• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.812-815
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• 2005

Effects of poly-${\gamma}$-glutamate (PGA) on antioxidative characteristics of amino-carbonyl reaction products of glucose were investigated. Rapid browning reaction was observed under heat and alkaline condition (pH 8.2). Browning products were separated by Sephadex G-50, and brown color intensity and electron-donating ability of DPPH (2,2-diphenyl-1-picrylhydrazyl) of each fraction were measured. Fraction-7 (F-7) and -20 (F-20) showed high DPPH scavenging values. UV-VIS absorption spectrum of F-20 was similar to melanoidin peak, and F-7 showed maximum absorption peak at 270 nm. Molecular weight of F-7 was over 35 kDa as determined by SDS-PAGE. Although F-20 could not be measured on SDS-PAGE, its size was smaller than F-7.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1333-1334
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• 2007

Page-oriented angle multiplexing Holographic data storage system is the one of promising techniques for high capacity and data transfer rate, but its size and narrow tilt margin is pointed as a demerit. To overcome this weak point, in this paper, 2-axis deck mechanism for compensation of disc is employed to Compact size Holographic Data Storage (CHDS) which consists of minimized optical components and small 2-axis actuator moving linear & angle direction. Compensation of radial/tangential disc tilt with 2-axis deck mechanism is demonstrated.

• Journal of the Ergonomics Society of Korea
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• v.31 no.2
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• pp.309-317
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• 2012

Objective: The aim of this paper is to inquire into the influences form factors and control types affect a search time and comfort at list menu of full touch phone. Background: Various studies have been proceeded that are related to the optimum touch area for enhancing usability of control and legibility in mobile touch device. In the environment of list menu which is widely used to provide various information effectively, however, not only comprehensive consideration for legibility and control is to be seek but also research for control type which is to scroll a list. Method: This study executed form factor experiment to inquire into the influence that font size, height of row and fixed area affect searching time and comfort in the while information processing even if the information on the list is unsorted in alphabetical order. Among the result of form factor experiment, control type experiment was executed by selecting shortest performance time, highest legibility comfort and control comfort. Control type experiment was implemented to figure out the influence which existing flicking type, scrolling bar type, newly established button page type and button raw types affect performance time and subjective comfort depending on location of the information. Results: Font size 12pt, height of row 7mm and fixed area 15mm was shortest performance time and got highest comfort and legibility score in form factor experiment. A Button page which was newly proposed type was shortest performance time and got highest comprehensive comfort in control type experiment. Conclusion: Form factor experiment showed similar results with the study through reading a long passage of character or controlling a grid icon type. However, height of row turned out to affect not only touch area for control but also legibility by ruling space between the lines. Button page type which was newly proposed showed shortest performance time and got highest comprehensive comfort. Because Button page type needs few finger movements than other control types and implements search in the fixed form, unlikely other type which list keeps moving. Application: This study should be applied in deciding form factors and control type for scroll when designing a list menu of full touch phone.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.463-476
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• 2006

R-trees have been traditionally optimized for the I/O performance with the disk page as the tree node. Recently, researchers have proposed cache-conscious variations of R-trees optimized for the CPU cache performance in main memory environments, where the node size is several cache lines wide and more entries are packed in a node by compressing MBR keys. However, because there is a big difference between the node sizes of two types of R-trees, disk-optimized R-trees show poor cache performance while cache-optimized R-trees exhibit poor disk performance. In this paper, we propose a cache and disk optimized R-tree, called the PR-tree (Prefetching R-tree). For the cache performance, the node size of the PR-tree is wider than a cache line, and the prefetch instruction is used to reduce the number of cache misses. For the I/O performance, the nodes of the PR-tree are fitted into one disk page. We represent the detailed analysis of cache misses for range queries, and enumerate all the reasonable in-page leaf and nonleaf node sizes, and heights of in-page trees to figure out tree parameters for best cache and I/O performance. The PR-tree that we propose achieves better cache performance than the disk-optimized R-tree: a factor of 3.5-15.1 improvement for one-by-one insertions, 6.5-15.1 improvement for deletions, 1.3-1.9 improvement for range queries, and 2.7-9.7 improvement for k-nearest neighbor queries. All experimental results do not show notable declines of the I/O performance.

• The KIPS Transactions:PartD
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• v.14D no.4 s.114
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• pp.447-458
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• 2007

The objective of this study is to provide faster mobile web service by improving performance of Contents Cache used for mobile web service in the existing Mobile Gate System. It was found that two elements existed in Mark-Up page transcoded by Contents Generator. One of the elements was dependent only on the requested DIDL page and Mark-Up type. The other was dependent on each of the requested DIDL page, Mark-Up type, size of mobile display 모바일 장치 to request service, type of images available and color depth count of the images available. The conventional Contents Cache saved the entire Mark-Up page to hold both of the two elements. This caused the problem where storage space was not effectively used because reusable elements were repetitively saved in cache memory domain due to change in one of the elements even though all the other elements were the same. As a result, a larger number of transcoded Mark-Up pages could not be saved in the same cache memory size. Therefore, in this study, Mark-Up pages transcoded by Contents Generator were divided into two elements and were separately saved. Also, in order to respond to the demand for replacing data in cache with new data, this study applied two algorithms of LFU and LRU. This study proposed the method to implement cache performance of faster speed by enabling to save more number of the transcoded Mark-Up pages in the same cache storage space.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.77-86
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• 2008

False sharing is a result of co-location of unrelated data in the same unit of memory coherency, and is one source of unnecessary overhead being of no help to keep the memory coherency in multiprocessor systems. Moreover, the damage caused by false sharing becomes large in proportion to the granularity of memory coherency. To reduce false sharing in page-based DSM systems, it is necessary to allocate unrelated data objects that have different access patterns into the separate shared pages. In this paper we propose sized and call-site tracing-based shared memory allocator, shortly SCSTallocator. SCSTallocator places each data object requested from the different call-sites into the separate shared pages, and at the same time places each data object that has different size into different shared pages. Consequently data objects that have the different call-site and different object size prohibited from being allocated to the same shared page. Our observations show that our SCSTallocator outperforms the existing dynamic shared memory allocators. By combining the two existing allocation technique, we can reduce a considerable amount of false sharing misses.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.291-302
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• 2013

NAND flash memory (NFM) based storage devices, e.g. Solid State Drive (SSD), are rapidly replacing conventional storage devices, e.g. Hard Disk Drive (HDD). As NAND flash memory technology advances, its specification has evolved to support denser cells and larger pages and blocks. However, efforts to fully understand their impacts on design objectives such as performance, power, and cost for various applications are often neglected. Our research shows this recent trend can adversely affect the design objectives depending on the characteristics of applications. Past works mostly focused on improving the specific design objectives of NFM based systems via various architectural solutions when the specification of NFM is given. Several other works attempted to model and characterize NFM but did not access the system-level impacts of individual parameters. To the best of our knowledge, this paper is the first work that considers the specification of NFM as the design parameters of NAND flash storage devices (NFSDs) and analyzes the characteristics of various synthesized and real traces and their interaction with design parameters. Our research shows that optimizing design parameters depends heavily on the characteristics of applications. The main contribution of this research is to understand the effects of low-level specifications of NFM, e.g. cell type, page size, and block size, on system-level metrics such as performance, cost, and power consumption in various applications with different characteristics, e.g. request length, update ratios, read-and-modify ratios. Experimental results show that the optimized page and block size can achieve up to 15 times better performance than the conventional NFM configuration in various applications. The results can be used to optimize the system-level objectives of a system with specific applications, e.g. embedded systems with NFM chips, or predict the future direction of NFM.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1199-1203
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• 2010

Data transfer between host system and storage device is based on the data unit called sector, which can be varied depending on computer systems. If NAND flash memory is used as a storage device, the variant sector size can affect storage system performance since its operation is much related to sector size and page size. In this paper, we propose an efficient FTL mapping management scheme to support multiple sector size within one NAND flash memory based storage device, and analyze the performance effect and management overhead. According to the proposed scheme, the management overhead of proposed FTL management is lower than conventional scheme when various sector sizes are configured in computer systems, while performance is less degraded in comparison with single sector size support system.

• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.1-8
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• 2017

In this paper, we propose a file system for flash memory which remedies shortcomings of existing flash memory file systems. Besides supporting large block size, the proposed file system reduces time in initializing file system significantly by adopting logical address comprised of erase block number and bitmap for pages in the block to find a page. The file system is suitable for embedded systems with limited main memory since it has small in-memory data structures. It also provides efficient management of obsolete blocks and free blocks, which contribute to the reduction of file update time. Finally the proposed file system can easily configure the maximum file size and file system size limits, which results in portability to emerging larger flash memories. By conducting performance evaluation studies, we show that the proposed file system can contribute to the performance improvement of embedded systems.

• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1758-1764
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• 2008

In this paper, we propose query restructure method which realizes not only to present the result from database in Web page but also to adapt user's browsing environments. Recently, wireless PDA (Personal Digital Assistant) and portable phone and terminals equipped with Web browser become very popular. Various browsers would be required to create the HTML which adapt to the user's browsing environment. We propose an adaptive data presentation system which is an extension of SQL which creates HTML pages dynamically adapting to the size of screen. In our proposed method, the three basic rules for the layout conversion are provided and applying these rules, an efficient layout conversion technique optimized to user environment is proposed. Moreover, we propose a standard for converting layouts and a layout optimization for adaptive conversion of layouts.