Tomoji Yoshida

Neural network approach to land cover mapping

A pattern classification method is proposed for remote sensing data using neural networks. First, the authors apply the error backpropagation (BP) algorithm to classify the remote sensing data. In this case, the classification performance depends on a training data set. In order to get stable and precise classification results, the training data set is selected based on geographical information and Kohonens self-organizing feature map. Using the training data set and the error backpropagation algorithm, a layered neural network is trained such that the training patterns are classified with a specified accuracy. After training the neural network, some pixels are deleted from the original training data set if they are incorrectly classified and a new training data set is built up. Once training is complete, a testing data set is classified by using the trained neural network. The classification results of LANDSAT TM data show that this approach produces excellent results which are more realistic and noiseless compared with a conventional Bayesian method. >

Tissue-Mimicking Materials Using Segmented Polyurethane Gel and Their Acoustic Properties

Accurate testing of an instrument by phantoms requires a tissue-mimicking material that has the acoustic velocity and density defined in the International Electrotechnical Commission (IEC) standard, and furthermore the tissue-mimicking material must be stable over time. To achieve the tissue-mimicking materials with the desired acoustic velocity and density defined in the IEC standard, new materials have been developed. The form of tissue-mimicking materials reported comprised polystyrene and poly(methyl methacrylate) (PMMA) particles dispersed in segmented polyurethane gel. They were stable over a period of 40 days and the changes in weight and acoustic velocity did not exceed 0.5%.

Reference Materials for the Measurement of Acoustic Attenuation Coefficients

In this work, we present a reference material for measuring the acoustic attenuation coefficient of biological tissues or tissue-mimicking materials by a transmission method. Accurate measurements by the method require a reference material that has the same acoustic velocity and density as the biological tissue. The newly developed reference material was prepared from NaCl and MgSO4 aqueous solutions. The inorganic material is stable through time. To formulate materials with the desired acoustic velocity and density, the ratio of three constituents (i.e., water, NaCl, and MgSO4) can be determined depending on the method of experiments with mixtures by Scheffe.

Optical chloride film detector against dioxins (No. 2)

The aim of the study is the development of an automatic chloride film detector of the treatment for waste garbage plastics, i.e., the Sanuki refuse derived fuel system against dioxin. The method is a blue light absorption detecting method for the transparent chloride plastic film of garbage wrapping using two dimensional FFT analyzer instead of X-ray or CuCl/sub 2/ green flame.

Blood-mimicking fluid using glycols aqueous solution and their physical properties

We present blood-mimicking fluids (BMFs) for the Doppler test object of medical ultrasound diagnostic instruments. Each of the acoustic velocity, density, and viscosity defined in the International Electrotechnical Commission (IEC) standard is given as a constant value. However, the viscosity of human blood depends greatly on the shear rate of the blood. In accurate studies using a specified flow phantom, therefore, the BMFs with the appropriate viscosity are required. To formulate fluids with the viscosity ranging from 4 to 30 mPas, we have developed a new fluid made of glycols and water-soluble silicone oil. We have used ethylene glycol, diethylene glycol, triechylene glycol, and poly(ethylene glycol) for the fluid. The glycols have different viscosities depending on their molecular weight and their acoustic velocity and density are almost the same. By selecting the glycol with the optimum molecular weight, the viscosity of the fluid could be set at the desired value and the acoustic properties of this fluid satisfied the values of the acoustic velocity and density defined by the IEC standard.

Blood-mimicking fluid for the Doppler test objects of medical diagnostic instruments

We present a blood-mimicking fluid for the Doppler test object of medical diagnostic instruments. Accurate measurement in a flow Doppler test requires a blood-mimicking fluid (BMF) that has the acoustic velocity, density, attenuation coefficient, and viscosity defined in the International Electrotechnical Commission (IEC) standard, and furthermore, they must be stable over time. To formulate a fluid with the desired density and acoustic velocity, we have developed a new fluid made of glycerine and water soluble silicone oil. The BMF is dispersed polystyrene particles as scatters in the new fluid. The density of the liquid can be adjusted to maintain the density of the liquid at the same value as that of the polystyrene particles, thus ensuring neutral buoyancy of the particles. The blood-mimicking fluid was stable overlong term, and the acoustic velocity, density, attenuation coefficient, and viscosity of the fluid meet the specific values.

A new tissue-mimicking material for phantoms

We present a tissue-mimicking material for the phantom of medical diagnostic instruments. Accurate testing of an instrument by phantoms requires a tissue-mimicking material that has the acoustic velocity, density, and attenuation defined in the International Electrotechnical Commission (IEC) standard, and furthermore the tissue-mimicking material must be stable over time. To achieve the material with the desired acoustic velocity, density, and attenuation, we have developed a new permanent gel with any arbitrary acoustic velocity and little attenuation. The gel originates a swollen segmented polyurethane gel with tetraethylene glycol dimethyl ether and 1-Butyl-3-methylimdazolium thiocyanate as medium. The developed tissue-mimicking material was prepared from the permanent swollen segmented polyurethane gel with dispersed poly(methyl methacrylate) particles.

Blood-Mimicking Fluid for Testing Ultrasonic Diagnostic Instrument

We present a blood-mimicking fluid (BMF) for the Doppler test object of medical diagnostic instruments. Accurate measurement in a flow Doppler test requires a BMF that has the acoustic velocity and density defined in the International Electrotechnical Commission (IEC) standard, and furthermore, they must be stable over time. To formulate a fluid with the desired density and acoustic velocity, we have developed a new fluid made of glycerine and water-soluble silicone oil. The new BMF includes dispersed polystyrene particles as scatterers. The density of the liquid can be adjusted to maintain it at the same value as that of the polystyrene particles, thus ensuring neutral buoyancy of the particles. The MBF was stable over a period of 2 weeks, during which the density and acoustic velocity did not change.