• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.429-432
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• 2002

The existing recovery technique using the logging technique in the client/sewer database system only administers the log as a whole in a server. This contains the logging record transmission cost on the transaction that is executed in each client potentially and increases network traffic. In this paper, the logging technique for redo-only log is suggested, which removes the redundant before-image and supports the client-based logging to eliminate the transmission cost of the logging record. Also, in case of a client crash, redo recovery through a backward client analysis log is performed in a self-recovering way. In case of a server crash, the after-image of the pages which needs recovery through simultaneous backward analysis log is only transmitted and redo recovery is done through the received after-image and backward analysis log. Also, we select the comparing model to estimate the performance about the proposed recovery technique. And we analyzed the redo and recovery time about the change of the number of client and the rate of updating operation.

• International journal of advanced smart convergence
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• v.1 no.2
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• pp.26-29
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• 2012

Recently, to efficiently support the real-time requirements of RTLS( Real Time Location System) services, interest in the main memory DBMS is rising. In the main memory DBMS, because all data can be lost when the system failure happens, the recovery method is very important for the stability of the database. Especially, disk I/O in executing the log and the checkpoint becomes the bottleneck of letting down the total system performance. Therefore, it is urgently necessary to research about the recovery method to reduce disk I/O in the main memory DBMS. Therefore, In this paper, we analyzed existing log techniques and check point techniques and existing main memory DBMSs' recovery techniques for recovery techniques research for main memory DBMS.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.387-396
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• 2016

As the number of people using digital devices has increased, the digital forensic, which aims at finding clues for crimes in digital data, has been developed and become more important especially in court. Together with the development of the digital forensic, the anti-forensic which aims at thwarting the digital forensic has also been developed. As an example, with anti-forensic technology the criminal would delete an digital evidence without which the investigator would be hard to find any clue for crimes. In such a case, recovery techniques on deleted or damaged information will be very important in the field of digital forensic. Until now, even though EVTX(event log)-based recovery techniques on deleted files have been presented, but there has been no study to retrieve event log data itself, In this paper, we propose some recovery algorithms on deleted or damaged event log file and show that our recovery algorithms have high success rate through experiments.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.4
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• pp.655-667
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• 2014

A disaster is the time-excess case that computerized service can tolerate a failure and financial industry is being set up the disaster recovery system based on the disaster recovery plan and the business continuity plan for preparing these disasters. However, existing system can not guarantee the business continuity when it comes to cyber terror. This paper analyzes the building type and building technology of disaster recovery system for the financial fields. Also this paper explain the type of data backup using online redo log and type of archive log backup using WORM storage. And this paper proposes the model of improved data recovery combining above two types. Lastly this paper confirm the effectiveness and reliability for proposal rocovery model through the implementation of the test environment.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.494-511
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• 2001

In the environment that database management systems manage disk spaces for storing databases directly, this paper proposes a correct and efficient scheme of performing pending actions for the removal of database files. As for performing pending actions, upon performing recovery, the recovery process must identify unperformed pending actions of not-yet-terminated transactions and then perform those actions completely. Making the recovery process identify those actions through the analysis of log records in the log file is the basic idea of this paper. This scheme, as an extension of the execution of transactions, fuzzy checkpoint, and recovery of ARIES, uses the following methods: First, to identify not-yet-terminated transactions during recovery, transactions perform pending actions after writing 'pa_start'log records that signify both the commit of transactions and the start of executing pending actions, and then write 'eng'log records. Second, to restore pending-actions-lists of not-yet-terminated transactions during recovery, each transaction records its pending-actions-list in 'pa_start'log record and the checkpoint process records pending-actions-lists of transactions that are decided to be committed in 'end_chkpt'log record. Third, to identify the next pending action to perform during recovery, whenever a page is updated during the execution of pending actions, transactions record the information that identifies the next pending action to perform in the log record that has the redo information against the page.

• 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 KIPS Transactions:PartD
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• v.9D no.6
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• pp.1097-1104
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• 2002

Recently, with a drop in memory chip price and rapid development of mass storage memory chip technology, research on client-server Database Management Systems has gained wide attention. This Paper discusses the recovery technique in a page-server OODBMS environment. Although most researchers have studied client-server systems, the recovery technique has been a poor researches. In this paper, client transfers only the completed log records to the server and resolves the problems in the current recovery techniques. In addition, the server manages only the execution of completed log records suggesting a simple recover algorithm, Client uses system concurrency, fully, by acting to abort actions and it suggests a page unit recovery technique to reduce time that is required in the whole database.

• Journal of the Korea Society of Computer and Information
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• v.6 no.2
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• pp.27-33
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• 2001

In this thesis, we present a simple and efficient recovery method, called ARIES/SR(ARIES/Selective Redo) which is based on ARIES(Algorithm for Recovery and Isolation Exploiting Semantics) ARIES performs redo for all updates done by either nonloser transaction or loser transaction, and thus significant overhead appears during restart after a system failure. To reduce this overhead, we propose ARIES/SR recovery algorithm. In this algorithm, to reduce the redo operations, redo is performed, using log record for updates done by only nonloser transaction. Also selective undo is performed. using log record for update done by only loser transaction for reducing recovery operation.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.720-723
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• 2006

The viability of Shigella sonnei, a significant cause of gastroenteritis in Korea, on TSA plates was determined after sublethal heating treatments and NaCl treatments. In addition, recovery levels of sublethally injured cells on TSA plates containing different concentrations of NaCl (TSAS) were investigated. The viability decreased significantly with increasing degree of sublethal heating treatments, but increases in NaCI treatment concentration from 0 to 6% had little effect on the viability. After being sublethally treated at $55^{\circ}C$ for 30 min, bacterial populations were reduced by 7.58, 7.83 and 7.93 log CFU/mL on 2, 4, and 6% TSAS, respectively. After being sublethally treated at $60^{\circ}C$ for 30 min, bacterial populations were reduced by 6.71, 6.73, and 6.73 log CFU/mL on 2, 4 and 6% TSAS, respectively. Decimal reduction times (D-values) decreased with increasing NaCl treatment concentrations after sublethal heating at 55 or $60^{\circ}C$. These data imply that the S. sonnei cells sublethally injured by insufficient heating processes had a lower recovery rate with increasing NaCl concentrations in the recovery media.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1105-1110
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• 2011

It is possible to synchronize the spatio-temporal data with a server using a wireless network. These data has the benefit to be up-to-date and able to service to the user efficiently. However, the mobile devices or the wireless network are very vulnerable to various hard or soft failures. If an failure occurs during a synchronization process, the spatio-temporal data which is synchronizing could be inconsistent state. In this paper, we propose the recovery scheme to solve the problem caused by the errors which occur during the synchronization on mobile environments. The proposed scheme writes the log records for the synchronization process into the both local storages of the server and the mobile client. When the errors arise, the data which are synchronizing are recovered using the written log records. Also, we design and implement the proposed recovery scheme on the synchronization system.