• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.247-252
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• 2014

Despite the facts that navigation technology and educational programs were developed, and that maritime law has been enforced strictly, the number of maritime accidents has not dropped significantly. Accident prevention is emphasized because of the extreme life, property, and environmental losses that accompany maritime accidents. Even though there are a variety of preventive activities, their performance is not satisfactory. In order to promote preventive activities and to organize safety management, a Preventive Index of Ship Accident(PISA) and a Preventive Level of Ship Accident(PLSA) which are abstracted from the statistical data of ship accidents (2009~2013) are proposed. The survey module by which these variables can be calculated is composed of preventive domains such as education, engineering, enforcement and information, and is applied for the preventive indexes measurement of cargo, passenger, tanker, tugboat and fishery ships. We compared and analyzed measured result with statistical accident rates and cases to confirm the index utilities. It was found that there is some correlation between the index value and the ship accident rate. It is expected that this index will become useful to evaluate a preventive status for the prevention of ship accidents and for the maritime safety culture.

• Korean journal of food and cookery science
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• v.20 no.2
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• pp.180-186
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• 2004

Evidence shows there are flavonoid and polyphenol compounds in Ulmus cortex which has excellent antioxidant, anticancer and antimicrobial properties. This study summarizes our findings on effects of Ulmus cortex extracts(UDE) on quality characteristics of bread and the changes of microbial counts during storage. Dough yield and specific loaf volume of bread decreased significantly because the amount of UDE increased. Lightness of bread surface, redness of crumb and yellowness of crust were significantly increased. Texture evaluation showed that hardness was the highest in the bread prepared with 30% UDE. Sensory evaluation showed that odor, taste, texture, and overall acceptability were the best in bread which was made with 10% UDE. At the beginning of the period of storage, there were not significant differences of microbial cell count as increasing UDE, but significant decreasing was observed after passing 6 days. A negative correlation was generally observed between the sensory and mechanical properties. The results of total microbial count show that adding UDE in processing bread extend bread's storage time.

• Journal of the Korea Safety Management & Science
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• v.22 no.3
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• pp.23-29
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• 2020

As the duty to report and investigate major elevator failures has expanded due to the total amendment of the Elevator Safety Management Act in 2018, more important information on major elevator failures that have been partially identified has been collected. As of 2019, the number of elevators in Korea exceeded 700,000, making it the eighth-class elevator powerhouse in the world, but there is a trend of increasing casualties due to accidents and breakdowns. An Seung-gang-gi is a term that encompasses an elevator that moves vertically and an escalator that moves horizontally. It is an important means of transportation for most citizens that are encountered almost every day in daily life, and it is also necessary as a means of transportation that enables the construction of skyscrapers. And it seems that its importance will never diminish in the future. Major elevator failures are the main cause of dispatch when accumulating the number of 119 dispatches, and the frequency of occurrence is high. It's a shame. According to Heinrich's Law, 300 minor signs and danger phenomena precede, 29 minor accidents and 1 major accident. Accidents caused by elevators are increasing every year due to the increase in the number of installations, and the damage is threatening the valuable lives and property of users and workers in related fields due to fatal risks such as death and serious injury. Elevator safety management can achieve its purpose only when it is managed with the usual interests, awareness of safety, and full efforts of the users, workers, and the government concerned. This study was analyzed based on 2019 data notified to the Korea Elevator Safety Agency on major breakdowns improved after the revision of the Elevator Safety Management Act in 2018, and a total of 8,256 data were analyzed using the SPSS 21 version, a statistical analysis tool, to analyze the correlation with technical statistics. Proceeded. Through the analysis, it was possible to obtain preventive safety management data to prevent serious elevator safety accidents from occurring, and to derive meaningful implications that related safety management and maintenance can be effectively operated to prevent serious failures. In addition, through this analysis, we expect the development of related industries and legal and institutional improvement.

• International Journal of Highway Engineering
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• v.17 no.3
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• pp.49-58
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• 2015

PURPOSES : The use of environmentally friendly construction methods has been recently encouraged to reduce fuel consumption and the effects of global warming. For this purpose, the roller compacted concrete pavement (RCCP) construction method has been developed. RCCP is more environmentally friendly and economically efficient than general concrete by reducing the amount of CO2 generated through the application of a smaller amount of cement. RCCP has a number of advantages such as an easy construction method, low cost, high structural hydration performance, and aggregate interlocking. However, mix design standards and construction guidelines of RCCP are required for domestic application. In addition, a study on aggregate selection, which has an effect on the characteristics of RCCP, is necessary owing to a limited number of researches. Thus, the aggregate effect on the performance of RCCP in securing the required strength and workability was evaluated in consideration of domestic construction. METHODS : Sand and coarse aggregates of both 19mm and 13mm in maximum size were used in this study. Four types of aggregate gradations (s/a = 30%, 58%, and 70% for the sand and coarse aggregate of 19mm in maximum size, and s/a = 50% for a combination of the three types of aggregates) were set up to investigate the effects of the PCA band on the RCC characteristics. The conditions of s/a = 30% and 70% were evaluated to check the gradation effect outside of the recommended band. The conditions of s/a = 58% and 50% were used because they are the optimum combination of the two and three types of aggregates, respectively. RCCP gradation band was suggested gradation with a proper construction method of RCCP by synthetically comparing and analyzing the correlation of optimum water content, maximum dry density, and strength of requirements through its consistency and compaction test. RESULTS : The lower and upper limit lines are insufficient to secure a relatively strong development and workability compared to an aggregate gradation in the RCCP gradation band region. On the other hand, the line in the RCCP gradation band and the 0.45 power curve in the RCCP gradation band region were satisfactory, ensuring the required strength and workability. CONCLUSIONS : The suitable aggregate gradation on RCCP process should meet the RCCP gradation band area; however, fine particles passing through a #60 sieve do not need to be within the recommended gradation band because the influence of this region on such fine particles is small.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.359-369
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• 2010

This study characterizes aquifer system and hydrogeologic property in the western half of Jeju Island where wells were drilled for regional water supply in three sub-areas (northwestern, western, and southwestern sub-areas). The aquifer system of the northwestern sub-area is largely composed of upper high-permeability layer, upper low-permeability layer, lower high-permeability layer, and lower low-permeability layer. On the other hand, the aquifer systems of the western and southwestern sub-areas are mostly composed of upper low-permeability layer, high-permeability layer, and lower low-permeability layer. Transmissivity and specific capacity decrease in the order of the northwestern, western, and southwestern sub-areas. The relationship between specific capacity and the top surface of tuff is negative with a high correlation coefficient of -0.848, indicating that the tuff acts as the bottom of the aquifer. Groundwater level change due to the 2004 Sumatra earthquake is an average of 23.74 cm in the northwestern sub-area, an average of 9.48 cm in the western sub-area, and none in the southwestern sub-area. Further, it is found that groundwater change due to the earthquake has a positive relationship with transmissivity and specific capacity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.325-338
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• 2016

Properties of aggregation and spatial distribution of fish were examined based on three lines in the South Sea of Korea using three frequencies (18, 38, and 120 kHz) of a scientific echosounder. The vertical distribution of fish was displayed using acoustic biomass namely nautical area scattering coefficient (NASC). As a result, at 120 kHz high NASC showed from water surface to 20 meters in deep while at 18 and 38 kHz very high NASC presented in 70 ~ 90 meters in depth, especially at line 3. Among three lines, the line 2 had lowest NASC. The horizontal distribution of fish using three frequencies together exhibited high NASC between the eastern South Sea and center of South Sea. In especial, NASC ($801{\sim}1,920m^2/n{\cdot}mile^2$) was observed along coastal waters from Busan to Tongyeong, Geoje, and Namhae. In regard with the property of aggregation of fish schools, the volume back-scattering strength ($S_V$) of three lines presented close each other, however, the range of $S_V$ in the line 2 was shortest (-53.5 ~ -43.4 dB). The average distributional depth was deep in the order of L3 ($32.8{\pm}9.0m$), L1 ($45.2{\pm}9.5m$), L2 ($49.7{\pm}5.6m$). The average altitude was high in the order of L3 ($13.4{\pm}10.3m$), L1 ($17.0{\pm}12.6m$), L2 ($56.7{\pm}5.6m$). The average length, thickness, and area were large in the order of L1, L3, and L2. This means that small sized fish schools were distributed near water surface in the line 2 while relatively large and similar sized fish aggregations between line 1 and line 3 appeared however, fish schools at line 3 had lower distributional depth and smaller compared to those at line 1. Acoustic data were visualized for demonstrating the entire circumstances of survey area. Additionally, there was no correlation between acoustic and trawl results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.439-446
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• 2007

We carried out this experiment on the purpose to investigate the quality properties of aseptic-packaged cooked rice by cultivars in 2006. Brown rice was milled for white rice to 89.6% weight of it. Based on cluster analysis of acceptance of sensory evaluation, eleven rice cultivars of 29 cultivars had superior palatability. Whiteness(r=0.42, p<5%), lightness(r=0.39, p<5%), Toyo value(r=0.35, p<10%), and moisture content(r=0.33, p<10%) of milled rice were correlated positively with acceptability. Protein content(r=-0.40, p<5%), expansion rate(r=-0.68, p<1%) and water absorption rate(r=-0.42, p<5%) of milled rice, and yellowness(r=-0.45, p<5%) of aseptic-packaged cooked rice were negatively correlated. In sensory evaluation, correlation coefficients of taste and texture with acceptability were higher than those of appearance and flavor. During storage, hardness and cohesiveness of aseptic-packaged cooked rice before reheating were increased and decreased, but those after reheating had no difference based on storage period and cultivar. On the contrary, whiteness of reheated aseptic-packaged cooked rice with no distinct differences before reheating was decreased during storage. There were no significant differences of texture property, color characteristics and moisture contents by cultivar during storage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.343-351
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• 2016

Cryogenic spray characteristics of a nitrogen swirl injector operating in supercritical environment have been numerically investigated. By comparing the equation of states(EOS) used for supercritical condition, SRK EOS was applied to predict the nitrogen thermodynamic property under supercritical environment. A Chung's method was implemented for the calculation of viscosity and conductivity and Takahashi's correlation based on Fuller's Theorem was implemented for the calculation of diffusion coefficient. By injecting the nitrogen with 5 bar differential pressure into 50 bar chamber filled with nitrogen, numerical simulation has been conducted. The dynamic Smagorinsky sub-grid scale (SGS) model has been compared with the algebraic Smagorinsky SGS model using FFT frequency analysis. The instability at the liquid film and gas core inside injector and the propagation of pressure oscillation into the injector has been investigated. The spreading angle of swirl injector obtained by numerical calculation has been validated with experimental result.

• Korean Journal of Plant Resources
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• v.19 no.1
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• pp.97-104
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• 2006

This study was conducted to investigate effect of temperature and NaCl on the seed germination and water absorption of Thuja orientalis. Seeds were treated with 0, 500, 1,000, 2,000 and 4,000ppm of NaCl and placed in different chambers at 15, 20, 25 and $30^{\circ}C$, respectively. And seed properties and relative water absorptions were analyzed. Germination decreased with the increase of both temperature and NaCl concentration, and especially the difference was obvious at $30^{\circ}C$. Dormancy and mortality increased with the increase of temperature in non-NaCl treatment. Two-way analysis of variance showed significant effects of temperature, NaCl concentration and interaction between temperature and NaCl concentration (p<0.001). Mean germination time increased with the increase of NaCl concentration at 15, 20 and $25^{\circ}C$ but decreased at $30^{\circ}C$ because the seeds were mortal by NaCl high concentration, Germination speed and germination performance index decreased with the increase of NaCl concentration. Those represented decreasing tendency with NaCl concentration but high positive correlation with germination. Relative water absorption decreased with the increase of NaCl concentration and represented high values at $15^{\circ}C$, and showed high positive correlations with germination, germination speed and germination performance index. It was reported that the high temperature and salinity were inhibitive factors of seed germination of Thuja orientalis.

• Korean Journal of Optics and Photonics
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• v.17 no.3
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• pp.248-255
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• 2006

Most optical security systems use a 4-f correlator, Mach-Zehnder interferometer, or a joint transform correlator(JTC). Of them, the JTC does not require an accurate optical alignment and has a good potential for real-time processing. In this paper, we propose an image encryption system using a position shift property of the JTC in the Fourier domain and a random phase image. Our encryption system uses two keys: one key is a random phase mask and the other key is a position shift factor. By using two keys, the proposed method can increase the security level of the encryption system. An encrypted image is produced by the Fourier transform for the multiplication image, which resulted from adding position shift functions to an original image, with a random phase mask. The random phase mask and position shift value are used as keys in decryption, simultaneously. For the decryption, both the encrypted image and the key image should be correctly located on the JTC. If the incorrect position shift value or the incorrect key image is used in decryption, the original information can not be obtained. To demonstrate the efficiency of the proposed system, computer simulation is performed. By analyzing the simulation results in the case of blocking of the encrypted image and affecting of the phase noise, we confirmed that the proposed method has a good tolerance to data loss. These results show that our system is very useful for the optical certification system.