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T. Matsumura - One of the best experts on this subject based on the ideXlab platform.

  • observation of transient behavior of magnetic flux in Inductive Type fault current limiter with ybco thin film disc
    Physics Procedia, 2012
    Co-Authors: Kosuke Higuchi, Yin Guan, Yasunobu Yokomizu, T. Matsumura
    Abstract:

    Abstract Recently, the installation of fault current limiters (FCLs) in power systems is expected for controlling large short circuit currents. In this study, we focus on Inductive-Type FCLs having a YBCO superconducting thin film disc that is fabricated by metal-organic deposition. AC currents were injected into the FCL so that the periodic transient behavior of the apparent magnetic flux density around the FCL could be measured by using a pick-up coil. The magnetic flux density exhibited hysteresis when AC current was injected into the FCL. The transition between the conducting states in the YBCO layer was explained by the hysteresis relationship between the magnetic flux density and current.

  • required limiting impedance and capacity of fault current limiter installed in customer system with synchronous generator
    Ieej Transactions on Electrical and Electronic Engineering, 2006
    Co-Authors: Daisuke Iioka, T. Matsumura, Yasunobu Yokomizu, M Goto, Hirotaka Shimizu
    Abstract:

    We investigated the required limiting impedance and capacity of a fault current limiter (FCL) installed at an incoming feeder of a customer system with a synchronous generator in a utility distribution system. It was assumed that two Types of FCL were installed, i.e. a resistive Type (R-Type) FCL and an Inductive Type (L-Type) FCL. A fault current out of the customer system and a voltage in the customer system were calculated following a three-phase, short-circuit fault occurrence. It was found that the required Type of FCL and the required limiting impedance depended on the rated capacity of the generator in order to obtain the suppression of the fault current under 0.1 kAS and to maintain of customer voltage between 85 and 100% of the nominal voltage (6.6 kV). The capacity of FCL consisting of the smallest limiting impedance is discussed. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

  • Inductive Type fault current limiter using Bi-2223 thick film on MgO cylinder with Bi-2212 buffer Layer
    IEEE Transactions on Appiled Superconductivity, 2005
    Co-Authors: H. Kado, M. Ichikawa, M. Shibuya, M. Kojima, M. Kawahara, T. Matsumura
    Abstract:

    We have been developing an Inductive Type superconducting fault current limiter with a superconducting cylinder. For practical use, a high critical current density (Jc) is needed in a large diameter. To achieve these items, we have developed a Bi-2223 thick film on a MgO substrate, with a Bi-2212 buffer layer. This cylinder was 450 mm in diameter and 120 mm in length. We describe the superconductive characteristics of this cylinder, and the limiting properties of the fault current limiter using these cylinders.

  • Inductive Type fault current limiter with Bi-2223 thick film on a MgO cylinder
    IEEE Transactions on Applied Superconductivity, 2003
    Co-Authors: M. Ichikawa, H. Kado, M. Shibuya, T. Matsumura
    Abstract:

    Fault current limiters for electric power systems have been researched. We have studied a Inductive Type superconducting fault current limiter. The limiter has superconducting cylinder as active element. We developed a high Jc Bi-2223 thick film on a MgO cylinder. Jc was over 5800 A/cm/sup 2/ at 77 K. We made a Inductive Type superconducting fault current limiter with the Bi-2223 thick film cylinder and investigated limiting performances.

Weileun Fang - One of the best experts on this subject based on the ideXlab platform.

  • On the detection interfaces for Inductive Type tactile sensors
    Sensors and Actuators A: Physical, 2019
    Co-Authors: Sheng-kai Yeh, Jiunn-horng Lee, Weileun Fang
    Abstract:

    Abstract This study presents the investigation of detection interface for the Inductive Type tactile sensor consisted of a polymer encapsulated CMOS chip with coils and a magnetic bump. The normal tactile load will change the distance between the magnetic bump and coils, and the tactile load is then detected by the magnetic flux change of the coils. Thus, the detection interfaces include (1) the magnetic bump which acts as the contact interface, and (2) the coils (on the CMOS chip) which act as the signal pick-up interface. For the contact interface, the size and material of the magnetic bump will influence the magnetic flux of the Inductive tactile sensor. The signal outputs resulted from the magnetic tactile bumps of different materials and sizes are studied. Moreover, the force responses, hysteresis measurements, and misalignment issues for magnetic bumps of different sizes are also investigated. For signal pick-up interface, two coil designs are presented to offer different sensing approaches for the Inductive tactile sensor. Since the CMOS chip is implemented using the commercially available standard process (the TSMC 0.35 μm 2P4M CMOS process), multi-layer coils are achieved by using the four metal films.

  • development of cmos mems Inductive Type tactile sensor with the integration of chrome steel ball force interface
    Journal of Micromechanics and Microengineering, 2018
    Co-Authors: Heng-chung Chang, Weileun Fang
    Abstract:

    This study presents an Inductive tactile sensor with a chrome steel ball sensing interface based on the commercially available standard complementary metal–oxide–semiconductor (CMOS) process (the TSMC 0.18 µm 1P6M CMOS process). The tactile senor has a deformable polymer layer as the spring of the device and no fragile suspended thin film structures are required. As a tactile force is applied on the chrome steel ball, the polymer would deform. The distance between the chrome steel ball and the sensing coil would changed. Thus, the tactile force can be detected by the inductance change of the sensing coil. In short, the chrome steel ball acts as a tactile bump as well as the sensing interface. Experimental results show that the proposed Inductive tactile sensor has a sensing range of 0–1.4 N with a sensitivity of 9.22(%/N) and nonlinearity of 2%. Preliminary wireless sensing test is also demonstrated. Moreover, the influence of the process and material issues on the sensor performances have also been investigated.

  • A novel polymer filled CMOS-MEMS Inductive-Type tactile sensor with wireless sensing capability
    2017 19th International Conference on Solid-State Sensors Actuators and Microsystems (TRANSDUCERS), 2017
    Co-Authors: Heng-chung Chang, Weileun Fang
    Abstract:

    This study presents a novel wireless Inductive Type CMOS-MEMS tactile sensing unit composed of underneath sensing coil and deformable polymer layer. The advantages of the proposed tactile sensing unit are as follows, (1) No released sensing diaphragm on the sensing unit. Thus, the residual stress caused by CMOS-MEMS process can be avoided. (2) The sensing coil underneath is protected by the above polymer layer, so the sensing unit would not be damaged under applied load. (3) Wireless sensing capability due to the magnetic coupling. (4) Sensing range can be modulated by varying the stiffness of the polymer (e.g. changing the ratio of pre-polymer and curing agent). This tactile-sensing unit is implemented using TSMC 0.18μm 1P6M CMOS process, in-house post-CMOS releasing, and polymer filling. Experiments show the tactile sensor has the sensitivity of 0.02%/mN within the sensing range of 0-80mN, and the wireless sensing ability is also demonstrated.

Jasper Hugunin - One of the best experts on this subject based on the ideXlab platform.

  • constructing Inductive Inductive Types in cubical Type theory
    Foundations of Software Science and Computation Structure, 2019
    Co-Authors: Jasper Hugunin
    Abstract:

    Inductive-Inductive Types are a joint generalization of mutual Inductive Types and indexed Inductive Types. In extensional Type theory, Inductive-Inductive Types can be constructed from Inductive Types, and this construction has been conjectured to work in intensional Type theory as well. In this paper, we show that the existing construction requires Uniqueness of Identity Proofs, and present a new construction (which we conjecture generalizes) of one particular Inductive-Inductive Type in cubical Type theory, which is compatible with homotopy Type theory.

  • FoSSaCS - Constructing Inductive-Inductive Types in Cubical Type Theory.
    Lecture Notes in Computer Science, 2019
    Co-Authors: Jasper Hugunin
    Abstract:

    Inductive-Inductive Types are a joint generalization of mutual Inductive Types and indexed Inductive Types. In extensional Type theory, Inductive-Inductive Types can be constructed from Inductive Types, and this construction has been conjectured to work in intensional Type theory as well. In this paper, we show that the existing construction requires Uniqueness of Identity Proofs, and present a new construction (which we conjecture generalizes) of one particular Inductive-Inductive Type in cubical Type theory, which is compatible with homotopy Type theory.

Thorsten Altenkirch - One of the best experts on this subject based on the ideXlab platform.

  • LICS - The Integers as a Higher Inductive Type
    Proceedings of the 35th Annual ACM IEEE Symposium on Logic in Computer Science, 2020
    Co-Authors: Thorsten Altenkirch, Luis Scoccola
    Abstract:

    We consider the problem of defining the integers in Homotopy Type Theory (HoTT). We can define the Type of integers as signed natural numbers (i.e., using a coproduct), but its induction principle is very inconvenient to work with, since it leads to an explosion of cases. An alternative is to use set-quotients, but here we need to use set-truncation to avoid non-trivial higher equalities. This results in a recursion principle that only allows us to define function into sets (Types satisfying UIP). In this paper we consider higher Inductive Types using either a small universe or bi-invertible maps. These Types represent integers without explicit set-truncation that are equivalent to the usual coproduct representation. This is an interesting example since it shows how some coherence problems can be handled in HoTT. We discuss some open questions triggered by this work. The proofs have been formally verified using cubical Agda.

  • The Integers as a Higher Inductive Type
    arXiv: Logic in Computer Science, 2020
    Co-Authors: Thorsten Altenkirch, Luis Scoccola
    Abstract:

    We consider the problem of defining the integers in Homotopy Type Theory (HoTT). We can define the Type of integers as signed natural numbers (i.e., using a coproduct), but its induction principle is very inconvenient to work with, since it leads to an explosion of cases. An alternative is to use set-quotients, but here we need to use set-truncation to avoid non-trivial higher equalities. This results in a recursion principle that only allows us to define function into sets (Types satisfying UIP). In this paper we consider higher Inductive Types using either a small universe or bi-invertible maps. These Types represent integers without explicit set-truncation that are equivalent to the usual coproduct representation. This is an interesting example since it shows how some coherence problems can be handled in HoTT. We discuss some open questions triggered by this work. The proofs have been formally verified using cubical Agda.

  • Constructing quotient Inductive-Inductive Types
    Proceedings of the ACM on Programming Languages, 2019
    Co-Authors: Ambrus Kaposi, András Kovács, Thorsten Altenkirch
    Abstract:

    Quotient Inductive-Inductive Types (QIITs) generalise Inductive Types in two ways: a QIIT can have more than one sort and the later sorts can be indexed over the previous ones. In addition, equality constructors are also allowed. We work in a setting with uniqueness of identity proofs, hence we use the term QIIT instead of higher Inductive-Inductive Type. An example of a QIIT is the well-Typed (intrinsic) syntax of Type theory quotiented by conversion. In this paper first we specify finitary QIITs using a domain-specific Type theory which we call the theory of signatures. The syntax of the theory of signatures is given by a QIIT as well. Then, using this syntax we show that all specified QIITs exist and they have a dependent elimination principle. We also show that algebras of a signature form a category with families (CwF) and use the internal language of this CwF to show that dependent elimination is equivalent to initiality.

  • free higher groups in homotopy Type theory
    Logic in Computer Science, 2018
    Co-Authors: Nicolai Kraus, Thorsten Altenkirch
    Abstract:

    Given a Type A in homotopy Type theory (HoTT), we can define the free ∞-group on A as the loop space of the suspension of A + 1. Equivalently, this free higher group can be defined as a higher Inductive Type F(A) with constructors unit: F(A), cons: A~F(A)~F(A), and conditions saying that every cons(a) is an auto-equivalence on F(A). Assuming that A is a set (i.e. satisfies the principle of unique identity proofs), we are interested in the question whether F(A) is a set as well, which is very much related to an open problem in the HoTT book [22, Ex. 8.2]. We show an approximation to the question, namely that the fundamental groups of F(A) are trivial, i.e. that ||F(A)||1 is a set.

  • free higher groups in homotopy Type theory
    Logic in Computer Science, 2018
    Co-Authors: Nicolai Kraus, Thorsten Altenkirch
    Abstract:

    Given a Type A in homotopy Type theory (HoTT), we can define the free ∞-group on A as the loop space of the suspension of A + 1. Equivalently, this free higher group can be defined as a higher Inductive Type F(A) with constructors unit: F(A), cons: A~F(A)~F(A), and conditions saying that every cons(a) is an auto-equivalence on F(A). Assuming that A is a set (i.e. satisfies the principle of unique identity proofs), we are interested in the question whether F(A) is a set as well, which is very much related to an open problem in the HoTT book [22, Ex. 8.2]. We show an approximation to the question, namely that the fundamental groups of F(A) are trivial, i.e. that ||F(A)||1 is a set.

Tanzo Nitta - One of the best experts on this subject based on the ideXlab platform.

  • power system characteristics of the scfcl in parallel with a resistor in series with a zno device
    IEEE Transactions on Applied Superconductivity, 2007
    Co-Authors: K Furushiba, Yasuyuki Shirai, K Fushiki, J Baba, T Yoshii, Tanzo Nitta
    Abstract:

    Superconducting fault current limiters (SCFCLs) are expected to improve the reliability and stability of power systems. The 3-phase FCL system, which consists of 3 superconducting fault current limiters of transformer Type in parallel with a resistor in series with a ZnO device, was proposed and its small model was designed and made. In a power system the FCL system is expected to limit the peak of the fault current Inductively and also to consume the acceleration energy of the generators by means resistive component. The power system characteristics of the proposed FCL system was experimentally investigated by use of the model FCL and a laboratory scale power system simulator. The FCL system switches its impedance from Inductive Type (L-Type) to Inductive+resistive Type (L + R-Type) in a cycle due to the ZnO device. The peak of the fault current was limited in the L-Type time interval and the energy was consumed in L + R-Type interval. The proposed FCL system limited the fault current at the simulated fault and successfully recovered the stand-by mode in the model power system. At the same time, the energy consumption in the resistor reduced the accelerating energy of the generator and then improves the power system transient stability.

  • current limiting characteristics of Inductive Type scfcl with zno device and resistor in parallel
    IEEE Transactions on Applied Superconductivity, 2006
    Co-Authors: Yasuyuki Shirai, Takayuki Morimoto, K Furushiba, M Shiotsu, K Fushiki, J Baba, Tanzo Nitta
    Abstract:

    A new FCL system which consists of a L-Type SCFCL in parallel with a resistor and a ZnO device is proposed. The proposed system limits the fault current Inductively and also consumes excessive energy like R-Type ones. A model system was made and studied experimentally. The ZnO device is off-state in stand-by mode. When a fault occurs, the SCFCL turns into current limiting mode and has high impedance. The voltage across the SCFCL exceeds a threshold voltage of the ZnO device. During one cycle of the voltage, the ZnO device is on-state around the peak of the voltage, and the current flows through both the SCFCL and the resistor. A certain amount of excessive energy is dissipated in the resistor. The ZnO device is off-state around the peak of the current which is suppressed only by the L-Type SCFCL. Finally the proposed FCL system switches L-Type and L+R-Type in a cycle. Relations among the threshold voltage, the current limiting impedance and the resistance of the resistor were discussed. It was confirmed the proposed FCL system represents desirable current limiting characteristics

  • EXPERIMENTAL ANALYSIS AND CIRCUIT MODEL OF AN Inductive Type HIGH TEMPERATURE SUPERCONDUCTING FAULT CURRENT LIMITER
    International Journal of Modern Physics B, 2000
    Co-Authors: Antonio Morandi, Francesco Negrini, Tanzo Nitta, S. Oshima, Pier Luigi Ribani
    Abstract:

    A basic Inductive Type high temperature superconducting fault current limiter protoType has been built and tested at the Department of Electrical Engineering of the University of Tokyo. The experimental static V-I characteristics shows a change in the impedance of the device when its limiting current is reached. A circuit model of the fault current limiter is developed by means of a non linear inductor with memory. A good agreement is obtained between numerical and experimental V-I characteristics. Dynamic characteristics are numerically studied by means of the circuit model.