• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.455-469
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• 2003

Recently, as new technologies such as SAN and NAS come into wide use to deal with a large amount of data, an efficient backup software for SAN and NAS is very required. In this paper, we design and implement a backup software for SAN that fully supports NDMP. The NUMP is an open standard protocol for network-based backup. The proposed backup software has various unique features such as SAN based tan free backup, automatic and manual backup, on-line backup by using snap shot, file-system, raw-device, database backup and so on. The proposed backup software also can be configured as a backup center that uses SAN as a backup media.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.6
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• pp.488-502
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• 2005

Recently, with the development of data communication techniques and storage devices, many researches have been done to process a large amount of data. As the size of storage media has been increased because of the storage technologies such as NAS and SAN, the efficient backup for a large amount of data is required. In this paper, we design and implement a disk based backup software that fully supports NDMP(Network Data Management Protocol) which is an open standard protocol for network based backup. The proposed backup software supports various types of backup and restore. In addition, it manages multiple network connected devices and supports a disk based backup by extending the NDMP protocol.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1133-1136
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• 2005

The proposed high-speed backup and recovery system is a high performance backup software based on multi streaming I/O and high speed/high compression technology, and can realize an increase efficiency of backup volume without any increase of backup H/W equipments since it provides a high performance in data backup of a user and executes high compression very fast. Particularly, it minimizes consumption of network band width through a development of algorism for high compression in connection with backup equipments in a large-scaled system environment, is automated when it is recovered due to danger and troubles, and allows users to conveniently access in various ways since GUI and CLI for execution and management are all provided.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.2
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• pp.47-57
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• 2016

Since the Global Navigation Satellite System (GNSS) may not provide navigation information due to external interferences, many countries have plans to prepare a backup system for this situation. One of the possible GNSS backup systems is a multiple radio positioning integration system in combination with the terrestrial radio navigation system. Before constructing such a GNSS backup system, M&S software is needed to analyze if the system satisfies the performance the required navigation performance. This study presents requirements of M&S software for coverage analysis of the navigation system, and proposes an M&S software design scheme on the basis of the requirements. The M&S software is implemented, and coverage analysis is performed to verify the validity of the proposed design scheme.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.2
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• pp.126-134
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• 2011

In this dissertation, in the light of the above situations, we intend to use new approach for stable and fast backup system. The approach that we propose network and software infrastructure has three different ways by comparison with existing network backup systems. First of all, we use a socket communication so that resolve the shortcoming of weakness of securities; second, TBD utility for minimizing target system loads in the way of instant operating; and third, time division and bandwidth division backup method considered transfer data size(byte) might be useful more stable and fast comparing with FTP Transfer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5200-5222
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• 2017

The separation of control plane and data plane in Software Defined Network (SDN) makes it flexible to control the network behavior, while also causes some inconveniences to the link failure recovery due to the delay between fail point and the controller. To avoid delay and packet loss, pre-defined backup paths are used to reroute the disrupted flows when failure occurs. However, it may introduce large overhead to build and maintain these backup paths and is hard to dynamically construct backup paths according to the network status so as to avoid congestion during rerouting process. In order to realize congestion aware fast link failure recovery, this paper proposes a novel method which installs multi backup paths for every link via source routing and per-hop-tags and spread flows into different paths at fail point to avoid congestion. We carry out experiments and simulations to evaluate the performance of the method and the results demonstrate that our method can achieve congestion aware fast link failure recovery in SDN with a very low overhead.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4725-4747
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• 2020

Software defined networking (SDN) is considered to be one of the most promising paradigms in the future. To solve the scalability and performance problem that a single and centralized controller suffers from, the distributed multi-controller architecture is adopted, thus forms multi-domain SDN. In a multi-domain SDN network, it is of great importance to ensure a reliable control plane. In this paper, we focus on the reliability problem of multi-domain SDN against controller failure from perspectives of backup controller deployment and controller replication. We firstly propose a placement algorithm for backup controllers, which considers both the reliability and the cost factors. Then a controller replication mechanism based on shared data storage is proposed to solve the inconsistency between the active and standby controllers. We also propose a shared data storage layout method that considers both reliability and performance. Besides, a fault recovery and repair process is designed based on the controller backup and shared data storage mechanism. Simulations show that our approach can recover and repair controller failure. Evaluation results also show that the proposed backup controller placement approach is more effective than other methods.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.81-90
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• 2001

As the rapid growth of Internet, computer systems are growing in its size and complexity. To meet high availability requirements for the systems, one usually uses both hardware and software fault tolerance techniques. To prevent failures of computer systems from software-aging phenomenon that come from long mission time, we adopt software rejuvenation method that stops and restarts the software in the servers intentionally. The method makes the systems clean and healthy state in which the probability of fault occurrence is very low. In this paper, we study how switchover time affects software rejuvenation of primary-backup server systems. Through experiments, we find that switchover time is an essential factor for deciding the rejuvenation policy.

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.21-26
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• 2014

The aircraft manufacturers are constantly driving to reduce manufacturing lead times and cost at the same time as the product complexity increases and technology continues to change. Integrated Modular Avionics (IMA) is a solution that allows the aviation industry to manage their avionics complexity. IMA defines an integrated system architecture that preserves the fault containment and 'separation of concerns' properties of the federated architectures. In software side, the air transport industry has developed ARINC 653 specification as a standardized Real Time Operating System (RTOS) interface definition for IMA. It allows hosting multiple applications of different software levels on the same hardware in the context of IMA architecture. This paper describes a study that provided the avionics software design for separation of fault and backup of core function to reduce workload of pilot with cost efficiency.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.47-48
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• 2020

네트워크 기능 가상화와 소프트웨어 정의 네트워킹의 융합은 현재의 네트워크를 대체할 새로운 매커니즘으로써 대두되고 있다. 특히 서비스 기능 체인은 네트워크에 유연성을 효율적으로 부여할 수 있다는 장점으로 인해 부각되고 있다. 그러나 서비스 기능 체인은 그 특유의 체인형 구조로 인해 생존성에 큰 약점을 갖고 있기도 하다. 이에 기존 방법들은 별도의 백업 가상 네트워크 기능을 배치하는데, 이는 자원 효율적이지 못하다. 본 논문에서는 추가적인 백업 가상 네트워크 기능 배치 없이 서비스 기능 체인의 생존성을 보장하는 백업 시스템을 제안한다.