• Korean Chemical Engineering Research
• /
• v.60 no.2
• /
• pp.249-254
• /
• 2022

With the rapid advance of the semiconductor and Information and communication technologies, remote environment monitoring technology, which can detect and analyze surrounding environmental conditions with various types of sensors and wireless communication technologies, is also drawing attention. However, since the conventional remote environmental monitoring systems require external power supplies, it causes time and space limitations on comfortable usage. In this study, we proposed the concept of the self-powered remote environmental monitoring system by supplying the power with the levitation-electromagnetic generator (L-EMG), which is rationally designed to effectively harvest biomechanical energy in consideration of the mechanical characteristics of biomechanical energy. In this regard, the proposed L-EMG is designed to effectively respond to the external vibration with the movable center magnet considering the mechanical characteristics of the biomechanical energy, such as relatively low-frequency and high amplitude of vibration. Hence the L-EMG based on the fragile force equilibrium can generate high-quality electrical energy to supply power. Additionally, the environmental detective sensor and wireless transmission module are composed of the micro control unit (MCU) to minimize the required power for electronic device operation by applying the sleep mode, resulting in the extension of operation time. Finally, in order to maximize user convenience, a mobile phone application was built to enable easy monitoring of the surrounding environment. Thus, the proposed concept not only verifies the possibility of establishing the self-powered remote environmental monitoring system using biomechanical energy but further suggests a design guideline.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.5
• /
• pp.489-496
• /
• 1997

This study was carried out to develop and investigate integrated mechanization system on polyethylene(P.E.) film mulching culture in sesame. Field trials were carried out to develop optimum mechanics for each step of manual operation in sesame culture and demonstrated those developed mechanics of sesame dibbling vinyl mulcher, sesame binder, sesame thresher and sesame grader at the farmer, s field of Hwasong (Kyunggi-do) in 1994 and 1995. Newly developed sesame dibbling vinyl mulcher brought saving manpower 280 hrs /ha for sowing and P.E. film mulching with it's 98％ of labour saving for the harvesting operation of sesame. Sesame Binder showed 93％ labour saving for cutting and binding with only 22 hrs /ha compared to 330 hrs /ha that of conventional. Sesame thresher was appeared to have 85％ effects of labour saving for threshing with completely dry sesame bundles at one time by 23 hrs /ha compared to 151 hrs /ha that of conventional. Sesame grader was appeared to have 72％ effects for sesame grain grading with 12 hrs /ha compared to that of conventional 54 hrs /ha. Grain yield of integrated mechanization culture system showed 6％ higher than that of coventional. Integrated mechanization culture system (sesame dibbling vinyl mulcher ＋ sesame binder ＋ sesame thresher ＋ sasame grader) showed 62％ of labour saving effects through whole steps of sesame culture by 472 hrs /ha compared to that of conventional 1, 230 hrs /ha.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.3
• /
• pp.374-383
• /
• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.4
• /
• pp.331-336
• /
• 2012

This study was carried out to evaluate the wheat cultivation system to reduce costs and mechanize wheat production. A field study was conducted for 2 years (2009 to 2010) at the National institute of crop science, Iksan, Korea. We used working system I and working system II for the experiment. Working system I is used a multiple machine attached with a spreader tractor (seeding, fertilization, seed coverage, and weed control functionality) and working system II is used a multiple machine with a tractor which works for simultaneous job when seeding step (seeding, fertilization, and seed coverage). Sowing to harvesting operation time is 118 hours/ha for mechanize with conventional planting. Working system I is a multiple machine and a combine machine with a tractor, which worked 26 hours/ha lower than conventional planting. Working system II is 18 hours/ha lower than conventional planting. The reduced work efforts of working system I and II were 78% and 85% respectively. The growth and yield of wheat according to working system I and II is lower than conventional planting. Therefore, a multiple machine needs to study for appropriate seeding rate. Mechanization cost in consideration of the mechanical break-even point when the working system I is 3.7 ha and working system II is 4.2 ha. The farm income is enhanced by working system I (778,110 won/ha) and working system II (849,930 won/ha). The results showed that application of a multiple machine lowered costs of wheat production.

• Journal of Korean Society of Forest Science
• /
• v.102 no.3
• /
• pp.390-397
• /
• 2013

The study, utilizing a data envelopment analysis (DEA) which is one of the nonparametric estimation methods, aims to evaluate the management efficiency of chestnut tree cultivators in such provinces in Chungchungnam-do as Cheong-yang, Gong-ju, Bu-yeo and so on. The analysis data of this study is based on inputs and outputs of 20 forestry households surveyed in the 2012 survey titled 'A Study on Current Level and Condition of Chestnut Cultivation and Management', which was conducted from March 2012 to October 2012. The elements of inputs are composed of management cost, harvesting cost, material cost, non-operation expenses and cultivation area, while the element of output is a gross margin only. Then the study analyzes a technical efficiency, a puretechnical efficiency and a scale efficiency using CCR and BCC model among DEA methods. Based on that, it also provides improvement methods for forestry households that turned out to be inefficient. In order to verify the result of DEA analysis, the study additionally compares a result of this efficiency study with that of chestnuts management standard diagnostic table. According to the result, the average value of technical efficiency analyzed was 0.667, proving to be inefficient in general. Given that the average value of pure-technical efficiency was 0.944 and that of scale efficiency was 0.703, it can be inferred that inefficiency exists in the field of scale, not in the field of cultivation techniques. As for forestry households with the efficiency score of 1, it is shown that there were 6 households that recorded 1 in the technical efficiency field and 13 households that recorded 1 in the pure technical efficiency. Meanwhile, there were 6 households that recorded 1 in all of the three aspects. In the comparison with the scores from chestnuts management standard diagnostic table, there were 5 households made a high score of over 80, among which are 3 households with score 1 in the technical efficiency. Also, the results of this study and the chestnuts management standard diagnostic table are proved to have the same result, both of them showing the same households that recorded the highest score and the lowest score. This means the management efficiency evaluation using DEA can be applied to the fieldwork along with the chestnuts management standard diagnostic table.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.15 no.3
• /
• pp.198-206
• /
• 1995

Baled silage making(BS) of selected forage crops was discussed during 1991-1993, to determine the best cutting time of the plants for BS production, BS yields and silage quality. Seven species of forage crops and pasture grasses(rye, barley, spring oat, Italian ryegrass, orchardgrass, alfalfa and grass-legume pasture mixtures) were harvested at different stage of growth from young plant to physiological maturity, and baled in a self constructed square baling chamber. Each bales, measured 90cm length, 60cm width and 50cm height, were wrapped with 0.05mrn thick polyethylene plastic film, and stored in stack silo. Each bales were weighed between 15-20 kg in dry matter basis. The effects of pre wilting and formic acid addition on the silage quality of young plant materials, which contained high water concentration, was also evaluated during the experiment. Rye plant including of barley and spring oat were evaluated as a good materials for baled silage making. Fodder rye produced high quality BS with a value of silage quality point 84(Flieg's point) when the plant harvested at stage of greatest dry matter accumulation by 12.64 tonha. The best quality BS of barley was obtained at stage of hard dough to yellow stage by 11.9 ton/ha dry matter yield and 81 point silage quality. Italian ryegrass and pasture grasses including of orchardgrass, alfalfa and grass-legume pasture mixtures procuced also high quality bale silage by harvesting at stage of late blooming. However pre witting operation and formic acid addition was required for BS production of grass materials because of high water contents. Water contents of Italian ryegrass and other pasture species ranged 18.9%(Italian) to 20.8%(alfalfa). Silage quality point of Italian BS harvested at late blooing was increased from 72 to 88 by 1/2-one day pre wilting and 0.3% formic acid treatment. Silage quality of young plant materials of rye and other forage crops, barley and spring oat were also improved markedly through the pre wilting treatment and formic acid addition.