• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.357-361
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• 2005

As flash technology is a widely used in Web pages, it tends to load a S/W flash player in mobile phones and PDAs to play flash contents on diverse H/W platforms currently. In this paper, we design and implement a linux-based standalone flash player which can be used in various fields like animation, game and advertizing. We also implement an web-based manager which user can effectively manage flash players anywhere.

• 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.8 no.1
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• pp.36-45
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• 2002

This paper introduces the design and implementation of a flash memory simulator to emulate a real flash memory. Since this simulator provides exact execution time information and parameter testing functions as well as the type, total capacity, block size, and page size of flash memory, it can be used as a real flash memory as viewed by the operating system. Furthermore, the simulator provides time logging functions of the internal routines of the flash memory management software allowing the monitoring of bottlenecks within the software. Finally, we show the performance measurements of applications under the Linux operating systems on both the simulator and a test board verifying the simulator's use as a replacement for real flash memory.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.143-146
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• 2003

In this paper, a new preform design method is proposed to eliminate the excessive flash in metal forging process. After carrying out finite element simulation of the process with an initial billet, backward particle tracing is performed from the outlet of the flash. Then, the region which belongs to the flash is easily found .. The process is analyzed again with the redesigned billet which is removed that region the above mentioned region. The optimal preform shape which minimizes the amount of flash without changing the forgibility can be obtained in several iterations.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.678-685
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• 1999

A UBET program is developed for determining flash the optimum sizes of preform and initial billet in plane-strain closed-die forging. The program consists of forward and backward tracing processes. In the forward program, flash, die filling and forging load are predicted. In backward tracing process the optimum dimensions of initial billet and preform are determined from the final-shape data based on flash design. Experiments are carried out with pure plasticine billets ar room temperature. The theoretical predictions of forging load and flow pattern are in good agree-ment with the experimental results.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.2
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• pp.146-151
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• 2009

It is known that muzzle flash can be generated by the reaction between the oxygen in the air and unburned gunpowder contained in the propellant gas if a barrel is not long enough to burn gunpowder fully inside of the barrel. A hugh muzzle flash, which is a characteristic of small arms with short barrel length, disturbs a shooter in aiming at the target at night by making the shooter blind for a while and endangers the shooter's life by revealing firing position to enemies. In addition, the heat of muzzle flash can deteriorate the performance of thermal sights, which are attached to small arms for effective night combat. In this paper, flash suppressors of different shapes were designed for a newly developed 5.56mm caliber rifle with short barrel length and the performance of each flash suppressor to reduce the muzzle flash was compared by on-site test firing. Through the test firing, a highly efficient design of flash suppressor for reducing the muzzle flash was identified. The result of the paper can be referred when designing flash suppressors for small arms with short barrel length.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.240-242
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• 2009

Flash memories are one of best media to support future computer's storages. However, we need to improve traditional data management scheme due to the relatively slow characteristics of flash operation of SSD. Due to the unique characteristics of flash media and hard disk, the efficiency of I/O processing is severely reduced without special treatment, especially in the presence of heavy workload or bulk data copy. In this respect, we need to design and develop efficient hybrid-RAID storage system.

• KIISE Transactions on Computing Practices
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• v.21 no.10
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• pp.639-644
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• 2015

The capacity of flash-based storage such as Solid State Drive(SSD) and embedded Multi Media Card(eMMC) is ever-increasing because of the needs from the end-users. However, if a flash-based storage crashes, such as during power failure, the flash translation layer(FTL) is responsible for the crash recovery based on the entire flash memory. The recovery time increases as the capacity of the flash-based storages increases. We propose O1FTL with O(1) crash recovery time that is independent of the flash capacity. O1FTL adopts the working area technique suggested for the flash file system and evaluates the design on a real hardware platform. The results show that O1FTL achieves a crash recovery time that is independent of the capacity and the overhead, in terms of I/O performance, and achieves a low P/E cycle.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.451-458
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• 2009

This experimental study was conducted to investigate macroscopic characteristics of the flash boiling spray with tow component mixing fuel. Homogeneous Charge Compression Ignition (HCCI) is a newer combustion method for internal combustion engines to reduce nitrogen oxide and particulate matter simultaneously. But it is difficult to put this combustion method to practical use in an engine because of such problems as instability of combustion in low load operating conditions and knocking in high load operating conditions. In HCCI, combustion characteristics and exhaust emissions depend on conditions of air/fuel mixture and chemical reactions of fuel molecules. The fuel design approach is achieved by mixing two components which differ in properties such as density, viscosity, volatility, ignitability and so on. We plan to apply the fuel design approach to HCCI combustion generated in a real engine, and examine the possibility of mixture formation control using the flash boiling spray. Spray characteristics of two component fuel with a flash boiling phenomenon was investigated using Shlieren and Mie scattering photography. Test fuel was injected into a constant volume vessel at ambient conditions imitated injection timing BTDC of a real engine. As a result, it was found that a flash boiling phenomenon greatly changed spray structure, especially in the conditions of lower temperature and density. Therefore, availability of mixture formation control using flash boiling spray was suggested.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.47-58
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• 2005

There are two major type of flash memory products, namely, NAND-type and NOR-type flash memory. NOR-type flash memory is generally deployed as ROM BIOS code storage because if offers Byte I/O and fast read operation. However, NOR-type flash memory is more expensive than NAND-type flash memory in terms of the cost per byte ratio, and hence NAND type flash memory is more widely used as large data storage such as embedded Linux file systems. In this paper, we designed an efficient flash memory file system based an Embedded system and presented to make up for reduced to Swapping a weak System Performance to flash file system using NAND-type flash memory, then proposed Swapping algorithm insured to an Execution time. Based on Implementation and simulation studies, Then, We improved performance bases on NAND-type flash memory to the requirement of the embedded system.