• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.21-30
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• 2009

Fusion flash memory such as OneNAND$^{TM}$ is popular as a ubiquitous storage device for embedded systems because it has advantages of NAND and NOR flash memory that it can support large capacity, fast read/write performance and XIP(eXecute-In-Place). Besides, OneNAND$^{TM}$ provides not only advantages of hybrid structure but also multi-block erase function that improves slow erase performance by erasing the multiple blocks simultaneously. But traditional NAND Flash Translation Layer may not fully support it because the garbage collection of traditional FTL only considers a few block as victim block and erases them. In this paper, we propose an Erase Group Flash Translation Layer for improving multi-block erase function. EGFTL uses a superblock scheme for enhancing garbage collection performance and invalid block management to erase multiple blocks simultaneously. Also, it uses clustered hash table to improve the address translation performance of the superblock scheme. The experimental results show that the garbage collection performance of EGFTL is 30% higher than those of traditional FTLs, and the address translation performance of EGFTL is 5% higher than that of Superblock scheme.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.685-689
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• 2009

Flash memory has several features such as low~power consumption and fast access so that there has been various research on using flash memory as new storage. Especially the Solid State Disk which is composed of flash memory chips has recently replaced the hard disk. At present, SSD adopts the multi-channel and multi-way architecture to exploit advantages of parallel access. In this architecture, data are written on SSD in a unit of a superblock which is composed of multiple blocks in which some blocks are put together. This paper proposes two schemes of selecting, segmenting and re-composing victim superblocks to optimize concurrent processing when a buffer flush occurs. The experimental results show that 35% of superblock- based write operations is reduced by selecting victims and additional 9% by composition of superblock.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.8
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• pp.109-118
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• 1994

We proposed new field/frame mode selection quantization and buffer control strategy for interlaced digital HDTV image coding system. The field/frame mode selection is performed based on the mean square error and number of generated bits for each superblock. The quantization factor for each superblock is determined by the characteristics of human visual system and buffer status. The statistical characteristics of the number of generated bits for basis block and the prediction of buffer status are used for buffer control. Simulation results show that the proposed field/frame mode selection and rate buffer control. Simulation results show that the proposed field/frame mode selection and rate buffer control strategy have good subjective image quality and have stable buffer status.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.8-16
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• 2022

In this paper, we propose a method of reconstructing the file system to obtain digital forensics information from the APFS file system when meta information that can know the structure of the file system is deleted due to partial damage to the disk. This method is to reconstruct the tree structure of the file system by only retrieving the B-tree node where file/directory information is stored. This method is not a method of constructing nodes based on structural information such as Container Superblock (NXSB) and Volume Checkpoint Superblock (APSB), and B-tree root and leaf node information. The entire disk cluster is traversed to find scattered B-tree leaf nodes and to gather all the information in the file system to build information. It is a method of reconstructing a tree structure of a file/directory based on refined essential data by removing duplicate data. We demonstrate that the proposed method is valid through the results of applying the proposed method by generating numbers of user files and directories.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.10
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• pp.71-82
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• 2019

This study tried to prove why a low-rise residential block is more vitalized than in a superblock consisted of an apartment housing complex. To do this, two adjacent superblocks in Yeoksam 2-dong were selected as a case study among superblocks of residential area in Gangnam, Seoul. It adopted the concept of 'complexity', 'Osmosis', 'Vitality' and 'Permeability' for evaluation indexes to measure street vitality. As a result, four indexes were clearly higher in low-density residential superblocks than apartment housing complex superblocks. First, the superblocks for apartment housing complexes showed a lower 'complexity' because large-scale parcels for an apartment housing complex reduces a possibility for various land uses. Second, smaller blocks improved "osmosis" compared to larger blocks, and the larger the block, the less likely it is that buildings and streets penetrate activity. Third, as the apartment complex block became larger, the number of accesses decreased. Thus, it did not provide vitality to the streets. Fourth, high permeability was shown in the low-density superblocks, while that of the superblock consisted of apartment housing complexes was very low because the entrance of the complexes entrance is closed to the public. The results of this study demonstrated that an apartment housing complex may hamper street vitality and deteriorate the quality of urban environments.

• Journal of the Korean housing association
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• v.26 no.6
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• pp.127-137
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• 2015

This investigation is to question as to whether and how much urban residential superblocks have changed the uses of facilities, as compared with original zoning plan. The difference between the original plan for 'land use' in 1960's and current 'building uses' has been examined on six superblocks in Seoul, and the reasons for change were analyzed. Investigation results are as follows: As the original urban planning was intended for use-purification by the subdivision of zones in a superblock through zoning, current buildings uses are different from the land-use. Commercial facilities are located in residential zone along community paths because of the necessity, and business buildings are placed on the appropriate-sized lots in the middle of residential blocks, due to the need of small and low-rent offices. Also, different types of residence have been built on convenient locations in commercial zone to meet various housing needs. In conclusion, the current zoning system plays a role of controling the volume of buildings rather than the use of land. Therefore, mixed use of land, not functional separation, becomes a natural phenomenon taken place in the contemporary cities, and it is high time to adopt a mixed-use zoning system.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.572-583
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• 2020

The purpose of this study is to find out how to effectively utilize the public facilities site that is being used in the new town for the expansion of newly required public facilities, because it is difficult to carry out redevelopment projects in apartment complexes of 1st generation new town due to the rigidity of land use and macroeconomic conditions. This study examined the following three ways to effectively utilize existing public facilities sites for Pyeongchon new town. First, it suggested how to secure the parking lot by deciding multi-dimensional urban planning facility of public facilities such as parks and schools in superblock that lacks parking space of apartment complex. Second, it suggested a plan to accommodate the demands of public facilities required by increasing the building density of existing public buildings in commercial district as an example of the Anyang Tax Office. Lastly, it suggested a way to install additional functions required by users through the reorganization of the existing public facilities and some extensions by examining the Pyeongchon library.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.495-502
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• 2023

If traditional Korean villages or residential districts have formed a community on the ground of coexisting with nature, there is a different historical development process in which many European cities have created residences for multi households on the basis of roads and blocks in fortresses. Along with the modernization of society together with large-scale housing supply, the urban landscape of series of large apartment complexes has become universal views of our urban structure; thus, the viewpoint that small and medium-sized block-based collective housing, which are more common urban structures in European cities can be linked to the improvement of urbanity and neighborship is examined. Through the process, the possibility of expanding collective housing supply based on small and medium-sized blocks as an alternative method other than complex-type apartments based on superblock, I would like to make meaningful in terms of how we can change the fundamental mutual relationship with our lifestyle and the tangible change of collective housing types which has large impact on our lives.