• The KIPS Transactions:PartD
• /
• v.19D no.2
• /
• pp.161-186
• /
• 2012

Recently, the flash memory consistently increases the storage capacity while the price of the memory is being cheap. This makes the mass storage SSD(Solid State Drive) popular. The flash memory, however, has a lot of defects. In order that these defects should be complimented, it is needed to use the FTL(Flash Translation Layer) as a special layer. To operate restrictions of the hardware efficiently, the FTL that is essential to work plays a role of transferring from the logical sector number of file systems to the physical sector number of the flash memory. Especially, the poor performance is attributed to Erase-Before-Write among the flash memory's restrictions, and even if there are lots of studies based on the log block, a few problems still exists in order for the mass storage flash memory to be operated. If the FAST based on Log Block-Based Flash often is generated in the wide locality causing the random writing, the merge operation will be occur as the sectors is not used in the data block. In other words, the block thrashing which is not effective occurs and then, the flash memory's performance get worse. If the log-block makes the overwriting caused, the log-block is executed like a cache and this technique contributes to developing the flash memory performance improvement. This study for the improvement of the random writing demonstrates that the log block is operated like not only the cache but also the entire flash memory so that the merge operation and the erase operation are diminished as there are a distinct mapping table called as the offset mapping table for the operation. The new FTL is to be defined as the XAST(extensively-Associative Sector Translation). The XAST manages the offset mapping table with efficiency based on the spatial locality and temporal locality.

• Korean Journal of Soil Science and Fertilizer
• /
• v.9 no.3
• /
• pp.149-163
• /
• 1976

In Korea, the ever-increasing population has become a serious problem and the decreasing of cultivated lard area per person has become a major concern. Therefore, today we are implementing a green revolution using miracle varieties which require more fertilizer. The increased use of fertilizer along with development and adoption of high yielding varieties is the key to carrying out this green revolution. Fertilizer consumption in Korea is mainly influenced by agricultural techniques, fertilizer prices and government policies for increasing food production. If there are no special change, such as a cataclysm or an exhaustion of resources, it is quite clear that the fertilizer demand will increase to the near maximum ceiling point of optimum levels for crops in the year 2000. Fertilizer demand is not the amount of fertilizer that will be used by the farmer, but the actual optimum amount of plant nutrients required for maximum production. In this report, two alternative strategies are consideded in forecasting the future feitilizer demands. Alternative I is projected by reviewing consumption amounts over the last 10 years (1966~75) in Korea. The annual rate of increase in fertilizer consumption for the last 10 years was approximately 8.7% (table 1). Plant nutrient consumption rates in later years have been more balanced, and also fertilizer consumption per total acreage is considerably higher in Korea than in other countries (table 11), consequently the rate of increase in the future is expected to decline. Looking at the long term projections, the average annual rate of increase is expected to be 7% for 1976~80, 2.5% for 1981~90, 1.5% for 1991~2000. Thus, total projected fertilizer demands are estimated at 1,208,000M/T by 1980, 1,547,000M/T by 1990, 1,795,000M/T by 2000 (table 16). Alternative II is based on projected optimum fertilizer levels for crops and on increased crop acreage. The government recommended fertilizer rate has increased by a factor of 0.99 to 5.49 over the past twelve years depending on the specific crops (table 4). Levels of fertilizer demand recommended by government (table 7) in 1976 are still low compared with actual optimum fertilizer demands for crops (table 5). Therefore, future incaeases in fertilizer usage are anticipated. Thus, total projected fertilizer demands are estimated at 1,229,000M/T by 1980, 1,493,000M/T by 1990 and 1,898,000M/T by 2000(table 16).

• Food Science of Animal Resources
• /
• v.27 no.1
• /
• pp.117-121
• /
• 2007

The number of internet users and the scale of electronic on-line trading are on the increase due to the development of information technology and the internet. The aim of this study was to monitor the accuracy of country-of-origin labels and the indicated contents of meat available by electronic on-line trading by using a structural interview sheet for 100 on-line meat product markets. The result of this investigation showed a 100% level of accuracy for business name and telephone number whereas the company address, meat manufacturer and supplier, and business registration were less reliable. We also investigated the accuracy of site policy, e-mail address, and fax number. The results showed that the accuracy of fax numbers was the lowest. The product name and the kind of meat actually in the product showed a 100% level of conformity, while the price (96.3%), place of origin (93.6%), capacity (90.4%), meat parts (80.9%) and contents of the product (73.4%) showed a relatively low level of conformity. Serious safety issues were exposed by the disturbingly low 20.2% accuracy of indicated expiration dates and 5.3% accuracy of indicated manufacturing dates. To ensure food safety, it is essential to improve consumer understanding and trust regarding food safety through continuous public relations. More education and information are needed to raise consumer awareness of the facts versus myths regarding food safety.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.30 no.1
• /
• pp.127-134
• /
• 2024

With the growth of offshore wind power generation market, the corresponding installation vessel market is also growing. It is anticipated that approximately 100 installation vessels will be required in the of shore wind power generation market by 2030. With a price range of 300 to 400 billion Korean won per vessel, this represents a high-value market compared to merchant vessels. Particularly, the demand for large installation vessels with a capacity of 11 MW or more is increasing. The rapid growth of the offshore wind power generation market in the Asia-Pacific region, centered around China, has led to several discussions on orders for operational installation vessels in this region. The seabed geology in the Asia-Pacific region is dominated by clay layers with low bearing capacity. Owing to these characteristics, during vessel operations, significant spudcan and leg penetration depths occur as the installation vessel rises and descends above the water surface. In this study, using penetration variables ranging from 3 to 21 m, the unique vibration period, structural safety of the legs, and conductivity safety index were assessed based on penetration depths. As the penetration depth increases, the natural vibration period and the moment length of the leg become shorter, increasing the margin of structural strength. It is safe against overturning moment at all angles of incidence, and the maximum value occurs at 270 degrees. The conditions reviewed through this study can be used as crucial data to determine the operation of the legs according to the penetration depth when developing operating procedures for WTIV in soft soil. In conclusion, accurately determining the safety of the leg structure according to the penetration depth is directly related to the safety of the WTIV.