• JSTS:Journal of Semiconductor Technology and Science
• /
• v.11 no.2
• /
• pp.121-129
• /
• 2011

It is progressing as new advents and remarkable developments of mobile device every year. On the upper line reason, NAND FLASH large density memory demands which can be stored into portable devices have been dramatically increasing. Therefore, the cell size of the NAND Flash memory has been scaled down by merely 50% and has been doubling density each per year. [1] However, side effects have arisen the cell distribution and reliability characteristics related to coupling interference, channel disturbance, floating gate electron retention, write-erase cycling owing to shrinking around 20nm technology. Also, FLASH controller to manage shrink effect leads to speed and current issues. In this paper, It will be introduced to solve cycling, retention and fail bit problems of sub-deep micron shrink such as Virtual negative read used in moving read, randomization. The characteristics of retention, cycling and program performance have 3 K per 1 year and 12.7 MB/s respectively. And device size is 179.32 $mm^2$ (16.79 mm ${\times}$ 10.68 mm) in 3 metal 26 nm CMOS.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.1
• /
• pp.79-89
• /
• 2014

It has been an increase in consumers who want a high-capacity and fast speed by the newly diffused mobile device(Smart phones, Ultra books, Tablet PC). As a result, the demand for Flash Memory is constantly increasing. Flash Memory is separated by a NAND-type and NOR-type. NAND-type Flash Memory speed is slow, but price is cheaper than the NOR-type Flash Memory. For this reason, NAND-type Flash Memory is widely used in the mobile market. So Fault Detection is very important for Flash Memory Test. In this paper, Proposed PMBIST for Pattern Test of NAND-type Flash Memory improved Fault detection.

• Proceedings of the IEEK Conference
• /
• 2007.07a
• /
• pp.355-356
• /
• 2007

This paper proposes a new panoramic image synthesis method using flash and no-flash image pairs, which reduces undesirable artifacts. Generally, in panoramic images, it is difficult to determine to use a flash in indoor environment. A flash image has unwanted artifacts such as hot spots and tunnel effect whereas a no-flash image also has artifacts like glass reflection. We derive cross projection tensors using flash and no-flash image pairs and transform the gradient field of a no-flash image using them. The image reconstructed from the modified gradient provides enhanced results, which are applied to synthesis of panoramic images. The proposed method can provide a better panoramic image than the conventional method. Experimental results show the effectiveness of the proposed method.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.18 no.1
• /
• pp.31-40
• /
• 2023

Recent advances in flash technologies, such as 3D processing and multileveling schemes, have successfully increased the flash capacity. Unfortunately, these technology advances significantly degrade flash's reliability due to a smaller cell geometry and a finer-grained cell state control. In this paper, we propose an asymmetric BER-aware reliability optimization technique (aBARO), new flash optimization that improves the flash reliability. To this end, we first reveal that bit errors of 3D NAND flash memory are highly skewed among flash cell states. The proposed aBARO exploits the unique per-state error model in flash cell states by selecting the most error-prone flash states and by forming narrow threshold voltage distributions (for the selected states only). Furthermore, aBARO is applied only when the program time (tPROG) gets shorter when a flash cell becomes aging, thereby keeping the program latency of storage systems unchanged. Our experimental results with real 3D MLC and TLC flash devices show that aBARO can effectively improve flash reliability by mitigating a significant number of bit errors. In addition, aBARO can also reduce the read latency by 40%, on average, by suppressing the read retries.

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

• Journal of the Korean Society of Safety
• /
• v.34 no.1
• /
• pp.34-39
• /
• 2019

Flash point is the important indicator to determine fire and explosion hazards of liquid solutions. In this study, flash points of n-propanol+n-hexanol and n-butanol+n-hexanol systems were obtained by Seta flash tester. The methods based on UNIFAC equation and multiple regression analysis were used to calculate flash point. The calculated flash point was compared with the experimental flash point. Absolute average errors of flash points calculated by UNIFAC equation are $2.9^{\circ}C$ and $0.6^{\circ}C$ for n-propanol+n-hexanol and n-butanol+n-hexanol, respectively. Absolute average errors of flash points calculated by multiple regression analysis are $0.5^{\circ}C$ and $0.2^{\circ}C$ for n-propanol+ n-hexanol and n-butanol+n-hexanol, respectively. As can be seen from AAE, the values calculated by multiple regression analysis are noticed to be better than the values by the method based on UNIFAC eauation.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.1
• /
• pp.1-13
• /
• 2009

Flash memory is widely used as a storage medium of mobile devices such as MP3 players, cellular phones and digital cameras due to its tiny size, low power consumption and shock resistant characteristics. Currently, there are many studies to replace HDD with flash memory because of its numerous strong points. To use flash memory as a storage medium, FTL(Flash Translation Layer) is required since flash memory has erase-before-write constraints and sizes of read/write unit and erase unit are different from each other. Recently, new type of flash memory called "large block flash memory" is introduced. The large block flash memory has different physical structure and characteristics from previous flash memory. So existing FTLs are not efficiently operated on large block flash memory. In this paper, we propose an efficient FTL for large block flash memory based on FAST(Fully Associative Sector Translation) scheme and page-level mapping on data blocks.

• Journal of the Korean Society of Safety
• /
• v.30 no.4
• /
• pp.86-91
• /
• 2015

The flash point is used to categorize inflammable liquids according to their relative flammability. Such a categorization is important for the safe handling, storage, and transportation of inflammable liquids. The flash point temperature of two binary liquid mixtures(n-octane+n-decane and n-octane+n-dodecane) has been measured for the entire concentration range using Seta-flash closed cup tester based on the ASTM D3278 method. The closed cup flash point temperature was estimated using the UNIFAC(Universal Functional Activity Coefficient) group contribution model. The experimentally derived flash point was also compared with the predicted flash point from the UNIFAC model. The UNIFAC model is able to estimate the flash point fairly well for n-octane+n-decane mixture and n-octane+n-dodecane mixture.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.5
• /
• pp.546-553
• /
• 2015

Recently, flash cache is widely adopted as the performance accelerator of legacy storage systems. Unlike other cache media, flash cache should be carefully managed as it has peculiar characteristics such as long write latency and limited P/E cycles. In particular, we make two prominent observations that can be utilized in managing flash cache. First, a serious worn-out problem happens when the working-set of a system is beyond the capacity of flash cache due to excessively frequent cache replacement. Second, more than 50% of data has no hit in flash cache as it is a second level cache. Based on these observations, we propose a cache admission control policy that does not cache data when it is first accessed, and inserts it into the cache only after its second access occurs within a certain time window. This allows the filtering of data disruptive to flash cache in terms of endurance and performance. With this policy, we prolong the lifetime of flash cache 2.3 times without any performance degradations.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.362-362
• /
• 2020

Flash flood is a dangerous weather phenomenon, affecting humans and the economy. The identification, forecast of the changing trend and its characteristics are increasingly concerned. In the world, there have many methods for determining the characteristics of flash floods, in which flash flood guidance (FFG) is a fast, effective and widely used method. The main source of flash floods is short-term rainfall. In this study, we used the data of cross-sectional measurement at the tributaries and the hourly rain data from the automatic rainfall measurement stations in the Geum river basin. Besides, we use a combination of the flash flood guidance and the best fit distribution function to estimate the repeatability of flash floods for head-water catchments in Geum river basin. In which, FFG determines the threshold of rainfall for flash floods. The study has determined the best hourly rainfall distribution function for the Geum river basin and estimated the maximum rainfall of 1hr according to the return periods.