• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.6
• /
• pp.986-993
• /
• 1994

As a part of development of traditional foods, mugwort boogag and dry laver boogag were fried insoybean oil, and BHA or tocopherol-added soybean oil. They were wrapped up in opp vinyl film, and preserved at $4^{\circ}C(RH{\;}40{\pm}5%){\;}and{\;}25^{\circ}C(RH{\;}80{\pm}5%)$. During the storage of bobogags, acid value, peroxide value, and TBA value were investigated. Changes of sensory evaluation and texture profile were also examined. Boogags were manufactured by washing the raw materials. drying in the shade, mixing them with glutinous rice flour, and hot-air drying up it to 13 % of moisture contents after dryed it up to 80% of moisture contents on dry table for 23days, in order. These boogags were packaged to manufacture goods with dryed state or fried at $160^{\circ}C$ for 10 sec. Acid value, peroxide value, and TBA value of boogags which preserved at $4^{\circ}C$ generally appeared lower than at $25^{\circ}C$. As storage time goes by, moisture contents of bobogagas preserved at $25^{\circ}C$ increased and its quality were gradually deteriorated. When the boogags were fried in BHA(0.01%) and tocopherol (0.01%) added soybean oil, changes of acid value, peroxide value, TBA value were generally low. During the storage of bobogagas antioxidant effect of BHA was higher than that of tocopherol. Texture was inclined to decrease as storage time goes, by that of boogags preserved at $4^{\circ}C$ was a little more satisfactory. Hardness was also high.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.576-582
• /
• 2017

The switching system in a maglev train is an indispensable element for distributing train routes, and it should be designed to ensure safe operation. Unlike conventional wheels on rails, the switching track in EMS-type maglev is supported by a group of 3 to 4 steel girders. When the vehicle changes its route, the segmented track allows the girders to change from a straight position to a curved one with a small radius of curvature. Hence, the structural characteristics of the segmented switching system may affect the levitation stability of the maglev vehicle. This study experimentally evaluates the dynamic interaction between maglev vehicles and a segmented switching system. The results may be helpful for improving the switching system. The measured levitation and lateral air gaps were evaluated at a vehicle speed of 25 km/h, and the ride quality of the Maglev vehicle was determined to be "comfortable" according to the UIC 513 standard.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.2
• /
• pp.68-75
• /
• 2018

In this study, to solve the problems of the conventional crack repair and injection method, high elasticity latex was used as the material of the storage tube to withstand the high pressure in the center part differently from the general port. When the repair solution was injected into the crack part, The TPS method was developed so that the air existing in the TPS can be discharged. In addition, a new infusion port in which a valve blocking the backflow of the remediation solution was installed at the injection port was developed and the physical characteristics of the port were analyzed. As a result of the evaluation, it was found that the filling rate of the remedial solution was improved compared to the existing ordinary injector method, and the cracks were completely filled in the test conditions. Compressive strength and tensile strength after repair showed about 20% decrease after repair in case of using ordinary injector method, while TPS method showed about 2~7% increase after repair. The results of this study showed that the injection port method using the elastic storage tube increased the injection performance and the quality after repair compared to the conventional injector method. The result of this study is expected to be utilized as the basic data for application and commercialization of the result to the practical structure.

• Journal of Advanced Navigation Technology
• /
• v.17 no.5
• /
• pp.516-523
• /
• 2013

In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) with the terminal with two antlers. We measured two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at passager terminal areas were 3.32 and 3.10 respectively in 128.2 MHz and 269.1 MHz. The deviation of prediction error is 9.69 and 9.65. The new path loss equation at the terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.3
• /
• pp.194-201
• /
• 2019

This study analyzed the properties of concrete depending on the coal gasification slag(CGS) contents in order to examine the applicability of CGS as the fine aggregate for concrete. Experimental results, trended that the slump and slump flow increased with increasing CGS contents, and air contents has decreased. Evaluation index for segregation of normal strength concrete(EISN) is showed was good from CGS 25% when using crushed sand A(CSa) and CGS 50% when using mixed sand(MS). The compressive strength decreased with increasing CGS contents when CSa was used. However, when MS was used, the maximum value was CGS 50% due to parabolic tendency. Depending on fine aggregates type, compared with compressive strength of CSa was about 8% higher than that of MS, and depending on the use or unuse of CGS, more advantageous at higher strength than low strength. As a result of relative performance study on the quality of concrete according to the CGS contents, it is considered that CGS can be positively contributed to enhancement of workability and strength development when mixed with fine aggregate around 25~50%.

• Journal of Integrative Natural Science
• /
• v.4 no.1
• /
• pp.38-43
• /
• 2011

The recent global warming may be estimated to give lots of impacts to the human society and biosphere of influencing climate change included by the natural climate variations through the human activity which can directly and/or indirectly play a major role of total atmospheric composition overall. Therefore it currently appears evidences such as hot wave, typhoon, and biosphere disturbance, etc. over the several regions to be influenced by global warming due to increasing the concentration of greenhouse gases in the atmosphere through inducing forest destruction, fossil fuel combustion, greenhouse gases emission, etc. since industrial revolution era. Through the working group report of IPCC (Intergovernmental Panel on Climate Change) for climate change was analyzed by the individual country's current status and figure out the important issues and problems related to the future trend of climate change science with advanced countries preparedness and research, In this study, the first working group report of IPCC focuses on those aspects of the current understanding of the physical science of climate change that are judged to be most relevant to policymakers. As this report was assessed and analyzed by including the progress of climate change science, the role of climate models and evolution in the treatment of uncertainties. This consists of the changes in atmospheric constituents(both aerosols and gases) that affect the radiative energy balance in the atmosphere and determine the Earth's climate, considering the interaction between biogeochemical cycles that affect atmospheric constituents and climate change, including aerosol/cloud interactions, the extensive range of observations snow available for the atmosphere and surface, for snow, ice, and frozen ground and for the oceans, respectively and changes in sea level, the paleoclimate perspective and assessment of evidence for past climate change and the extension, the ways in which physical processes are simulated in climate models and the evaluation of models against observed climate, the development plans and methods of improving expert and building manpower urgently and R&D fund expansion in detail for climate change science in Korea will be proposed.

• Journal of Korea Water Resources Association
• /
• v.54 no.12
• /
• pp.1255-1263
• /
• 2021

While it could become an alternative water resource, fog could undermine traffic safety and operational performance of infrastructures. To reduce such adverse impacts, it is necessary to have spatially continuous fog risk information. In this work, tree-based machine-learning models were developed in order to quantify fog risks with routine meteorological observations alone. The Extreme Gradient Boosting (XGB), Light Gradient Boosting (LGB), and Random Forests (RF) were chosen for the regional fog models using operational weather and visibility observations within the Jeollabuk-do province. Results showed that RF seemed to show the most robust performance to categorize between fog and non-fog situations during the training and evaluation period of 2017-2019. While the LGB performed better than in predicting fog occurrences than the others, its false alarm ratio was the highest (0.695) among the three models. The predictability of the three models considerably declined when applying them for an independent period of 2020, potentially due to the distinctively enhanced air quality in the year under the global lockdown. Nonetheless, even in 2020, the three models were all able to produce fog risk information consistent with the spatial variation of observed fog occurrences. This work suggests that the tree-based machine learning models could be used as tools to find locations with relatively high fog risks.

• Journal of The Korean Society For Urban Railway
• /
• v.6 no.4
• /
• pp.319-326
• /
• 2018

The safety interval to prevent collision between trains in a train control system is based on the braking distance according to the emergency braking of the train. The evaluation of the braking performance is based on the longitudinal train dynamics or the commissioning test in the test track, but since the conditions such as the weakening of the adhesion coefficient between the wheel and rail can not all be considered, these conventional methods are not sufficient to design of the train control systems. Therefore, in this study, the Monte Carlo Method (MCM) which can consider various environments is used to analyze braking performance and limitations. The braking model is based on the air braking used in the emergency braking and is modeled to take into account the braking pressure, efficiency, friction coefficient, adhesion condition, and vehicle mass distribution. It is confirmed that braking performance can be improved by controlling the quality of braking device. In addition, the change of the braking performance was confirmed according to the vehicle constituting the train. The results of this study are expected to be used as basic information for designing safety clearance for the train control systems and as a basis for improving the braking performance of railway vehicles.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.25 no.4
• /
• pp.15-31
• /
• 2022

The Green Purification Unit System (GPUS) is a green infrastructure facility applicable to the roadside to reduce particulate matter from road traffic. This study introduces two types of GPUS (type1 and type2) and assesses the performance and maintenance costs of each of them. The GPUS's performance analysis used the data collected in November 2021 after the installation of the GPUS type1 and type2 at the study site in Suwon. The changes in the particulate matter concentration near the GPUS were measured. The maintenance cost of GPUS type1 and type2 was assessed by calculating the initial installation cost and the management and repair cost after installation. The results of the performance analysis showed that the GPUS type1, which was manufactured by combining plants and electric dust collectors, had a superior particulate matter reduction performance. In particular, type1 produced a greater effect of particulate matter reduction in the time with a high concentration (50㎍/m³ or higher) of particulate matter due to the operation of electric dust collectors. GPUS type2, which was designed in the form of a plant wall without applying an electric dust collector, showed lower reduction performance than type1 but showed sufficiently improved performance compared to the existing band green area. Meanwhile, the GPUS type1 had three times higher costs for the initial installation than GPUS type2. In terms of costs for managing and repairing, it was evaluated that type1 would be slightly more costly than type2. Finally, this study discussed the applicability of two types of GPUS based on the result of the analysis of their particulate matter performance and maintenance cost at the same time. Since GPUS type2 has a cheaper cost than type1, it could be more economical. However, in the area suffering a high concentration of particulate matter, GPUS type1 would be more effective than type2. Therefore, the choice of GPUS types should rely on the status of particulate matter concentration in the area where GPUS is being installed.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.29 no.2
• /
• pp.119-128
• /
• 2023

This study was examined for investigating the quality changes of spring kimchi cabbage under various treatments (pre-drying/pre-cooling, packaging types, and stacking and loading in container and pallete in the storage room) during cold storage. The results showed that control (upward stacking without pre-drying/pre-cooling and HDPE or PVC film cover) was increased significantly in weight loss and trimming loss, compared to other treatments such as DPDH (downard stacking + pre-drying + HDPE), DPDP (downard stacking + pre-drying + PVC), DPCH (downnard stacking + pre-cooling + HDPE), and UPCH (upward stacking + pre-cooling +HDPE) during storage for three months. In Sensory evaluation, judging from marketable properties, the desirable appearance of spring kimchi cabbage with the modified pallet-unit MA packed, PE, and PVC film wrapping could be maintained until 9 weeks after pre-drying/pre-cooling. Meanwhile, the control without any treatments after 6 weeks, the sensory score was declined, significantly. In general, the low temperature (10℃ and 2℃) of pre-treatment with combination of plastic film packaging in spring kimchi cabbage storage could inhibit the physiological activity and reduce the direct exposure of environmental cold air in the storage. Therefore, these two variables were the key points for extending the shelf-life of spring kimchi cabbage.