• Korean Journal of Organic Agriculture
• /
• v.23 no.4
• /
• pp.615-641
• /
• 2015

This study analyzes an economic efficiencies of apples, pears, and grapes farming. We evaluate an annual economic overall efficiency (OE), allocative efficiency (AE), technology efficiency (TE), pure technology efficiency (PTE), and scale efficiency (SE) using data envelopment analysis (DEA). We also measure returns to scale of farms, and the change of technical efficiency of frontier farms. Lastly we estimate the effects of some explanatory variables on allocative, pure technical, and scale efficiencies.

• Journal of Korean Society of Rural Planning
• /
• v.7 no.2 s.14
• /
• pp.65-73
• /
• 2001

Animal manure and manure compost produced from livestock farms are widely applied in crop lands. Leachate and runoff water from them are presumed to be one of the major sources of water quality deterioration in rural streams. Laboratory experiments were conducted to investigate water quality characteristics and loading of leachate obtained under rainfall simulation. Manure composts for the experiments were collected from beef cattle farms, dairy farms, and pig farms. Water quality parameters include SS, COD, TN, and TP. Most parameters of leachate from pig manure compost was higher than others. Both TN and TP concentrations were reflecting the composition of manure itself. It is recommended, therefore that the leachate from the manure composts should be controlled not to be discharged into streams.

• Journal of Korean Society of Rural Planning
• /
• v.7 no.2 s.14
• /
• pp.3-11
• /
• 2001

A portable GPS receiver and a navigation software were used to investigate land application practices of manure composts. The field investigation indicated that most of the land application of manure composts were observed before April. Plowing for incorporation of manure with soil were continued from the middle of April. The results also revealed that over 60% of the farms were within 1 km from livestock farms from which manure composts were transported. Most of the farms having land application were dry field rather than paddies, Some of fields located near livestock farms frequently experience over-application of manure composts. It seems to have been difficult to complete the investigation in this study without the Gps/navigation system. The GPS/navigation system will become an essential tool in field investigations such as ecological/environmental monitoring works that require repeated observation at a number of sites.

• Korean Journal of Veterinary Service
• /
• v.27 no.2
• /
• pp.121-131
• /
• 2004

This experiment was executed to control effectively endemic disease of swine farms in Incheon metropolitan city. Mainly using PigMon program which had been developed by the College of Veterinary Medicine in the University of Minnesota(USA), we examined lesions of gastric ulcer and interstitial nephritis additionally. 446 heads of pigs shipped from 5 farms in Incheon to a slaughterhouse from June in 2003 to May in 2004 were examined. Infection rates by farms were obtained as follows; 1. Pneumonia was varied from 34.6% to 74.1% and pneumonic score was 1.47∼7.06. As for atrophic rhinitis, four farms were 100% and one farm was 89.5% and rhinitis score was 1.3∼3.2. 2. The infection rate of pericarditis and peritonitis was 1.0∼3.9% and liver white spots, papular dermatitis were observed in pigs of 9.8∼29.7%, 16.7∼51.4% respectively. 3. The outbreak rates of interstitial nephritis, lesions of ileal thickening and gastric ulcer were 15.4∼24.1%, 7.7∼13.5%, and 62.7%∼86.2% respectively.

• Korean Journal of Veterinary Service
• /
• v.34 no.2
• /
• pp.149-152
• /
• 2011

From January to November in 2010, a result of chicken infectious anemia virus (CIAV) antibodies ELISA test about 500 number in 25 broiler breeder farms and 500 number in a broiler chickens slaughterhouse from 25 farms in Iksan area, Jeonbuk. The result of 100% (25/25) positive rate in broiler breeder farms group and 98.6% (493/500) positive rate from each individual. In each week-age group, 98.8% of 18~20 weeks and 98.3% of 21~24 weeks showed positive without any significant differences. In slaughterhouse case, broilers from the farms showed 36.0% (9/25) positive rate and each individual showed 20.4% (102/500) positive rate.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.12
• /
• pp.1965-1970
• /
• 2016

This paper studies generator rescheduling technique for congestion management in power system with wind farms. The proposed technique is formulated to minimize the rescheduling cost of conventional and wind generators to alleviate congestion subject to operational line overloading. The generator rescheduling method has been used with incorporation of wind farms in the power system. The locations of wind farms are selected based upon power transfer distribution factor (PTDF). Because all generators in the system do not need to participate in congestion management, the rescheduling has been done by generator selection based on the proposed generator sensitivity factor (GSF). The selected generators have been rescheduled using linear programming(LP) optimization techniques to alleviate transmission congestion. The effectiveness of the proposed methodology has been analyzed on IEEE 14-bus systems.

• Journal of Agricultural Extension & Community Development
• /
• v.27 no.1
• /
• pp.33-50
• /
• 2020

This study aims at shedding light on two questions: 1) how livelihood strategies hired by heterogeneous farm households differ and in what aspect, and 2) would the strategy change over time or remain identical across farm types? Using 2013-2017 Farm Economy Survey panel data, we divide the sample farms into 4 sub-groups based on income level and sources. Key findings are as follows. First, regardless of farm types, strong path dependency has been observed. That is, lots of farms are likely (enforced) to maintain the livelihood strategies, accounting for why many farms fail to response to market and/or policy signals. Second, along with compounding risks, farms are more vulnerable to specific sorts risks. Third, based on the findings, we made policy suggestions.

• KEPCO Journal on Electric Power and Energy
• /
• v.1 no.1
• /
• pp.73-77
• /
• 2015

Offshore wind farms extend a distance from an onshore grid to increase their generating power, but long distance and high power transmissions raise a lot of cost challenges. LFAC (Low Frequency AC) transmission is a new promising technology in high power and low cost power transmission fields against HVDC (High Voltage DC) and HVAC (High Voltage AC) transmissions. This paper presents an economic comparison of LFAC and HVDC transmissions for large offshore wind farms. The economic assessments of two different transmission technologies are analyzed and compared in terms of wind farm capacities (600 MW and 900 MW) and distances (from 25 km to 100 km) from the onshore grid. Based on this comparison, the economic feasibility of LFAC is verified as a most economical solution for remote offshore wind farms.

• Korean Journal of Agricultural Science
• /
• v.24 no.1
• /
• pp.21-28
• /
• 1997

For the investigation of occurrence of insect pests and their natural enemies, total number of 353 controlled agricultural farms were visited and surveyed. In the 73% of total controlled agricultural farms, 52 species insect pests were occurred. Among these pests, the western flower thrip (Frankliniella occidentalis), the two spotted spider mite (Tetranychus urticae), the greenhouse whitefly (Trialeurodes vaporariorum), the cotton aphid (Aphis gossypii) and the green peach aphid (Myzus persicae) were mainly occurred. On the other hand, small numbers of natural enemies were sustained in 40 controlled agricultural farms, which was 11% and 17% of visited farms and pest occurred farms, respectively. For the most part of collected natural enemies, there were included in Braconid, Coccinellid and Anthocorid, as 63, 20 and 8% of them, respectively.

• Parasites, Hosts and Diseases
• /
• v.56 no.5
• /
• pp.477-485
• /
• 2018

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections.