• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.1-8
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• 1991

Population dynamics of Matted sole Limanda yokohamae($G{\"{U}}NTHER$) in Tokyo bay, Japan has been studied by virtual population analysis (VPA) for multi cohort and experimental fishing. Based on the biological data, the present parameters of the Limanda yekohamae stock at the Tokyo bay, Japan were estimated as follows: natural mortality coefficient(M) were 0.313 for male and 0.250 for female, terminal fishing mortality coefficient(F) were 2.190 for male, and 0.798 for female, rate of exploitation(E) was $30\%\;to\;50\%$. From the result of virtual population analysis for multi cohort, the population size were estimated from 3,5000,000 to 9,200,000 fishes, according to the result of experimental fishing, estimated stock size were 2,400,000 to 8,700,000 fishes. Stock size difference of the two methods were about two times in 1987, however, other years has been showed from 0.8 to 1.5 times. Both method has been showed same increase and decrease tendency of the c. p. u. e. and catches. From the isopleth diagram plot by Beverton and Holt's yield per recruit, the catches could be increase two times for female, 1.3 times for male than present aspects by the fishing management. And further, as reducing fishing effort, extension of mesh size and rising the length at first caputre, are reasonable in order to manage the stock at the optimum level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.606-619
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• 2020

This study investigated the effects of crude protein levels in diets containing monobasic potassium phosphate (MKP) on water quality and the growth of Japanese eels Anguilla japonica and leafy vegetables in a Hybrid BFT-Aquaponics (HBFT-AP) system. The first experiment (EXP1) was designed to verify the effects of the feed itself on leafy vegetable productivity using two diets (CP48 and CP30) with MKP and one commercial eel diet (COM58). The second experiment (EXP2) examined the effects of the three diets on productivity of the fish and leafy vegetables in the HBFT-AP for 6 weeks. After the 6 week feeding trial, the weight gain, feed efficiency, specific growth rate and protein efficiency ratio of fish fed COM58 and CP48 were higher than those of fish fed CP30 (P<0.05) and the growth of the four leafy vegetables was the highest with fish fed CP48. Water quality was measured six times per week using a portable water quality meter and reagent measurements and showed variance with time for TAN (0.01-0.09 mg/L), NO₂-N (0.010-0.064 mg/L), NO₃-N (5.52-27.15 mg/L), PO₄-P (2.03-5.32 mg/L) and pH (7.86-6.15).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.254-261
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• 2012

To reduce the injury by continuous cropping of sweet potato (Ipomoea batatas (L.) Lam.), the farmer's plant and virus-free plant were cultivated with the density of $70{\times}25cm$ (June 10, 2011) in continuous cropping soil (CCS) and subsoiling reversion soil (SRS). Fertilizer was applied at the rates of 55-63-156 $kg\;ha^{-1}$ ($N-P_2O_5-K_2O$) and 10 $ton\;ha^{-1}$ of cattle manure in CCS, and it was applied the 50% increased cattle manure compost and nitrogen in DRS. Symptoms of viral infection were revealed in the farmer's plant at 30 days after planting, but there were no symptoms in virus-free plant. The yield of virus-free plant was more increased 15% and 10.5% than that of farmer's plant in DRS and CCS, respectively. The yield of sweetpotato in SRS was more increased 8.8% and 3.2% in farmer's plant and virus-free plant compared to CCS, respectively. In DRS, the rate of marketable tuber of virus-free plant was increased by 80% compared to the farmer's plant (60.1%). The virus-free plant was produced the tuber with more brilliant peel color and well-formed shape compared to the farmer's plant. The increased yield of virus-free plant and in SRS soil condition showed a positive relationship (p=0.05) with the number of leaf per plant at 30 days and the number of branch per plant at 120 days after planting. The results showed that the early growth after planting was very important for the development of storage root. Therefore, the deep-subsoil reversion and cultivation of virus-free plant could be reduced the injury by continuous cropping of sweet potato, and increased farm income.

• Korean Journal of Environmental Agriculture
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• v.20 no.2
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• pp.108-111
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• 2001

This study examined effects of aqueous extracts of rice bran on the inhibition of germination and early growth of annual weeds, barnyardgrass and eclipta. Germination of barnyardgrass treated with 5%(w/v)-sterilized and nonsterilized extracts of rice bran were inhibited by 27% and 63% at 7 days after treatment(DAT), respectively, compared to control. However, plant height and fresh shoot weight of barnyardgrass treated with aqueous extract of rice bran was reduced significantly at higher than 1% for both sterilized and nonsterilized extracts. Plant height and fresh shoot weight of barnyardgrass treated with 5% extract of rice bran were inhibited by 66 to 68% and 75 to 78% at 7 DAT, irrespective of sterilization. The germination of eclipta treated with sterilized and nonsterilized extracts of rice bran were significantly inhibited at concentrations of more than 0.5% and completely at 4% and 5%. Plant height and fresh shoot weight of eclipta affected by the rice bran extracts showed trends similar to the germination rate. The sterilization of rice bran extract resulted in higher inhibition of germination and early growth of eclipta. Rice bran extract was more inhibitory to the germination and growth of eclipta than barnyardgrass. These results suggest that aqueous extracts of rice bran may have inhibitory potential to germination and early growth of weeds.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.1
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• pp.31-43
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• 1982

Engineering phase of dairy housing systems has close connection with the milk produc- tivity of dairy cattle, the quality of milk, extension of dairy production systems, labor- saving in management of dairy cattle and the like. Moreover, the rate of investment of dairy housing facilities is of relatively high level, However, there has been almost no research effort for the improvement of engineering aspects of dairy housing systems in Korea. The purpose of this study is to find out general engineering problems and to recomm- end the improvement in dairy housing systems in Korea. Field survey by means of questionaire, direct measurements, taking pictures and sketching was conducted to get necessary information for the study. Kyung-ki Do region was firstly chosen for sampling area since it has included more than half of the number of dairy farms of the whole country. The results obtained are summarized as follows: 1. In overall dairy farm layout, the dwellings of workers were ignored in the light of sanitary environment 2. The layout of stalls in a dairy barn belongs mostly to the type of double-row face-out, which is compatible with the emphasis of manure disposal activities. 3. While the width and length of stalls were sufficiently close to the standard dimension, the width of mangers was much less than the standard dimension. 4. The width and depth of manure gutters and the width of working alleys were much. less than the standard dimension. 5. The mooring equipment was mostly in the classes of chain or rope. The watering equipment was not facilitated independantly except the one cese of using watercup. 6. The bucket milkers with one or two bucket milkers with the capacity of two cattles. each were used as milking equipment in most dairy farms. 7. There were only few milk rooms independently spaced from other space, in which the arrangement of milking equipment was much less than the standard condition. 8. The lounging ground area was averaged to be sufficient for the activity of dairy herd. 9. Silos for silage used during winter consisted of mostly bunker silos, trench silos and underground vertical silos. Ordinary vertical silos were considered for the farmers to be inconvenient for the labor saving. 10. From the view point of heat conservation and moisture removal within the dairy barns, windows were not flexible for the easy ventilation and ceiling part was not adequate for temperatur maintenance. 11. Waste treatment and disposal systems were not provided with most dairy farms, therefore the livestock waste pollution problems would be serious in the near future.

• Journal of Internet Computing and Services
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• v.15 no.4
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• pp.141-152
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• 2014

According to proliferation of smartphones and extension of various services utilizing location information, markets of Location Based Service(LBS) have been activating all over the world. However, as the privacy violations of personal location information have been continuously increased, interests in the deregulation have been grown as well. While the regulations of location information can protect personal information and privacy, it causes some negative affect in terms of development of diverse services and industry activation. In particular, Korea is the only country that has applied strict restrictions of LBS by making location information related independent 'Location Information Protection Act'. As a result of this, the issues that LBS industry has no longer developed in Korea and it is necessary for us to relax the regulations have been consistently raised. Thus, this study confirmed that there was the negative(-) relationship between the regulations and the market activation of LBS by comparing and analyzing the correlation between the market growth rate of LBS and relevant regulations at home and abroad; the regulations are strengthened, restrictions in market entry and the business performance can occur. In other words, LBS business will be able to be activated if the regulations which have not directly related to the privacy have been relaxed.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.527-541
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• 2000

The purpose of this study was to find out the characteristics of learning contents structure of K-12 science textbooks. The characteristics are related to 7 main concepts of matter properties; reaction rate, other reaction, density, solution, state change, absorption, and surface property. The contects are analyzed into 5 types of characteristics; type of concept extension, type of concept deepness, type of same level concept, type of confusion with other concepts, and type of concept interruption. First two types are positive content structures, but the others are negative structures. The findings are as follows. First, a lot of learning contents have the characteristic of 'type of same level concept'. There are few which have the characteristic of 'type of concept deepness'. Second, there are a lot of concepts related to 'properties of matter' which are not represented any more in middle and high school science textbooks. Those concepts are importantly taught in early childhood education and elementary school science. Most of the learning contents don't represent 'type of concept deepness'. Therefore the science textbooks needs to be restructuring.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.69-82
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• 1994

In order to find out physiological effects of diets supplemented with seamustard (Undaria pinnatifida) on the growth, survival rate, body compositions and blood properties of young rockfishes (Sebastes schlegeli) in range of average total length from $2.99{\pm}0.23\;cm\;to\;18.52{\pm}1.07\;cm$ and average body weight from $1.03{\pm}0.18\;g\;to\;120.64{\pm}19.32\;g$, experiments were performed for 140 days by feeding four experimental diets supplemented with $0\%,\;3\%,\;5\%\;and\;7\%$ of seamustard powder. In addition, the tests on tolerance of the fishes against low $O_2$ saturation and starvation were carried out after the feeding experiments. The fishes fed diet supplemented with $5\%$ of seamustard powder revealed the best results in growth of total length and body weight. Crude lipid content in the whole viscera of fishes fed diets supplemented with seamustard powder was higher than that of fishes fed diet without seamustard powder, while the moisture, crude protein, crude lipid and crude ash composition in the dorsal muscle did not show any remarkable differences among diet groups with or without seamustard powder. Hematocrit and mean number of red blood cell in fishes fed diets supplemented with seamustard powder was elevated, despite of no notable changes in mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The resistance of the fish to low $O_2$ saturation was elevated by feeding seamustard powder. Upon the starvation of fish for 31 days after the feeding experiments, body weight loss of three groups fed diets with seamustard was smaller compared with the group fed diet without seamustard.

• Journal of Periodontal and Implant Science
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• v.31 no.3
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• pp.581-595
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• 2001

In performing implant procedures in the anterior portion of the maxilla, many difficulties exist because of anatomical reasons, such as the proximity of the nasal floor, lateral extension of the incisive canal, and labial concavity. On the other hand, in the posterior region of the maxilla, there is often insufficient recipient bone between the maxillary sinus and alveolar ridge due to alveolar ridge resorption and pneumatization of the maxillary sinus. In order to perform implants in such regions, ridge augmentation procedures such as onlay bone graft, guided bone regeneration, and maxillary sinus grafting are performed. In studies of Caucasians, use of autograft from mandibular symphysis has been reported to be highly successful in maxillary sinus grafting. However, in a clinical study of Koreans, autograft of mandibular symphysis has been reported to have significantly low success rate. It has been hypothesized that this is because of insufficient cancellous bone due to thick cortical bone. In order to test this hypothesis, bone quality and morphology of Koreans can be compared with those of Caucasians. In this study, the bone density and morphology of the cortical bone and cancellous bone in the mandibular symphysis of 35 Korean cadavers were evaluated. The following results were obtained: 1. In terms of bone density, type I, type II, and type III consisted of 1.4%(3/213), 72.3%(154/213), and 26.3%(56/213) of the cross-sectioned specimens, respectively. In general, the bone density tended to change from type II to type III, as cross-sectioned specimens were evaluated from the midline to the canine. Type IV wasn't observed in this study. 2. The distance between the root apex and the lower border of the cancellous bone was 18.34mm-20.59mm. Considering that the bone has to be cut 5mm below the root apex during the procedure, autografts with about 15mm of vertical thickness can be obtained. 3. The thickness of cortical bone on the labial side increased from the root apex to the lower border of the mandible. The average values ranged from 1.43mm to 2.36mm. 4. The labio-lingual thickness of cancellous bone ranged from 3.43mm to 6.51mm. The thickness tended to increase from the apex to the lower border of the mandible and decrease around the lower border of cancellous bone. From the above results, the anatomic factors of the mandibular symphysis (bone density, thickness, quantity and length of the cortical bone and cancellous bone) didn't show any difference from Caucasians, and it cannot be viewed as the cause of failure in autografts in the maxillary sinus for implants.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.63-68
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• 2015

This study was conducted to find out optimum cultivars, and growth temperature and stage in peanut sprout for resveratrol production. Morphological characteristic, days to 50% of the final germination percentage($T_{50}$) and early growth vigor were measured in 8 different peanut varieties. In result 'Jopyeong' appeared to be the most appropriate cultivar for peanut production because of its lower contamination rate, lesser lateral root formation, and thicker hypocotyl length. Optimum temperature for growing peanut sprouts was determined 27. Content of resveratrol was examined by high performance liquid chromatography(HPLC) to investigate appropriate growth stage of peanut sprouts for resveratrol production. Resveratrol was higher than $17.0{\mu}g/g$ in peanuts sprouts 9 days after plating. Considering peanut sprout's shapes and content of resveratrol into account, it was most appropriate to harvest in 9-day after germination.