This research was conducted to evaluate feasibility of a crank-type walking cultivators for weeding in furrowed upland. Methods: A walking cultivator developed by RDA was selected and evaluated with its working speed (S), cultivation depth (CD) and weeding performance (WP). The evaluation was performed in upland field on July and August, 2012. Also kinematic analysis of the machine was performed to draw out design improvements. Results: S in flat, uphill and downhill were about 0.11 m s-1 , 0.11 m s-1 , and 0.13 m s-1 respectively. It was found that S had a low relevance with user conditions. The CD was 35 ~ 40 mm which was satisfied with the RDA guide for weeding machine. A wide variation was observed in values of WP depending on the growth stages of weeds and field conditions. The cultivator showed low performance in eliminating the well-grown weeds. Kinematic simulation revealed that high forward speed caused a high ratio of un-weeded area. Conclusions: The weeding performance of the cultivator was satisfactory for weeds in early growth stage but it showed difficulties in handling on up-slope and in entering up-land. Specifically, the weight of the cultivator was judged as overweight for female workers. The crank-hoe type cultivator was judged as unsuitable for small walking type machine due to weight of the four-bar linkage system. Kinematic analysis revealed that the ratio of crank speed to the ground speed must be 850 rpm s m-1 (255 rpm based on 0.3 m s-1) or greater to avoid uncultivated area. Selection of forward speed is a decisive factor in designing the weeding cultivator.
Purpose:The modern IT can give enormous impacts on the agricultural production and consumption. However, farmer's ability to use IT devices has been known as one of the critical factors on success of IT in agriculture. This survey study was performed to evaluate the informatization status of farmers and to draw a strategy to develop and distribute a ubiquitous agricultural information system. Methods: A survey questionnaire with 19 questions on the degree of IT devices such as computers and smartphones and their utilization were developed. The survey was questioned 3 groups of farmers in Gyounggi Province and analyzed statistically by the χ 2 test. Results: The order of IT devices distribution were computers, smartphones, smart TVs and tablet PCs in all groups. The ratios of ownerships of the devices are 97.7, 78.6%, 31.4%, 17.8% respectively. The active farmers in this survey showed higher informatization level than that of native and the general farmers. Conclusions: The ubiquitous agricultural information system was judged to be developed for the computer because spread and use of it exceeds the other devices. Also, the information system based on the smartphone could be a complementary way if the rapid of the smartphones continues and proper education on use of the phone is provided.
Purpose: Short-circuit current of a solar module that is widely used as a power source for wireless environmental sensors is proportional to solar radiation although there are a lot of factors affecting the short-circuit current. The objective of this study is to develop a model for estimating solar radiation for using the solar module as a power source and an irradiance sensor. Methods: An experiment system collected data on the short-circuit current and environmental factors (ambient temperature, cloud cover and solar radiation) during 65 days. Based on these data, two linear regression models and a non-linear regression model were developed and evaluated. Results: The best model was a linear regression model with short-circuit current, angle of incidence and cloud cover and its overall RMSE(Root Means Square Error) was 66.671 . The other linear model (RMSE 69.038 ) was also acceptable when the cloud cover data is not available.
Purpose:The objective of this study is to develop a data middleware for u-IT convergence in agricultural environment monitoring, which can support non-standard data interfaces and solve the compatibility problems of heterogenous sensor networks. Methods: Six factors with three different interfaces were chosen as target data among the environmental monitoring factors for crop cultivation. PostgresSQL and PostGIS were used for database and the data middleware was implemented by Python programming language. Based on hierarchical model design and key-value type table design, the data middleware was developed. For evaluation, 2,000 records of each data access interface were prepared. Results: Their execution times of File I/O interface, SQL interface and HTTP interface were 0.00951 s/record, 0.01967 s/record and 0.0401 s/record respectively. And there was no data loss. Conclusions: The data middleware integrated three heterogenous sensor networks with different data access interfaces.
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