Market prediction using machine learning based on social media specific features

Artificial Life and Robotics - In recent years, unspecified messages posted on social media have significantly affected the price fluctuations of online-traded products, such as stocks and virtual...     

Direct uses of geothermal energy in Japan

The purpose of this review is to outline the present state of direct uses of geothermal energy in Japan as of April 1989. Firstly, the representative examples are briefly illustrated. Secondly, an analysis is carried out to characterize each application, with a diagram combining the inlet temperature with the flow rate of individual direct use facilities. Finally, the total installed thermal power and the total thermal energy used are estimated at 171 MWt and 107 MWt yr, respectively, resulting in a total average load factor of 63%. The oil saved by geothermal direct uses is also evaluated at 0.06% of national consumption.     

Geothermal observations by use of a helicopter-borne remote sensing system

Detailed infrared images are useful for investigating thermal features of geothermal fields. A remote sensing system which is installed on low-altitude-flying helicopters is developed to get the infrared images with high resolution. But those images can cover only a limited domain. As the system can fit visible images on infrared ones simultaneously obtained, within a common field of view, this makes it possible to determine the positions of target areas by finding out geographical and topographical features over the visible images in spite of its limited areas. Observations by means of the helicopter-borne system are described for the two geothermal fields in Japan. Finally, heat discharge from those fields are estimated by analyzing the observed thermal images.     

Controllable electrode activities of nano-carbon films while maintaining surface flatness by electrochemical pretreatment

A carbon film consisting nanocrystallites with mixed sp² and sp³ bonds formed by using the electron cyclotron resonance (ECR) sputtering method was studied with respect to the changes in characteristics caused by electrochemical pretreatment (ECP). Unlike glassy carbon, our sputtered nanocrystalline carbon film deposited at an acceleration voltage of 75 V (ECR-75 nano-carbon film) largely retained its surface flatness after the ECP. This robust surface could be caused by an increase of 42% in the sp³ carbon realized by increasing the acceleration voltage during sputtering. The electrode activity of ECR-75 nano-carbon film was improved for surface sensitive species including Fe^3+/2+ unlike the boron doped diamond (BDD) electrode. This is because a sufficient quantity of surface sp² bonds remained and because the introduction of surface oxygen-containing groups is more efficient than with the BDD electrode. With pretreated ECR-75 nano-carbon film, the peak potential of glutathione was reduced solely due to the increase in the surface hydrophilicity with a sufficient quantity of surface sp² bonds, thus achieving the lowest detection limit (0.4 μM) ever obtained with carbon electrodes. We also achieved the stable measurement of 30 μM of serotonin (20 times) without the electrode surface fouling found with other electrodes.     

Calcium sensitization in perfused beating guinea pig heart by a positive inotropic agent MCI-154

An in vitro import system was used to characterize the mechanism of import of phospholipid hydroperoxide glutathione peroxidase (PHGPx) into mitochondria. Mitochondria were isolated from rat liver and incubated at 25 degrees C with [35S]methionine-labeled products of the in vitro translation of mRNA that encoded 23-kDa and 20-kDa PHGPx. 23-kDa PHGPx was imported into mitochondria in a time-dependent manner and was processed to yield the 20-kDa form of PHGPx. The 20-kDa form of PHGPx, without a leader sequence, associated weakly with mitochondria but was not imported. An analysis with an uncoupler of oxidative phosphorylation showed that a membrane potential in the mitochondria was also required for the import of PHGPx. It appears, therefore, that the leader sequence in the precursor to PHGPx is the signal for import into the mitochondria. This is the first report to indicate that the precursor to PHGPx is imported into the mitochondria via the action of a leader sequence.     

Development of weatherproof mobile impulse voltage generator and its application to experiments on nonlinearity of grounding resistance

This paper describes a newly developed impulse voltage generator (IG). It has the following features: (1) The IG consists of three components (a 1.6 MV unit, a 1.4-MV unit and a base box); this facilitates mounting on 10-ton trucks, therefore making it easier to move to a test field. (2) Capacitors, discharge gaps and a control unit are enclosed in fiber-reinforced plastics, making it possible to use the IG in all weather. (3) The IG can generate several ten kA when a load is a few ten Ω. (4) Composition of the circuits for lightning/switching impulse voltage/current tests can be easily done by changing the damping and discharge resistance cassettes. Control and data acquisition are made by personal computer. For IG application during an outdoor test, this paper presents the characteristics of resistances of a 77-kV substation grounding and a concrete pole when applying a high impulse current. The resistances are dependent on the crest value of the applied current.     

Probability analysis method using Fast Fourier transform and its application

This paper presents an efficient probability analysis method using Fast Fourier transform taking into account that (1) a probability density function and its characteristic function are a pair of Fourier transforms, and (2) the characteristic function of the sum of statistically independent random variables is given by the product of the characteristic functions of each random variable. The efficient probability analysis method is extended for the sum of correlated non-normal random variables with correlation coefficients expressed by the power of a common value. Expressing the correlated basic variables in terms of two sets of uncorrelated random variables, the characteristic function of their sum can be estimated approximately by the characteristic functions of the correlated basic variables. The probability density function of the sum is obtained using Fast Fourier transform. The accuracy and applicability of the approximation method are investigated based on the estimation error of the cumulant and using numerical examples. Applications of the proposed method to various aspects of structural reliability analysis and design are illustrated.     

High energy resolution PIXE with high efficiency using the heavy ion microbeam

An X-ray crystal spectrometer using a position sensitive proportional counter combined with tandem microbeam line at Osaka National Research Institute have been developed. This system realizes high energy resolution PIXE analysis using a heavy ion microbeam (E < 6 MeV) with reasonable detection efficiency. The design of the spectrometer, such as detection geometry, detectable energy range and energy resolution, are described. This system was applied to high energy resolution PIXE analysis of Ti, SUS and Si with 2 MeV proton and 5 MeV Si³⁺ focused or collimated beams. The best energy resolution was 2 eV for the Si K line.     

Estimation of the current peak value distribution of all lightning to the ground by electro‐geometric model

When we examine the lightning frequency and the lightning shielding e?ect of the electro‐geometric model (EGM), we need the current distribution of all lightning to the ground. The distribution of lightning current to structures is di?erent from this distribution, but it has been used in EGM conventionally. We assumed the lightning striking distance coe?cient related to the height of structures in order to obtain a result which corresponds to the observed frequency of lightning to structures, and estimated the current distribution of all lightning to the ground from data listed in the IEC 62305 series of EGM. The estimated distribution adjusted by the LLS detection e?ciency agreed well with the distribution observed by LLS. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(3): 14–26, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22356     

High speed detection of R-R intervals for universal Holter recordings

Heart rate variability (HRV) has been gaining popularity for its potential to estimate the autonomic nerve function and prognosis of patients with cardiovascular diseases. Holter recordings have been used for the measurement of R-R intervals in out-patients and for the estimation of circadian variations of HRV. However, when the manufacturer of the Holter tape recorder is not the same as that of the Holter analyzer a correction of the tape speed error for the accurate measurement of the R-R intervals is abandoned. The simultaneous assessment of additional physical parameters recorded on the Holter recorder and R-R interval is not possible with commercial software. To overcome these problems, we developed a system to detect R-R intervals at the playback speed of a Holter analyzer 500 times real-time with the correction of tape speed error from a system clock recorded on the Holter tape. High- and low-pass filter processed ECG signals and a comparator provided digital signals representing the R-R intervals. The R-R intervals and system clock intervals (tape speed) were measured simultaneously by interrupt-driven software, using timer-counters in a personal computer. The measured R-R intervals were corrected with the system clock intervals. The power spectra of the tape speed error showed that tape speed error significantly affects the power spectra of HRV, if not corrected. This method is applicable to Holter tape recorders of any manufacturer. This system also enables the simultaneous measurement of HRV and other physical parameters to evaluate their relations.