Sang-yeon Lee

Analysis of Research Trend and Core TechnologiesBased on ICT to Materialize Smart-farm

Korean government has planned to increase the productivity of horticultural crops and to expand supply smart greenhouse for energy saving by modernization of horticultural facilities based on ICT in policy. However, the diversity and linkages of monitoring and control are significantly insufficient in the agricultural sector in the current situation. Therefore, development of a service system with smart-farm based on the internet of things(IoT) for intelligent systemization of all the process of agricultural production through remote control using complex algorithm for diverse monitoring and control is required. In this study, domestic and international research trend related to ICTbased horticultural facilities was briefly introduced and limits were analyzed in the domestic application of the advanced technology. Finally, future core technologies feasible to graft in agricultural field were reviewed. Additional key words : converging technology, greenhouse, monitoring, remote control, service platform

Design of a windbreak fence to reduce fugitive dust in open areas

The wind characteristics of the Saemangeum reclaimed land are quite different from those of inland because of the prevalence of strong wind environments near the seashore. Thus, the probability of fugitive dust dispersion would be higher under these wind environmental conditions, and civil complaints regarding fugitive dust have increased in the residential area. Therefore, we must establish countermeasures to reduce fugitive dust. In this study, the dispersion behavior of fugitive dust at the Saemangeum reclaimed land was simulated by using a two-dimensional CFD simulation. A CFD model was simulated by considering the wind velocity and the design properties of the windbreak fences, such as their height, installation interval and number of layer. The percent of upstream velocity (PUV) is applied in this study to quantitatively evaluate the reduction in the wind velocity by a windbreak fence. The behavior of saltating dust was analyzed by comparing the simulation results with the threshold wind velocity, which is the wind velocity at which the soil particulates come off the surface and erosion starts. The behavior of suspended dust was analyzed by using the reduction rate of dust concentration according to the installation conditions of the windbreak fence. A strategy for installing windbreak fences was suggested according to these results to reduce fugitive dust in the Saemangeum reclaimed land.

Design of Energy Model of Greenhouse Including Plant and Estimation of Heating and Cooling Loads for a Multi-Span Plastic-Film Greenhouse by Building Energy Simulation

The importance of energy saving technology for managing greenhouse was recently highlighted. For practical use of energy in greenhouse, it is necessary to simulate energy flow precisely and estimate heating/cooling loads of greenhouse. So the main purpose of this study was to develope and to validate greenhouse energy model and to estimate annual/maximum energy loads using Building Energy Simulation (BES). Field experiments were carried out in a multi-span plastic-film greenhouse in Jeju Island (33.2N, 126.3E) for 2 months. To develop energy model of the greenhouse, a set of sensors was used to measure the greenhouse microclimate such as air temperature, humidity, leaf temperature, solar radiation, carbon dioxide concentration and so on. Moreover, characteristic length of plant leaf, leaf area index and diffuse non-interceptance were utilized to calculate sensible and latent heat exchange of plant. The internal temperature of greenhouse was compared to validate the greenhouse energy model. Developed model provided a good estimation for the internal temperature throughout the experiments period (coefficients of determination > 0.85, index of agreement > 0.92). After the model validation, we used last 10 years weather data to calculate energy loads of greenhouse according to growth stage of greenhouse crop. The tendency of heating/cooling loads change was depends on external weather condition and optimal temperature for growing crops at each stage. In addition, maximum heating/cooling loads of reference greenhouse were estimated to 644,014 and 756,456 kJ·hr, respectively. Additional key words : building energy simulation, energy loads, greenhouse