• Journal of Environmental Science International
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• v.26 no.11
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• pp.1247-1253
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• 2017

The Fuji variety of apple, introduced in Japan, has excellent storage quality and good taste, such that it is the most commonly cultivated apple variety in Gunwi County, North Gyeongsang Province, Korean Peninsula. Accurate prediction of harvest maturity allows farmers to more efficiently manage their farm in important aspects such as working time, fruit storage, market shipment, and labor distribution. Temperature is one of the most important factors that determine plant growth, development, and yield. This paper reports on the beta distribution (function) model that can be used to simulate the the phenological response of plants to temperature. The beta function, commonly used as a skewed probability density in statistics, was introduced to estimate apple harvest maturity as a function of temperature in this study. The model parameters were daily maximum temperature, daily optimum temperature, and maximum growth rate. They were estimated from the input data of daily maximum and minimum temperature and apple harvest maturity. The difference in observed and predicted maturity day from 2009 to 2012, with optimal parameters, was from two days earlier to one day later.

• Journal of Communications and Networks
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• v.14 no.2
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• pp.140-150
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• 2012

In this paper, we investigate the optimal packet scheduling problem in a two-user multiple access communication system, where the transmitters are able to harvest energy from the nature. Under a deterministic system setting, we assume that the energy harvesting times and harvested energy amounts are known before the transmission starts. For the packet arrivals, we assume that packets have already arrived and are ready to be transmitted at the transmitter before the transmission starts. Our goal is to minimize the time by which all packets from both users are delivered to the destination through controlling the transmission powers and transmission rates of both users. We first develop a generalized iterative backward waterfilling algorithm to characterize the maximum departure region of the transmitters for any given deadline T. Then, based on the sequence of maximum departure regions at energy arrival instants, we decompose the transmission completion time minimization problem into convex optimization problems and solve the overall problem efficiently.

• The Korean Journal of Food And Nutrition
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• v.31 no.2
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• pp.213-219
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• 2018

This study was performed to determine the optimal time of harvest for ramie leaves with the two varieties (Seocheon Seobang and Seoncheon Baekpi) by comparison of physiological activity and physicochemical characteristics. The crude protein, minerals, ascorbic acid, folate, chlorophyll, ACE inhibitory activity and AChE inhibitory activity were determined. The amount of crude protein in ramie leaf, which was collected in Seocheon-gun, Chungcheongnam-do, grew up steadily from early May to September. The content of calcium in was higher in Baekpi than in Seobang. Seobang displayed its highest value of 3,569.90 mg% in September, while Baekpi displayed its highest value of 3,163.84 mg% in October. Although, folate and vitamin C contents in the two varieties were slightly different, they were higher as the growth date grew in October. The highest value of chlorophyll content was observed in October, which was later in the vegetative state. ACE inhibitory activity and AChE inhibitory activity appeared to be higher in Baekpi than in Seobang. Between June and August, ACE inhibitory activity was highest in Baekpi variety.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.381-393
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• 2019

A smart farm is a system that combines information and communication technology (ICT), internet of things (IoT), and agricultural technology that enable a farm to operate with minimal labor and to automatically control of a greenhouse environment. Machine learning based on recently data-driven techniques has emerged with big data technologies and high-performance computing to create opportunities to quantify data intensive processes in agricultural operational environments. This paper presents research on the application of machine learning technology to diagnose the growth status of crops and predicting the harvest time of strawberries in a greenhouse according to image processing techniques. To classify the growth stages of the strawberries, we used object inference and detection with machine learning model based on deep learning neural networks and TensorFlow. The classification accuracy was compared based on the training data volume and training epoch. As a result, it was able to classify with an accuracy of over 90% with 200 training images and 8,000 training steps. The detection and classification of the strawberry maturities could be identified with an accuracy of over 90% at the mature and over mature stages of the strawberries. Concurrently, the experimental results are promising, and they show that this approach can be applied to develop a machine learning model for predicting the strawberry harvesting time and can be used to provide key decision support information to both farmers and policy makers about optimal harvest times and harvest planning.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.222-222
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• 2017

This study aimed to determine an optimal temperature of root zone for the chive cultivation in a greenhouse during the winter season that may raise the possibility of chive (Allium schoenoprasum L.) harvest any time year-round by reducing energy consumption. The maximum and minimum temperatures of root zone were 26.8 and $19.8^{\circ}C$ for the R-Z20, 28.3 and $23.6^{\circ}C$ for the R-Z25 and 22.4 and $14.3^{\circ}C$ for the control. The highest fresh weights of shoot and root, plant height, root length and stem diameter were observed in the R-Z20 treatment. There was no significant difference in the growth between the R-Z25 and control treatment. These results suggest that the optimal temperature of root zone is $20^{\circ}C$ for the chive cultivation in the greenhouse during winter season.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.333-339
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• 2015

A thermal time-based phenology model of Kimchi cabbage was developed by using the field observed growth and temperature data for the purpose of accurately predicting heading and harvest dates among diverse cropping systems. In this model the lifecycle of Kimchi cabbage was separated into the growth stage and the heading stage, while the growth amount of each stage was calculated by optimal mathematical functions describing the response curves for different temperature regimes. The parameter for individual functions were derived from the 2012-2014 crop status report collected from seven farms with different cropping systems located in major Kimchi cabbage production area of South Korea (i.e., alpine Gangwon Province for the summer cultivation and coastal plains in Jeonnam Province for the autumn cultivation). For the model validation, we used an independent data set consisting of local temperature data restored by a geospatial correction scheme and observed harvest dates from 17 farms. The results showed that the root mean square error averaged across the location and time period (2012-2014) was 5.3 days for the harvest date. This model is expected to enhance the utilization of the Korea Meteorological Administration's daily temperature data in issuing agrometeorological forecasts for developmental stages of Kimchi cabbage grown widely in South Korea.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.125-131
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• 2009

To facilitate the sustainable forest management, Forest Service in Korea has assigned 2.9 million hectare forests as 'intensive management forests' and encouraged local governments to develop a strategic management plan for their forests. One of problems for the sustainable forest management in Korea is the skewed distribution of forest age classes. Currently the majority of forestlands in Korea is occupied by age classes III and IV. In this study, we intended to find an optimum harvest volume, which enable one to make the intensive management forest in Youngdong-Gun evenly distributed for the age classes and allow an even harvest volume through a 50 year time horizon. To develop an optimization model, we applied the goal programming technique which is adequate for a multi-purpose management planning. The results indicated that it is necessary to harvest 1.2 million cubic meters in each decade to achieve the most stable distribution of age classes for the study site. The harvest volume target resulted from this study would be used in a management planning or an associated policy making process in the future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1653-1659
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• 2015

This study compared physicochemical properties and antioxidant activities according to different harvest times in five varieties of black rice (BR). Five cultivars of BR, Nunkeunheukchal (NKHC), Sinnongheugchal (SNHC), Sintoheugmi (STHM), Josaengheugchal (JSHC), and Heugjinju (HJJ), were selected for the study. Cultivars were transplanted on June 20th and cultivated by the Department of Southern Area Crop Science, NICS in Miryang, Korea. Heading dates of NKHC, SNHC, STHM, JSHC, and HJJ were Aug. 17th, Aug. 30th, Sep. 1st, Aug. 20th, and Aug. 12th, respectively. The five different harvest times were as follows; 35, 40, 45, 50, and 55 days after heading date. The highest level of anthocyanin was 35 days after heading date in all varieties. Levels of anthocyanin in NKHC, SNHC, STHM, JSHC, and HJJ were 164, 203, 251, 67, and 210 mg/100 g, respectively. Content of anthocyanin significantly decreased 35 days after heading in four varieties, excluding JSHC. Highest DPPH $IC_{50}$ values were 57, 29, 10, and $27{\mu}g/mL$ in NKHC, SN HC, STHM, and JSHC extracts, respectively. Highest ABTS $IC_{50}$ values were 24, 13, 9, and $11{\mu}g/mL$ in NKHC, SNHC, STHM, and JSHC extracts, respectively. The antioxidant activities were highest 35 days after the heading date and significantly decreased in four varieties, excluding HJJ. The antioxidant activity of HJJ showed no significant difference, according to harvest time. This study suggests that the content of anthocyanin and antioxidant activity could be considered as factors affecting optimal harvest period to produce highly qualified black rice.

• Journal of Fisheries and Marine Sciences Education
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• v.16 no.1
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• pp.84-98
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• 2004

Due to a publicly owned resources, the overexploitation of the fisheries resources can result in externalities in the form of reduced future levels of yield. These problems can be theoretically improved through effective management of the fishery. The paper illustrates maximum sustainable yield(MSY), maximum economic yield(MEY) and F0.1 level of fishing mortality as the concept of optimal yield, and it theoretically shows that MSY is more appropriate for the optimal yield than MEY where prices increase even though MEY achieves the maximization of economic rent in a fishery assuming constant prices. And the paper presents several fisheries management tools and policies such as input controls, output controls and taxes. As the traditional approach to fishery management, input controls involve restrictions on the physical inputs into the production process(e.g. capital, time or technology) and output controls involve limits on the quantity of fish that can be landed. To introduce user cost into the harvest decisions of rent-seeking fishers, taxation, as a bioeconomic management policy of the fisheries, directly addresses the problems associated with the resource being unpriced. As most fisheries management plans, however, have increasing fisher income as an objective, taxes have not been introduced into any fisheries management policies despite their theoretical attraction.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.2
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• pp.207-214
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• 1994

This study was carried out to develop the methodology of chromosome preparation from blood cultures in mammals which included human, mouse, cattle and pig. For karyotyping, 0.5-5.0ml of peripheral blood were collected and cultured. The satisfactory results were obtained from macroculture and microculture in all species. In culture, the patterns of cell growth were no difference among media except serum concentration and mitogen supplement. The presence of mitogen and fetal bovine serum in medium significantly affected the mitotic index. The optimal culture condition was 37$^{\circ}C$ for 3 days. And the concentration of colcemid and reincubation time also affected the chromosome morphology. In harvest, chromosome patterns were mainly affected on hypotonic treatment which included treated time and temperature, dropwise of fixative solution, and drying after slide preparation.