• Journal of Energy Engineering
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• v.24 no.4
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• pp.1-10
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• 2015

For successful operation of waterflooding which is one of secondary recovery methods, suitable water injection allocation is important to increase oil recovery. Well allocation factor(WAF) which is one way to quantify the injector and producer connectivity, is utilized to allocate water injection of waterflooding. Static WAF cannot represent the field condition and can induce incorrect value. To compensate for limitation of static WAF, modified WAF which includes several parameters that affect patterns including well radius, distance between wells, and injection rates is proposed. In this study, static and modified WAFs were applied to injection optimization of waterflooding and results by each WAF were compared. In case of modified WAFs, produced water were less and produced oil were more than case of static WAF especially in big change of distance between producer and injector. Therefore, modified WAFs can allocate water injection more efficiently than static WAF.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.184-195
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• 2005

A preliminary quantitative model of the trophic structure in Gwangyang bay, Korea was obtained using ECOPATH and data from relevant studies to date in the region. The model integrates and analyzes biomass, food spectrum, trophic interactions and the key trophic pathways of the system. The bay model comprises 9 groups of benthic primary producer, phytoplankton, zooplankton, benthos, bivalve, pelagic fish, demersal fish and piscivorous fish. The total system throughput was estimated at $2.4\;kgWW/m^2/yr$, including a consumption of $41\%$, exports of $9\%$, respiratory flows of $24\%$ and flows into detritus of $26\%$. All of which originate from primary producers measured at $52\%$ and detritus of $48\%$. The total biomass was seen to be high compared to the levels of Somme, Delaware, Chesapeake Bays and Seine Estuary. This seems to be possibly due to artificial bivalve aquaculture and overestimation of benthos and benthic primary producer groups. The deviation can be calibrated by neglecting aquaculture and decreasing the habitat area for the groups. The trophic network of the bay shows a low level of recycling and organization as indicated by Finn's cycling index $3.3\%$, Ascendancy $3.1\;kgC/m^2/yr$ bits, Capacity $5.1\;kgC/m^2/yr$ bits and Redundancy $2.2\;kgC/m^2/yr$ bits. A high relative ascendancy of $62\%$ and a low internal relative ascendancy of $18\%$ indicate the system is not fully organized and stable towards disturbances, depending upon external connections. Although the model should be continuously provided with field data and calibrated further in depth, this study is the first trophic model applied to the region. The model can be a useful tool to understand the ecosystem in a quantitative manner.

• Plant Journal
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• v.9 no.1
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• pp.50-57
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• 2013

This study investigates the risks that can occur during the development stage of IPP project in developing countries. In case that ECA and MLA cannot participate due to poor credit rating of the country, the diversification of power purchaser in marginal states can be a great help to reduce both market risk and country risk at the same time. In case of thermal power plants and combined cycle power plants, the effect of performance degradation as time passed will be considered and expected profit of sponsors should be maintained. Recently, developing countries are expanding IPP projects to reduce the financing cost and Korean power companies are positively participating in IPP projects. Accordingly, the loss of Korean companies should be minimized by risk management through the risk mitigation methods of this study.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.138-148
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• 2003

In the study, current status of waste plastic recycling was investigated. Some factors to obstruct recycling of waste plastic was analyzed. These factors include the difficulty of obtaining location and man power, unclear marking of recyclable plastic and inefficient rate in producer and consumer deposit system. Life cycle assessment(LCA) study was performed to investigate the environmental impact of waste plastic(PET) recycling. When the recycled raw plastic material is used together with the virgin raw plastic material, all the environmental impact showed (-) value except ozone depletion impact category. The environmental avoided impact was the greatest in the global warming impact category. For active promotion of recycling activity, source separation system of waste plastic should be established first of all. Also, marking system of the recycling waste plastic should be made more clear so that consumers can understand it easily. Other strategies include the determination of decent rate for producer and consumer deposit system, establishment of infrastructure and information system for waste plastic recycling and citizen's cooperation through intensive public education.

• Child Health Nursing Research
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• v.8 no.3
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• pp.313-321
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• 2002

We would like to suggest the guideline of use of materials of sexual education for adolescent in school by examining the status of use of materials and by evaluating the video materials frequently used. Survey was done by enquetes on status of use of materials of sexual education from school nurses in 190 primary, 44 middle and 50 high schools in Seoul, Kyonggi-do and Kangwon-do from August 1999 to February 2000. The frequently used 84 videotapes were evaluated on their contents. As for the status of use, 99.3% of subjected schools possessed the materials for sexual education. Decision of purchase was determined according to the review of contents (92.6%). Information about materials was received by the advertisement in newspapers or broadcasting (46.1%) or recommendation of peer teacher (32.4%). Videotape was most frequently used (64.1%) rather than books or CD. Teachers concerns on the materials were the educational content according to developmental stage of students (41.9%), content provoking interest (33.5%) and concrete guide for teacher (10.6%). As for the evaluation of the contents of videotapes, a subject of education was not described out of 46.6%. Videotape producer were mostly the Government-affiliated institutes or non-profit organizations (86.8%). The year of production was indicated from 41.7%. Running time range of 21-30 minutes was highest (55.9%). The price was marked in only one videotape. Subjects of contents were general sexual education (34.5%), sexual violence or sexual harassment (21.4%), pregnancy and contraception (14.2%) and AIDS and sexually transmitted diseases (8.3%) and dating and adolescent change (4. 8%), and etc (11.9 %). According to above results, we suggested that materials for sexual education should be completed with a description on the subjected group, summary of content, information on the tape producer, year of production, running time and sale price.

• The Journal of Fisheries Business Administration
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• v.41 no.3
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• pp.59-78
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• 2010

This paper tries to apply the asymmetrical price transmission(APT) behavior observed in the agricultural industry to supply chains of the domestic fishery industry by a statistical manner. The fore mentioned asymmetrical price transmission refers to when price movements in the later stage of the supply chain do not move in a normal or symmetrical manner corresponding to price movements in the earlier stage of the supply chain. Therefore, when the earlier stage price increase and the later stage price increases to a larger degree, it is called positive(+) asymmetry and the opposite behavior is called negative(-) asymmetry. The study examines the data from domestic producers of three fresh fish types, hairtail, mackerel, and cuttlefish, and tries to examine the price asymmetry between the producer or farm, wholesaler, and retail prices via an APT test utilizing unit root, cointegration, and error correction model. The study found, hairtail wholesale and retail pricing bas a negative asymmetric relationship while mackerel has a negative asymmetric pricing relationship at the producer and retail levels of the supply chain. In the case of cuttlefish, all levels of the supply chain showed negative asymmetrical behavior in the supply chain price transmission, meaning the earlier stage price changes are more rapidly and greatly inputted in the later stage of the supply chain pricing. We believe that the reason why the analysis results show negative price asymmetry is due to the uniqueness of fishery products having an important variable such as freshness. If price increases are greater and quicker than price decreases, then consumer demand, which is sensitive to price increases will decrease and subsequently result in the increase of inventory levels, reducing profits for retailers. Also, frozen hairtail, mackerel, and cuttlefish will act as substitute goods to fresh fishery products. Therefore, fresh fishery products have a high demand of price elasticity. When prices increase, demand quickly decreases. Therefore the profit of wholesalers and retailers to decrease, I think this is the main reason of APT in the supply chain of Korea' s fisheries industry.

• Journal of Agricultural Extension & Community Development
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• v.7 no.2
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• pp.257-277
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• 2000

The objectives of this study are to investigate the relationship between the growth of the horticultural sector and horticultural research and extension and to examine the socioeconomic returns to investment on research and extension in Korean horticulture. Data for horticultural production values, producer price indices and research and extension budgets for horticultural sector from 1965 to 1998 are collected from various sources. Multi-variate time series analysis technique with vector auto-regression model and Akino-Hayami Formula were employed for the analysis. This study finds (1) horticultural production responds about seven years later to the horticultural research investment shock. the magnitude of the impacts increases to a peak in seventeen years from the initial expenditures and then declines slowly thereafter until twenty years. and this peak gives a tip that horticultural research impact lasts much longer than grain's or agriculture's: (2) the social surplus from research investment benefits more to the consumer rather than to the horticultural producer: (3) B/C ratios in horticultural research are quite high with the range of 9 to 55 from 1965 to 1998. but these have been decreased since the early 1990s: (4) the socioeconomic returns to horticultural research is quite high with 56 percents of internal rate of return. It remains to be analyzed returns to investment on extension in horticulture because of no statistic significance in this study.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.533-544
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• 2020

In this paper, we conducted a dynamic ex-post assessment on the grape business cessation support System. Based on the analysis results, in the short term, there was an increase in grape price due to a decrease in production and accompanying increases in the prices of consumption substitution items. However, in the long run, grape prices fell again due to an increase in grape production because of the entry of new grape farmers and the growth of adult grape trees. In addition, the analysis showed that the balloon effect caused by the conversion of crops caused indirect damage such as an increase in the production volume of substitution crops and a decrease in prices. When analyzing the social welfare measurement, the results showed that the support system for business cessation increased the overall social welfare due to an increase in producer welfare because of a price increase in the short term, but in the long term, both producer and consumer welfare decreased. In the end, it is necessary to review the system because the government's intervention may cause market distortion and inefficient resource allocation. Above all, it is necessary to minimize the indirect effect of the industry's contraction and balloon effect due to excessive business cessation. For this, conditional support should be provided in parallel with post management rather than unconditional support. In addition, it is necessary to provide a strategic support system that considers substitution items in addition to those items to be supported.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.33-33
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• 2016

Mycotoxins are toxic secondary metabolites produced by fungi. They can be present in where agricultural-based commodities are contaminated with toxigenic fungi. These mycotoxins cause various toxicoses in human and livestock when consumed. Small grains including corn, barley, rice or wheat are frequently contaminated with mycotoxins due to infection mainly by toxigenic Fusarium species and/or under environment favorable to fungal growth. One of the most well-known Fusarium toxin groups in cereals is trichothecenes consisting of many toxic compounds. Deoxynivalenol (DON), nivalenol (NIV), T-2 toxin, and various derivatives belong to this group. Zearalenone and fumonisin (FB) are also frequently produced by many species of the same genus. In order to monitor Korean cereals for contamination with Fusarium and other mycotoxigenic fungal species as well, barley, corn, maize, rice grains, and soybean were collected from fields at harvest or during storage for several years. The fungal colonies outgrown from the grain samples were identified based on morphological and molecular characteristics. Trichothecene chemotypes of Fusarium species or presence of FB biosynthetic gene were determined using respective diagnostic PCR to predict possible toxin production. Heavy grain contamination with fungi was detected in barley, rice and wheat. Predominant fungal genus of barley and wheat was Alternaria (up to 90%) while that of rice was Fusarium (~40%). Epicoccum also appeared frequently in barley, rice and wheat. While frequency of Fusarium species in barley and wheat was less than 20%, the genus mainly consisted of Fusarium graminearum species complex (FGSC) which known to be head blight pathogen and mycotoxin producer. Fusarium composition of rice was more diverse as FGSC, Fusarium incarnatum-equiseti species complex (FIESC), and Fusarium fujikuroi species complex (FFSC) appeared all at considerable frequencies. Prevalent fungal species of corn was FFSC (~50%), followed by FGSC (<30%). Most of FFSC isolates of corn tested appeared to be FB producer. In corn, Fusarium graminearum and DON chemotype dominate within FGSC, which was different from other cereals. Soybeans were contaminated with fungi less than other crops and Cercospora, Cladosporium, Alternaria, Fusarium etc. were detected at low frequencies (up to 14%). Other toxigenic species such as Aspergillus and Penicillium were irregularly detected at very low frequencies. Multi-year survey of small grains revealed dominant fungal species of Korea (barley, rice and wheat) is Fusarium asiaticum having NIV chemotype.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.2
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• pp.192-200
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• 2016

A characteristics of microwave drying-gasification was analyzed for converting a dewatered sewage sludge generated a wastewater treatment plant. Gas (60%) was the largest component of the product of microwave gasification, followed by sludge char (33%) and tar (2%). The main components of the producer gas were hydrogen (33%) and carbon monoxide (40%), and there was some methane and hydrocarbons ($C_2H_4$, $C_2H_6$, $C_3H_8$). Larger nitrogen and smaller oxygen amounts were generated. Gravimetric tar generated $414g/m^3$. This means a total tar which is a heavy hydrocarbons from the volatile organic substance in the sewage sludge. Selected light tars were benzene, anthracene, naphthalene, pyrene, showing lower concentrations as 2.62, 0.37, 0.49, $0.28g/m^3$, respectively. Sludge char has larger meso pores which is a mean pore size of $50.85{\AA}$ and has high adsorptivity. An amount of adsorption was $228.71cm^3/g$, showing higher quantity than acommercial adsorbers. This indicates that the gas obtained from the microwave gasification of wet sewage sludge can be used as fuel, but the heavy tar in the gas must be treated. Sludge char can be used as a tar reduction adsorbent in the process, and then burns as a solid fuel.