• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.491-498
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• 2016

Recently leakages of confidential information and internal date have been steadily increasing by using booting technique on portable OS such as Windows PE stored in portable storage devices (USB or CD/DVD etc). This method allows to bypass security software such as USB security or media control solution installed in the target PC, to extract data or insert malicious code by mounting the PC's storage devices after booting up the portable OS. Also this booting method doesn't record a log file such as traces of removable storage devices. Thus it is difficult to identify whether the data are leaked and use trace-back technique. In this paper is to propose method to help facilitate the process of digital forensic investigation or audit of a company by collecting and analyzing BIOS firmware images that record data relating to BIOS settings in flash memory and finding traces of portable storage devices that can be regarded as abnormal events.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.350-362
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• 2002

A new architecture called the Storage Area Network(SAN) was developed in response to the requirements of high availability of data scalable growth, and system performance. In order to use SAN more efficiently, most SAN operating systems support storage virtualization concepts that allow users to view physical storage devices attached to SAN as a large volume virtually. A logical volume manager plays a key role in storage virtualization. It realizes the storage virtualization by mapping logical addresses to physical addresses. In this paper, we design and implement an efficient and flexible mapping method for logical volume manager. The nin method in this paper supports a snapshot that preserves a volume image at certain time and on-line reorganization to allow users to add or remove storage devices to SAN even while the system is running.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.3
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• pp.121-126
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• 2014

Demand of the data storage becomes more and more growing. This requests the next generation of storage devices to have the dominated storage capability associated with superfast read/write rate. Holographic data storage (HDS) is investigated for a long time and is considered to be a candidate for the future storage system. However, it has two-dimensional intersymbol interference that conventional one-dimensional detection solutions have not yet handled strictly because of the complexity level of system as well as the cost. We propose a new scheme that combines iterative soft output Viterbi algorithm with noise filter for improving the bit error rate performance of HDS.

• Transactions of the Society of Information Storage Systems
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• v.7 no.1
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• pp.7-12
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• 2011

The flash memory has been remarked as the next generation media of portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major data storage components for desktop and servers. The purpose of our study is to upgrade a traditional mirroring scheme based on SSD storages due to the relatively slow or freezing characteristics of write operations, as compared to fast read operations. For this work, we propose a new storage management scheme called Memory Mirror-Switching based on traditional mirroring scheme. Our Mirror-Switching scheme improves flash operation performance by switching write-workloads from flash memory to RAM and delaying write operations to avoid freezing. Our test results show that our scheme significantly reduces the write operation delay and storage freezing.

• Journal of information and communication convergence engineering
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• v.8 no.4
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• pp.377-382
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• 2010

With the advent of flash memory based new storage device (SSD), there is considerable interest within the computer industry in using flash memory based storage devices for many different types of application. The dynamic index structure of large text collections has been a primary issue in the Information Retrieval Applications among them. Previous studies have proven the three approaches to be effective: In- Place, merge-based index structure and a combination of both. The above-mentioned strategies have been researched with the traditional storage device (HDD) which has a constraint on how keep the contiguity of dynamic data. However, in case of the new storage device, we don' have any constraint contiguity problems due to its low access latency time. But, although the new storage device has superiority such as low access latency and improved I/O throughput speeds, it is still not well suited for traditional dynamic index structures because of the poor random write throughput in practical systems. Therefore, using the experimental performance evaluation of various index maintenance schemes on the new storage device, we propose an efficient index structure for new storage device that improves significantly the index maintenance speed without degradation of query performance.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.27 no.5
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• pp.47-57
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• 2009

• Journal of Information Processing Systems
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• v.9 no.2
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• pp.287-300
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• 2013

Cloud storage is provided as a service in order to keep pace with the increasing use of digital information. It can be used to store data via networks and various devices and is easy to access. Unlike existing removable storage, many users can use cloud storage because it has no storage capacity limit and does not require a storage medium. Cloud storage reliability has become a topic of importance, as many users employ it for saving great volumes of data. For protection against unethical administrators and attackers, a variety of cryptography systems, such as searchable encryption and proxy re-encryption, are being applied to cloud storage systems. However, the existing searchable encryption technology is inconvenient to use in a cloud storage environment where users upload their data. This is because this data is shared with others, as necessary, and the users with whom the data is shared change frequently. In this paper, we propose a searchable re-encryption scheme in which a user can safely share data with others by generating a searchable encryption index and then re-encrypt it.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.282-296
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• 2013

With the emergence of cloud computing, more and more sensitive user data are outsourced to remote storage servers. The privacy of users' access pattern to the data should be protected to prevent un-trusted storage servers from inferring users' private information or launching stealthy attacks. Meanwhile, the privacy protection schemes should be efficient as cloud users often use thin client devices to access the data. In this paper, we propose a lightweight scheme to protect the privacy of data access pattern. Comparing with existing state-of-the-art solutions, our scheme incurs less communication and computational overhead, requires significantly less storage space at the user side, while consuming similar storage space at the server. Rigorous proofs and extensive evaluations have been conducted to show that the proposed scheme can hide the data access pattern effectively in the long run after a reasonable number of accesses have been made.

• Transactions of the Society of Information Storage Systems
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• v.7 no.1
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• pp.42-46
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• 2011

Holographic Data Storage System (HDSS), one of the next generation data storage devices, is a 2-dimensional page oriented memory system using volume hologram. HDSS has many noise sources such as crosstalk, scattering and inter pixel interference, etc. The noise source is changing intensity of the light used for carrying the data signal in HDSS. The inter pixel interference results in decrease of Signal to Noise Ratio and increase of Bit Error Rate. In order to improve these problems, this paper proposes to compensate the inter pixel interference with simple interference mask.

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.1-10
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• 2016

Magnetic disks have been used for decades in auxiliary storage devices of computer systems. In recent years, the use of NAND flash memory, which is called SSD, is increased as auxiliary storage devices. However, NAND flash memory, unlike traditional magnetic disks, necessarily performs the erase operation before the write operation in order to overwrite data and this leads to degrade the system lifetime and performance of overall NAND flash memory system. Moreover, NAND flash memory has the lower endurance, compared to traditional magnetic disks. To overcome this problem, this paper proposes EPET (Enhanced Prediction and Elapsed Time) wear leveling technique, which is especially efficient to portable devices. EPET wear leveling uses the advantage of PET (Prediction of Elapsed Time) wear leveling and solves long-term system failure time problem. Moreover, EPET wear leveling further improves space efficiency. In our experiments, EPET wear leveling prolonged the first bad time up to 328.9% and prolonged the system lifetime up to 305.9%, compared to other techniques.