• Journal of Internet Computing and Services
• /
• v.24 no.6
• /
• pp.171-180
• /
• 2023

Hydrogen energy technology is gaining importance in the era of the Fourth Industrial Revolution, offering military advantages when applied to military vehicles due to its characteristics such as reduced greenhouse gas emissions, noise, and low vibration. Korea's military has initiated the Army Tiger 4.0 plan, focusing on hydrogen application, downsizing, and AI-based smart features. The Ministry of National Defense plans to collaborate with the Ministry of Environment to expand hydrogen charging stations nationwide, anticipating increased deployment of military hydrogen vehicles. However, considering the Jet Fire and VCE(Vapor Cloud Explosion) nature of hydrogen, ensuring safety during installation is crucial. Current military guidelines specify a minimum safety distance of 2m from adjacent buildings for charging stations. Scientific methods have been employed to quantitatively assess the accident damage range of hydrogen, proposing a minimum safety distance beyond the affected area.

• Korean Journal of Plant Resources
• /
• v.13 no.1
• /
• pp.1-10
• /
• 2000

Pecan is deciduous tree and belongs to the Julandaceae family. Pecan is an economically important as a nut and timber crop. Heterozygosity is expected to be high for typically cross-pollinated. Yet little is known about the nature of genetic variation within this species. In addition, the pedigree of many pecan cultivars remains unknown or is questionable. In this study, the phylogenetic relationships between 22 pecan cultivars and its analyzed by RAPD (randomly amplified polymorphic DNA). PCR Amplification used 40 randomly selected oligoes as primers. Based on their genetic similarities derived from the RAPD data, the 22 pecan cultivars were classified into different five groups in agarose gel. The 22 pecan cultivars were classified into five sectional groups by UPGMA clustering analysis, too. C. flacra and Black walnut showed the 0.9 of similarity index and Farley, Pawnee showed the 0.85 of similarity index. The 22 pecan cultivars were classified into different five groups by analysis of the 4% polyacrylamide gel fraction. (Group I : 1, 2, 3, 4, 13, 16, 17, 20, 21 Group II : 14,18 GroupIII : 6,12 GroupIV : 5, 11, 15, 19, 22 CroupV : 7, 8, 9, 10) Group V show the 1.0 of similarity index and Farley, Sturya, Clarke, Pawnee show the 0.98 of similarity index and Kiowa, Schley show the 0.92 of similarity index. Results from this study indicated that RAPD can be used to establish the genetic relationships among the 22 pecan cultivars. Similarity coefficients generally agreed with what would be predicted in cultivars with known pedigrees, and we could accurately construct relationships among cultivars. In addition, we have shown that RAPD provides useful information on the origin of unknown cultivars.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1151-1156
• /
• 2011

Leveraged buyouts (LBO) means the acquisition of a company using bonds and loans. There are the prolific volumes of LBO transactions in the international M&A markets, and its influence to the financial market is increasingly huge. However, there are very few LBO transaction in the domestic M&A market and there are also few researches in this field due to the private nature of LBO transactions. Once a company is privatized through a LBO transaction, it is not so long before it is relisted on the stock exchange or it is resold to a third-party investor. In order to repay the borrowed money, an LBO investor may decide to end a company's private status through an exit via an initial public offering (IPO) or a takeover. In this paper, we expand Kaplan's study on the organizational status of post leveraged buyout (LBO) transaction. We find that there is a significant change starting 1986. Most notably, fewer LBOs remain private, the median holding period of the LBO was cut in half to 3.2 years and of those that exit, IPO exits had significantly shorter holding periods. Regression analysis shows that good market conditions lengthen the holding period of a LBO investment whereas the size of the transaction shortens it.

• Journal of the Korean association of regional geographers
• /
• v.10 no.1
• /
• pp.192-205
• /
• 2004

The purpose of this paper is to analyze the factors, which have influence upon changes of hydrological environment in time series, and evaluate water balance changes caused by urbanization. The results of the analysis and evaluation are as follow: At first, the river runoff at Gwangju River Basin keep base flow of river by storage capacity recharged in June to September and show peak in August and minimum flow in May. The groundwater recharge by urbanization accounted for 46.1% of rainfall at early-urban stage, and decreased to 36.5% and 29.9% in the 1960's and the 1990's respectively, and is likely to decrease to 27.8% in the 2010's. On the other hand, the overland flow was 9.6% of rainfall in the 1960's and 16.2% in the 1990's, and is likely to increase to 18.3% in the 2010's. When such a phenomenon is kept continuously, distorted water balance shall be worsened to create not only frequent occurrence of urban flood but also decreased base flow of Gwangju River to accelerate dry stream phenomenon. The time series study on urban redevelopment and environment maintenance describes distorted phenomenon to supply the information for nature-friendly land use, and examines relations between human activities and natural environment.

• Journal of the Korean earth science society
• /
• v.36 no.6
• /
• pp.512-519
• /
• 2015

Although Quaternary marine terraces and onshore paleo-shoreline records provide clues to our understanding for the mode and nature of neotectonics in the Korean peninsula, it cannot be accomplished without knowledge on both independent information of the past sea level records and tectonic deformation field together with precise results of numerical dating for higher terraces. This study reported cosmogenic radionuclides ($^{10}Be$) dating results conducted in higher terraces in the eastern and western coasts of the Korean peninsula. As a result, the measured concentration ratio of $^9Be/^{10}Be$ and the exposure ages were much younger than expected. It implies that either there is possibility of error in experimental processes or the samples experienced a complex exposure history probably included a burial at some stage. Considering the past climatic conditions around the Korean peninsula and a possible complex exposure history after the emergence of marine terrace, the discovery of a suitable study area and a sampling site are an essential part of successful $^{10}Be$ dating technique.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.3
• /
• pp.7-17
• /
• 2010

In this paper, an innovative low-power SRAM based on 4-transistor latch cell is described. The memory cells are composed of two cross-coupled inverters without access transistors. The sources of PMOS transistors are connected to bitlines while the sources of NMOS transistors are connected to wordlines. They are accessed by totally new read and write method which results in low operating power dissipation in the nature. Moreover, the design reduces the leakage current in the memory cells. The proposed SRAM has been demonstrated through 16-kbit test chip fabricated in a 0.18-${\mu}m$ CMOS process. It shows 17.5 ns access at 1.8-V supply while consuming dynamic power of $87.6\;{\mu}W/MHz$ (for read cycle) and $70.2\;{\mu}W/MHz$ (for write cycle). Compared with those of the conventional 6-transistor SRAM, it exhibits the power reduction of 30 % (read) and 42 % (write) respectively. Silicon measurement also confirms that the proposed SRAM achieves nearly 64 % reduction in the total standby power dissipation. This novel SRAM might be effective in realizing low-power embedded memory in future mobile applications.

• Korean Journal of Heritage: History & Science
• /
• v.37
• /
• pp.349-369
• /
• 2004

Today, in the cultural properties research, there are several methods for knowing the culture of the past through a lot of information that remains and relics contain. Especially, statistical method like presumption of producing center were introduced from computer development at the early 20th century. This study showed the characteristic about firing historic sites presumed as a tile-kiln in the remains of Cheonwang temple sites, Hanam, Gyeonggi province. Also, I used nature scientific methods for correlation between tiles excavated at historic sites and circumference building and obtained there results as follows. First, soft tile parts showed similar water suction ratio(over 10%) like another tiles, except hard tile parts. Second, identification about mineral crystallization in a sample showing low water suction ratio confirmed a result that Mullite, Tridymite, Cristobalite as high temperature crystal form were presented. I know that firing temperature was higher than the other tile parts from this result. Third, statistical analysis from micro-component resulted that tiles excavated at firing historic sites and Cheonwang temple sites were closely connected. As the results, I knew that the tiles got a supply after the establishment of tile-kiln, not at a long distance at the period of Cheonwang temple construction.

• Journal of Convergence for Information Technology
• /
• v.11 no.8
• /
• pp.36-41
• /
• 2021

Although the technology for prediction or analysis using artificial intelligence is constantly developing, a black-box problem does not interpret the decision-making process. Therefore, the decision process of the AI model can not be interpreted from the user's point of view, which leads to unreliable results. We investigated the problems of artificial intelligence and explainable artificial intelligence using Blockchain to solve them. Data from the decision-making process of artificial intelligence models, which can be explained with Blockchain, are stored in Blockchain with time stamps, among other things. Blockchain provides anti-counterfeiting of the stored data, and due to the nature of Blockchain, it allows free access to data such as decision processes stored in blocks. The difficulty of creating explainable artificial intelligence models is a large part of the complexity of existing models. Therefore, using the point cloud to increase the efficiency of 3D data processing and the processing procedures will shorten the decision-making process to facilitate an explainable artificial intelligence model. To solve the oracle problem, which may lead to data falsification or corruption when storing data in the Blockchain, a blockchain artificial intelligence problem was solved by proposing a blockchain-based explainable artificial intelligence model that passes through an intermediary in the storage process.

• Economic and Environmental Geology
• /
• v.2 no.4
• /
• pp.23-71
• /
• 1969

Sediment samples were taken at about half-mile intervals from all the inajor rivers draining the St. Austell granite mass. The minus 80 mesh(B.S.S.) fraction of each sample was analysed, using semiquantitative methods, for sodium, potassium, lithium, phosphorus, nickel, chromium, tin, tungsten, arsenic copper, zinc and lead. The work was carried out with the view to gaining further information as to the geographical distribution of such different granite facies as might axist, and to investigate the geochemical dispersion of these elements with relation to mineralisation in this area. The sesults confirm Exley's suggestion that the mass consists of two major granite intrusions, the earlier undifferentiated one is joined on the west by a later differentiated intrutive. During the work grid deviation maps proved particularly useful in obtaining data concerning the nature of the granite but frequency diagrams were not particularly helpful. All the known lode areas were associated with stream sediments containing anomalously high concentrations of lode metals and it is concluded that these high concentrations are due premarily to lode material transferred to the streams in the form of tailings lost during milling operations.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.6 no.1
• /
• pp.1-12
• /
• 2004

The purpose of this research is to recognize college students' thinking way for hair fashion. The tendency of hair style, hair dyeing and hair administration was examined with college students in Seoul, some cities and towns. Research analyzed and compared the result according to the distinction of sex, age and area. The questionnaire was asked to 257 boy students and 328 girl students. The result in this research is as following. 1. It was shown that our country college students were satisfied with their hair style on the whole. Especially, college students in Seoul appeared more satisfied tendency than other city or town. Seoul's college students preferred hair style of short haircut. Wide area city or small town's college students preferred long hair style. The degree of satisfaction about beauty salon service of Seoul city's college students is higher than that of wide area city or small town's college students. The reasons that they want to go to the beauty salon they used to are distance for boy students and excellent technology for girl students. Boy students change hair style regularly, but girl students change it when need to change their mood. 2. In our country, most college students had experienced that they had their hair dyed. More senior students had their hair dyed than junior students. Hair color that most like was nature brown. Seoul college students liked gold color. Seoul college students are more satisfied than wide area city or small town's college students after hair dyeing. Girl students thought that hair dyeing made their hair style excellent. 4. Girl students responded that their hair was much damaged. College students in Seoul had healthy hair. Girl students selected 「beauty art surgical operation」 for cause of hair damage, and boy student had the various causes of hair damage. College students in Seoul had much hair damage than students in any other area. Most were using shampoo, and girl students used much shampoo than boy students. Girl students selected shampoo according to their hair state, Seoul's college students had their hair washed with shampoo more frequently than other students. Girl students were getting more hair administration information with various form than boy students. Girl students used Hair Clinic for hair administration, but boy students never did it.