• 한국정보처리학회논문지
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• 제5권10호
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• pp.2615-2626
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• 1998

본 논문에서는 방향성 그래프인 Rotator 그래프와 Faber-Moore 그래프를 병합한 새로운 상호 연결망으로 RFM그래프를 제안하고, RFM그래프에 대하여 고장 허용도, 라우팅 알고리즘, 노드 중복 없는 싸이클, 방송 알고리즘을 분석한다. 또한 2차원 토러스, Strar 그래프, Bubblesort 그래프를 RFM 그래프에 연장비율(dilation) 2와 확장비율(expansion)1에 임베딩하는 방법을 제시한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.824-826
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• 2000

네트워크 데이터 traffic 특성은 네트워크의 성능분석과 설계에 중요한 요소이고 적절한 traffic modeling을 통해 load balancing, fault tolerance 및 전송속도 개선 둥 시스템 성능을 높이는데 보다 유용한 자료를 제공할 수 있어 지금까지 많은 연구가 진행되어 왔다. 그러나 네트워크 traffic은 네트워크의 규모와 서비스 종류 등 여러 가지 이유로 어느 한가지 모델로 규정짓는 것이 용이하지 않다. 또한 근래 인터넷 사용자의 수가 급속히 증가함에 따라 네트워크 traffic의 대부분이 world wide web에 기인하는 특성을 볼 수 있다. 본 논문에서는 웹서버 운용환경 하에서 적용될 수 있는 traffic model들에 대해 고찰하고 실제 네트워크에서의 패킷 모니터 링을 통한 traffic 분석 예를 보인다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2008년도 한국컴퓨터종합학술대회논문집 Vol.35 No.1 (D)
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• pp.81-85
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• 2008

침해감내는 침입을 악의적인 의도를 가지고 Fault를 유발시키는 행위로 보고 이러한 공격이 성공한 경우에도 적절한 수준의 가용성, 무결성, 기밀성을 유지하면서 시스템의 중요 서비스를 일정한 시간 동안 지속적으로 제공하여 생존 성을 보장하는 것을 목표로 하고 있는 연구 분야이다. 본 논문에서는 기존의 네트워크 정보 시스템에 대한 재 구성 및 수정을 최소화하면서 주요 서비스에 대한 생존 성을 강화 시킬수 있는 침해감내 프락시 서버 프레임워크를 제시하고 있다.

• 동굴
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• 제80호
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• pp.11-19
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• 2007

Most studies in the past in testing and benchmarking on Intrusion Detection System (IDS) were conducted as comparisons, rather than evaluation, on different IDSs. This paper presents the evaluation of the performance of one of the open source IDS, snort, in an inexpensive high availability system configuration. Redundancy and fault tolerance technology are used in deploying such IDS, because of the possible attacks that can make snort exhaust resources, degrade in performance and even crash. Several test data are used in such environment and yielded different results. CPU speed, Disk usage, memory utilization and other resources of the IDS host are also monitored. Test results with the proposed system configuration environment shows much better system availability and reliability, especially on security systems.

• 한국군사과학기술학회지
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• 제1권1호
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• pp.82-91
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• 1998

본 논문에서는 실제 물리적인 여유 센서를 가지지 않는 수중운동체의 센서 고장진단 및 극복에 관한 문제를 신경회로망을 사용하여 접근하였다. 이를 위하여 설계된 신경회로망은 센서 고장 진단을 위한 신경회로망과 고장 확인 및 대체정보 생성을 위한 신경회로망으로 구성하였으며, 온라인(on-line) 학습을 위하여 확장 역전(Extended Back-Propagation) 학습법을 사용하였다. 시뮬레이션은 수중운동체의 방위변화율 센서에 대하여 수행하였으며, 제안된 기법이 센서에 대한 고장진단기와 센서 추정기로 사용할 수 있음을 확인하였다.

• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.376-380
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• 2008

This paper deals with a performance analysis of real-time control systems, which engages DMR(dual modular redundancy) to detect transient errors and checkpointing technique to tolerate transient errors. Transient errors are caused by transient faults and the most significant type of errors in reliable computer systems. Transient faults are assumed to occur according to a Poisson process and to be detected by a dual modular redundant structure. In addition, an equidistant checkpointing strategy is considered. The probability of the successful task completion in a real-time control system where periodic checkpointing operations are performed during the execution of a real-time control task is derived. Numerical examples show how checkpoiniting scheme influences the probability of task completion. In addition, the result of the analysis is compared with the simulation result.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1339-1342
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• 2002

It is difficult to design system software to meet a better separation of concerns, which can provide a number of benefits such as adaptability, extensibility, and modularity in the design and implementation. During design, some aspectual properties, such as synchronization, scheduling, performance and fault tolerance, crosscut the basic functionalities of the system software. By separating functional components from the different aspectual components of the system software in the design, we can provide a better generic design model of system software. Aspect-Oriented Programming is a methodology that aims at separating components and aspects from the early stages of the software life cycle, and using techniques to combining them together at the implementation phase. In this paper we discuss an aspect-oriented framework that can simplify system software design and implementation by expressing it at a higher level of abstraction. Our work concentrates on how to achieve a higher separation of aspectual components, functional components, and layers from each other. Our goal is to achieve a better design model for implementing system software in terms of modularity, reusability and adaptability.

• ETRI Journal
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• 제39권2호
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• pp.202-212
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• 2017

With the advent of the Internet-of-Things paradigm, the amount of data production has grown exponentially and the user demand for responsive consumption of data has increased significantly. Herein, we present DART, a fast and lightweight stream processing framework for the IoT environment. Because the DART framework targets a geospatially distributed environment of heterogeneous devices, the framework provides (1) an end-user tool for device registration and application authoring, (2) automatic worker node monitoring and task allocations, and (3) runtime management of user applications with fault tolerance. To maximize performance, the DART framework adopts an actor model in which applications are segmented into microtasks and assigned to an actor following a single responsibility. To prove the feasibility of the proposed framework, we implemented the DART system. We also conducted experiments to show that the system can significantly reduce computing burdens and alleviate network load by utilizing the idle resources of intermediate edge devices.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1068-1074
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• 2010

In high speed railway, event recorder is essential system for analyzing the cause of train accident. It stores train operation sent by train control system in safe memory unit. Crash protected memory, the safe memory unit for event recorder, keeps the stored contents from severe environment. For crash protected memory, we have designed the architecture of concrete enclosure and controller board. Proposed system provides large volume of memory capacity and fault tolerance architecture. For checking the characteristics of proposed crash protected memory specification, the simulation is executed. Simulation results shows the designed crash protected memory meets all requirements.

• 제어로봇시스템학회논문지
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• 제4권6호
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• pp.765-771
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• 1998

An artificial neural network(NN) technique is developed for hardware redundant sensor validation. Since the measurement space is a continuous space with many operating regions, it is difficult to train a NN to correctly detect failure in an accurate measurement system. A conventional backpropagation NN is modified to include an additional preprocessing layer that extracts classification features from scalar measurements. This feature extraction means transform the measurement space to parity space. The NN is independent of the state variable being measured, the instrument range, and the signal tolerance. This NN resembles the parity space approach to signal validation, except that analytical parity equations are unneeded and the NN pattern recognition capability is utilized for decision making.