• International Journal of Advanced Culture Technology
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• 제8권3호
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• pp.292-299
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• 2020

This paper presents an evaluation criteria of an information system availability for guaranteeing availability (service target level) from the perspective of the SLA contract and its technical point of view. In order to verify the effectiveness for information system failure and availability guarantee measures, three cases were examined. In summary, the failure time was reduced by 32% ~ 62% after applying the availability guarantee measure, verifying the excellence in the evaluation of an information system availability.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.77-82
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• 2006

Integrity plays a fundamental role in the feasibility of 'liability critical' applications. Road charging, e.g. road tolling in urban zones or on highways, represents a series of liability critical applications where a guarantee in integrity could be a true enabler: being the mechanism that prevents the incorrect charging of users and enabling the advancement of these applications using GNSS such as Galileo and EGNOS that provide integrity mechanisms. However, the integrity of the end user position is not guaranteed by the EGNOS and Galileo integrity services alone as provided. Algorithms have been developed to supply a guarantee on the performance attainable at the user level through the provision of a horizontal protection level that responds to local user conditions such as multipath or interference. In addition, an application has been developed that implements road charging mechanisms based on the availability of user-level integrity. Results obtained show that the user-level integrity algorithms provided the required level of integrity guarantee and granularity of the horizontal protection levels necessary for executing urban and rural (highway) road charging. In addition, the road charging application developed shows that the current application domain requirements can be met through the provision of guaranteed integrity and that further reductions in the horizontal protection levels along with increased signal availability will enable future road charging modalities.

• 정보보호학회논문지
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• 제23권2호
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• pp.279-286
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• 2013

최근 전력 수요의 급증으로 인한 전력난은 효율적 전력 사용을 위한 스마트그리드 기술의 중요성을 부각시키고 있다. 스마트그리드 네트워크의 필수구성요소인 스마트미터기의 가용성 취약점에 대한 실험적 내용이 보고되고 있다. 따라서 안전한 스마트그리드의 실현가능성을 위한 가용성 보호 메커니즘 고안이 필수불가결하다. 본 논문에서는 스마트그리드 구조 및 트래픽패턴의 특징 분석을 통해 스마트미터기에 대한 가용성 침해 공격을 탐지하고, 이상 트래픽을 발생하는 공격노드를 검출할 수 있는 메커니즘을 제안한다. 제안하는 탐지 메커니즘은 공격 탐지를 수행하는 시스템의 탐지 부하를 줄이고 적은 샘플 수에도 높은 탐지율을 제공하기 위해 근사엔트로피 기법을 사용한다. 또한 공격노드가 공격트래픽에서 변경할 수 없는 물리정보(CIR 또는 RSSI 등)를 이용하여 공격 탐지 및 공격노드 검출을 수행한다. 마지막으로 본 논문 제안 기법에 대한 시뮬레이션 결과, 탐지 성능과 실현가능성을 보인다.

• International Journal of Contents
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• 제6권3호
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• pp.15-18
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• 2010

Grid system is based on the Grid Security Infrastructure (GSI). GSI uses user's proxy to guarantee availability among multi-trust domains. Since grid system has been developed focusing on availability, GSI provides authentication and authorization performed by systems, but there are lacks of privacy consideration. For this reason, some researchers decide to use their own cluster system and do not want to use public grid systems. In this paper, we introduce a new privacy enhanced security mechanism for grid systems. With this mechanism, user can participate in resource allocation and authorization to user's contents more actively. This mechanism does not need to change previous middleware and minimize the computational overheads.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2004년도 추계종합학술대회 논문 초록집
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• pp.167-167
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• 2004

• 디지털산업정보학회논문지
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• 제16권2호
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• pp.35-43
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• 2020

Cloud computing integrates computing resources such as servers, storage, and networks with virtualization technology to provide suitable services according to user needs. Due to the structural characteristics of sharing physical resources based on virtualization technology, threats to availability can occur, so it is essential to respond to availability threats in cloud computing. Existing over-provisioning method is not suitable because it can generate idle resources and cause under-provisioning to degrade or disconnect service. System resources must be allocated in real-time according to the system load to guarantee the cloud system's availability. Through appropriate management measures, it is necessary to reduce the system load and increase the performance of the system. This paper analyzes the work response time according to the allocation or migration of virtual machines and discusses an efficient resource management method considering the system load.

• 한국항행학회논문지
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• 제15권4호
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• pp.510-516
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• 2011

위성항법시스템(GNSS)을 민간항공 분야에 활용하기 위해서는 국제민간항공기구(ICAO)가 정한 비행단계별 정확성(Accuracy), 무결성(integrity), 연속성(continuity), 가용성(availability) 성능요구조건을 만족시켜야 한다. 사용자의 무결성을 확보하기 위해서는 사용자의 보호 수준을 크게 잡아야 하고 가용성을 향상시키기 위해서는 보호수준이 작을수록 좋다. 따라서 주어진 항행요구조건을 만족하기 위해서는 사용자의 무결성을 확보하면서 보호수준을 최대한 작게 잡아야 한다. 본 논문에서는 한국형 광역보정시스템 테스트베드 중앙처리국 모듈의 현재까지 진행 상황에 대해서 설명하고 현재 사용되고 있는 무결성 관련 알고리듬을 적용하였을 때 사용자의 무결성 및 가용성 성능에 대한 예측을 수행하였다. 또한 항법위성의 궤도 및 시계오차에 대한 공분산 행렬을 사용자 무결성 감시에 적용하였을 때의 가용성 향상 정도를 시뮬레이션을 통해 예측하도록 한다.

• 한국철도학회논문집
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• 제9권3호
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• pp.264-270
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• 2006

In this paper we present a safety plan to be applied to the development of the TCS(Train Control System). The safety plan that can be applied to the life cycle of a system, from the conceptual design to the dismantlement, shows the whole process of the paper work in detail through the establishment of a goal, analysis and assessment, the verification. In this paper we study about the making a plan, the preliminary hazard analysis, the hazard identification and analysis to guarantee the safety of the TCS. The process far the verification of the system safety is divided into several steps based on the target system and the approaching method. The guarantee of the system safety and the improvement of the system reliability is fellowed by the recommendation of the international standards.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 춘계 종합학술대회 논문집
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• pp.193-198
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• 2006

인터넷을 이용한 서비스와 산업 그 중에서 게임 산업의 급속한 발전으로 인하여 게임 서비스를 더욱 효율적이고 확장성이 뛰어난 시스템으로의 구축이 중요시되고 있다. 이에 고가용성 시스템이 주목을 받고 있고 본 논문에서는 heartbeat 알고리즘을 이용한 고가용성 온라인 게임 서버를 제안한다. 분산화된 게임 서버에 대하여 각 대응되는 standby server를 두어 실시간 real server의 장애를 체크하여 지속적인 게임 서비스에 지장이 없도록 하여 항상 안정된 게임 서비스를 할 수 있는 시스템이다.

• 전기학회논문지
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• 제66권1호
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• pp.33-39
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• 2017

A top priority in the design of underwater vehicle is to guarantee the dependability of the electric system because failure of the electrical power supply system is directly related to the life of the passengers. In this paper, we present four kinds of alternative designs to improve reliability of electrical system in underwater vehicle. To reduce the risk and to increase availability of the electrical system, we use the redundancy of the grid structure and power converter. For all design alternatives, we carry out Fault Tree Analysis. Based on the FTA result, we implement RAM simulation to compare the risk and availability for the proposed design alternatives.