• Title, Summary, Keyword: dual modules

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Redundancy Management of Brake-by-wire System using a Message Scheduling (메시지 스케줄링을 이용한 Brake-by-wire 시스템의 Redundancy Management)

  • Yune, J. W.;Kim, K. W.;Kim, T. Y.;Kim, J. G.;Lee, S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.717-720
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    • 2000
  • Event-driven communication protocols such as CAN(Controller Area Network) have inherent packet delays due to the contention process for the use of network medium. These delays are stochastic in nature because most packets arrive at random time instants. The stochastic property of the delay adversely influences the control system's performance in terms of stability, responsiveness and steady-state error. Another problem for safety-critical application such as brake-by-wire systems is the reliability of the communication modules that can fail abruptly. This paper deals with two methods to overcome the above problems : (i) scheduling method that can maintain packet delays under some acceptable level, and (ii) redundancy management of communication modules that prescribes dual-redundancy modules' behavior when one of them fails.

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A Simple Capacitor Voltage Balancing Method with a Fundamental Sorting Frequency for Modular Multilevel Converters

  • Peng, Hao;Wang, Ying;Wang, Kun;Deng, Yan;He, Xiangning;Zhao, Rongxiang
    • Journal of Power Electronics
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    • v.14 no.6
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    • pp.1109-1118
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    • 2014
  • A Fundamental Frequency Sorting Algorithm (FFSA) is proposed in this paper to balance the voltages of floating dc capacitors for Modular Multilevel Converters (MMCs). The main idea is to change the sequences of the CPS-PWM carriers according to the capacitor voltage increments during the previous fundamental period. Excessive frequent sorting is avoided and many calculating resources are saved for the controller. As a result, more sub-modules can be dealt with. Furthermore, it does not need to measure the arm currents. Therefore, the communication between the controllers can be simplified and the number of current sensors can be reduced. Moreover, the proposed balancing method guarantees that all of the switching frequencies of the sub-modules are equal to each other. This is quite beneficial for the thermal design of the sub-modules and the lifetime of the power switches. Simulation and experimental results acquired from a 9-level prototype verify the viability of the proposed balancing method.

Reconstruction of In-beam PET for Carbon therapy with prior-knowledge of carbon beam-track

  • Kim, Kwangdon;Bae, Seungbin;Lee, Kisung;Chung, Yonghyun;An, Sujung;Joung, Jinhun
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.6
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    • pp.384-390
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    • 2015
  • There are two main artifacts in reconstructed images from in-beam positron emission tomography (PET). Unlike generic PET, in-beam PET uses the annihilation photons that occur during heavy ion therapy. Therefore, the geometry of in-beam PET is not a full ring, but a partial ring that has one or two openings around the rings in order for the hadrons to arrive at the tumor without prevention of detector blocks. This causes truncation in the projection data due to an absence of detector modules in the openings. The other is a ring artifact caused by the gaps between detector modules also found in generic PET. To sum up, in-beam PET has two kinds of gap: openings for hadrons, and gaps between the modules. We acquired three types of simulation results from a PET system: full-ring, C-ring and dual head. In this study, we aim to compensate for the artifacts that come from the two types of gap. In the case of truncation, we propose a method that uses prior knowledge of the location where annihilations occur, and we applied the discrete-cosine transform (DCT) gap-filling method proposed by Tuna et al. for inter-detector gap.

Performance Characteristics of a Chirp Data Acquisition and Processing System for the Time-frequency Analysis of Broadband Acoustic Scattering Signals from Fish Schools (어군에 의한 광대역 음향산란신호의 시간-주파수 분석을 위한 chirp 데이터 수록 및 처리 시스템의 성능특성)

  • Lee, Dae-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.2
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    • pp.178-186
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    • 2018
  • A chirp-echo data acquisition and processing system was developed for use as a simplified, PC-based chirp echo-sounder with some data processing software modules. The design of the software and hardware system was implemented via a field-programmable gate array (FPGA). Digital signal processing algorithms for driving a single-channel chirp transmitter and dual-channel receivers with independent TVG (time varied gain) amplifier modules were incorporated into the FPGA for better real-time performance. The chirp-echo data acquisition and processing system consisted of a notebook PC, an FPGA board, and chirp sonar transmitter and receiver modules, which were constructed using three chirp transducers operating over a frequency range of 35-210 kHz. The functionality of this PC-based chirp echo-sounder was tested in various field experiments. The results of these experiments showed that the developed PC-based chirp echo-sounder could be used in the acquisition, processing and analysis of broadband acoustic echoes related to fish species identification.

Kinematic Analysis of Fault-Tolerant 3 Degree-of-Feedom Spherical Modules (고장에 강인한 구형 3자유도 모듈에 관한 기구학적 해석)

  • 이병주;김희국
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.11
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    • pp.2846-2859
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    • 1994
  • This work deals with kinematic analysis of fault-tolerant 3 degree-of-freedom spherical modules which have force redundancies in its parallel structure. The performance of a redundantly actuated four-legged module with no actuator failure, a single actuator failure, partial and half failure of dual actuator are compared to that of a three-legged module, in terms of maximum force transmission ratio, isotropic characteristics, and fault-tolerant capability. Additionally, a system with an excess number of small floating actuators is considered, and the contribution of these small actuators to the force transmission and fault-tolerant capability is evaluated. This study illustrates that the redundant actuation mode allows significant saving of input actuation effort, and also delivers a fault tolerance.

Solar Module Glass Coating Technology for Improvement of the transmittance (태양광 모듈용 Glass의 투과율 향상을 위한 Coating 기술 개발)

  • Jung, Jin-Su;Jung, In-Sung;Lee, Bum-Su;Jang, Jin-Ho;Ban, Seong-Tae;Kim, Jong-Il
    • 한국신재생에너지학회:학술대회논문집
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    • pp.120.1-120.1
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    • 2011
  • Increase the efficiency of PV modules for high-efficiency solar cells, light transmittance improvements, increasing the module, and much more research and development. Dual we light transmittance for photovoltaic module materials in low iron tempered glass in SiO2 using liquid AR implementation, light transmittance to solar modules to increase the efficiency of research.

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Three-Phase High-Power-Density Bidirectional DC-DC Converter (3상 변압기를 이용한 고밀도 양방향 전력변환기)

  • Le, Tuan-Vu;Choi, Woo-Seok;Kim, Sun-Pil;Park, Sung-Jun
    • Proceedings of the KIPE Conference
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    • pp.45-46
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    • 2014
  • This paper presents a three-phase high-power-density bidirectional DC-DC converter. The converter employs dual three-phase active bridges and a three-phase transformer. The presented converter is controlled by two symmetric PWM modules and phase between two symmetric PWM modules to control the power flow. Simulation is included to verify the presented converter.

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A Two-Step Scheduling Algorithm to Support Dual Bandwidth Allocation Policies in an Ethernet Passive Optical Network

  • Lee, Ho-Sook;Yoo, Tae-Whan;Moon, Ji-Hyun;Lee, Hyeong-Ho
    • ETRI Journal
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    • v.26 no.2
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    • pp.185-188
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    • 2004
  • In this paper, we design a two-step scheduling algorithm to support multiple bandwidth allocation policies for upstream channel access in an Ethernet passive optical network. The proposed scheduling algorithm allows us a simultaneous approach for multiple access control policies: static bandwidth allocation for guaranteed bandwidth service and dynamic bandwidth allocation for on-demand, dynamic traffic services. In order to reduce the scheduling complexity, we separate the process of the transmission start- time decision from the process of grant generation. This technique does not require the timing information of other bandwidth allocation modules, so respective modules are free from a heavy amount of timing information or complex processing.

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Pipelined Scheduling of Functional HW/SW Modules for Platform-Based SoC Design

  • Kim, Won-Jong;Chang, June-Young;Cho, Han-Jin
    • ETRI Journal
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    • v.27 no.5
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    • pp.533-538
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    • 2005
  • We developed a pipelined scheduling technique of functional hardware and software modules for platform-based system-on-a-chip (SoC) designs. It is based on a modified list scheduling algorithm. We used the pipelined scheduling technique for a performance analysis of an MPEG4 video encoder application. Then, we applied it for architecture exploration to achieve a better performance. In our experiments, the modified SoC platform with 6 pipelines for the 32-bit dual layer architecture shows a 118% improvement in performance compared to the given basic SoC platform with 4 pipelines for the 16-bit single-layer architecture.

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MONOIDAL FUNCTORS AND EXACT SEQUENCES OF GROUPS FOR HOPF QUASIGROUPS

  • Alvarez, Jose N. Alonso;Vilaboa, Jose M. Fernandez;Rodriguez, Ramon Gonzalez
    • Journal of the Korean Mathematical Society
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    • v.58 no.2
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    • pp.351-381
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    • 2021
  • In this paper we introduce the notion of strong Galois H-progenerator object for a finite cocommutative Hopf quasigroup H in a symmetric monoidal category C. We prove that the set of isomorphism classes of strong Galois H-progenerator objects is a subgroup of the group of strong Galois H-objects introduced in [3]. Moreover, we show that strong Galois H-progenerator objects are preserved by strong symmetric monoidal functors and, as a consequence, we obtain an exact sequence involving the associated Galois groups. Finally, to the previous functors, if H is finite, we find exact sequences of Picard groups related with invertible left H-(quasi)modules and an isomorphism Pic(HMod) ≅ Pic(C)⊕G(H∗) where Pic(HMod) is the Picard group of the category of left H-modules, Pic(C) the Picard group of C, and G(H∗) the group of group-like morphisms of the dual of H.