• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.194-202
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• 2021

Ionosphere, one of the largest error sources, can pose potentially harmful threat to single-frequency GNSS (global navigation satellite system) user even after applying ionospheric corrections to their GNSS measurements. To quantitatively assess ionospheric impacts on the satellite navigation-based applications using simulation, the standard deviation of residual ionospheric errors is needed. Thus, in this paper, we determine conservative statistical quantity that covers typical residual ionospheric errors for nominal days. Extensive data-processing computes TEC (total electron content) estimates from GNSS measurements collected from the Korean reference station networks. We use Klobuchar model as a correction to calculate residual ionospheric errors from TEC (total electron content) estimate. Finally, an exponential delay model for residual ionospheric errors is presented as a function of local time and satellite elevation angle.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.273-284
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• 2022

YouTube usage continues to increase, and the age group who spends the most time on YouTube is surveyed in the teens. It is practically impossible to prevent children and young people from being exposed to harmful content, so nurturing the ability to choose and use YouTube content in a healthy way can be a fundamental solution. Therefore, in this study, we tried to identify what YouTube literacy is for the digital native generation, and to prepare standards to be considered in common. The purpose of this study is to refine the definition of YouTube literacy competency and to develop a checklist that can be used when guiding and guiding children and adolescents to use the YouTube platform. To this end, a conceptual definition and checklist were developed by conducting prior research and overseas case analysis, and validity was secured through expert and educator reviews. The finally developed checklist includes 4 categories, 10 areas, and 23 criteria: media access, critical understanding, media participation, and ethical use.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.895-911
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• 2023

Processed meat products play a vital role in our daily dietary intake due to their rich protein content and the inherent convenience they offer. However, they often contain synthetic additives and ingredients that may pose health risks when taken excessively. This review explores strategies to improve meat product quality, focusing on three key approaches: substituting synthetic additives, reducing the ingredients potentially harmful when overconsumed like salt and animal fat, and boosting nutritional value. To replace synthetic additives, natural sources like celery and beet powders, as well as atmospheric cold plasma treatment, have been considered. However, for phosphates, the use of organic alternatives is limited due to the low phosphate content in natural substances. Thus, dietary fiber has been used to replicate phosphate functions by enhancing water retention and emulsion stability in meat products. Reducing the excessive salt and animal fat has garnered attention. Plant polysaccharides interact with water, fat, and proteins, improving gel formation and water retention, and enabling the development of low-salt and low-fat products. Replacing saturated fats with vegetable oils is also an option, but it requires techniques like Pickering emulsion or encapsulation to maintain product quality. These strategies aim to reduce or replace synthetic additives and ingredients that can potentially harm health. Dietary fiber offers numerous health benefits, including gut health improvement, calorie reduction, and blood glucose and lipid level regulation. Natural plant extracts not only enhance oxidative stability but also reduce potential carcinogens as antioxidants. Controlling protein and lipid bioavailability is also considered, especially for specific consumer groups like infants, the elderly, and individuals engaged in physical training with dietary management. Future research should explore the full potential of dietary fiber, encompassing synthetic additive substitution, salt and animal fat reduction, and nutritional enhancement. Additionally, optimal sources and dosages of polysaccharides should be determined, considering their distinct properties in interactions with water, proteins, and fats. This holistic approach holds promise for improving meat product quality with minimal processing.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.190-195
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• 2023

In this research, the marine medaka Oryzias javanicus underwent a 96 h exposure to two concentrations of the red tide dinoflagellate Karenia mikimotoi (1,000 and 5,000 cells mL^-1), and the temporal variations in biochemical responses related to antioxidant and immunity parameters were assessed in the liver tissue. The study revealed a significant increase in ichthyotoxicity with elevated cell concentrations of K. mikimotoi, especially evident at 96 h in marine medaka exposed to 5,000 cells mL^-1. At 1,000 cells mL^-1 of K. mikimotoi, the opercular respiratory rate showed a significant increase, whereas exposure to 5,000 cells mL^-1 resulted in a lowered rate. The intracellular malondialdehyde content was significantly elevated in response to both cell concentrations at 96 h. Regarding glutathione content, levels were significantly increased by exposure to both cell concentrations. Catalase and superoxide dismutase enzymatic activities experienced an increase at 1,000 cells mL^-1 of K. mikimotoi, while their activities were reduced at 5,000 cells mL^-1 at 96 h. The analysis of two immunity parameters, alternative complement pathway and lysozyme, demonstrated significantly reduced activities in the liver tissue exposed to 5,000 cells mL^-1 of K. mikimotoi. These findings aim to enhance the understanding of K. mikimotoi toxicity in marine fish by offering insights into biochemical responses associated with harmful algal blooms.

• Journal of Mushroom
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• v.22 no.1
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• pp.17-21
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• 2024

Mushroom-based vegan meat has thus far been used as a food for humans instead of pets. However, based on its texture and nutritional content, it is considered suitable for processing into pet treats. In the present study, we developed a prototype dog chew with a sweetening coating added to a fungal mycelium mat obtained by culturing the Basidiomycetous fungus Trametes orientalis. The palatable coating applied to the mycelium mat by plasticizing the mat with glycerol improved the taste and aroma of the existing mat, and the dog consumed it without difficulty. Future improvements may include a softening process to reduce the chewiness level and a procedure to reduce the crude fiber content. Mycelium-mat-based dog chews, manufactured using eco-friendly materials and processes that are not harmful to the environment are expected to enter the market as eco-friendly alternatives to conventional pet treats. Controlling their physical properties require further study.

• International Journal of Industrial Entomology and Biomaterials
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• v.48 no.3
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• pp.147-155
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• 2024

This study aimed to validate the nutritional superiority and safety of fermented coffee byproducts (CB) and fermented oyster mushroom cultivation by-products (OMCB) as alternative food sources for Protaetia brevitarsis larvae. Thus, we conducted a comparative analysis of the nutrient composition of the food sources and developmental characteristics of the larvae. P. brevitarsis larvae have traditionally utilized various by-products as food sources and are able to efficiently utilize these. The analysis of the nutrient composition of the food sources indicated that, in comparison to control group fermented oak sawdust (FOS), the content of crude protein was 2.2 folds higher in larvae fed with OMCB and 3.2 folds higher in larvae fed with fermented 50% CB + 50% OMCB (CB + OMCB). Moreover, the cellulose content, utilized as a nutritional source for the larvae, was 1.3 folds higher in the CB + OMCB group than in the control group. Significantly, the weight of larvae fed with OMCB and CB + OMCB increased 1.7-4.2 folds compared to those fed with FOS. Additionally, the survival rate of larvae before the formation of pupal cells was over 90% in all groups. Therefore, it was concluded that CB and OMCB contain various nutrients without harmful composition and have a larval growth-promoting effect. Consequently, they are considered appropriate dietary materials for P. brevitarsis larvae. This study enhances our understanding of by-product usages by P. brevitarsis larvae and confirms their potential as sustainable food resources.

• Environmental Engineering Research
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• v.23 no.1
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• pp.114-119
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• 2018

Yarn dyed wastewater has to be treated prior to disposal into the water bodies due to its high content of harmful organic compounds. In this study, the performance of Chemical Oxygen Demand (COD) removal and kinetic rate constant are investigated via hybrid electrocoagulation-Fenton in a continuous system using wastewater discharged from a yarn dyed industry in Surabaya city. The wastewater was treated in a batch mode using electrocoagulation to reduce Total Suspended Solid, followed by Fenton method in a continuous system to reduce COD level. Various Fe(II) feeding modes, molar ratio of $Fe(II)/H_2O_2$, initial pH of wastewater, and flow rate are used in this study. The results show that COD removal process obeys a pseudo-first order kinetics. At $Fe(II)/H_2O_2$ ratio of 1:10, initial wastewater pH of 3.0, and feed flow rate of 30 mL/min, the COD removal efficiency was observed to be 80%, and the kinetic rate constant is $0.07046min^{-1}$. The chemical cost for the treatment estimated to be IDR 160 per L wastewater, which is cheaper than the previously reported batch system of IDR 256/L.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.333-335
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• 2003

Deep Ocean Water is formed within restricted area including polar sea (high latitude) by cooling of surface seawater and globally circulated in the state of insolation with surface seawater. Although not as obvious as estuaries mixing, Brine groundwater is mixture of recirculated seawater and groundwater. Seawater having high osmotic pressure infiltrate into unconfined aquifer where is connected to the sea. The ions dissolved in seawater are present in constant proportions to each other and to the total salt content of seawater. However deviation in ion proportions have been observed in some brine groundwater. Some causes of these exception to the Rule of constant proportions are due to many chemical reactions between periphery soil and groundwater. While Deep Ocean Water (DOW) have a large quantity of functional trace metals and biological affinity relative to brine groundwater, DOW have relatively small amount of harmful bacteria and artificial pollutants.

• Journal of the Korean Society of Food Culture
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• v.12 no.1
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• pp.1-9
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• 1997

The contents of articles on food safety and policy in the Donga and Chosun Ilbo from January 1960 to June 1996 were analyzed for the evaluation of subjects and trends in mass media. Among the total of 490 articles, those on cereals were most frequently appeared (20.0%), followed by the articles on sea foods (10.6%) and meats (10.0%). Articles on fats and oils were the least (2.0%) in frequencies. The proportions of articles classified based on the 10-year interval were 28.0% in the 60's, 28.0% in the 70's, 20.6% in the 80's, and 23.4% in the 90's. Major contents of articles were the safety of imported foods, food contaminations by agricultural chemicals, heavy metals and harmful additives.

• Journal of Nutrition and Health
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• v.29 no.10
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• pp.1096-1104
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• 1996

This study was performed to evaluate the effect of sodium cholride supplementation on bone metabolism in female rats consuming a low calcium diet. Twenty five female rats were divided into three dietary groups (control Na : 0.1038%, 1% Na : 1.036%, 2% Na : 2.072%). All experimental diets contained 0.27% Ca and were fed to rats with deionized water for 7 weeks. Bone mineral density(BMD) and bone mineral content(BMC) of total body, spine and femur were measured using energy x-ray absorptiometry(DEXA) by small animal software. Then Ca efficiency was calculated from BMD and BMC. Serum Ca, P, Na and urine Ca, P, Na were determined. Urinary pyridinoline, serum ALP were measured to monitor bone resorption. Following 7 weeks, sodium cholride supplemented groups had higher urinary Ca excreteion, urinary pyridinoline, crosslinks value and serum ALP. There was no significant difference in case of serum Ca among all groups. Sodium chloride supplemnted groups had lower Ca effciency of total, spine and femur BMD and BMC than that of control group. In conclusion high salt intake not only increases urinary Ca excretion as urinary Na excretion does but also increase bone resorption and decrease Ca efficiency of each bone. It is been suggested that high salt intake may be harmful for bone maintenance. Therfore, the decrease of salt intake to the level of recommendation would be desirable.