• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권3호
• /
• pp.735-748
• /
• 2014

The fault-tolerance routing problem is one of the most important issues in the application of the Internet of Things, and has been attracting growing research interests. In order to maintain the communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which alternate paths are created once the previous routing is broken. Then, we propose an improved efficient and intelligent fault-tolerance algorithm (IEIFTA) to provide the fast routing recovery and reconstruct the network topology for path failure in the Internet of Things. In the IEIFTA, mutation direction of the particle is determined by multi-swarm evolution equation, and its diversity is improved by the immune mechanism, which can improve the ability of global search and improve the converging rate of the algorithm. The simulation results indicate that the IEIFTA-based fault-tolerance algorithm outperforms the EARQ algorithm and the SPSOA algorithm due to its ability of fast routing recovery mechanism and prolonging the lifetime of the Internet of Things.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권4호
• /
• pp.1178-1191
• /
• 2014

The fault-tolerance routing problem is one of the most important issues in the application of the Internet of Things, and has been attracting growing research interests. In order to maintain the communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which alternate paths are created once the previous routing is broken. Then, we propose an improved efficient and intelligent fault-tolerance algorithm (IEIFTA) to provide the fast routing recovery and reconstruct the network topology for path failure in the Internet of Things. In the IEIFTA, mutation direction of the particle is determined by multi-swarm evolution equation, and its diversity is improved by the immune mechanism, which can improve the ability of global search and improve the converging rate of the algorithm. The simulation results indicate that the IEIFTA-based fault-tolerance algorithm outperforms the EARQ algorithm and the SPSOA algorithm due to its ability of fast routing recovery mechanism and prolonging the lifetime of the Internet of Things.

• 정보학연구
• /
• 제9권4호
• /
• pp.25-34
• /
• 2006

As most application programs are more sophisticated and are adopted the distributed object technology, the object based distributed design became widespread since it supports portability and reusability. The approaches for fault-tolerant distributed computing are categorized into the active replica mechanism for mission-critical application programs and the passive replica mechanism for non mission-critical ones, when fault-tolerant facilities are added on. Our paper introduces the pros and drawbacks of several approaches for the add-on low-overhead fault-tolerant services by the surveys and shows the results of experiments for bench-mark models in order to demonstrate their performance.

• Geomechanics and Engineering
• /
• 제23권2호
• /
• pp.127-137
• /
• 2020

To study the reverse fault formation process and the stress evolution feature, a simulation test system of reverse fault formation is developed based on the analysis of reverse fault formation mechanism. The system mainly consists of simulation laboratory module, operation console and horizontal loading control system, and data monitoring system. It can represent the fault formation process, induce fault crack initiation and simulate faults of different throws. Simulation tests on reverse fault formation process are conducted by using the simulation test system: horizontal loading is added to one side of the model. the bottom rock layer cracks under the effect of the induction device. The crack dip angle is about 29°. A reverse fault is formed with the expansion of the crack dip angle towards the upper right along the fracture surface and the slippage of the hanging wall over the foot wall. Its formation process unfolds five stages: compressive deformation of rock, local crack initiation, reverse fault penetration, slippage of the hanging wall over the foot wall and compaction of fault plane. There is residual structural stress inside rock after fault formation. The study methods and results have guiding and referential significance for further study on reverse fault formation mechanism and rock stress evolution.

• 한국군사과학기술학회지
• /
• 제10권2호
• /
• pp.61-68
• /
• 2007

In a naval combat system, the information processing node is a key functional equipment and performs major combat management functions including control sensor and weapon systems. Therefore, a failure of one of the node causes fatal impacts on overall combat system capability. There were many methodologies to enhance system availability by reducing the impact of system failure like a fault tolerant method. This paper proposes a fault tolerant mechanism for information processing node using a replication algorithm with hardware duplication. The mechanism is designed as a generic algorithm and does not require any special hardware. Therefore all applications in combat system can use this functionality. The asynchronous characteristic of this mechanism provides the capability to adapt this algorithm to the module which has low performance hardware.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.207-210
• /
• 2001

Electrical equipment for railway is always experiencing wear and degradation by mechanical, electrical and environmental stress in service and the fault or the accident of high voltage main circuit directly causes operation interruption. Particularly propulsion drive of high speed switching inverter takes the form of specific degradation mechanism such as fast rising transient surge, reflective overvoltage and harmonic stress, and it is known that it threatens the long life and the reliability of electrical equipment. In this paper, statistics of fault and accident on main electrical equipment for railway are presented and also insulation degradation mechanism, which governs end life of electrical device, is analyzed. Finally the method of fault respondence and reliability improvement on the main electrical equipments will be reviewed in order to prevent operation interruption.

• Journal of Electrical Engineering and Technology
• /
• 제8권4호
• /
• pp.813-823
• /
• 2013

On-line monitoring system is important for high voltage vacuum circuit breakers (HVCBs) in operation condition assessment and fault diagnosis. A distributed multilayer system with client/server architecture is developed on rated voltage 10kV HVCB with spring operating mechanism. It can collect data when HVCB switches, calculate the necessary parameters, show the operation conditions and provide abundant information for fault diagnosis. Ensemble empirical mode decomposition (EEMD) is used to detect the singular point which is regarded as the contact moment. This method has been applied to on-line monitoring system successfully and its satisfactory effect has been proved through experiments. SVM and FCM are both effective methods for fault diagnosis. A combinative algorithm is designed to judge the faults of HVCB's operating mechanism. The system's precision and stability are confirmed by field tests.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
• /
• pp.559-562
• /
• 2003

In this paper, we introduce a new method detecting thyristor faults of the power converter module in Control Rod Control System. When we control the currents in each coil of Control Rod Drive Mechanism by using the current control method, the current value can follow the current reference despite the faults like the missing phase or the diode acting. Comparing the fault current values with the normal current values, the bad transient characteristics of the abnormal current can make the operations of control rods incorrect. In this case, the information from the current trends cannot be enough to detect the fault occurrence in thyristors. Instead of the coil currents, the state of thyristors can be watched by measuring the coil voltages. In the existing system of Westinghouse type, the ripple detector takes charge of this task. But this detector has some shortcomings in the point of time for fault detection, we come to devise a new fault detection method solving the problems which belong to the ripple detector.

• 전자공학회논문지B
• /
• 제32B권12호
• /
• pp.1687-1696
• /
• 1995

An integrated fault diagnosis system for heterogeneous manufacturing environments is developed. This system has a contrast with existing diagnosis systems in the respect that they are mostly for diagnosing faults on individual machines. In addition to the usual (e.g., audio, electrical) diagnostic signals, the characteristics of products from the machines are considered as the unifying diagnostic parameters among heterogeneous machines in the diagnosis. The system is composed of a knowledge representation scheme and a diagnostic query processing mechanism. Its knowledge representation scheme allows the diagnostic knowledges from heterogeneous unit diagnostic systems to be uniformly expressed in terms of the causal relations among relevant data items. It is flexible in the sense that causes for one relation can be effects for another may be reflected on our knowledge representation scheme. The diagnosis mechanism is based on a probabilistic inferencing method. This probablistic diagnosis mechanism provides more general diagnosis than existing ones in that it accommodates multiple causes and takes complication among causes into account. These scheme and mechanism are applied to a typical example to demonstrate how our system works.

• 정보과학회 논문지
• /
• 제42권11호
• /
• pp.1339-1348
• /
• 2015

서비스 지향 시스템 환경에서는 하나의 독립된 시스템이 다른 시스템에서 제공하는 서비스를 사용함으로써 시스템의 목표를 달성한다. 이러한 시스템 환경에서는 사용중인 서비스의 품질 저하가 실시간으로 시스템 장애를 유발할 수 있다. 기존 자가 적응 방법들은 서비스의 품질 저하 발생 후 대처하는 fault tolerance 방식을 따르고 있기 때문에 서비스 품질 저하로 인한 피해 발생을 예방하지 못한다. 따라서, 자가 적응 시스템의 신뢰도를 보존하기 위해서는 사용 중인 서비스를 fault tolerance 방식의 품질 기반 적응이 아닌 서비스 안정성 케이스를 기반으로 자가 적응해야 한다. 본 논문에서는 기존의 보증 속성 표현 방법인 Goal Structuring Notation 모델링을 활용하여 서비스 안정성 케이스를 표현 및 분석하기 위한 방법과, 서비스 안정성 케이스 분석 결과에 따른 적응 조치 방법, 서비스 생명주기에 따른 서비스 안정성 케이스 기반 자가 적응 메커니즘 적용 방법, 서비스 안정성 케이스 기반 자가 적응을 위한 프레임워크 아키텍처를 제안한다.