• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.569-575
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• 2014

A highly efficient class E power amplifier is demonstrated for application to wireless power transfer system. The amplifier is designed with an L-type matching at the output for harmonic rejection and output matching. The power loss and the effect of each component in the amplifier with the matching circuit are analyzed with the current ratio transmitted to the output load. Inductors with a quality factor of more than 120 are used in a dc feed and the matching circuit to improve transmission efficiency. The single-ended amplifier with 20 V supply voltage shows 7.7 W output power and 90.8% power added efficiency at 6.78 MHz. The wireless power transfer (WPT) system with the amplifier shows 5.4 W transmitted power and 82.3% overall efficiency. The analysis and measurements show that high-Q inductors are required for the amplifier design to realize highly efficient WPT system.

• Journal of Power Electronics
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• v.15 no.4
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• pp.939-950
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• 2015

A single-stage AC-AC converter has been designed for a wind energy conversion system (WECS) that eliminates multistage operation and DC-link filter elements, thus resolving size, weight, and reliability issues. A simple switching strategy is used to control the switches that changes the variable-frequency AC output of an electrical generator to a constant-frequency supply to feed into a distributed electrical load/grid. In addition, a modified random sinusoidal pulse width modulation (RSPWM) technique has been developed for the designed converter to make the overall system more efficient by increasing generating power capacity and reducing the effects of inter-harmonics and sub-harmonics generated in the WECS. The technique uses carrier and reference waves of variable switching frequency to calculate the firing angles of the switches of the converter so that the three-phase output voltage of the converter is very close to a sine wave with reduced THD. A comparison of the performance of the proposed RSPWM technique with the conventional SPWM demonstrated that the power generated by a turbine in the proposed approximately increased by 5% to 10% and THD reduces by 40% both in voltage and current with respect to conventional SPWM.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1117-1126
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• 2017

The main contribution of this paper is the use of sensorless active diodes to generate the gate signals for a three-phase boost-rectifier with a self-powered control scheme. The sensorless operation is achieved making use of the gate control signals generated by the active diode schemes on each of the switching devices using a pulse width half-controlled boost rectifier modulation technique (PWM-HCBR). The proposed scheme synchronizes the gate control signals with a three phase voltage supply. Autonomous operation is obtained making use of the output DC bus to feed the control circuitry, the active diodes and the driver circuitry. The three-phase boost-rectifier is supplied by a three-phase permanent magnet electric generator powered by a solar concentrator dish with variable voltage and variable frequency conditions. Experimental results report an efficiency of up to 94.6% for 25 W and an input of 3.6 V peak per phase with 450.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1379-1386
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• 2018

Conventional underwater cameras used in fish farms can only shoot limited areas and are vulnerable to underwater contamination. There is also a problem with contaminated farms as surplus residues are deposited as a result of feed supply to farms' nets. This paper proposes underwater drones for underwater monitoring of fish farms and cleaning nets. If underwater drones are used for management of fish farms, underwater imaging, monitoring and cleaning of fish farms' nets can be possible. By using this technology, data can be collected by detecting changes in the environment of a fish farm and responding to changes that occur within a fish farm based on the data. In addition, the establishment of an integrated control system will enable to build efficient and stable smart farms.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.20-26
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• 2019

The purpose of this study is to show probability of alternate food by using edible insects through the reports (Edible insects: Future prospects for food and feed security) edited by WFO (World Food Organization). We were carried out to develop the functional meat new product using Mealworm (Tenebrio molitor lavare) and Chicken breast. People's interest to the healthy, low-calories food is growing up, the Foodservice industry is developing and making Functional food, which helps to a sale strategy. Insects have played an important role as human food throughout history, especially in Africa, Asia and Latin America. A rapid increase in the human population is expected in the second half of the 21 century, which will lead to lower availability of food, especially animal protein As the problem of food supply and demand has come to the fore with climate change, Food and Agriculture Organization of the United Nations (FAO) has noticed edible insects as future food resources in order to prepare against the shortage of protein source. Recently consumers, especially patients have doubts about safety of raw materials for food. To overcome these limitations, I propose an enteral nutrition formula using edible insects as a raw material.

• Food Science and Industry
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• v.50 no.2
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• pp.60-73
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• 2017

Recently, the whole world is facing an unprecedented moment of opportunity, so-called The Fourth Industrial Revolution. As emphasized in the World Economic Forum held in January of 2016 at Davos, the Fourth Industrial Revolution is not merely a changes of technological devices. The fundamental of the revolution is new, innovative, and visionary business models which change the whole systems dramatically. One of the greatest challenges is to feed an expected population of 9 billion by 2050 in a impactful way. The system should be sustainable as well as beneficial in improving the lives of people in the food chain along with the ecological health of environment. The technological advances of the Fourth Industrial Revolution are expected to improve our food system. The smart farm technology such as precision planting and irrigation techniques will improve the yields of food materials. The smart food transportation and logistics systems will substantially improve the safety and human nutrition. The adaptation the Fourth Industrial Revolution technology will induce the smart supply chains, smart production, and smart products in food industry due to its flexibility and standardization. This will lead the manufactures to adapt to customers' changing product specifications and traceable services in a timely manner.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.647-652
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• 2018

The emission of nitrogen oxides has a great environmental impact. It leads to Los Angeles type smog, and it recently has attracted attention as a source of ultrafine dust. The main sources of nitrogen oxides are internal combustion engines and industrial boilers. These emission sources are processes that are essential for human industrial activities, so the regulation of original use is impossible. Therefore, special control methods should be applied to reduce NOx emissions into the atmosphere. In this study, we investigated how the supply of ER and urea influences the removal of nitrogen oxides from SRF combustion boilers. Experimental results show that the removal efficiency of nitrogen oxides can be up to 80% under the conditions of ER 2.0 and a urea feed of 0.5 LPM.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.3-12
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• 2016

Vitamin D plays a vital role in maintaining blood concentrations of Ca and P. In lipid metabolism, vitamin D is also known to negatively affect the development of adipocytes, but it has received little attention with regard to improve marbling score in beef cattle via restricting its supply. Recently, the method of feeding fat soluble vitamins(including vitamin D)-deficient diets in Korean native cattle (Hanwoo) has been spread by feed companies and TMR plants. But proper guidelines in feeding vitamin D-deficient diets should be provided, otherwise it can adversely affect the health of cattle. To maximize marbling score, a controlled level of vitamin D in blood needs to be maintained and the proper period for feeding vitamin D-deficient diets should be provided. This review was conducted to highlight the regulatory effects of vitamins D on adipocyte differentiation, and provide information on improving beef quality grades in relation to feeding vitamin D-deficient diets in beef cattle.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.121-126
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• 2020

This study was conducted to investigate the effect of drinking ion water on the performance, egg quality, and serum biochemical properties of laying hens in a high-temperature environment. A total of 180 laying hens with equal egg production rates were randomly divided into three treatments with five replicates. Treatments were applied from 24 to 27 weeks of age and included the supply of ion water (IW), tap water (TW), and cold water (CW). The results showed that the egg production rate, egg weight, and feed intake of hens were significantly (P<0.01) improved in the IW group compared with those in the TW group but did not differ from those in the CW group. Egg quality parameters such as albumen height, Haugh unit, and eggshell thickness were found to be higher in the IW than in the TW group (P<0.05); however, no significant differences were observed in comparison with the CW group. Serum Ca and P concentrations tended to increase (P<0.10) in the IW group, and serum high-density lipoprotein cholesterol and albumin levels were greater (P<0.05) in response to IW than those to TW. This study provides evidence that the supply of IW can relieve the high-temperature stress during the summer. In particular, because the improved effects of the IW were confirmed to be similar to those of CW, it shows potential as a method to manage the drinking water of hens in the summer season along with the supply of CW.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.2
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• pp.168-174
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• 2021

According to the World Agricultural Productivity Report, the current annual average growth rate of agriculture is 1.63%, which is lower than 1.73% to support the world's 10 billion people, which is growing by 2050. The demand for food, feed, and bioenergy is not growing enough to continue to meet the demand, and it is predicting a future food shortage. The purpose of this study was to create a regional irrigation control model for the purpose of reducing the production cost of crops, increasing production, and improving quality, and presenting a model that can give advice to farmers who start farming in the region. The irrigation control modeling presented in this study means to represent the change of medium weight·supply liquid·drainage amount due to changes in the root zone environment according to the passage of time and climate in a graph model. For water control modeling, we collected data on the change in the amount of the root zone environment and the weight of the badge·supply amount·drainage amount from March to June in Nonsan, Buyeo, and Yesan regions in Chungnam Province through the measuring device of the Ministry of Environment in the root region. We set up the parameters for derivation and derived an irrigation control model that can confirm the change in weight·supply liquid·drainage amount over time through the parameters.