Otsuka N.,Tokyo Denki University
Systems and Control Letters | Year: 2010
In this paper, disturbance decoupling problems without stability and with quadratic stability for switched linear systems are formulated in the framework of the so-called geometric approach. Firstly, necessary and sufficient conditions for the problem without stability to be solvable are given. Secondly, sufficient conditions for the problem with quadratic stability to be solvable are given. Further, for switched linear systems composed of two subsystems necessary and sufficient conditions for the problem with quadratic stability to be solvable are also investigated. Finally, an illustrative example is shown. © 2010 Elsevier B.V. All rights reserved.
Yabuuchi N.,Tokyo University of Science |
Yabuuchi N.,Kyoto University |
Yabuuchi N.,Tokyo Denki University |
Kubota K.,Tokyo University of Science |
And 5 more authors.
Chemical Reviews | Year: 2014
The material's abundance is a simple and clear reason as to why sodium ions are attractive as charge carriers for rechargeable batteries. It is also expected that potassium ions have a further smaller desolvation energy compared with the Li and Na systems in aprotic solvents. However, further energy sacrifice is also unavoidable for the potassium system due to heavy atomic weight. In addition to the oxides, a wide variety of crystal structures is known for polyanionic compounds and the structural chemistry of the Na system is much more complicated in comparison to the Li system. Na ions are apparently coordinated by four fluoride ions at bottleneck sites when the Na ions migrate across the perovskite-type framework structure.
Kawamae N.,Tokyo Denki University
Proceedings of the 4th ACM International Conference on Web Search and Data Mining, WSDM 2011 | Year: 2011
This paper presents a topic model that identifies interpretable low dimensional components in time-stamped data for capturing the evolution of trends. Unlike other models for time-stamped data, our proposal, the trend analysis model (TAM), focuses on the difference between temporal words and other words in each document to detect topic evolution over time. TAM introduces a latent trend class variable into each document and a latent switch variable into each token for handling these differences. The trend class has a probability distribution over temporal words, topics, and a continuous distribution over time, where each topic is responsible for generating words. The latter class uses a document specific probabilistic distribution to judge which variable each word comes from for generating words in each token. Accordingly, TAM can explain which topic co-occurrence pattern will appear at any given time, and represents documents of similar content and timestamp as sharing the same trend class. This class allows TAM to project these data on a latent space of trend dimensionality and predict the temporal evolution of words and topics in them. Experiments on various data sets show that the proposed model can capture interpretable low dimensionality sets of topics and timestamps, take advantage of previous models, and is useful as a generative model in the analysis of the evolution of trends. Copyright 2011 ACM.
Hatanaka M.,Tokyo Denki University
Journal of Physical Chemistry C | Year: 2012
Magnetic ordering in porous graphenes is analyzed by crystal orbital methods. While in triangle- and parallelogram-pored graphenes, the frontier bands have wide band widths, and in hexagon-pored graphenes, the HOCOs (highest occupied crystal orbitals) and LUCOs (lowest unoccupied crystal orbitals) are completely flat at the Hückel approximation. The flat bands in the resultant honeycomb systems are disjoint/nondisjoint composite types, and ferromagnetic interactions in the cationic and anionic states are predicted by quantum-chemical calculations including electronic correlations. Possible isoelectronic systems with nitrogen and boron atoms are also investigated as spin doped materials. The origin of spin alignment and pore size effects on magnetism are clarified by Wannier analysis. These systems are promising candidates for two-dimensional organic ferromagnets. © 2012 American Chemical Society.
Nishikata S.,Tokyo Denki University |
Tatsuta F.,Tokyo Denki University
IEEE Transactions on Industrial Electronics | Year: 2010
A new interconnecting method for a cluster of wind turbine/generators is proposed, and some examples of the basic characteristics of the integrated system are shown. This method can be achieved with a wind turbine generating system using a shaft generator system. A group of wind turbine/generators can be interconnected easily with the proposed method, and high reliability and electric output power with high quality are also expected. Moreover, since this method enables transmission of the generated power through a long-distance dc transmission line, the optimum site for wind turbines can be selected so as to acquire the maximum wind energy. © 2009 IEEE.
Hatanaka M.,Tokyo Denki University
Chemical Physics Letters | Year: 2010
Band structures of porous graphenes are deduced by crystal orbital method. The dispersions suggest ca. 3.7 eV of band gaps. Bandwidths of the HOCOs and LUCOs are zero within Hückel approximation due to the nodal character of phenylene units. The graphene ribbons with n porous ladders also have singular electronic states, of which flat HOCOs and LUCOs are n-fold degenerate, respectively. The flat bands are useful for possible magnetic materials. © 2010 Elsevier B.V. All rights reserved.
Nissan Motor Co. and Tokyo Denki University | Date: 2014-09-03
A reference signal is mixed with a bioelectric signal, the capacitance between a biological composition and an input device is detected from the intensity of the reference signal, and the gain of the bioelectric signal is corrected on the basis of the detected capacitance.
Nissan Motor Co. and Tokyo Denki University | Date: 2016-08-03
[SOLUTION] A reference signal is mixed with a bioelectric signal, the capacitance between a biological composition and an input means is detected from the intensity of the reference signal, and the gain of the bioelectric signal is corrected on the basis of the detected capacitance.
Tokyo Denki University | Date: 2013-04-11
Exposure areas are wholly overlapped by moving a gradient refractive index lens array in a direction perpendicular to a scanning direction, or by providing a plurality of gradient refractive index lens arrays, an optical filter having a density distribution of lightness and darkness to compensate light transmission nonuniformity of the gradient refractive index lens array is arranged, or an opening control plate for limitedly using only of a uniform portion is provided. Two or more means may be simultaneously provided among the aforementioned mean. Moreover, any one of a microscopic transmission shutter array, a microscopic reflection shutter array, and a microscopic light emitter array is used instead of a mask, or an illuminating device and the mask.
Tokyo Denki University and Oiles Corporation | Date: 2010-07-21
[Subject] To provide a seismic isolation device, regardless of a load to be supported, capable of reducing acceleration through lengthening a natural period of an upper structure, with excellent vibration energy absorbing capacity by obtaining a properly preferable frictional force as well as a returning characteristic, and others. [Means for Solution] A seismic isolation device 1 comprising: an upper plate 11 fixed to an upper structure 3, such as a building, and having a spherically concave lower surface 11a with a downward opening; a lower plate 12 fixed to a lower structure 2, such as a foundation, and having a spherically concave upper surface 12a with an upward opening; and a movable body 13 movably arranged between the upper plate 11 and the lower plate 12, wherein the movable body 13 comprises a spherically convex upper surface 13a opposing to the spherically concave lower surface 11a of the upper plate 11; and a spherically convex lower surface 13b opposing to the spherically concave upper surface 12a of the lower plate 12, and the spherically convex upper surface 13a and the spherically convex lower surface 13b have plural air blowout ports 13c. And, a seismic isolation structure with at least three seismic isolation devices 1.