• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.159-164
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• 2003

Location of stock in a warehouse directly affects the total materials handling expense of all goods moving through the warehouse. The purpose of this paper is to develop a storage policy in order picking warehouse, the block-based storage policy to minimize the total order picking time. In block-based storage policy, the rack is divided into blocks and items are assigned to each block based on the turn-over rate of each item and the average distance between the blocks and the dock. To demonstrate the performance of the proposed policy, we compare with the existing method called class-based storage policy under various matching methods.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.59-65
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• 2007

Scanning Prove Microscope (SPM) - based Data Storage (SDS)는 Atomic Force Microscope (AFM)을 이용하여 Cantilever Tip 이 저장 장치 미디어에 나노미터 단위로 비트를 읽고, 쓰고 지우는 저장 장치로써, x, y 두 축을 이용한다. 따라서 축간 coupling 의 영향이 크게 발생한다. 따라서 축간 coupling 의 영향을 고려하여 제어기를 설계하여야 한다. 본 논문은 coupling 요소를 제거하기 위하여 Feedforward Decoupler 를 설계하여 Stage 의 입력 앞 단에 추가하는 방법을 제안하였다. Feedforward Decoupler 를 추가함으로써 coupling 요소가 줄어드는 것을 모의 실험을 통해 확인한다. 이를 통해 나노급으로 보다 정밀한 제어가 가능함을 확인하였다.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.73-80
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• 2007

Atomic Force Microscopy (AFM)방식을 이용한 Scanning probe Data Storage (SDS) 시스템은 array cantilever 를 이용하여 나노 단위로 데이터 읽기, 쓰기를 하는 시스템이다. 따라서 미디어가 있는 stage 의 x 축과 y 축 및 두 축간 coupling 을 고려한 제어기 설계가 요구된다. 본 논문은 SDS 시스템의 축간 coupling 을 고려하지 않은 기존의 제안된 LQG 에 PI 를 추가한 제어기 구조를 사용한다. 두 축간 coupling 공진의 영향을 최소화 하기 위해 convex optimization 으로 설계된 최적의 position profile를 기준 입력신호로 사용한다. 제안된 제어기를 SDS 시스템에 적용하여 모의실험을 하고 그 결과 position profile 로 인해 각 축간 coupling 공진 영향이 감소하여 tracking performance 가 기존의 LQG 제어기 보다 향상된 것을 확인한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7C
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• pp.581-586
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• 2010

The holographic data storage system stores multiple data pages by multiplexing. But the inter-page interference(IPI) caused by multiplexing reduces the intensity of the hologram. The simulation of the holographic storage systems has to consider the IPI. Therefore, we introduce a channel modeling that takes care of inter-page interference in the holographic data storage system. We simulate the performance of PRML detection on the hologrpahic data storage system with IPI modeling.

• Transactions of the Society of Information Storage Systems
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• v.7 no.2
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• pp.47-52
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• 2011

This paper presents a method to improve vibration characteristics of servo track write (STW) fixture. STW fixtures supported by flexible mounts are subject to various vibration sources. Using Finite element analysis (FEA) vibration modes of the fixture are identified. The FEA results suggest certain vibration modes be reduced through design change of flexible mounts to improve vibration responses of the fixture. Based on layered flexible mounts theory a parametric study on shear and bending stiffness is performed to obtain a suitable flexible mount design leading to increased resistance to rocking motion. Experiments confirm improvement of vibration characteristics and drive performance through new mounts design.

• 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 Information Processing Systems
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• v.17 no.3
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• pp.658-673
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• 2021

Data deduplication technology improves data storage efficiency while storing and managing large amounts of data. It reduces storage requirements by determining whether replicated data is being added to storage and omitting these uploads. Data deduplication technologies require data confidentiality and integrity when applied to cloud storage environments, and they require a variety of security measures, such as encryption. However, because the source data cannot be transformed, common encryption techniques generally cannot be applied at the same time as data deduplication. Various studies have been conducted to solve this problem. This white paper describes the basic environment for data deduplication technology. It also analyzes and compares multiple proposed technologies to address security threats.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.6
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• pp.1247-1257
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• 2013

The security vulnerabilities of cloud storage virtualization environments are different from those of the existing computer system and are difficult to be protected in the existing computer system environment. Therefore we need some technical measures to address this issue. First of all, the technology used in cloud storage virtualization environment needs to be thoroughly analyzed, and also, we should understand those security requirements of various stakeholders in the view of cloud storage service and perform the research on security guidelines of the research security requirements. In this paper, we propose security requirements based on layers and roles of cloud storage virtualization. The proposed security requirements can be a basement for development of solution of cloud storage virtualization security.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.302-307
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• 2004

It need remote storage system using iSCSI to overcome a limit of PDA storage device used in currently wireless network environment, and IPSec to solve a security problem of wireless environment increasing continually. In this paper, it design and implement iSCSI to use a remote storage system on PDA, and IPSec for security. The experimental results in real environment show a system performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.992-993
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• 2002

We have fabricated the diffractive optical head(DOH) for optical pick up, which one adaptable to a optical recoding information storage. DOH consists of a focusing grating coupler(FGC) and a solid immersion Jens(SIL). FGC is device that the light converge into a focus by surface lattice. FGC have been studied as a potential application of pick up head for the information storage. In this study, FGC was designed and fabricated to make focus near to possible diffraction limit. We also fabricated recording head combined with SIL. The focus was measured in the range of $1.1{\mu}m$ as near to possible diffraction limit in the FGC having a focusing length of $600{\mu}m$ and a lattice area of 500 * $500{\mu}m$.