• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.163-163
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• 2019

The rapidly growing global population increases the awareness of water, energy, and food security worldwide. The concept of Water, Energy, and Food nexus (hereafter, WEF nexus) has been widely introduced as a new resources management concept that integrate the water, energy, and food in a single management framework. Recently, WEF nexus analyzes not only the interconnections among the resources, but also considers the external factors (such as environment, climate change, policy, finance, etc) to enhance the resources sustainability by proper understanding of their relations. A nation-level resources management is quite complex task since multiple regions (e.g., watersheds, cities, and counties) with different characteristics are spatially interconnected and transfer the resources each other. This study proposes a multiple region WEF nexus simulation and transfer model. The model is equipped with three simulation modules, such as local nexus simulation module, regional resources transfer module, and optimal investment planning module. The model intends to determine an optimal capital investment plan (CIP), such as build-up of power plants, water/waste water treatment plants, farmland development and to determine W-E-F import/export decisions among areas. The objective is to maximize overall resources sustainability while minimize financial cost. For demonstration, the proposed model is applied to a semi-hypothetical study area with three different characterized cities. It is expected the model can be used as a decision support tool for a long-term resources management planning process.

• Journal of Environmental Science International
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• v.30 no.6
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• pp.429-439
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• 2021

Food waste is both an industrial and residential source of pollution, and there has been a great need for food waste reduction. As a preliminary step in this study, waste reduction is quantitatively modeled. This study presents two models based on kinetics: a simple kinetic model and a mass transport-shrinking model. In the simple kinetic model, the smaller is the reaction rate constant ratio k₁, the lower the rate of conversion from the raw material to intermediate products. Accordingly, the total elapsed reaction time becomes shorter. In the mass transport-shrinking model, the smaller is the microbial decomposition resistance versus the liquid mass transfer resistance, the greater is the reduction rate of the radius of spherical waste particles. Results showed that the computed reduction of waste mass in the second model agreed reasonably with that obtained from a few experimantal trials of biodegradation, in which the microbial effect appeared to dominate. All calculations were performed using MATLAB 2020 on PC.

• Journal of the FoodService Safety
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• v.2 no.2
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• pp.91-96
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• 2021

This study was performed to provide fundamental data on hygiene and quality control of ready-to-eat sandwiches. Predictive models were developed to the kinetics of Staphylococcus aureus growth in these sandwiches as a function of temperature (10, 15, 25, and 35℃). The result of the primary model that used the Gompertz equation showed that the lag phase duration (LPD) and generation time (GT) decreased and the exponential growth rate (EGR) increased with increasing storage temperature. The secondary model showed an R² for M and B of 0.9967 and 09916, respectively. A predictive growth model of the growth degree as a function of temperature was developed. L(t)=A+Cexp(-exp(-B(t-M))) (A=Initial contamination level, C=MPD-A, B=0.473166-0.045040*Temp-0.001718*Temp*Temp, M=19.924824-0.627442*Temp-0.004493*Temp*Temp, t=time, Temp=temperature). This model showed an R² value of 0.9288. All the models developed in this study showed a good fit.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.280-286
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• 1988

Freezing is becoming incressingly important in the food industry as a means of food preservation since the turn of the century. For quality, processing and economic reasons, it is important to predict the freezing time for foods. A number of models have been proposed to predict freezing time. However, most analytical freezing time prediction techniques apply only to specific freezing conditions. Therefore, it is necessary to develop an improved analytical method for freezing time prediction under various conditions. The objectives of this study, by reviewing previous experimental data obtained by uncertain freezing condition and thermo-physical data, were to develop simple and accurate analytical method for prediction freezing time, and to obtain the freezing time of various foodstuffs by still air freezing and immersion freezing method. The result of this study showed that the proposed method offered better results than the other complex method compared.

• The Journal of Asian Finance, Economics and Business
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• v.4 no.4
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• pp.27-37
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• 2017

This study examines the behaviour of staple food price using Multivariate BEKK-GARCH Model. Understanding of staple food price behaviour is important for determining the unpredictability of staple food market and also for policy making. In this paper, we focus on the commodity prices of sugar, rice, soybean and wheat to examine the volatility behaviour of those commodities. The empirical results show that the own-volatility spillover are relatively significant for all food prices. The own-volatility spillover effect for sugar price is relatively large compared with the volatility spillover of other staple food commodities. The findings also highlight that the price volatility of wheat increases during food crisis more than it does when the condition is stable. Also, the own-volatility of rice and wheat in the period of the food crisis is significant and higher compared to the period before food crisis indicates that the past own-volatility effects during food crisis are relatively more difficult to predict because of the uncertainty and high price volatility. Policy recommendations that can be proposed based on the findings are: (1) a better trade agreement in food commodity trade, (2) lower the dependence on wheat importation in Indonesia, and (3) reliable system to minimize food price volatility risks.

• The Korean Journal of Food & Health Convergence
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• v.7 no.2
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• pp.1-10
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• 2021

The purpose of this study is to examine the impact of the service quality of delivery food on customers' emotional response and repurchase intention during the COVID19 pandemic. The proposed research model examined the effect on the service quality, customer sentiment response, and repurchase intention of delivery food. A questionnaire was distributed and measured for 300 consumers who had experience using food delivery services in the last 30 days. The questionnaires from previous researches were revised to fit the purpose of the present study. The survey results were analyzed to verify the reliability and validity of the measured variables. To verify the hypotheses a Structural Equation Modelling (SEM) was used for the study. The results showed that taste, price fairness, and package design positively affected emotional response; moreover, repurchase intention was enhanced by emotional response. This research analyzed the relationships between service qualities of delivery food, emotional response, and repurchase intention when customers consume delivery food during COVID19 in Korea. This study extends the delivery food literature by combining customers' emotional behavior with SEM model. The result suggested competitive strategic plans and development directions of food delivery companies in the rapidly increasing food delivery industry, providing implications for further research.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.327-335
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• 2002

Effects of available food on growth of commercially cultured Pacific oysters, Crassostrea gigas in Goseong Bay on the south coast were studied using a numerical model. levels of total protein, carbohydrate and lipid in particulate organic matter in the water column as well as chlorophyll a concentration were determined for estimating total available food for oyster growth. Environmental parameters including water temperature, salinity and total suspended solid were also monitored for the model. Oyster growth was also monitored by means of measuring shell length and tissue wet weight increase on a monthly basis. Simulation results from the numerical model indicated that chlorophyll a is not a good representative of available food for the oysters in Goseong Bay. In contrast, available food in the water column measured by filtration of the organic particles and analyzed in terms of total lipids, carbohydrates and protein was well matched with simulated oyster growth in the Bay which is similar to observed growth. The model also suggested that oysters have relatively low retention efficiency of $50\%$ or less. This result indicates that oysters in the bay utilize only a part of food particle available in the water column, as reported in other studies.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.642-650
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• 2008

A mathematical model was developed for predicting the growth rate of Enterobacter sakazakii in tryptic soy broth medium as a function of the combined effects of temperature (5, 10, 20, 30, and $40^{\circ}C$), pH (4, 5, 6, 7, 8, 9, and 10), and the NaCl concentration (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10%). With all experimental variables, the primary models showed a good fit ($R^2=0.8965$ to 0.9994) to a modified Gompertz equation to obtain growth rates. The secondary model was 'In specific growth $rate=-0.38116+(0.01281^*Temp)+(0.07993^*pH)+(0.00618^*NaCl)+(-0.00018^*Temp^2)+(-0.00551^*pH^2)+(-0.00093^*NaCl^2)+(0.00013^*Temp*pH)+(-0.00038^*Temp*NaCl)+(-0.00023^*pH^*NaCl)$'. This model is thought to be appropriate for predicting growth rates on the basis of a correlation coefficient (r) 0.9579, a coefficient of determination ($R^2$) 0.91, a mean square error 0.026, a bias factor 1.03, and an accuracy factor 1.13. Our secondary model provided reliable predictions of growth rates for E. sakazakii in broth with the combined effects of temperature, NaCl concentration, and pH.

• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.1-7
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• 2009

Control of hyperglycemia and dyslipidemia is strongly correlated with decreased risk for cardiovascular disease, the most common and fatal diabetic complication. The purpose of this study is to determine the effects of garlic and aged black garlic on glycemic control and blood lipid profile in animal model of type 2 diabetes. Three week-old db/db mice (C57BL/Ks, n=21) were fed AIN-93G semipurified diet or diet containing 5% freeze-dried garlic or aged black garlic for 7 weeks after 1 week of adaptation. Fasting serum glucose, insulin, triglyceride, total cholesterol, and HDL-cholesterol and blood glycated hemoglobin were measured. Body weight and food intake of garlic and aged black garlic group were not significantly different from those of the control group. Fasting serum glucose and blood glycated hemoglobin levels were significantly decreased and insulin level was significantly increased in garlic group compared with control group (p<0.05). Consumption of aged black garlic significantly decreased homeostasis model assessment for insulin resistance (HOMA-IR) and tended to decrease serum glucose. Garlic consumption significantly decreased total cholesterol, while aged black garlic significantly reduced serum total cholesterol and triglyceride and increased HDL-cholesterol levels. These results suggest that garlic exerts hypoglycemic and hypocholesterolemic effect and aged black garlic improved insulin sensitivity and dyslipidemia in db/db mice.

• Korean System Dynamics Review
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• v.10 no.3
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• pp.105-124
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• 2009

The situation of the global food markets has been being rapidly restructured and entering on a new phase by new dynamic and driving forces. The factors such as economic growth and income increase, high energy price, globalization, urbanization, and global climate change are transforming patterns of food consumption, production, and markets. The prices and markets of world food and energy are getting increasingly linked each other. Food and fuel are the global dilemma issues associated with the risk of diverting farmland or of consuming cereals for biofuel production in detriment of the cereals supply to the global food markets. An estimated 100 million tons of grain per year are being redirected from food to fuel. Therefore, the objectives of this study are as follows: Firstly, the study examines situations of the world food and energy resources, analyzes the trends of prices of the crude oil and biofuel, and formulates the food-energy links mechanism. Secondly, the study builds a simulation model, based on system dynamics approach, for not only analyzing the global cereals market and energy market but also forecasting the global production, consumption, and stock of those markets by 2030 in the future. The model of this study consists of four sectors, i.e., world population dynamics sector, global food market dynamics sector, global energy market dynamics sector, scenario sector of world economic growth and oil price.