• Title/Summary/Keyword: Farm-scale

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A Study on the Output and Reliability Characteristics of Ultra Barrier Film PV Module (고분자 보호 필름을 적용한 태양광 모듈의 출력 및 신뢰성에 관한 연구)

  • Lim, Jong Rok;Shin, Woo Gyun;Yoon, Hee Sang;Kim, Yong Sung;Ju, Young-Chul;Ko, Suk-Whan;Kang, Gi-Hwan;Hwang, Hye-Mi*
    • Journal of the Korean Solar Energy Society
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    • v.39 no.5
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    • pp.1-10
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    • 2019
  • Recently, the installation capacity of PV (photovoltaic) systems has been increasing not only field installation but also floating PV, farm land, BIPV/BAPV. For this reason, the new design and materials of PV module are needed. In particular, in order to apply a PV system to a building, lightweight of the PV module is essential. PV modules made of generally used texturing glass are excellent in output and reliability, but there is a limit to the weight that can be reduced. For the lightweight of the PV module, it necessary to use a film instead of a glass. However, the application of film rather than a glass may cause various problems such as decrease in photocurrent by decrease in transmittance and a increase of CTM (cell to module) loss, a degradation of the reliability, and so on. In this paper, PV modules using Ultra barrier film, which is recently a lot of interest as a substitute for a glass, its characteristic analysis and reliability test were conducted. The transmittance and UV characteristics of each material were verified, and the output of the fabricated 1 cell PV module was measured. In addition, 24 cell PV modules were fabricated at the lab-scale and its reliability tests were conducted. As a result of the experiment, the reliability characteristics of the ultra barrier film PV module were excellent, and it was confirmed that it could be used as the front material of the PV module instead of glass

An Analysis of Water Vapor Pressure to Simulate the Relative Humidity in Rural and Mountainous Regions (고해상도 상대습도 모의를 위한 농산촌 지역의 수증기압 분석)

  • Kim, Soo-ock;Hwang, Kyu-Hong;Hong, Ki-Young;Seo, Hee-Chul;Bang, Ha-Neul
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.22 no.4
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    • pp.299-311
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    • 2020
  • This paper analyzes the distribution of water vapor pressure and relative humidity in complex terrains by collecting weather observation data at 6 locations in the valley in Jungdae-ri, Ganjeon-myeon, Gurye-gun, Jeolla South Province and 14 locations in Akyang-myeon, Hadong-gun, Gyeongsang South Province, which form a single drainage basin in rural and mountainous regions. Previously estimated water vapor pressure used in the early warning system for agrometeorological hazard and actual water vapor pressure arrived at using the temperature and humidity that were measured at the highest density (1.5 m above ground) at every hour in the valley of Jungdae-ri between 19 December 2014 and 23 November 2015 and in the valley of Akyang between 15 August 2012 and 18 August 2013 were compared. The altitude-specific gradient of the observed water vapor pressure varied with different hours of the day and the difference in water vapor pressure between high and low altitudes increased in the night. The hourly variations in the water vapor pressure in the weather stations of the valley of Akyang with various topographic and ground conditions were caused by factors other than altitude. From the observed data of the study area, a coefficient that adj usts the variation in the water vapor pressure according to the specific difference in altitude and estimates it closer to the actual measured level was derived. Relative humidity was simulated as water vapor pressure estimated against the saturated water vapor pressure, thus, confirming that errors were further reduced using the derived coefficient than with the previous method that was used in the early warning system.

A study on Digital Agriculture Data Curation Service Plan for Digital Agriculture

  • Lee, Hyunjo;Cho, Han-Jin;Chae, Cheol-Joo
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.2
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    • pp.171-177
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    • 2022
  • In this paper, we propose a service method that can provide insight into multi-source agricultural data, way to cluster environmental factor which supports data analysis according to time flow, and curate crop environmental factors. The proposed curation service consists of four steps: collection, preprocessing, storage, and analysis. First, in the collection step, the service system collects and organizes multi-source agricultural data by using an OpenAPI-based web crawler. Second, in the preprocessing step, the system performs data smoothing to reduce the data measurement errors. Here, we adopt the smoothing method for each type of facility in consideration of the error rate according to facility characteristics such as greenhouses and open fields. Third, in the storage step, an agricultural data integration schema and Hadoop HDFS-based storage structure are proposed for large-scale agricultural data. Finally, in the analysis step, the service system performs DTW-based time series classification in consideration of the characteristics of agricultural digital data. Through the DTW-based classification, the accuracy of prediction results is improved by reflecting the characteristics of time series data without any loss. As a future work, we plan to implement the proposed service method and apply it to the smart farm greenhouse for testing and verification.

Analysis of Salad Purchaser Types and Purchasing Behaviors through Social Network Analysis (사회연결망분석을 통한 샐러드 구매자 유형 및 구매행태 분석)

  • Ha, Ji Young;Lim, Se Hwa
    • Journal of Korean Society for Quality Management
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    • v.50 no.2
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    • pp.287-304
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    • 2022
  • Purpose: The size of the salad consumption market has expanded since Covid-19, and continuous growth is predicted. Therefore, by extracting influential core purchasers in the salad consumption market and analyzing their purchasing behaviors and consumer types, this study intended to provide basic data for establishing a marketing strategy. Methods: The analysis data is the purchasing data of 576 people who have purchased salads between 2016 and 2020 (panel data of the Rural Development Administration), and in the social network analysis, the centrality structure was analyzed. Results: First, in the results of analyzing the causes of the rapid increase in salad consumption in 2020, it was found that the increase in consumption of new purchasers (n=102) had little effect. The existing consumer type (n = 474), which has been the majority of the salad consumption market so far, were consumers with stable income. However, the results of study indicated that the type of consumers has expanded since low-income class as well as high-income class increased consumption of purchasing salad. Second, in the results of analyzing the types of key purchasers with great influence in the salad consumption market, there was a difference from the results of frequency analysis in age, number of family members, existence/absence of children, and income decile. This suggests that there should be a difference between the type of customers according to the apparent quantitative figure and the actual influential purchasers. Third, in the results of analyzing the salad purchasing behaviors of core purchasers, the purchasing site for existing purchasers was large-scale marts and for new purchasers it was corporate-type supermarkets. Purchases were concentrated on Saturdays for both existing and new purchasers. As for the purchased products, existing purchasers had a high preference for products made of chicken, and new purchasers had a high preference for vegetable/fruit salad. In particular, in the results of purchased products by age group, in the case of 50s and 60s, it was an interesting result that there was a difference between the products purchased by the existing and new purchasers even though they were the same age. Conclusion: When establishing a marketing strategy in the salad consumption market, it is necessary to pay attention to the purchasing behavior of key buyers.

The Characteristics of the Rural Landscape of Daesan Plain Around the Japanese Colonial Era (일제강점기 전후 대산평야 농촌경관의 형성과 변화)

  • Jeong, Jae-Hyeon;Lee, Yoo-Jick
    • Journal of Korean Society of Rural Planning
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    • v.30 no.1
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    • pp.15-31
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    • 2024
  • The study primarily aims to examine the characteristics of the transition from natural landscape to modern agricultural landscape on the Daesan plain in Dong-myeon, Changwon-si, in the lower reaches of the Nakdong River. The periods covered in the transition include the late Joseon Dynasty, the early Japanese colonial period, and the late Japanese colonial period. The study concluded the following: It was found that the Daesan Plain used to function as a hydrophilic landscape before it formed into a rural landscape. This is characterized by the various water resources in the Plain, primarily by the Nakdong River, with its back marsh tributaries, the Junam Reservoir and Jucheon. To achieve its recent form, the Daesan Plain was subjected to human trial and error. Through installation of irrigation facilities such as embankments and sluices, the irregularly-shaped wetlands were transformed into large-scale farmlands while the same irrigation facilities underwent constant renovation to permanently stabilize the rural landscape. These processes of transformation were similarly a product of typical colonial expropriation. During the Japanese colonial period, Japanese capitalists initiated the construction of private farms which led to the national land development policy by the Governor-General of Korea. These landscape changes are indicative of resource capitalism depicted by the expansion of agricultural production value by the application of resource capital to undeveloped natural space for economic viability. As a result, the hierarchical structure was magnified resulting to the exacerbation of community and economic structural imbalances which presents an alternative yet related perspective to the evolution of landscapes during the Japanese colonial period. In addition, considering Daesan Plain's vulnerability to changing weather conditions, natural processes have also been a factor to its landscape transformation. Such occurrences endanger the sustainability of the area as when floods inundate cultivated lands and render them unstable, endangering residents, as well as the harvests. In conclusion, the Daesan Plain originally took the form of a hydrophilic landscape and started significantly evolving into a rural landscape since the Japanese colonial period. Human-induced land development and geophysical processes significantly impacted this transformation which also exemplifies the several ways of how undeveloped natural landscapes turn into mechanized and capitalized rural landscapes by colonial resource capitalism and development policies.

A Study on the Calculation of Optimal Compensation Capacity of Reactive Power for Grid Connection of Offshore Wind Farms (해상풍력단지 전력계통 연계를 위한 무효전력 최적 보상용량 계산에 관한 연구)

  • Seong-Min Han;Joo-Hyuk Park;Chang-Hyun Hwang;Chae-Joo Moon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.1
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    • pp.65-76
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    • 2024
  • With the recent activation of the offshore wind power industry, there has been a development of power plants with a scale exceeding 400MW, comparable to traditional thermal power plants. Renewable energy, characterized by intermittency depending on the energy source, is a prominent feature of modern renewable power generation facilities, which are structured based on controllable inverter technology. As the integration of renewable energy sources into the grid expands, the grid codes for power system connection are progressively becoming more defined, leading to active discussions and evaluations in this area. In this paper, we propose a method for selecting optimal reactive power compensation capacity when multiple offshore wind farms are integrated and connected through a shared interconnection facility to comply with grid codes. Based on the requirements of the grid code, we analyze the reactive power compensation and excessive stability of the 400MW wind power generation site under development in the southwest sea of Jeonbuk. This analysis involves constructing a generation site database using PSS/E (Power System Simulation for Engineering), incorporating turbine layouts and cable data. The study calculates reactive power due to charging current in internal and external network cables and determines the reactive power compensation capacity at the interconnection point. Additionally, static and dynamic stability assessments are conducted by integrating with the power system database.

Research on Optimized Operating Systems for Implementing High-Efficiency Small Wind Power Plants (고효율 소형 풍력 발전소 구현을 위한 최적화 운영 체계 연구)

  • Young-Bu Kim;Jun-Mo Park
    • Journal of the Institute of Convergence Signal Processing
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    • v.25 no.2
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    • pp.94-99
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    • 2024
  • Recently, wind power has been gaining attention as a highly efficient renewable energy source, leading to various technological developments worldwide. Typically, wind power is operated in the form of large wind farms with many wind turbines installed in areas rich in wind resources. However, in developing countries or regions isolated from the power grid, off-grid small wind power systems are emerging as an efficient solution. To efficiently operate and expand off-grid small-scale power systems, the development of real-time monitoring systems is required. For the efficient operation of small wind power systems, it is essential to develop real-time monitoring systems that can actively respond to excessive wind speeds and various environmental factors, as well as ensure the stable supply of produced power to small areas or facilities through an Energy Storage System (ESS). The implemented system monitors turbine RPM, power generation, brake operation, and more to create an optimal operating environment. The developed small wind power system can be utilized in remote road lighting, marine leisure facilities, mobile communication base stations, and other applications, contributing to the development of the RE100 industry ecosystem.

A Study on Transition of Rice Culture Practices During Chosun Dynasty Through Old References IX. Intergrated Discussion on Rice (주요(主要) 고농서(古農書)를 통(通)한 조선시대(朝鮮時代)의 도작기술(稻作技術) 전개(展開) 과정(過程) 연구(硏究) - IX. 도작기술(稻作技術)에 대(對)한 종합고찰(綜合考察))

  • Guh, J.O.;Lee, S.K.;Lee, E.W.;Lee, H.S.
    • Korean Journal of Weed Science
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    • v.12 no.1
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    • pp.70-79
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    • 1992
  • From the beginning of the chosun dynasty, an agriculture-first policy was imposed by being written farming books, for instance, Nongsajiksul, matched with real conditions of local agriculture, which provided the grounds of new, intensive farming technologies. This farming book was the collection of good fanning technologies that were experienced in rural farm areas at that time. According to Nongsajiksul, rice culture systems were divided into "Musarmi"(Water-Seeded rice), /"Kunsarmi"(dry-seeded rice), /transplanted rice and mountainous rice (upland rice) culture. The characteristics of these rice cultures with high technologies were based of scientific weeding methods, improved fertilization, and cultivation works using cattle power and manpower tools systematically. Reclamation of coastal swampy and barren land was possible in virtue of fire cultivation farming(火耕) and a weeding tool called "Yoonmok"(輪木). Also, there was an improved hoe to do weeding works as well as thinning and heaping-up of soil at seeding stages of rice. Direct-seeded rice culture in flat paddy fields were expanded by constructing the irrigation reservoirs and ponds, and the valley paddy fields was reclaimed by constructing "Boh(洑)". These were possible due to weed control by irrigation waters, keeping soil fertility by inorganic fertilization during irrigation, and increased productivity of rice fields by supplying good physiological conditions for rice. Also, labor-saving culture of rice was feasible by transplanting but in national-wide, rice should not basically be transplanted because of the restriction of water use. Thus, direct-seeded rice in dry soils was established, in which rice was direct-seeded and grown in dry soils by seedling stages and was grown in flooded fields when rained, as in the book "Nongsajiksul". During the middle of the dynasty(AD 1495-1725), the excellent labor-saving farmings include check-rowing transplanting because of weeding efficiency and availability in rice("Hanjongrok"), and, nurserybed techniques (early transplanting of rice) were emphasized on the basis of rice transplanting ["Nongajibsung"]. The techniques for deep plowing with cattle powers and for putting more fertilizers were to improve the productivity of labor and land, The matters advanced in "Sanlimkyungje" more than in "Nongajibsung" were, development of "drybed of rice nursery stock", like "upland rice nursery" today, transplanting, establishment of "winter barly on drained paddy field, and improvement of labor and land-productivity in rice". This resulted in the community of large-scale farming by changing the pattern of small-farming into the production system of rice management. Woo-hayoung(1741-1812) in his book "Chonilrok" tried to reform from large-scale farmings into intensive farmings, of which as eminent view was to divide the land use into transplanting (paddy) and groove-seeding methods(dry field). Especially as insisted by Seo-yugo ("Sanlimkyungjeji"), the advantages of transplanting were curtailment of weeding labors, good growth of rice because of soil fertility of both nurserybed and paddy field, and newly active growth because rice plants were pulled out and replanted. Of course, there were reestimation of transplanting, limitation of two croppings a year, restriction of "paddy-upland alternation", and a ban for large-scale farming. At that period, Lee-jiyum had written on rice farming technologies in dry upland with consider of the land, water physiology of rice, and convenience for weeding, and it was a creative cropping system to secure the farm income most safely. As a integrated considerations, the followings must be introduced to practice the improved farming methods ; namely, improvement of farming tools, putting more fertilizers, introduction of cultural technologies more rational and efficient, management of labor power, improvement of cropping system to enhance use of irrigation water and land, introduction of new crops and new varieties.

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Investigation on Characteristics of Swine Manure of Optimum Volume for Escalator Reversing Composting Facility (돼지분뇨 특성에 따른 기계교반 퇴비화시설의 적정용적 산정 연구)

  • Kwag, J.H.;Choi, D.Y.;Park, C.H.;Jeong, K.H.;Kim, J.H.;Yoo, Y.H.;Youn, C.K.;Ra, C.S.
    • Journal of Animal Environmental Science
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    • v.14 no.2
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    • pp.105-112
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    • 2008
  • This study was carried out to investigate evaporation rate of moisture per surface area and degradation rate of organic matter in full scale escalator reversing composting facility were analyzed to develope a computer program for the computation of an optimum volume of composting facility according to handling methods of swine farm, moisture levels of manure, degradation rate of organics and evaporation rate of moisture during composting. The obtained results can be followed as bellow; The temperature in full scale escalator reversing composting facility during composting reached $70^{\circ}C$ in 4 days and maintained until 11 days. Reduction rate of moisture and density was average 1.20% and 29.7%, respectively. Annual degradation rate of organic matter was 3.53%, showing lowest rate in winter as 3.23%. These seasonal degradation rate could be a factor to be considered for proper management and installation of composting facility. When computed with the amount of feces, urine, slurry and manure plus wastewater produced, the optimum volumes of composting facility for slurry and manure plus wastewater including each 95% moisture was $229m^3$ and $277m^3$, respectively, showing 21% ($48m^3$) difference.

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Depressive Disorders among Hansen Disease Patients Living in a Collective Farm (한 집단 농원 한센병 환자들의 우울장애)

  • Kim, Yun-Gu;Park, Min-Ho;Park, Jae-Won;Song, Joon-Ho;Sim, Seong-Gyun;Lee, Joo-Hyoung;Lee, Hee-Young;Yun, Dong-Il;Jung, Sung-Hwan;Min, Young-Sun;Bae, Geun-Ryang;Jung, Cheoll;Lim, Hyun-Sul;Cheong, Hae-Kwan
    • Journal of agricultural medicine and community health
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    • v.29 no.1
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    • pp.133-145
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    • 2004
  • Objectives: Depression is a major health concern that can be life threatening if not recognized and treated early. However, there is few report on the depressive disorder of Hansen disease patients in Korea. Therefore, the authors executed this study in order to check factors related to a depressive disorder of a Hansen disease patients and compare with factors to reach to a depressive symptoms of ordinary people with studying their life state and the trouble that Hansen disease patients were currently experiencing Method: The authors surveyed depressive symptoms using self-reported questionnaires in 74 Hansen disease patients and 84 controls. The severity of depressive symptoms was measured using Korean Form of Geriatric Depression Scale (KGDS) score. Result: Positive rate of depressive disorders among Hansen disease patients was 70.3% and that the referents was 31.0%. There is significant difference positive rate of depressive disorders between Hansen disease group and the referents in the factors such as gender, age, frequency of going out, familial type, and familial income. Depressive disorder of Hansen disease group was associated with sex, familial income. According to the multiple logistic regression, the odds ratios of the Hansen disease group versus referents, gender, familial income, frequency of going out were significant (p<0.05). Conclusion: Hansen disease patients had statistically significant higher depressive symptom score than the referents. Also, Hansen disease patients who have lower familial income were more likely to have depressive disorders. Therefore, Economical supports and policy are required for the Hansen disease patients.

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