Wyniki wyszukiwania - BazTech

1

Application of grammatical evolution to stock price prediction

Kita E., Sugiura H., Zuo Y., Mizuno T.

Computer Assisted Methods in Engineering and Science

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2017

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Vol. 24, no. 1

67--81

EN

Grammatical evolution (GE) is one of evolutionary computation techniques. The aim of GE is to find the function or the executable program or program fragment that will find the optimal solution for the design objective such as the function for representing the set of given data, the robot control algorithm and so on. Candidate solutions are described in bit string. The mapping process from the genotype (bitstring) to the phenotype (function or program or program fragment) is defined according to the list of production rules of terminal and non-terminal symbols. Candidate solutions are evolved according to the search algorithm based on genetic algorithm (GA). There are three main issues in GE: genotype definition, production rules, and search algorithm. Grammatical evolution with multiple chromosomes (GEMC) is one of the improved algorithms of GE. In GEMC, the convergence property of GE is improved by modifying the genotype definition. The aim of this study is to improve convergence property by changing the search algorithm based on GA with the search algorithm based on stochastic schemata exploiter (SSE) in GE and GEMC. SSE is designed to find the optimal solution of the function, which is the same as GA. The convergence speed of SSE is much higher than that of GA. Moreover, the selection and crossover operators are not necessary for SSE. When GA is replaced with SSE, the improved algorithms of GE and GEM Care named “grammatical evolution by using stochastic schemata exploiter (GE-SSE)” and “grammatical evolution with multiple chromosome by using stochastic schemata exploiter (GEMC-SSE)”, respectively. In this study, GE-SSE is compared with GE in the symbolic regression problem of polynomial function. The results show that the convergence speed of GE-SSE is higher than that of original GE. Next, GE-SSE and GEMC-SSE are compared in stock price prediction problem. The results show that the convergence speed of GEMC-SSE is slightly higher than that of GE-SSE.

2

Study of the effect of intermittent type of mental work-load by physiological psychological index

Mizuno T., Nomura S., Nozawa A., Asano H., Ide H.

Journal of Medical Informatics & Technologies

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2009

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Vol. 13

249--253

EN

This paper was aimed at evaluating the mental work-load (MWL) with psycho-physiological indices. Especially, we focused on the intermittent type of MWL, which is assumed as a predisposing factor of various somatic and mental disorders. In the experiment, we introduced a facial skin thermo image comparing with conventional physiological indices, such as electrocardiogram (ECG) and electroencephalogram (EEG). As a result, the facial skin image was suggested to be a useful tool for evaluating such an intermittent type of MWL.

3

Single-electron transport characteristics in quantum dot arrays due to ionized dopants

Moraru D., Ligowski M., Tarido J. C., Miki S., Nakamura R., Yokoi K., Mizuno T., Tabe M.

Journal of Automation Mobile Robotics and Intelligent Systems

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2009

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Vol. 3, No. 4

52-54

EN

Single charge manipulation for useful electronic functionalities has become an exciting and fast-paced direction of research in recent years. In structures with dimensions below about 100 nm, the physics governing the device operation turn out to be strikingly different than in the case of larger devices. The presence of even a single charge may completely suppress current flow due to the basic electronelectron repulsion (so called Coulomb blockade effect) [1]. It is even more exciting to control this effect at the level of single-electron/single-atom interaction. The atomic entity can be one donor present in silicon lattice with a Coulombic potential well. In principle, it can accommodate basically a single electron. We study the electrical behavior of nanoscale-channel silicon-on-insulator field-effect transistors (SOI-FETs) that contain a discrete arrangement of donors. The donors can be utilized as "stepping stones" for the transfer of single charges. This ability opens the doors to a rich world of applications based on the simple interplay of single charges and single atoms, while still utilizing mostly conventional and well established fabrication techniques. In this work, we distinguish the effects of single-electron transport mediated by one or few dopants only. Furthermore, we show how the single-electron/single-donor interaction can be tuned by using the external biases. We demonstrate then by simulation and experiment the feasibility of single-electron/bit transfer operation (single-electron turnstile).

4

Detection of individual dopants in singe-electron devices - a study by KFM observation and simulation

Ligowski M., Moraru D., Miftahul A., Tarido J. C., Mizuno T., Tabe M., Jabłoński R.

Journal of Automation Mobile Robotics and Intelligent Systems

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2009

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Vol. 3, No. 4

130-133

EN

Single electron devices (SEDs) are candidates to become a keystone of future electronics. They are very attractive due to low power consumption, small size or high operating speed. It is even possible to assure compatibility with present CMOS technology when natural potential fluctuations introduced by dopant atoms are used to create quantum dots (QD). However, the main problem of this approach is due to the randomness of dopant distribution which is characteristic for conventional doping techniques. This leads to scattered characteristics of the devices, which precludes from using them in the circuits. In these work we approach the problem of correlating the distribution of QD's with the device characteristics. For that, we investigate with a Kelvin probe force microscope (KFM) the surface potential of Si nanodevice channel in order to understand the potential landscape. Results reveal the features ascribable to individual dopants. These findings are supported also by simulation results.

5

Lead and zinc determination in cooper alloys by sequential metal vapor elution analysis with an improved column

Ohta K., Kawaguti K., Uegomori H., Mizuno T.

Chemia Analityczna

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1999

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Vol. 44, No. 2

187-194

EN

The determinatjon of lead and zinc in copper alloys by sequential metal vapor elution analysis (SMVEA) using an improved column is reported. An improved molybdenum column ( open column, I.D. 1.22 mm) with three ring supporters was developed. An optimum flow rate of the carrier gas (pure argon), the column and vaporization tempe-ratures for separation of the metal vapors were 0.5 ml min-l, 1260°C, and 1470°C, respectively. Under the optimal experimental conditions, Pb and Zn peaks are comple-tely separated from Al, Cd, Cr, Cu, Fe, Ti and Zr peaks. The interferences of matrix elements observed in the determination by GFAAS could be eliminated and an accurate determination of lead and zinc in copper alloys is possible just after only acid-digestion.

PL

Opracowano metodę oznaczania ołowiu i cynku w stopach miedzi metod'l sekwencyj-nego wydzielania par metali przy użyciu udoskonalonej kolumny. Zastosowano mołibdenow'l, udoskonaloną kolumnę (kołumna otwarta, I.D. 122 mm) z trzema wspieraj'lcymi pierścieniami. Optymalna szybkość przepływu gazu nośnego (czysty argon) wynosi 0.5 ml min-l, temperatury -kolumny i odparowania (stosowane do rozdzieIania par metali) wynosz'l odpowiednio 1260°C i 1470°C W optymalnych warunkach doświadczalnych piki Pb i Zn zostały całkowicie oddzielone od pików Al, Cd, Cr, Cu, Fe, Ti and Zr. Wpływy pierwiastków matrycy, obserwowane przy oznacza-niu metodą GFAAS, mogły być usunięte umożliwiaj'lc dokładne oznaczenie ołowiu i cynku w stopach miedzi jedynie po roztworzeniu ich w kwasie.