• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.368-374
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• 2020

Journaling file systems (JFS) manage changes of file systems not yet committed in a data structure known as a journal to restore the file system in the event of an unexpected failure. Extra write operations required for journaling negatively affect the performance of JFS. The high-performance and byte-addressable non-volatile memory (NVM) was expected to easily mitigate these performance problems by providing NVM space as journal storage. However, even with such non-volatile memory technologies, performance problems still arise due to scalability problems inherent in processing transactions of JFS. To solve this problem, we proposes a technique for processing file system transactions for scalable performance. To this end, lock-free data structures are used and multiple I/O requests are allowed to simultaneously be processed on high-performance storage devices with multiple I/O channels. We evaluate the file system with the proposed technique by comparing the original ext4 file system and the recent proposed NVM-based journaling file system on a multi-core server, and experimental results show that our file system has better performance (up-to 2.9/2.3 times) than the original ext4 file system and the recent NVM-based journaling file system, respectively.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.11
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• pp.581-591
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• 2001

We consider some problems of remote file accesses of multiple clients in mobile computing environments. In this environment, user mobility affects file access latency. Mobile hosts have severe resource constraints in terms of limited size of non-volatile storage. Thus, the burden of computation and communication load raise file access latency. In this paper, we propose a scheme for reducing the file access latency through the file migration. The objective is to minimize of file accesses for all mobile hosts which delivering the file to clients as quickly as possible. We develope an on-demand scheme which determines when the file server should migrate files to another server, or when it should transfer files to mobile hosts. Using simulation, we examine the effects which parameters such as file access frequency, file size, mobility rate have on file system access latency. Through simulation results, we show that our proposed migration scheme is effective in reducing the access latency on the requested file of a mobile host with high access rate and low mobility.

• Journal of Internet Computing and Services
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• v.17 no.3
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• pp.55-66
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• 2016

A local storage of HTML5 is a Web Storage, which is stored permanently on a local computer in the form of files. The contents of the storage can be easily accessed and modified because it is stored as plaintext. Moreover, because the internet browser classifies the local storages of each domain using file names, the malicious attacker can abuse victim's local storage files by changing file names. In the paper, we propose a scheme to maintain the integrity and the confidentiality of the local storage's source domain and source device. The key idea is that the client encrypts the data stored in the local storage with cipher key, which is managed by the web server. On the step of requesting the cipher key, the web server authenticates whether the client is legal source of local storage or not. Finally, we showed that our method can detect an abnormal access to the local storage through experiments according to the proposed method.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.4
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• pp.376-388
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• 2002

Recently, although there are strong requirements to manage multimedia data, there are a few researches on efficient storage and retrieval of multimedia data. In this paper, we design an object storage engine which can store and retrieve various multimedia objects efficiently. For this, we design an object manager for storing a variety of multimedia data and an inverted file manager for indexing unformatted text objects. In addition, we implement the objects storage engine which can support concurrency control and recovery schemes of DBMS by integrating the object manager and the inverted file manager with the SHORE low-level storage system. Finally, we develope a TIROS(Thesis Information Retrieval using Object Storage engine) system in order to verify the usefulness of our object storage engine.

• Smart Media Journal
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• v.4 no.3
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• pp.62-67
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• 2015

The trend keywords in ICT sector will be Big Data, Internet of Things, and Cloud Computing. The rear end to support those techniques requires a large-capacity storage technology of low-cost. Therefore, we proposed the prototype of low-cost and mass distributed storage system based on PC using open-source Ceph FS for SMB.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.266-271
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• 2010

In this paper, we chose IOPS(input output operation per second) and MB/s as a performance standard, and we developed the evaluation standard for the storage performance. Since there is no vendor-neutral evaluation criteria for storage performance, it is difficult to evaluate storage performance and design the storage resource's sizing. We proposed block size for measurement of the storage's IOPS for OLTP(online transaction processing) application to 4KB, 8KB and 16KB and read/write rate of it to 7:3. On the other hand, we proposed block size for measurement of the storage's IOPS for backup, VOD, Large file processing) to 64KB, 256KB and 1024KB and read/write rates of it to 7:3 and 1:0. Finally, we proposed the Vdvench BMT tool, which is independent on platform. We also developed the result reporting tool for developed evaluation criteria.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.65-69
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• 2019

This paper presents an optimized adoption of NVM for the storage system considering application characteristics. To do so, we first characterize the storage access patterns for different application types, and make two prominent observations that can be exploited in allocating NVM storage efficiently. The first observation is that a bulk of I/O does not happen on a single storage partition, but it is varied significantly for different application categories. Our second observation is that there exists a large proportion of single accessing in storage data. Based on these observations, we show that maximizing the storage performance with NVM is not obtained by fixing it as a specific storage partition but by allocating it adaptively for different applications. Specifically, for graph, database, and web applications, using NVM as a swap, a journal, and a file system partitions, respectively, performs well.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3694-3722
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• 2022

In today's globalized world, there is no transparency in exchanging data and information between producers and consumers. However, these tasks experience many challenges, such as administrative barriers, confidential data leakage, and extensive time delays. To overcome these challenges, we propose a decentralized, secured, and verified smart chain framework using Ethereum Smart Contract which employs Inter Planetary File Systems (IPFS) and MongoDB as storage systems to automate the process and exchange information into blocks using the Tendermint algorithm. The proposed work promotes complete traceability of the product, ensures data integrity and transparency in addition to providing security to their personal information using the Lelantos mode of shipping. The Tendermint algorithm helps to speed up the process of validating and authenticating the transaction quickly. More so in this time of pandemic, it is easier to meet the needs of customers through the Ethermint Smart Chain, which increases customer satisfaction, thus boosting their confidence. Moreover, Smart contracts help to exploit more international transaction services and provide an instant block time finality of around 5 sec using Ethermint. The paper concludes with a description of product storage and distribution adopting the Ethermint technique. The proposed system was executed based on the Ethereum-Tendermint Smart chain. Experiments were conducted on variable block sizes and the number of transactions. The experimental results indicate that the proposed system seems to perform better than existing blockchain-based systems. Two configuration files were used, the first one was to describe the storage part, including its topology. The second one was a modified file to include the test rounds that Caliper should execute, including the running time and the workload content. Our findings indicate this is a promising technology for food supply chain storage and distribution.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.71-76
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• 2022

Buffer cache bridges the performance gap between memory and storage, but its effectiveness is limited due to periodic flush, performed to prevent data loss in smartphones. This paper shows that selective flushing technique with small persistent memory can reduce the flushing overhead of smartphone buffer cache significantly. This is due to our I/O analysis of smartphone applications in that a certain hot data account for most of file writes, while a large proportion of file data incurs single-writes. The proposed selective flushing policy performs flushing to persistent memory for frequently updated data, and storage flushing is performed only for single-write data. This eliminates storage write traffic and also improves the space efficiency of persistent memory. Simulations with popular smartphone application I/O traces show that the proposed policy reduces write traffic to storage by 24.8% on average and up to 37.8%.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.47-56
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• 2002

Previous buffer cache schemes for multimedia storage systems only exploited the sequential references of multimedia files and didn't consider looping references. However, in some video applications like foreign language learning, users mark the scene as loop area and then application automatically playbacks the scene several times. In this paper, we propose a new buffer replacement scheme, called HBM(Hybrid Buffer Management), for multimedia storage systems that have both sequential and looping references. Proposed scheme assumes that application layer informs reference pattern of files to file system. Then HBM applies an appropriate replacement policy to each file. Our simulation experiments show that HBM outperforms previous buffer cache schemes such as DISTANCE and LRU.