• 정보저장시스템학회논문집
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• 제3권2호
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• pp.86-93
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• 2007

In this paper we explain why future probe storage systems will use patterned media. As a model system, magnetic patterned media will be discussed, even though their data density is limited to about $7Tbit/in^2$. The first results on magnetic probe storage on patterned media are presented, and the problem of switching field distribution is discussed in detail. Finally we will present the first steps into two-dimensional coding for patterned media.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권5호
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• pp.909-937
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• 2011

Energy efficiency is one of the most critical issues in the design of wireless sensor networks. In object-tracking sensor networks, the data storage and query processing should be energy-conserving by decreasing the message complexity. In this paper, a Prediction-based Energy-conserving Approximate StoragE schema (P-EASE) is proposed, which can reduce the query error of EASE by changing its approximate area and adopting predicting model without increasing the cost. In addition, focusing on reducing the unnecessary querying messages, P-EASE enables an optimal query algorithm to taking into consideration to query the proper storage node, i.e., the nearer storage node of the centric storage node and local storage node. The theoretical analysis illuminates the correctness and efficiency of the P-EASE. Simulation experiments are conducted under semi-random walk and random waypoint mobility. Compared to EASE, P-EASE performs better at the query error, message complexity, total energy consumption and hotspot energy consumption. Results have shown that P-EASE is more energy-conserving and has higher location precision than EASE.

• 한국컴퓨터정보학회논문지
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• 제24권9호
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• pp.1-8
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• 2019

In this paper, we propose a performance isolation of shared space for virtualized SSD based storage systems, to solve the weakness in a VSSD framework. The proposed scheme adopts a CFQ scheduler and a shared space-based FTL for the fairness and the performance isolation for multiple users on virtualized SSD based storage systems. Using the CFQ scheduler, we ensure SLOs for the storage systems such as a service time, a allocated space, and a IO latency for users on the virtualized storage systems. In addition, to improve a throughput and reduce a computational latency for garbage collection, a shared space-based FTL is adopted to maintain the information of SLOs for users and it manages shared spaces among the users. In our experiments, the proposal improved the throughput of garbage collection by 7.11%, on average, and reduced the computational latency for garbage collection by 9.63% on average, compared to the previous work.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.1-22
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• 2005

There are two important trends in the modern information society, including digital networking and ubiquitous environment. Thus it is strongly required to develop new information storage devices such as high density storages to match the increased data capacity and small size storage devices to be applied to the mobile multimedia electronics. So far, many approaches have been studied for the high density memory, including the holographic memory, super-RENS and near-field recording using solid immersion lens (SIL) or nano-probe for the ODD (Optical Disk Drive) system, and the perpendicular magnetic recording and heat-assisted magnetic recording for the HDD (Hard Disk Drive) system. In addition, new mobile storage devices have been prepared using 0.85" HDD and 30mm ODD systems from a lot of foreign and domestic companies and institutes. In this paper, the recent technology trend for the next generation information storage system is summarized to offer a research motivation and encouragement to new researchers in this field with an emphasis on the technical issues of the increase of data capacity and decrease of device size.

• 한국도서관정보학회지
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• 제34권2호
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• pp.187-207
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• 2003

정보기술과 인터넷의 진화에 따라 기하급수적으로 증가하는 디지털콘텐츠를 효율적으로 저장, 검색, 변경, 관리할 수 있는 네트워크 기반 저장관리시스템이 요구되고 있다. 분산 네트워크 환경하에 이 기종 시스템의 데이터 통합관리, 저장 장치의 효과적인 활용, 데이터 전송 한계 등의 문제에 대한 해결방안으로 SAN이 대두되었다. SAN은 개별적으로 서버에 연결되던 저장장치들을 광 채널과 같은 고속네트워크에 직접 연결시켜 대용량 데이터를 효과적으로 관리하고 공유할 수 있도록 해주는 시스템이다. 본 연구는 저장관리시스템의 기술과 표준화 및 시장동향 조사와 다중 시스템 저장장치의 통합과 저장장치의 가상화를 이루기 위한 구조와 구성장치 및 성능을 비교 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권4호
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• pp.1182-1199
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• 2023

Fractional repetition (FR) codes can achieve exact uncoded repair for multiple failed nodes, with lower computational complexity and bandwidth overhead, and effectively improve repair performance in distributed storage systems (DSS). The actual distributed storage system is dynamic, that is, the parameters such as node storage overhead and number of storage nodes will change randomly and dynamically. Considering that traditional FR codes cannot be flexibly applied to dynamic distributed storage systems, a new construction scheme of adaptive-and-resolvable FR codes based on hypergraph coloring is proposed in this paper. Specifically, the linear uniform regular hypergraph can be constructed based on the heuristic algorithm of hypergraph coloring proposed in this paper. Then edges and vertices in hypergraph correspond to nodes and coded packets of FR codes respectively, further, FR codes is constructed. According to hypergraph coloring, the FR codes can achieve rapid repair for multiple failed nodes. Further, FR codes based on hypergraph coloring can be generalized to heterogeneous distributed storage systems. Compared with Reed-Solomon (RS) codes, simple regenerating codes (SRC) and locally repairable codes (LRC), adaptive-and-resolvable FR codes have significant advantages over repair locality, repair bandwidth overhead, computational complexity and time overhead during repairing failed nodes.

• 한국정보통신학회논문지
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• 제24권11호
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• pp.1558-1561
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• 2020

In this paper, we propose a blockchain scheme to enhance fault tolerance in distributed storage blockchain systems. Traditional blockchain systems suffer from ever-increasing storage cost. To overcome this problem, distributed storage blockchain techniques have been proposed. Distributed storage blockchain schemes effectively reduce the storage cost, but there are still limitations in reducing recovery cost and fault tolerance. The proposed approach recovers multiple errors within a group by utilizing locally repairable codes with availability. This improves the fault tolerance of the blockchain systems. Simulation results show that the proposed scheme enhances the fault tolerance while minimizing storage cost and recovery cost compared to other state-of-art schemes.

• 정보보호학회논문지
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• 제25권1호
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• pp.155-164
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• 2015

저장된 데이터에 대한 높은 가용성과 기밀성을 보장하는 정보분산 알고리즘은 클라우드 스토리지 등 장애 발생 비율이 높고 신뢰할 수 없는 분산 스토리지 시스템에서 유용한 방법이다. 스토리지에 저장되는 데이터의 양이 증가하면서 IT 자원을 효율적으로 활용하기 위한 데이터 중복제거기법이 많은 주목을 받고 있으며 이에 따라 데이터 중복제거가 가능한 정보분산기법에 대한 연구도 필요한 시점이다. 본 논문은 분산 스토리지 시스템에서 클라이언트 기반 중복 제거를 위한 정보분산 알고리즘과 소유권 증명 기법을 제안한다. 제안하는 방법은 저장공간 뿐만 아니라 네트워크 대역 절감이 가능하여 높은 효율성을 얻을 수 있으며 신뢰할 수 없는 스토리지 서버와 악의적인 클라이언트로부터 안전성을 보장할 수 있다.

• 정보저장시스템학회논문집
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• 제3권1호
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• pp.40-42
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• 2007

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.137-142
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• 2005

In this paper, we propose a new servo system design strategy to reduce the position error signal(PES) and track mis-registration(TMR) in magnetic disk drive systems. The proposed method provides a systematic design procedure based on the plant model and an optimal solution via an optimization with a 'Robust Random Neighborhood Search(RRNS)' algorithm. In addition, it guarantees the minimum PES level as well as stability to parametric uncertainties. Furthermore, the proposed method can be used to estimate the performance at the design stage and thus can reduce the cost and time for the design of the next generation product. The reduction of PES as well as robust stability is demonstrated by simulation and experiments.