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  • 1
    Electronic Resource
    Electronic Resource
    2-D Simulation and New Structures of Heterojunction Phototransistor for Higher Optical Amplification in Optoelectronic Integrated Devices (1995)
    Springer
    Optical review 2 (1995), S. 120-122 
    Details
    ISSN: 1349-9432
    Keywords: heterojunction phototransistor ; two-dimensional simulation ; optoelectronic integrated device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The improvement of optical gain is an important priority for performance design in most of optoelectronic integrated devices (OEIDS). A two-dimensional simulator is developed for the rigorous analysis and optimum design of devices. With it, we analyze the characteristics of heterojunction phototransistor (HPT) which acts as a light-detector in OEID, and we propose new structures of HPT to increase the conversion gain without much increase in dark current. Then, the simulation of an OEID composed of an HPT integrated over a light-emitting diode (LED) is implemented, and it is shown that the new structures significantly improve the optical amplification for low input light power over the conventional structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10043-995-0120-0
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  • 2
    Electronic Resource
    Electronic Resource
    Life history of the temperate subtidal gastropod Umbonium costatum (1995)
    Springer
    Marine biology 122 (1995), S. 73-78 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The life history and reproductive biology of the trochid sand snail Umbonium costatum (Kiener) were investigated on a subtidal sandy shore in Hakodate Bay, Japan between 1988 and 1991. Female U. costatum mature at 1 yr of age (shell diameter-11 mm), reproduce twice (in June-July and September-October) in successive years, grow to a maximum size (shell diameter=22 mm) at age 8 yr, increase annual fecundity with age from 2000 (age 1 yr) to 37000 (age 8 yr), and show a maximum monthly gonad somatic index of 8% which is constant among ages. In comparison to a previously studied life history of a tropical Umbonium vestiatium, temperate U. costatum shows more sustained growth and a longer life span after maturation. This could be explained by: (1) the optimal size model concerned with resource investment, in gametes (Sebens 1987); and by (2) bet hedging to compensate large variability in larval success at high latitudes. These two hypotheses are not mutually exclusive, but both are based on season-related extremes of environment at high latitudes where the period suitable for reproduction is short.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349279
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  • 3
    Electronic Resource
    Electronic Resource
    A possible hybrid zone in the Mytilus edulis complex in Japan revealed by PCR markers (1997)
    Springer
    Marine biology 128 (1997), S. 91-95 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The adhesive protein allele of mussels collected at 13 points in Japan from Hokkaido to Kyushu was analyzed by the polymerase chain reaction using a set of primers which amplifies a part of the nonrepetitive region of the adhesive protein gene. While most mussels exhibited a 126 bp fragment, characteristic of the pure Mytilus galloprovincialis, 55 of 64 mussels sampled at Hiura and 1 of 14 mussels at Hakodate Port exhibited 168 and 126 bp fragments. Sequence analysis of the two fragments indicated that the 168 and 126 bp fragments are almost identical to previously reported sequences in M. trossulus and M. galloprovincialis, respectively. Since the frequency of heterozygous individuals in Hiura is very high, it is unlikely that they are simple hybrids. However, it is evident that mixing of genes occurred between the two species off Hokkaido.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050072
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  • 4
    Electronic Resource
    Electronic Resource
    A high-speed and continuous 3D measurement system (1995)
    Springer
    Machine vision and applications 8 (1995), S. 79-84 
    Details
    ISSN: 1432-1769
    Keywords: Slit-ray projection ; Position-sensitive device ; 3D range data ; High-speed range finders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A new system for high-speed and continuous 3D measurement is presented. It is based on the slit-ray projection method. The key component is the image plane constructed by a position-sensitive device (PSD) array that is horizontally un segmented and linear, but vertically numbered. All PSD row elements are attached to their respective analog signal processors. The analog signals are multiplexed and digitized by multiplexers and A/D converters at appropriate sampling intervals and stored in memory. By virtue of this configuration of the image plane, basis data for 3D measurement are acquired during only one scan of the slit ray at high speed in the form of memory addresses and data. Moreover, if we use large capacity and/or dual port memories, we can continuously obtain 3D range data for as many scenes as needed. The trial system has been implemented with a newly designed 128-channel PSD array and has verified our method, enabling us to obtain successive 3D range data at video rates with an error within±0.3%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01213473
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  • 5
    Electronic Resource
    Electronic Resource
    Spatio-temporal population dynamics of the sand snail Umbonium costatum: importance of ontogenetic migration and annual recruitment variability (1995)
    Springer
    Marine biology 123 (1995), S. 815-820 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatio-temporal population dynamics of the subtidal snail Umbonium costatum (Kiener) in Hakodate Bay, northern Japan, are described over a 9-yr period (1982 to 1988, 1992). Annual variations in recruitment success not only caused the highly variable age structure of the population, but also affected its distribution pattern. In heavy recruitment years (1982, 1984 and 1988), location of the densest population differed from the other years, and the areas with 0 yr old individuals were larger. Every year, the distribution of 0 yr olds was mostly restricted to inshore (within 320 m from shore), while the distribution of adults (〉0 yr) was mostly restricted to offshore (〉320 m from shore). Such patterns may be generated by ontogenetic migration of cohorts to offshore areas. Ontogenetic migration also could have buffered the large annual variation in spat distribution and maintained the small variation in the distribution of adults. (Prince et al. 1988). Density-related migration has also been reported in Acmaea digitalis (Frank 1965), Patella cochlear (Branch 1974) and Patelloida alticostata (Black 1977). Dense populations of the gastropod Umbonium costatum are found in some clean subtidal sandy-bottoms in Japan, e.g. inner part of Hakodate Bay. In the bay, the age structure of U. costatum revealed predominant year-classes. The 0 yr olds were restricted to the shallowest zone (〈4 m depth) and most adult (〈0 yr) cohorts were restricted to 6 to 7 m depths (Noda 1991a). This paper describes the temporal variability of population structure and distributional patterns of Umbonium costatum, and examines the distribution-regulating processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349125
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  • 6
    Electronic Resource
    Electronic Resource
    Assignment of the developmentally regulated gene NEDD1 to human chromosome 12q22 by fluorescence in situ hybridization (1995)
    Springer
    Human genetics 〈Berlin〉 95 (1995), S. 96-98 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The developmentally regulated mouse gene Nedd 1 encodes a protein showing similarities with the β-subunit of heterotrimeric GTP-binding proteins and has growth suppressing activity when overexpressed in various cultured cell types. We have mapped the human homolog (NEDD1) of the mouse gene to chromosome 12q22 by fluorescence in situ hybridization using R-banded human (pro)metaphase chromosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225082
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  • 7
    Electronic Resource
    Electronic Resource
    Anomalous enhancement of DD reaction in Pd and Au/Pd/PdO heterostructure targets under low-energy deuteron bombardment (1998)
    Springer
    JETP letters 68 (1998), S. 823-829 
    Details
    ISSN: 1090-6487
    Keywords: 25.45.−z ; 27.60.+j ; 27.80.+w
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Yields of protons emitted in the D+D reaction in Pd, Au/Pd/PdO, Ti, and Au foils are measured by a d E-E counter telescope for bombarding energies between 2.5 and 10 keV. The experimental yields are compared with those predicted from a parametrization of the cross section and stopping power at higher energies. It is found that for Ti and Au target the enhancement of the D(d,p)T reaction is similar to that observed with a deuterium gas target (several tens of eV). The dependence of the yields on the bombarding energy corresponds well to the screening potential parameters U s=250±15 eV for Pd and 601 ±23 eV for Au/Pd/PdO. Possible models of the enhancement obtained are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567800
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  • 8
    Electronic Resource
    Electronic Resource
    Purposive Behavior Acquisition for a Real Robot by Vision-Based Reinforcement Learning (1996)
    Springer
    Machine learning 23 (1996), S. 279-303 
    Details
    ISSN: 0885-6125
    Keywords: reinforcement learning ; vision ; learning from easy mission ; state-action deviation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper presents a method of vision-based reinforcement learning by which a robot learns to shoot a ball into a goal. We discuss several issues in applying the reinforcement learning method to a real robot with vision sensor by which the robot can obtain information about the changes in an environment. First, we construct a state space in terms of size, position, and orientation of a ball and a goal in an image, and an action space is designed in terms of the action commands to be sent to the left and right motors of a mobile robot. This causes a state-action deviation problem in constructing the state and action spaces that reflect the outputs from physical sensors and actuators, respectively. To deal with this issue, an action set is constructed in a way that one action consists of a series of the same action primitive which is successively executed until the current state changes. Next, to speed up the learning time, a mechanism of Learning from Easy Missions (or LEM) is implemented. LEM reduces the learning time from exponential to almost linear order in the size of the state space. The results of computer simulations and real robot experiments are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018237008823
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  • 9
    Electronic Resource
    Electronic Resource
    Purposive behavior acquisition for a real robot by vision-based reinforcement learning (1996)
    Springer
    Machine learning 23 (1996), S. 279-303 
    Details
    ISSN: 0885-6125
    Keywords: reinforcement learning ; vision ; learning from easy mission ; state-action deviation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper presents a method of vision-based reinforcement learning by which a robot learns to shoot a ball into a goal. We discuss several issues in applying the reinforcement learning method to a real robot with vision sensor by which the robot can obtain information about the changes in an environment. First, we construct a state space in terms of size, position, and orientation of a ball and a goal in an image, and an action space is designed in terms of the action commands to be sent to the left and right motors of a mobile robot. This causes a “state-action deviation” problem in constructing the state and action spaces that reflect the outputs from physical sensors and actuators, respectively. To deal with this issue, an action set is constructed in a way that one action consists of a series of the same action primitive which is successively executed until the current state changes. Next, to speed up the learning time, a mechanism of Learning from Easy Missions (or LEM) is implemented. LEM reduces the learning time from exponential to almost linear order in the size of the state space. The results of computer simulations and real robot experiments are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00117447
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  • 10
    Electronic Resource
    Electronic Resource
    Fabrication of ceramic composites consisting of powders with different specific gravity by the slip-casting technique (1997)
    Springer
    Journal of materials science 32 (1997), S. 2665-2669 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract For composites, it is of great importance to fabricate well-dispersed green compacts, in order to improve their mechanical properties and reliability. In the present study, the slip-casting technique was applied to the fabrication of ZrO2–WC–Al2O3 composites. The specific gravity of each composition in this material was very different, that is, 6.07 for ZrO2, 15.6 for WC and 3.94 for Al2O3. The compositions in the green compacts were afraid to separate from each other owing to the difference in their specific gravities, leading to heterogeneity in the microstructure. The relative density of the obtained compacts was approximately 60%. WC and Al2O3 were well-dispersed in the ZrO2 matrix. The separation and/or heterogeneity due to difference could not be recognized by energy-dispersive X-ray analysis. The slip-casting technique was found to be applicable to the fabrication of ceramic composites consisting of raw powders with different specific gravities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018675106394
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