7 results on '"Choi, Jong Hyun"'
Search Results
2. Reassembling Linux‐based Hybrid RAID.
- Author
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Choi, Jong‐Hyun, Park, Jungheum, and Lee, Sangjin
- Subjects
- *
NETWORK-attached storage , *CRITICAL analysis - Abstract
Network‐attached storage (NAS) is a system that uses a redundant array of disks (RAID) to create virtual disks comprising multiple disks and provide network services such as FTP, SSH, and WebDAV. Using these services, the NAS's virtual disks store data about individuals or groups, making them a critical analysis target for digital forensics. Well‐known storage manufacturers like Seagate, Synology, and NETGEAR use Linux‐based software RAID, and they usually support Berkeley RAID (e.g., RAID 0, 1, 5, 6, and 10) as well as self‐developed hybrid RAID. Those manufacturers have published data on the introduction and features of hybrid RAID, but there is not enough information to reassemble RAID from a digital forensic perspective. Besides, digital forensic tools (such as EnCase, FTK, X‐ways, and RAID Reconstructor) do not support automatic RAID reassembly for hybrid RAID, so research on hybrid RAID reassembly methods is necessary. This paper analyzes the disk array composed of hybrid RAID and explains the layout of disk array, partition layout in hybrid RAID, and hybrid RAID configuration strategy. Furthermore, it suggests parameters that are required for RAID reassembly and then propose a hybrid RAID reassembly procedure using them. Finally, we propose a proof‐of‐concept tool (Hybrid RAID Reconstructor) that identifies hybrid RAID from disk array and parse RAID parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
3. Auxetic Two‐Dimensional Nanostructures from DNA**.
- Author
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Li, Ruixin, Chen, Haorong, and Choi, Jong Hyun
- Subjects
- *
AUXETIC materials , *POISSON'S ratio , *DNA folding , *DEFORMATIONS (Mechanics) , *MOLECULAR dynamics , *NANOSTRUCTURES - Abstract
Architectured materials exhibit negative Poisson's ratios and enhanced mechanical properties compared with regular materials. Their auxetic behaviors emerge from periodic cellular structures regardless of the materials used. The majority of such metamaterials are constructed by top‐down approaches and macroscopic with unit cells of microns or larger. There are also molecular auxetics including natural crystals which are not designable. There is a gap from few nanometers to microns, which may be filled by biomolecular self‐assembly. Herein, we demonstrate two‐dimensional auxetic nanostructures using DNA origami. Structural reconfigurations are performed by two‐step DNA reactions and complemented by mechanical deformation studies using molecular dynamics simulations. We find that the auxetic behaviors are mostly defined by geometrical designs, yet the properties of the materials also play an important role. From elasticity theory, we introduce design principles for auxetic DNA metamaterials. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
4. Auxetic Two‐Dimensional Nanostructures from DNA**.
- Author
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Li, Ruixin, Chen, Haorong, and Choi, Jong Hyun
- Subjects
- *
AUXETIC materials , *POISSON'S ratio , *DNA folding , *DEFORMATIONS (Mechanics) , *MOLECULAR dynamics , *NANOSTRUCTURES - Abstract
Architectured materials exhibit negative Poisson's ratios and enhanced mechanical properties compared with regular materials. Their auxetic behaviors emerge from periodic cellular structures regardless of the materials used. The majority of such metamaterials are constructed by top‐down approaches and macroscopic with unit cells of microns or larger. There are also molecular auxetics including natural crystals which are not designable. There is a gap from few nanometers to microns, which may be filled by biomolecular self‐assembly. Herein, we demonstrate two‐dimensional auxetic nanostructures using DNA origami. Structural reconfigurations are performed by two‐step DNA reactions and complemented by mechanical deformation studies using molecular dynamics simulations. We find that the auxetic behaviors are mostly defined by geometrical designs, yet the properties of the materials also play an important role. From elasticity theory, we introduce design principles for auxetic DNA metamaterials. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Combination of step sizes for affine projection algorithm with variable mixing parameter.
- Author
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Choi, Jong Hyun, Cho, Hyeonwoo, Jeong, Jae Jin, and Kim, Sang Woo
- Abstract
An algorithm that introduces a novel scheme for the combination of the two adaptation terms of the affine projection algorithm with different step sizes is proposed. The mixing parameter of the proposed algorithm is determined by minimising the mean‐square deviation. The simulation results show that the proposed algorithm has a faster convergence rate and a smaller steady‐state error than other existing combination algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
6. Engineering the Nanoscaled Morphologies of Linear DNA Homopolymers.
- Author
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Zheng, Mengxi, Li, Qian, Paluzzi, Victoria E., Choi, Jong Hyun, and Mao, Chengde
- Subjects
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DNA , *SUPRAMOLECULAR polymers , *FINITE rings , *SYSTEMS engineering - Abstract
Supramolecular polymers have unique characteristics such as self‐healing and easy processing. However, the scope of their structures is limited to mostly either flexible, random coils or rigid, straight chains. By broadening this scope, novel properties, functions, and applications can be explored. Here, DNA is used as a model system to engineer innovative, nanoscaled morphologies of supramolecular polymers. Each polymer chain consists of multiple copies of the same short (38–46 nucleotides long) DNA strand. The component DNA strands first dimerize into homo‐dimers, which then further assemble into long polymer chains. By subtly tuning the design, a range of polymer morphologies are obtained; including straight chains, spirals, and closed rings with finite sizes. Such structures are confirmed by AFM imaging and predicted by molecular coarse simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Recent advances in metabolic engineering of Corynebacterium glutamicum as a potential platform microorganism for biorefinery.
- Author
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Baritugo, Kei‐Anne G., Kim, Hee Taek, David, Yokimiko C., Choi, Jong Hyun, Choi, Jong‐il, Kim, Tae Wan, Park, Chulhwan, Hong, Soon Ho, Na, Jeong‐Geol, Jeong, Ki Jun, Joo, Jeong Chan, and Park, Si Jae
- Subjects
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CORYNEBACTERIUM glutamicum , *PETROLEUM refineries , *LIGNOCELLULOSE , *BIOMASS energy , *GALACTOSE - Abstract
Abstract: The fermentative production of platform chemicals in biorefineries is a sustainable alternative to current petroleum‐refining processes. Industrial microorganisms, such as Escherichia coli, Saccharomyces cerevisiae, and Corynebacterium glutamicum, have been engineered as microbial cell factories that are able to utilize biomass for the production of value‐added platform chemicals and polymers. Compared to E. coli and S. cerevisiae, C. glutamicum displays weak carbon catabolite repression and can co‐utilize mixed sugars as carbon sources, without any significant growth retardation. Pathways for the utilization of alternative carbon sources, such as d‐xylose and l‐arabinose from lignocellulosic biomass, lactose and galactose from whey, glycerol from biodiesel, and methanol from natural gas refineries, have been evaluated for chemical production. However, the application of C. glutamicum in biorefineries is limited because it does not secrete hydrolases for the efficient utilization of cellulose, xylan, and starch from lignocellulosic and starch biomass. To solve the limitation, C. glutamicum has been engineered for the consolidated bioprocessing of biomass by the heterologous expression of amylolytic and cellulolytic enzymes. Recently, C. glutamicum has been extensively engineered for polyamide monomer production owing to its ability to produce l‐lysine and l‐glutamate. This review summarizes recent advances in the development of C. glutamicum strains that can utilize renewable biomass resources for the production of industrially important chemicals. It highlights recent progress in metabolic engineering for the production of polyamide monomers. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
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