• Title/Summary/Keyword: Fault-tolerant control method

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A Novel Implementation of Fault-Tolerant Ethernet NIC (Network Interface Card) Using Single MAC (단일 MAC을 이용한 자동 고장 극복 Ethernet NIC (Network Interface Card) 장치 구현)

  • Kim, Se-Mog;Pham, Hoang-Anh;Lee, Dong-Ho;Rhee, Jong Myung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.11
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    • pp.1162-1169
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    • 2012
  • One of the important operational requirements for mission critical Ethernet networked system is having the fault tolerant capability. Such capability can be obtained by equipping multiport Network Interface Card (NIC) in each node in the system. Conventional NIC uses two or more Media Access Controls (MACs) and a co-processor for the MAC switching whenever an active port fails. Since firmware is needed for the co-processor, longer fail-over switching and degraded throughput can be generally expected. Furthermore the system upgrading requiring the firmware revision in each tactical node demands high cost. In this paper we propose a novel single MAC based NIC that does not use a co-processor, but just use general discrete building blocks such as MAC chip and switching chip, which results in better performances than conventional method. Experimental results validate our scheme.

Hybrid Excitation Control of SRM Drive for Reduction of Vibration and Acoustic Noise

  • Lee, Dong-Hee;Lee, Sang-Hun;Ahn, Jin-Woo;Park, Sung-Jun
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.11B no.4
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    • pp.151-155
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    • 2001
  • The simple motor construction and low cost, fault tolerant power electronic drive has made the switched reluctance drive a strong contender for many applications. But the switched reluctance drive does exhibit higher levels of vibration and acoustic noise than that of most competing drives. The main source of vibration in the switched reluctance drive is generated by rapid change of radial magnetic force when phase current is extinguished during commutation action. In this paper, a hybrid excitation method is proposed to reduce vibration and acoustic noise of the switched reluctance drive. The hybrid excitation has 2-phase excitation by long dwell angle as well as conventional 1-phase excitation. The vibration and acoustic noise are reduced because the scheme reduces abrupt change of excitation level by distributed and balanced excitation.

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Study of Fault Tolerant and Circulating Current Control Method for Three-Phase 2-Parallel PWM Converter Systems (3상 2-병렬 PWM 컨버터의 고장허용 제어 및 순환전류 저감에 관한 연구)

  • Park, Jin-Woo;Jung, Jun-Hyung;Kim, Jang-Mok
    • Proceedings of the KIPE Conference
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    • 2016.07a
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    • pp.58-59
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    • 2016
  • 본 논문에서는 3상 2-병렬 PWM 컨버터의 단일 스위치 개방 고장 시 고장 허용 제어 방법과 그에 따라 발생하는 순환전류를 저감하는 연구를 진행 하였다. PWM 컨버터의 스위치 개방 고장은 DC단 전압 맥동과 계통 측 전류의 왜곡을 유발하며 이는 고장허용제어를 통해 개선 가능하다. 하지만 고장허용제어를 병렬형 PWM 컨버터에 적용하는 경우에는 컨버터의 비동기적인 스위칭으로 발생된 순환 전류 때문에 기존의 방법을 적용 할 수 없다. 따라서 본 논문에서는 2-병렬 PWM 컨버터의 스위치 개방 고장 허용제어에 따른 순환전류 저감에 대한 연구를 진행하였다. 연구한 내용은 시뮬레이션을 통해 확인하였다.

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Design of Fault Tolerant Controller for Electromagnetic Supension System (자기부상시스템에서의 내고장성 제어기 설계)

  • Seong, Ho-Gyeong;Jo, Heung-Jae;Jeong, Seok-Yeong;Seong, So-Yeong
    • 연구논문집
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    • s.30
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    • pp.79-92
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    • 2000
  • Chopper and sensors failures resulting from electric shock and mechanical vibration generated by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension systems. Thus, this paper proposes a reliable output feedback control scheme for the electromagnetic suspension systems in the present of chopper, gap sensor and acceleration sensor failures. The designed controller is an extended version of a novel design technique which has the design method of the output feedback controller using dynamic compensator. The benefits of this scheme are demonstrated through the simulation and experimental results for proposed controller against chopper, gap sensor and acceleration sensor failures of electromagnetic suspension system.

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Quorum Consensus Method based on Ghost using Simplified Metadata (단순화된 메타데이타를 이용한 고스트 기반 정족수 동의 기법의 개선)

  • Cho, Song-Yean;Kim, Tai-Yun
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.1
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    • pp.34-43
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    • 2000
  • Replicated data that is used for fault tolerant distributed system requires replica control protocol to maintain data consistency. The one of replica control protocols is quorum consensus method which accesses replicated data by getting majority approval. If site failure or communication link failure occurs and any one can't get quorum consensus, it degrades the availability of data managed by quorum consensus protocol. So it needs for ghost to replace the failed site. Because ghost is not full replica but process which has state information using meta data, it is important to simplify meta data. In order to maintain availability and simplify meta data, we propose a method to use cohort set as ghost's meta data. The proposed method makes it possible to organize meta data in 2N+logN bits and to have higher availability than quorum consensus only with cohort set and dynamic linear voting protocol. Using Markov model we calculate proposed method's availability to analyze availability and compare it with existing protocols.

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Redundancy operation method for a distributed public address system (분산형 전관방송 시스템의 이중화 운영 방법)

  • Ryu, Taeha;Kim, Seungcheon
    • Journal of the Korea Convergence Society
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    • v.11 no.8
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    • pp.47-53
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    • 2020
  • In the case of a failure due to equipment deterioration in the public address system or a worker's mistake during construction, broadcasting becomes impossible. In this situation, we have designed a more advanced management broadcast system that can broadcast. The broadcasting service is operated using main broadcasting device, and local broadcasting device operates separately only in the local area. If the main broadcasting device becomes inoperable, the procedure for transferring the control activates the device with the local broadcasting devices based on data backed up by the main controller. This paper proposes an improved method of the conventional emergency broadcasting device duplication method. The existing method could not use the standby equipment in the normal state, but in the proposed method, the standby equipment can be used as local broadcasting equipment in usually. This method enables stable system operation while minimizing resource waste due to redundant configuration of expensive devices.

Construction and Application of Intelligent Decision Support System through Defense Ontology - Application example of Air Force Logistics Situation Management System (국방 온톨로지를 통한 지능형 의사결정지원시스템 구축 및 활용 - 공군 군수상황관리체계 적용 사례)

  • Jo, Wongi;Kim, Hak-Jin
    • Journal of Intelligence and Information Systems
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    • v.25 no.2
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    • pp.77-97
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    • 2019
  • The large amount of data that emerges from the initial connection environment of the Fourth Industrial Revolution is a major factor that distinguishes the Fourth Industrial Revolution from the existing production environment. This environment has two-sided features that allow it to produce data while using it. And the data produced so produces another value. Due to the massive scale of data, future information systems need to process more data in terms of quantities than existing information systems. In addition, in terms of quality, only a large amount of data, Ability is required. In a small-scale information system, it is possible for a person to accurately understand the system and obtain the necessary information, but in a variety of complex systems where it is difficult to understand the system accurately, it becomes increasingly difficult to acquire the desired information. In other words, more accurate processing of large amounts of data has become a basic condition for future information systems. This problem related to the efficient performance of the information system can be solved by building a semantic web which enables various information processing by expressing the collected data as an ontology that can be understood by not only people but also computers. For example, as in most other organizations, IT has been introduced in the military, and most of the work has been done through information systems. Currently, most of the work is done through information systems. As existing systems contain increasingly large amounts of data, efforts are needed to make the system easier to use through its data utilization. An ontology-based system has a large data semantic network through connection with other systems, and has a wide range of databases that can be utilized, and has the advantage of searching more precisely and quickly through relationships between predefined concepts. In this paper, we propose a defense ontology as a method for effective data management and decision support. In order to judge the applicability and effectiveness of the actual system, we reconstructed the existing air force munitions situation management system as an ontology based system. It is a system constructed to strengthen management and control of logistics situation of commanders and practitioners by providing real - time information on maintenance and distribution situation as it becomes difficult to use complicated logistics information system with large amount of data. Although it is a method to take pre-specified necessary information from the existing logistics system and display it as a web page, it is also difficult to confirm this system except for a few specified items in advance, and it is also time-consuming to extend the additional function if necessary And it is a system composed of category type without search function. Therefore, it has a disadvantage that it can be easily utilized only when the system is well known as in the existing system. The ontology-based logistics situation management system is designed to provide the intuitive visualization of the complex information of the existing logistics information system through the ontology. In order to construct the logistics situation management system through the ontology, And the useful functions such as performance - based logistics support contract management and component dictionary are further identified and included in the ontology. In order to confirm whether the constructed ontology can be used for decision support, it is necessary to implement a meaningful analysis function such as calculation of the utilization rate of the aircraft, inquiry about performance-based military contract. Especially, in contrast to building ontology database in ontology study in the past, in this study, time series data which change value according to time such as the state of aircraft by date are constructed by ontology, and through the constructed ontology, It is confirmed that it is possible to calculate the utilization rate based on various criteria as well as the computable utilization rate. In addition, the data related to performance-based logistics contracts introduced as a new maintenance method of aircraft and other munitions can be inquired into various contents, and it is easy to calculate performance indexes used in performance-based logistics contract through reasoning and functions. Of course, we propose a new performance index that complements the limitations of the currently applied performance indicators, and calculate it through the ontology, confirming the possibility of using the constructed ontology. Finally, it is possible to calculate the failure rate or reliability of each component, including MTBF data of the selected fault-tolerant item based on the actual part consumption performance. The reliability of the mission and the reliability of the system are calculated. In order to confirm the usability of the constructed ontology-based logistics situation management system, the proposed system through the Technology Acceptance Model (TAM), which is a representative model for measuring the acceptability of the technology, is more useful and convenient than the existing system.