• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.503-508
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• 2009

There are many researches on human effect by electromagnetic equipments and applications. However, most of research and guidelines for limiting human exposure to electromagnetic fields are established by mobile communication of SAR(Specific Absorption Ratio). Therefore we need to study different effects on human body when exposed to high frequency(HF) band equipments, such as human induced current etc. In this paper, we measured human induced current by RFID reader antenna of HF band in the near field and we propose human equivalent antenna which has orthogonal loops to each other. Then, we compared the induced currents on proposed equivalent antenna with human.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.4
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• pp.231-238
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• 2004

The conditions are obtained for the decomposition of solid radioactive wastes, including ion exchange resin, zeolite, charcoal, and sludge from nuclear power plant. In the process of decomposing the radioactive wastes was used the microwave acid digestion method with mixed acid. The solution after acid digestion by the following method was colorless and transparent. Each solution was analyzed with ICP-AES and AAS and the recovery yield for 5 different elements added into the simulated radioactive wastes were over $94{\%}$. The elemental analysis of destructive low and medium level radioactive wastes by the proposed microwave acid digestion conditions concerning the chemical characteristics of each radioactive waste are expected to be useful basic data for development of optimal glass formulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.514-517
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• 2017

In solar photovoltaic systems, power generation is greatly affected by the weather conditions, so it is essential to predict solar energy for stable load operation. Therefore, data on weather conditions are needed as inputs to machine learning algorithms for solar energy prediction. In this paper, we use 15 kinds of weather data such as the precipitation accumulated during the 3 hours of the surface, upward and downward longwave radiation average, upward and downward shortwave radiation average, the temperature during the past 3 hours at 2 m above from the ground and temperature from the ground surface as input data to the algorithm. We analyzed the statistical characteristics and correlations of weather data and extracted the downward and upward shortwave radiation averages as a major elements of a feature vector with high correlation of 70% or more with solar energy.

• Journal of the Korean Solar Energy Society
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• v.33 no.4
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• pp.94-100
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• 2013

The objective of this study was to compare and analyze for seasonal long short-wave radiation characteristics between downtown area and suburban area in Daegu through field observations. This study was confirmed the regional and seasonal radiation environments and it can utilize as basic data for the analysis of the urban radiation environment and the effects of urbanization. The followings are main results from this study. 1) The downward shortwave radiation showed the similar value of the radiation generally in the downtown area and the suburban area of the city during the winter and summer season. but, long-wave radiation is always higher in downtown area. 2) In case of the long-wave radiation at two stations, we observed $230{\sim}270W/m^2$ in the winter season and $415{\sim}470W/m^2$ in summer season. As a result, we can see summer season is higher than winter about two times in long-wave radiation. 3) In case of short wave radiation, there is high correlation between two stations in winter season but very low correlation between two stations in summer season because of local atmosphere unstability and etc.

• Korean Journal of Organic Agriculture
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• v.16 no.2
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• pp.219-230
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• 2008

This trial was conducted to assess effects of cattle slurry application on productivity and feed values of barley and hairy vetch when they were influenced by single or mixed-sowed cultivation in paddy fields, and to obtain good quality of organic forage resources. The results summarized are as follows. For barley and hairy vetch, single-sowed cultivation was lower in annual dry matter (DM) and total digestible nutrients (TDN) yields than mixed-sowed (P<0.05). Although crude protein (CP) contents for the barley within single-sowed treatments were lowest as 6.5%, those of hairy vetch within the same sowed method were highest as 16.7%. However, mixed-sowed cultivation with barley and hairy vetch, showing 13.8% CP content, was significantly (P<0.05) higher than CP and relative feed value (RFV) of barley alone treatment. For barley alone treatment, cattle slurry application significantly increased annual DM and TDN yields in comparison with treatments of P+K fertilization as chemical fertilizers and no fertilizer as controls. Results from cattle slurry application showed 84% and 82% in contrast with chemical fertilizer for annual DM and TDN yields, respectively. For mixed-sowed cultivation with barley and hairy vetch, cattle slurry application showed 90% and 94% annual DM and TDN yields, respectively as compared with N+P+K fertilization as chemical fertilizers. Crude protein contents ($14.2{\sim}15.9%$) for cattle slurry application treatments were significantly (P<0.05) higher than those of other treatments. Moreover, cattle slurry application treatment had the highest TDN and RFV among treatments, showing $60.7{\sim}61.8%$ and $112.2{\sim}118.1$, respectively. For hairy vetch alone treatments, annual DM and TDN yields of cattle slurry alone application treatment were highest among fertilization treatments. Furthermore, CP, TDN and RFV of cattle slurry alone application treatments were significantly (P<0.05) higher than those of other treatments. The results showed that mixed-sowed cultivation rather than single-sowed for barley or hairy vetch improved their nutritive value and quality, and also within mixed-sowed cultivation, cattle slurry application increased production yield per ha and CP contents. In the application of above system to organic livestock farming, it would be expected that forages produced by cattle slurry application under mixed-sowed method might become a substitute for foreign organic grain as protein sources.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.49-58
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• 2010

This experiment was carried out to estimate the nutritive value of mixed-sowing winter forage crop and whole crop barley by investigating the effects of feeding mixed-sowing winter forage crop and whole crop barley in KBG (Korean black goat) on feed intake, average daily body weight gain, nutrient digestibility and nitrogen retention. The 12 male KBG were divided into four experimental groups - i.e. T1: barley silage added group, T2: mixed-sowing hairy vetch silage added group, T3: mixed-sowing field peas added silage, T4: mixed-sowing Italian rye grass added silage group. Three KBG per each treatment were allotted into individual metabolic cages by Latin-square design. The results from this study are as follow. The DMI (dry matter intake) and organic matter intake in T4 were significantly (p<0.05) higher than those in T1 and T3 and crude protein intake in T4 also recorded the highest among treatments (p<0.05). The highest values in intakes of ADF and NDF were observed in T4 followed by T2, T1 and T3 in order. The average daily body weight gains in T4 and T2 were significantly (p<0.05) higher than those in TI and T3. The dry and organic matter digestibility in T2 and T4 were significantly (p<0.05) higher than those in T1 and T3. The crude protein digestibility in T1 was significantly (p<0.05) lower than those in T2 and T4. The nitrogen intakes in T2 and T4 were significantly (p<0.05) higher than those in T3. The results obtained from this study suggested that the feeds supplemented with whole crop barley with hairy vetch and Italian rye grass mixture silage increased KBG productivity resulted from increases in feed intake, nutrient digestibility and nitrogen retention.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.1
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• pp.49-58
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• 2003

This study was conducted to determine the effect of seeding times and mixture rates of oat and forage rape on the growth characteristics and forage yields during rest periods from March to June after the harvest of potatoes in potato cultivation fields located in the areas about 600m above the sea level in Jeju. The experiment was a split plot desist with seeding times(early, middle and late March) sown . at intervals of ten days from early March to late March as the nam plots and mixture rates as subplots, consisted of oat single(150kg/ha), forage rape single(15kg/ha), oat/rape mixtures 75 : 25% (112.5kg/ha of oat and 3.75kg/ha of rape), oat/rape mixtures 50 : 50％(75kg/ha of oat and 7.5kg/ha of rape) and oat/rape mixtures 25 : 75％(37.5kg/ha of oat and 11.3kg/ha of rape). The germination and establishment of eat and rape were not significantly different among seeding times and mixture rates. The plant heights were higher when seeded middle March compared to seeding times of early and late March. The growth stage of the oats seeded early March was dough stage, while that of oats seeded middle or late March was milk stage. The dry matter yields per ha were higher(p<0.05) when seeded middle March than those of seeding time of early and late March. The crude protein contents of rape single, mixtures and oat single treatments were 15.9, 12.4∼14.5 and 8.5％, respectively.

• Journal of Animal Science and Technology
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• v.51 no.4
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• pp.337-342
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• 2009

The feasibility of reutilization of magnesium ammonium phosphate (MAP) or struvite slurry recovered from the process through microwave irradiation was studied in this experiment. For this purpose, 4 different operations were performed with or without Mg source addition and different levels of MAP recycled in a batch reactor. Dissolution rate of MAP, ${NH_4}^+$ elimination pattern and physicochemical changes of MAP during microwave irradiation were also studied. The result showed that only 33% orthophosphate ($PO_4-P$) and 27% $NH_4-N$ removal occurred without adding any external Mg source (run A), whereas 87% $PO_4-P$ and 40% $NH_4-N$ removed when 1.0 M ratio of $MgCl_2$ (run B) was added based on $PO_4-P$ in influent. Although the addition of 1.0 molar ratio of microwave irradiated MAP (Run C) removed lower $PO_4-P$ and $NH_4-N$ than 1.0 M $MgCl_2$ (run B), $PO_4-P$ removal was double when compared with no Mg addition (run A). Addition of half MAP and half $MgCl_2$ (run D) showed the similar removal efficiency (88% $PO_4-P$ and 35% $NH_4-N$) with sole $MgCl_2$ addition (run B). Based on these results, the reutilization of MAP irradiated by microwave would be a feasible way to enhance the removal efficiencies of N and P, as well as curtail the Mg chemical usage. Track study showed that $NH_4-N$ gradually increased at initial stage of microwave irradiation of MAP, and then started eliminating from liquor as temperature increased over $45^{\circ}C$. Dissolution rate of ${PO_4}^{-3}$ during microwave irradiation was proportional to the initial MAP concentration, having $0.0091x^{0.6373}$ mg/sec. It was found from the scanning electron microscope (SEM) study that physical structure of MAP crystal started breaking down into small cube granules within very short time by electromagnetic vibration force during microwave irradiation and then gradually melted down into solution.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.583-593
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• 2015

This study was conducted to investigate the effects of mixed-sowing of legume forage and applying of cattle manure on the productivity of organic rye to provide dairy farmers with safe organic feeds. Also the present study aimed to evaluate optimal applying level of cattle manure and carrying capacity of Korean native cattle (Hanwoo) per unit area. The amount of crude protein was significantly higher in the mixed-sowing of legume forage (average 760~786 kg/ha) than in the single-sowing of rye (average 353 kg/ha) (p<0.05). The mixed-sowing of forage peas and the single-sowing of rye tended to improve by increasing the level of nitrous fertilization rather than the fertilization treatment. The amount of crude protein on the rye according to the mixed-sowing of legume was significantly higher in the mixture (average 8.29~9.90%) than in the single (average 4.93%) (p<0.05). The comparison by the level of nitrogen fertilization indicated significantly high for the rye in 50 kg N/ha than in fertilization treatments (p<0.05). Total digestible nutrients (TDN) amount in the single-sowing of rye was average 46.86% and has lower than average 49.96~50.12% of the mixed-sowing of legume, and especially the mixed-sowing of forage pea was the highest with 54.55% in 150 kg N/ha for the level of nitrogen fertilization (p<0.05). The breeding ability of annual organic livestocks per unit area according to the feed value of rye presented significantly higher ability in the mixed-sowing of legume (3.72~4.12 heads) than the single-sowing of rye (average 2.26 heads) (p<0.05). By summarizing above results, the mixed-sowing of legume is required to improve the productivity and the feed value of rye for increasing organic livestock breeding ability in southern area of Gyeongbuk regions, and the study for identifying the appropriate fertilization level using livestock excretions is further necessary.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.35-45
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• 2016

Melatonin hormone involved in human's circadian rhythm adjustment sensitively responds to light's specific short wavelength ratio. A shift worker's circadian rhythm disturbance and sleep disorder are caused by the existing lighting conditions, whose short wavelength ratio is fixed. The life pattern of a shift worker changes irregularly because of irregular working hours and the same lighting environment; thus, his/her concentration is reduced. For such a reason, negative effects ensue to the detriment of healthy everyday life, including a high risk of accidents or having unsound sleep after leaving work. A smartphone-based wavelength control LED lighting system that targets shift workers and that can easily measure and control lighting suitable for wake-sleep cycle, according to working hours and closing hours, is proposed in this paper. First, after the light characteristics of LED lighting that changes depending on light control ratio are measured through the color sensor installed on the smartphone and the externally-linked Mini-Spectrometer, they are stored in the database. Based on the stored optical characteristics data, the measurement module and light control module are implemented. Lighting is offered using a control ratio having the maximum rate of short wavelength in consideration of the target illuminance, classified according to work type by identifying working hours as time when waking is required for shift workers. After a shift work leaves work, the amount of lighting is varied, using a control ratio having a minimum short wavelength rate so that a shift worker can enter the sleep state naturally.