• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.95-101
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• 2015

The backup site operation of the Image Data Acquisition and Control System (IDACS) for Communication Ocean Meteorological Satellite (COMS) is discussed in terms of the ground station configuration, image data processing, and the characteristics of backup activities for both the meteorological image data and the ocean image data. The well-performed backup operation of the COMS IDACS is also confirmed with the first three years normal operation results from April, 2011 to March, 2014. The operation results are analyzed through statistical approach to provide the achieved operational performance of the image data reception, preprocessing, and broadcast.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5156-5161
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• 2013

In distributed spatial data stream processing, processed tuples of downstream nodes are replicated to the upstream node in order to increase the utilization of distributed nodes and to recover the whole system for the case of system failure. However, while the data input rate increases and multiple downstream nodes share the operation result of the upstream node, the data which stores to output queues as a backup can be lost since the deletion operation delay may be occurred by the delay of the tuple processing of upstream node. In this paper, the adaptive upstream backup scheme based on operation throughput in distributed spatial data stream system is proposed. This method can cut down the average load rate of nodes by efficient spatial operation migration as it processes spatial temporal data stream, and it can minimize the data loss by fluid change of backup mode. The experiments show the proposed approach can prevent data loss and can decrease, on average, 20% of CPU utilization by node monitoring.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.1
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• pp.1-17
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• 2008

Recently, the object based storage devices systems(OSDs) have been actively researched. They are different from existing block based storage systems(BSDs) in terms of the storage unit. The storage unit of the OSDs is an object that includes the access methods, the attributes of data, the security information, and so on. The object has no size limit and no influence on the internal storage structures. Therefore, the OSDs improve the I/O throughput and the scalability. But the backup systems for the OSDs still use the existing backup techniques for the BSDs. As a result, they need much backup time and do not utilize the characteristics of the OSDs. In this paper, we design and implement a new object based backup system that utilizes the features of the OSDs. Our backup system significantly improves the backup time over existing backup systems because the raw objects are directly transferred to the backup devices in our system. It also restores the backup data much faster than the existing systems when system failures occur. In addition, it supports various types of backup and restore requests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.6
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• pp.486-490
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• 2005

The web is used widely and the users of the majority are depending to get the information on web, the necessity of the data management by web is increasing. The sudden system failure frequently occurs from network environment, we must protect data from this danger. In this paper, we present web based data management method, which is composed of two type backup and restoration. This method support data management through web browser and provides systematic, efficient and stable data management on web.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.205-214
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• 2012

The main thing that IT operation managers consider is protecting assets of corporation from system failure and disaster. Therefore, this research proposed a backup system for a disaster recovery. Previous backup method is that if database update occurs, this record is saved in redo log, and if the size of record file is over than expected, this file is saved in archive log in order. Thus, it is possible to occur errors of data loss from the process of data backup which change in real time while changes of database occur. Suggested backup system is back redo log up to database of transaction log in real time, and back a record that can be omitted from previous backup method up to archive log. When recover the data, it is possible to recover redo log in real time online, and it minimizes data loss. Also, throughout multi thread processing method data recovery is performed and it is designed that system performance is improved. To verify stability of backup system CPN(Coloured Petri Net) is introduced, and each step of backup system is displayed in diagram form, and th e stability is verified based on the definition and theorem of CPN.

• The Journal of Information Technology and Database
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• v.7 no.1
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• pp.17-26
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• 2000

To provide highly available services in the distributed object system, it is required to support the object group. The state machine approach and primary-backup approach are proposed as two representative approaches for support of object group. The primary-backup approach does not only give merits such as transparency of object group and non-deterministic execution but also require less resource than state machine approach. This paper describes an extension of CORBA that is required to support of the primary-backup object group. In this paper, the state of backup is synchronized with primary through the atomic multicast protocol whenever the request of client is executed at primary. As a result, it does not require message logging and check pointing. The object group of this paper also provides fast response time in case of failure of the primary since it makes primary election unnecessary. And through an extension of IDL, it makes possible to avoid consistency control depending on characteristic of application. A prototype has been implemented and the performance of object group has been compared with a single object invocation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5058-5077
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• 2019

Traditional regenerating codes are designed to tolerate node failures with optimal bandwidth overhead. However, there are many types of partial failures inside the node, such as latent sector failures. Recently, proposed regenerating codes can also repair intra-node failures with node-level redundancy but incur significant bandwidth and I/O overhead. In this paper, we construct a new scheme of regenerating codes, called IR-RBT codes, which employs intra-node redundancy to tolerate intra-node failures and serve as the help data for other nodes during the repair operation. We propose 2 algorithms for assigning the intra-node redundancy and RBT-Helpers according to the failure probability of each node, which can flexibly adjust the helping relationship between nodes to address changes in the actual situation. We demonstrate that the IR-RBT codes improve the bandwidth and I/O efficiency during intra-node failure repair over traditional regenerating codes but sacrifice the storage efficiency.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.3
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• pp.177-184
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• 2017

High performance non-volatile memory system can mitigate the gap between main memory and storage. However, no single memory devices fulfill the requirements. Non-volatile Dual In-line Memory Module (NVDIMM) consisted of DRAMs and NAND Flashes has been proposed to achieve the performance and non-volatility simultaneously. When power outage occurs, data in DRAM is backed up into NAND Flash using a small-size external energy storage such as a supercapacitor. Backup and restore operations of NVDIMM do not cooperate with the operating system in the NVDIMM standard, thus there is room to optimize its operation. This paper analysis the operation of NVDIMM and proposes a method to reduce backup and restore time. Particularly, data compression is introduced to reduce the amount of data that to be backed up and restored. The simulation results show that the proposed method reduces up to 72.6% of backup and restore time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1291-1312
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• 2013

Cloud computing changes the service models of information systems and accelerates the pace of technological innovation of consumer electronics. However, it also brings new security issues. As one of the important foundations of various cloud security solutions, entity authentication is attracting increasing interest of many researchers. This article proposes a layered security architecture to provide a trust transmission mechanism among cloud systems maintained by different organizations. Based on the security architecture, four protocols are proposed to implement mutual authentication, data sharing and secure data transmission in federated cloud systems. The protocols not only can ensure the confidentiality of the data transferred, but also resist man-in-the-middle attacks and masquerading attacks. Additionally, the security properties of the four protocols have been proved by S-pi calculus formal verification. Finally, the performance of the protocols is investigated in a lab environment and the feasibility of the security architecture has been verified under a hybrid cloud system.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.135-143
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• 2009

The purpose of this research is to reduce editors' workload and automation to update(v) Digital Map(n) regarding changed topography. In Digital Map case, it usually uses the way of various survey to update(v). In this case, it costs a great deal and doesn't be efficient backup management. Accordingly, it can reduce editors' the period of the process and be efficiently managed the backup data due to well organized backup data management. We present update plan that used clipping and join for this result by analyzing Boundary of input data.