficiently reducing the physical storage and the noise in images. For evaluating the relationship between image parameter and compression ratio, the PIV standard images were compressed by JPEG2000 and JPEG. It was found that the superior performance of JPEG2000 as compared to JPEG at any compression ratio. JPEG2000 method performs beyond compression ratios where JPEG breaks down, enabling compression of high-resolution PIV images.
The study of the formation and migration of sand dunes has a long history, but a sound understanding of the turbulent mechanisms behind dune has proved elusive. In this paper, in order to reveal the detailed vortical structures behind a three-dimensional dune, PIV measurements were performed in a circulating water channel with a constant free-stream velocity of 0.2 m/s. Instantaneous and time-averaged velocity distribution in the side and top planes were obtained and the complex reverse flow and eddies behind the dune were examined.
Characteristic value method was applied to PIV systems for improving PIV accuracy in this paper. Characteristic pattern of the PIV images is extracted and is used as image cognition. As a new method, it is proposed to calculate the velocity vectors from the correlation of characteristic pattern of PIV images. It is found that characteristic value method is effective in PIV system.
In order to reduce power consumption, pipe wear and conveying velocity, a pneumatic conveying system that a dune is installed in pipeline is proposed in this paper. An experimental study focuses on the effect of installed dune in the horizontal pneumatic conveying system in terms of the overall pressure drop and particle flow patterns. Polyethylene pellets with mean diameter of 3.1 mm were transported as test particles in a horizontal pipeline of 4.6 m length and 80 mm inside diameter. The mean air velocity was varied from 8 m/s to 17 m/s, and the solid mass flow rate from 0.08 kg/s to 0.38 kg/s. It is found that in the lower air velocity range, the pressure drop of the pneumatic conveying with installing dune was lower than that for the conventional pneumatic conveying system. The maximum reduction rate was 17 percent.
The aerodynamic noise and drag are associated with the flow structures and the unsteady behavior of the vortex causes the wind noise. However, litter attention has been paid to the complex vortical structures around externally mounted car mirror from the measured data. In this paper the turbulent structure of mirror wake has been experimentally investigated. The flow structures of the mirror wake were first visualized by the smoke-wire technique. The shedding vortices that are produced by two side of the mirror edge were clearly visualized. Then the instantaneous velocity fields were measured using PIV technique at Reynolds number of 6300. Instantaneous and mean streamlines, vorticity contours and Reynolds stresses were examined. The separation bubble and the region of the reverse flow behind the mirror were observed.
A circulatory assist pump, which can be used for around two weeks after an operation, is under development by AIST. For R&D of a centrifugal blood pump, it is important to prevent the hemolysis, which is caused by high shear rate. Since the back gap of the impeller and the volute are the typical high shear regions, flow visualization analysis was conducted to investigate the shear rate distribution. Judging from the shear rate at impeller back space and on the volute surface, it was found that the shear rates were far below the hemolysis level. The results of the flow visualization well explained the hemolysis test results, where the hemolysis level was found to be 40% of a commercial centrifugal pump. So it was proved that this centrifugal blood pump had good fluid dynamic characteristics to prevent hemolysis.
Hemolysis is connected with high shearing velocity near the wall in a blood pump. Therefore, we have investigated the quantitative method of the shearing velocity in the blood pump to evaluate the hemolysis of the blood pump from fluid mechanical point of view. In this study, we compared between the result from particle image velocimetry (PIV) and the result from particle tracking velocimetry (PTV) about the shearing velocity with the space resolution of about 4 um per pixel using the 2.5 times scale model. First, the velocity difference between methods was about 10%, and the shearing velocity difference between methods was about 30%.
A rotational shear stressor has been developed that could load the shear with the average shearing velocity of from O.to 15, 000/sec in order to clarify the quantitative relationship between the flow shear and the hemolysis. To collapse the flow behavior in this apparatus, the flow visualization was conducted with using particle tracking velocimetry to quantify the velocity, the turbulent intensity, the shearing velocity and the shear stress. As a result, it was found that the flow transited from the laminar Couette flow to the flow with some fluctuation that has the gentle core flow region and the boundary flow region with the average shearing velocity threshold of from 7, 400 to 9, 200/sec.
The purpose of our study was to visualize hemodynamics in a silicon vascular model with a middle cerebral aneurysm using Time-Resolved Three-Dimensional Phase-Contrast MR Imaging (4D-Flow). We created a realistic silicon model of a right middle cerebral artery bifurcation aneurysm. We ran an aqueous solution of glycerol as a flowing fluid through the silicon vessel model with a pulsatile pump. The 4D-Flow technique is based on a radiofrequency-spoiled gradient-echo sequence and it encodes flow velocity in three orthogonal directions. This technique was carried out using 1.5T MR scanner with a voxel size of 0.88x0.88x3mm, 20 phases during one cardiac cycle, and imaging time of 48min. Time-resolved images of three-dimensional streamlines clearly demonstrated that the aneurysm had three-dimensional complex vortex flows within it during systolic phase. A helical flow at the left aspect of the aneurysm was seen along the aneurysmal wall. The point where the helical flow reversed direction was coincident with the bleb. Flow rate of the bleb was low. In our model the 4D-Flow technique provided us with time-resolved three-dimensional hemodynamic information about the intracranial aneurysm and the adjacent parent artery.
Human sneeze has been analyzed by flow visualizations, a particle image velocimetry (PIV), a phase Doppler anemometer (PDA) and a numerical calculation. For the visualization, a home video camera and a high-speed video camera are applied. The visualization indicates the temporal and spatial developments of human sneeze. The shape of it is almost the same as the plume. From the visualization, the penetration length and velocities in both directions are obtained. The ratio of the development in stream-wise and the lateral directions is nearly equal at the initial stage. After, the sneeze develops in stream-wise direction, and it loses its velocity rapidly. The PIV results show that the tip of the sneeze had large velocity and the tail has small velocity. The PDA results show that a lot of droplets have less than 3 μm in diameter and about 2m/s in mean velocity. Results of numerical simulation is also compared with that of experiment.
A particle method for computer simulation of blood flow is proposed to directly analyze the characteristic mechanical behavior of red blood cells (RBCs) in blood flow. The entire simulation region including plasma and an RBC was discretized by particles that move in Lagrangian coordinates. The MPS method was applied to the incompressible flow analysis of plasma, and an elastic spring model based on the minimum energy principle to the motion of deformable RBC. A two-dimensional simulation of blood flow between parallel plates revealed that the proposed method successfully expressed the deformation of RBC depending on membrane stiffness during its movement downstream, corresponding to a deformation in a parachute shape observed in experiments.
Visualization is an important approach utilized in life science studies, one of which is bio-numerical simulation. A part of bio-numerical simulation, bio-aero-acoustic simulation is performed by dentists in order to treat a speech difficulty found in prostheses wearers. Moreover, Evidence Based Medicine is the key to promote prospective studies, which require a Semantic database constructed by a standardized structural language, such as XML. In this paper, a service-based approach was proposed to create a Semantic database and simulations in a prospective study of a dental speech problem.
A huge amount of data has been produced from computations and experiments. Owing to the volume of data, it is quite difficult to extract useful information from these data even if using scientific/information visualization techniques. We have developed a new visualization environment using a concept of intelligent space to overcome these issues. In this paper, we remark displaying method in the intelligent space, and propose a new displaying system of the visualized results. The concept of tangible user interface (TUI) that can operate digital information physically and intuitively is introduced into wall visualization (WV) that has achieved various effects such as the collaborations among researchers, a presence and a full-scale, and provided an immersive virtual environment by displaying information to a large screen. And then, key techniques for constructing a system are examined.
In the advanced photon experimental research, real-time visualization and steering system is thought as desirable method of data analysis. This approach is valid only in the fixed analysis at one time or in the easily reproducible experiment. But, in the research for an unknown problem like the advanced photon experimental research, it is necessary that the observation data can be analyzed many times because profitable analysis is difficult at the first time. Consequently, output data should be filed to refer and analyze at any time. To support the research, we need the followed automatic functions, transporting data files from data generator to data storage, analyzing data, tracking history of data handling, and so on. The supporting system will be integrated database system with several functional servers distributed on the network.
It is highly important to comprehend the destruction phenomenon of bedrock structures because earthquakes usually occur by destroying the rocks inside the earth. This destruction sometimes oc-curs concurrently at different places because of aftershocks. For instance, the Mid-Niigata Prefecture Earthquake occurred in 2004 has generated several aftershocks, as a result it was considered an uncommon and complex earthquake. Traditional earthquake analysis has used the three orthographic views, however the use of 3D visualization for showing the destruction phenomenon can be considered as of highly importance. Taking this into consideration, we describe in this paper an attempt to visualize the destruction phenomenon of the Mid-Niigata prefecture Earthquake by using an Immersive Projection based Technology (IPT).
We have constructed a diagnostic support system for circulatory disease based on a volume communications environment. The volume communications environments support for multi-dimensional volume data such as a time dependently three dimensional data will enable remote communication by means of volume data transmission. In this environment, three dimensional data reconstructed from CT/MRI images and the simulation data became possible imparting information to the clinician adequately.
For the efficient maintenance, an example of the visualization of remote sensing data is shown. Remote diagnosis systems of utilities come into notice to cut down the running cost, however, the difficulties of the development of the diagnosis systems are increasing according the complexity of the utilities and systems. Data mining technologies are the effective analyzing method to model the various behaviors of complex systems. We show comparative displays of the time-series data with moving average calculation, which provide the overview of the whole and the place of notice data in regard to it. We use transparency (alpha blending) attribution to express the density of data or the comparison to the average data.
We propose a similarity judgment method between critical point graphs (CPGs) in two volume data sets by using the directional element feature (DEF) that has been employed in the field of handwritten character recognition techniques (HCRT). A graph comparison technique called passing voxel method (PVM) which allows visualizing both similarity and differential of two CPGs. However, PVM has a drawback to the ability of its similarity judgment. On the other hand, CPG is composed of small straight-line segments. Therefore, we applied extended DEF to the similarity judgment of CPG, and solved the problem of PVM by using CPG with DEF.
This paper presents a visualization technique of hierarchical data which each leaf and non-leaf node has multi parameters. The technique determines the dominant two parameters from the multi parameters, by applying response surface technique. By assigning the two parameters to horizontal and vertical axes of display spaces, the technique represents the dependency among the dominant parameters of hierarchical data. The technique applies Heiankyo View, a visualization technique for large-scale hierarchical data. The paper introduces some visualization results proofing the effectiveness of the presented technique, and a scientific application that the presented technique is to be effectively used.
Visualization of a brain neural pathway is considered as a very useful tool for support of the surgery planning. In this paper, we propose visualization techniques that estimate the neural pathway from DT-MRI (Diffusion Tensor Magnetic Resonance Image). We utilize vector plots, streamlines, and volume rendering. By calculating critical points, we use them as start points of streamlines. In addition, we overlay both the brain neural pathway and brain from MRI (Magnetic Resonance Image). We applied our visualization techniques into DT-MRI, and several images are shown in this paper.
This paper presents the design of multi-dimensional transfer functions which take into account the nested structures of evolving isosurfaces in a given volume dataset. The effectiveness of the resultant topological transfer functions is proven empirically through an application to a simulated dataset for implosion phenomena in laser fusion.
Isosurfacing is one of the most useful visualization technique. Although isosurfacing can visualize a given volume dataset faster than other visualization techniques, more accelerated isosurface extraction algorithm is required for large-scale and complex dataset. This paper represents an accelerated isosurface extraction algorithm using a critical point graph. Sevelal datasets such as analytic dataset are used to prove the temporal efficiency of the presented extraction algorithm compared with a well-known isosurfacing algorithm called Marching Cubes.
Nowadays, a huge volume datasets has been generated from numerical simulations and measurement equipments. However the classification and reference has been usually performed manually, such as vision or experience of a measurement engineer. There still has not been revealed efficient techniques for searching similarity between volumetric datasets. On the other hand, some techniques for expressing the structure of the volume data in a simple figure are proposed. In this report, Critical Point Graphs and Contour Trees are used as a key to the similar level judgment from among those techniques. A similar level is judged to some data, and the merit and the weak point of each technique are clarified.
According to increase frequency in use of computer simulation, a methodology that classifies a large amount of computational results in a database and searches a certain data set has been needed. To classify and search a result of simulation, it is necessary to evaluate the similarity between a certain data and a reference. A similarity estimation method which employs "Critical Point Graph (CPG)" as an index of data is effective in evaluating. However, this method proposed in past time can not allow to transformation of the data such as rotation and scaling. In this paper, we propose a similarity estimation method which allows to affine transformation with using CPG method about two and three dimensional scalar data sets (volume data sets). In our method, we normalized data sets by principal component analysis. And we estimated a similarity between two volume data sets. From the result, one can safely state that this method allow to affine transformation.
A wavelet multi-resolution technique has been applied to analysing the temperature data simultaneously obtained by a rake of 16 cold-wires in the turbulent near-wake of a circular cylinder. The fluctuating temperature is decomposed into a number of wavelet components based on their characteristic or central frequencies using the wavelet multi-resolution technique. The flow structure is examined in terms of temperature contours and variance of each wavelet component.