• Transactions of the Korean hydrogen and new energy society
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• v.30 no.6
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• pp.490-498
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• 2019

The intermittent electric power supply of renewable energy can have extremely negative effect on power grid, so long-term and large-scale storage for energy released from renewable energy source is required for ensuring a stable supply of electric power. Power to gas which can convert and store the surplus electric power as hydrogen through water electrolysis is being actively studied in response to increasing supply of renewable energy. In this paper, we proposed the novel concept of hydrogen liquefaction process combined with pre-cooling process using the liquid air. It is that hydrogen converted from surplus electric power of renewable energy was liquefied through the hydrogen liquefaction process and vaporization heat of liquid hydrogen was conversely recovered to liquid air from ambient air. Moreover, Comparisons of specific energy consumption (kWh/kg) saved for using the liquid air pre-cooling was quantitatively conducted through the performance analysis. Consequently, about 12% of specific energy consumption of hydrogen liquefaction process was reduced with introducing liquid air for pre-cooling and optimal design point of helium Brayton cycle was identified by sensitivity analysis on change of compression/expansion ratio.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.3
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• pp.512-534
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• 2016

This paper is to see what appears to be an economic crisis as urban crisis, to explore its emerging process and its major distinctive figures in the context of S. Korea, and to consider alternatives to overcome such an urban crisis. For this purpose, it first tries to show that the capitalist economic development (i.e. capital accumulation) has been stimulated and driven largely by extending investments into built environments. Then it analyzes how crises of overaccumulation, coupled with other crises such as the IMF crisis in 1997 and the financial crisis in 2008 which have been brought about by serious impacts of foreign financial capitals working on the global level, have led to accumulating of huge surplus reserves within both big companies and the central government on the one hand, increasing tremendously debts of households as well as government and private companies on the other. In particular, the debt crisis seems to be accelerated by fictitious capital generated through government's financial strategies to promote both supplies and demands in housing and property markets. There seem several ways of overcoming the urban crisis spiraled around accumulating surplus capital and increasing financial debt; raising real income, moderating investments into built environment, and increasing inputs into the fields of technology and well-being. In order to open up these ways, it is concluded, recent urban movements in terms of the right to the city are required not only to make the government and capital to do so, but also to realize interest of urban people who have produced such surplus but who are suffering from the debt crisis.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.265-274
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• 2016

In this paper, we consider a diffusion risk process, in which, its surplus process behaves like a Brownian motion in-between adjacent epochs of claims. We assume that the claims occur following a Poisson process and their sizes are independent and exponentially distributed with the same intensity. Our main goal is to derive the exact formula of the joint moment generating function of the ruin time and the total amount of aggregated claim sizes until ruin in the diffusion risk process. We also provide a method for computing the related first and second moments using the joint moment generating function and the augmented matrix exponential function.

• Transactions of Materials Processing
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• v.21 no.8
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• pp.467-472
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• 2012

Shaving shear-welding is a solid-state welding process, which utilizes plastic deformation of surplus material. The solid-state nature of this process contributes to high integrity and strength of the weld. The objective of this study was to investigate the effects of process variables on the material flow patterns and identify the process condition for obtaining the best weld. FEM simulations were carried out along with experimental characterizations. The results showed the importance of the cutter angles and the overlap lengths, and helped attain the optimum shaving shear-welding die and the best process condition.

• Journal of the Korean Society of Food Culture
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• v.24 no.1
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• pp.10-22
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• 2009

This study was conducted to evaluate changes in food consumption during the 1950's on the basis of articles that reflected national policy and changes in society during that time period. Many factors are involved in the development and changes in food consumption culture, and these factors can affect each other. As a result, the process involved in the development of food consumption culture acts as a living system. This study evaluated the food consumption culture during the 1950's because this period was subjected to obvious influences that may explain the modern food consumption market logic and commercialism. Changes in the national food consumption are dependent on natural changes such as income enlargement or cultural exchange with a foreign country. Accordingly, food consumption during the 1950's was influenced by changes in economical, social, and political needs. In addition, the influx of surplus agricultural products from the United States had an adverse effect on local agriculture and resulted in an increased external dependence on food during the 1950s. Moreover, the import of raw materials and simple manufacturing techniques led to the development of an industrial food processing industry that enabled accelerated mass production of food at a low-price. Furthermore, the importation of surplus agricultural products from the United States that were used as the raw materials for foods that had traditionally been produced domestically led to an increased burden and qualitative decline in the local food-service industry. Taken together, the results of this study indicate that during the 1950's fresh food began to be replaced with processed foods in Korea.

• KIEAE Journal
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• v.7 no.2
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• pp.17-23
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• 2007

While heat island has been recognized as an unique environmental nuisance in cities, the phenomenon tends to be regarded as an inevitable side effect on urbanization. Recently the nature of the heat island has been disclosed and efforts for the remedy have been discussed in many ways. Some pioneering actions have been taken to mitigate the strength of the heat island's intensity in several countries. After studies for the heat island and speculations on current pilot policies of 3 different countries has been done, mitigation policies for heat island has been suggested as followings. 1. Preservation of natural topography is essential because latent energy consumption(evapotranspiration) from the site is the single most important factor to mitigate the energy surplus caused by urban heat island. 2. Because current national zoning ordinance or building law can not effectively control the site specific local environment, heat island policy should be established or employed at local level. 3. Incentives for the mitigation should be adopted on the process of implementation because environment is public concern. 4. Wind can easily dissipate energy surplus which is the major driving force for heat island. Therefore local wind, the direction and intensity should be sustained and sometimes facilitated fully through policies.

• Korean Journal of Human Ecology
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• v.13 no.6
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• pp.1055-1062
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• 2004

The food bank program is one of the social welfare programs that collects surplus food and grocery products from food service and manufacturing industries, and then distributes them to those in need. The objective of this study was to investigate the food donors' perception of the program and the current status of food donation, and make a few suggestions to improve the program. A total of 200 respondents from 84 restaurants, 40 buffet restaurants, 40 bakeries, and 36 contract food service management companies participated in this study. The average amount of surplus food was 5.39 kg/day, and its 51.4% was being done away with. One of the donation benefits that most respondents expected was public relations for themselves as a program participant. The respondents' main information sources about the program were newspapers, magazines, and TV. Needs assessments regarding the program information showed that the respondents needed information about formalities, process, and donation benefits. One of the major setbacks in improving the program was insufficient information on it.

• Ocean and Polar Research
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• v.41 no.3
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• pp.183-191
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• 2019

This study sought to find which model is most appropriate for estimating potential yield in the East Sea, Republic of Korea. For comparison purposes, the Process-error model, ASPIC model, Maximum entropy model, Observation-error model, and Bayesian state-space model were applied using data from catch amounts and total efforts of the whole catchable fishes in the East Sea. Results showed that the Bayesian state-space model was estimated to be the most reliable among the models. Potential yield of catchable species was estimated to be 227,858 tons per year. In addition, it was analyzed that the amount of fishery resources in 2016 was about 63% of the biomass that enables a fish stock to deliver the maximum sustainable yield.

• Journal of Drive and Control
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• v.19 no.1
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• pp.26-33
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• 2022

This study dealt with a self-propelled spinach harvester, which is capable of carrying out sequential harvesting work. This study aimed to find the cause of the harvester's occasional performance deterioration, which occurs in the process of simplifying the hydraulic circuit, using a multi-domain analysis model. The study was carried out in the following manner. First, a hydraulic system analysis model, which combines linear motion, rotary motion, hydrodynamic behavior, and an electrical signal, was developed through SimulationX software, specialized in multi-domain analysis. Second, a scenario for single behavior and coupled behavior was set out on an actuator basis. Third, the flow rate of the hydraulic system, which is not required for the movement of the actuator, was quantitatively analyzed. The results showed that a change in oil temperature was the cause of the harvester's occasional performance deterioration. And the higher the oil temperature, the more serious the performance deterioration, especially as the number of actuators operated simultaneously was small.

• Journal of Dairy Science and Biotechnology
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• v.24 no.2
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• pp.47-54
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• 2006

Consumers have become increasingly more aware of food safety issues, as a consequence of s number of food scandals. Most of these scandals have been related to livestock products. However, most consumers still believe that it is possible to produce safe food at low prices, while a small group of consumers is willing to pay a price surplus for special quality. Organic standards, especially for livestock products, have very few definitions of process quality, and even fewer of these definitions that influence product quality. This paper work to organic milk production and marketing trends in Korea.