• Journal of the Korean Society of Earth Science Education
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• v.10 no.3
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• pp.262-277
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• 2017

Digital textbooks enable learning that is appropriate to the characteristics and level of learners through various interactions. The purpose of this study was to develop an instruction model that can more effectively use digital textbooks in elementary science classes and to verify its effectiveness. The results were as follows. The instruction model for helping learners complete their learning by using digital textbooks needs to receive diagnostic assessment and feedback on entry behavior, to build a self-directed learning environment, and to interact with teachers, students, and digital textbooks as scaffolding. In this study, we developed an instruction model using digital textbooks reflecting these characteristic. The instructional model consists of preparation, practice and solidity step. In the preparation step, the learner performs a diagnostic evaluation using digital textbooks. Based on the results, feedback provided at each level can complement the entry behavior and maintain interest in learning activities. In the practice step, self-directed learning is implemented using diverse functions of digital textbooks and various types of data. In the solidity step, learners can internalize the learning contents by reviewing video clips which are provided by teachers, performing problem-solving activities, and accessing outcomes accumulated by learners in the community online. In order to verify the effectiveness of this model, we selected the "Weather and our Life" unit. This experiment was conducted using 101 students in the 5th grade in B Elementary School in Gwangju Metropolitan City. In the experimental group, 50 students learned using a smart device that embodies digital textbooks applied with the instruction model. In the comparative group, 51 students were taught using the paper textbooks. The results were as follows. First, there was a significant effect on the improvement of the learning achievement in the experimental group with low academic ability compared with the comparative group with low academic ability. Second, there was a significant effect on self-directed learning attitude in the experimental group. Third, in the experimental group, the number of interactions with the learner, teacher, and digital textbook was higher than the comparative group. In conclusion, the digital textbooks based on the instruction model in elementary science classes developed in this study helped to improve learners' learning achievement and self-directed learning attitudes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.1-8
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• 2013

This study focuses on a ship detection and tracking method using Frequency Modulated Continuous Wave (FMCW) radar used for horizontal surveillance. In general, FMCW radar can play an important role in maritime surveillance, because it has many advantages such as low warm-up time, low power consumption, and its all weather performance. In this paper, we introduce an effective method for data and signal processing of ship's detecting and tracking using the X-band radar. Ships information was extracted using an image-based processing method such as the land masking and morphological filtering with a threshold for a cycle data merged from raw data (spoke data). After that, ships was tracked using search-window that is ship's expected rectangle area in the next frame considering expected maximum speed (19 kts) and interval time (5 sec). By using this method, the tracking results for most of the moving object tracking was successful and those results were compared with AIS (Automatic Identification System) for ships position. Therefore, it can be said that the practical application of this detection and tracking method using FMCW radar improve the maritime safety as well as expand the surveillance coverage cost-effectively. Algorithm improvements are required for an enhancement of small ship detection and tracking technique in the future.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.84-84
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• 2017

직립식 마늘파종기는 마늘 종구를 한 알씩 집어 올려 중간이송컵으로 이송하는 자세교정컵과 배종부와 자세교정컵에서 낙하된 마늘종구를 땅속으로 파종하는 구조로 설계 제작되었으며,전라북도 익산시에 테스트베드를 구축하여 기계파종을 통한 파종기의 성능개선연구를 수행하였다. 기계파종은 1차년도 기존 파종기의 성능을 개선한 7조식 시제품과, 국내산과 스페인산 마늘을 파종하였으며, 11조용 참여기업의 기존 파종기를 이용하여 테스트베드에서 수행하였다. 비가 온 뒤의 땅에 파종한 라인의 샘플링 자료조사 결과(5m 구간 기준으로 체크) 결주율이 각각 17.81%, 35.6%로 평균적인 결주율이 0.57%인 일반 기상상태와 비교하면 매우 높은 결주율을 보이는 것을 알 수 있다. 마늘 파종법에 대한 결과로, 총 4가지의 파종법을 사용하였으며, 사용한 파종방법에는 2조 병목식 스페인식 파종법, 11조식 트랙터용 파종법, 7조식 트랙터용 파종법, 6조식 이양기용 파종법이다. 이 4가지 파종법 중에서 3가지 파종법에 대한 성장률에 대해서 조사를 해보았다. 11조식의 경우에는 제주도식 파종을 하여 비닐 멀칭이 되어있지 않으며, 7조식의 경우에는 비닐 멀칭이 되어있는 파종방식을 사용하였고, 2조식 병목식 스페인식 파종법의 경우에는 자유낙하 방식으로 비닐 멀칭의 유무에 따라 성장률에 대해서 조사를 하였다. 결주율은 파종된 마늘 중 샘플링한 데이터에 대해서 얼마나 파종이 잘되었는지에 퍼센트로 나타낸 것으로 11조식의 경우 비닐멀칭도 없고 비온 뒤에 파종 되어 파종시기에 문제가 있는 것으로 사료됨. 비가오지 않은 날씨에서 측정한 7조식 1차년도 성능개선 시작품의 결주율은 0.57%로 우수하게 나타났다. 발아율은 파종된 마늘 중 샘플링한 데이터에 대해서 다립파종 되어서 미성장된 것과 결주율을 합하여 퍼센트로 나타낸 것으로 시제품으로 개발한 7조식 파종기는 스페인산과 국내산 마늘의 발아율이 모두 90% 이상으로 나타났으며, 차이점은 파종시기의 차이에 따라 발아율의 차이가 있는 것으로 사료(토양, 재배환경 및 기후에 따른 변동요인이 많음)되며, 이는 파종법의 종류뿐만 아니라 비닐멀칭의 온도유지가 마늘 성장률에 얼마나 영향을 끼치는지에 대한 병행연구도 필요한 것으로 나타났다. 마늘의 성장률에 대해서는 아직 표준화, 정형화 되어있는 측정방법이 없기 때문에 이를 표준화, 정형화를 할 필요가 있다. 향후 이와 같은 결과를 토대로 직립식 마늘파종기의 성능을 더욱 개선시키는 연구를 지속적으로 수행할 계획이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.480-488
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• 2018

The development of information and communication technology has been carried out actively in the field of agriculture to generate valuable information from large amounts of data and apply big data technology to utilize it. Crops and their varieties are determined by the influence of the natural environment such as temperature, precipitation, and sunshine hours. This paper derives the climatic factors affecting the production of crops using the garlic growth process and daily meteorological variables. A prediction model was also developed for the production of garlic per unit area. A big data analysis technique considering the growth stage of garlic was used. In the exploratory data analysis process, various agricultural production data, such as the production volume, wholesale market load, and growth data were provided from the National Statistical Office, the Rural Development Administration, and Korea Rural Economic Institute. Various meteorological data, such as AWS, ASOS, and special status data, were collected and utilized from the Korea Meteorological Agency. The correlation analysis process was designed by comparing the prediction power of the models and fitness of models derived from the variable selection, candidate model derivation, model diagnosis, and scenario prediction. Numerous weather factor variables were selected as descriptive variables by factor analysis to reduce the dimensions. Using this method, it was possible to effectively control the multicollinearity and low degree of freedom that can occur in regression analysis and improve the fitness and predictive power of regression analysis.

• Journal of the Korean earth science society
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• v.33 no.3
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• pp.219-232
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• 2012

The intensive observation (ProbeX-2010) was performed to investigate an urban effect on summer rainfall over the Seoul metropolitan area from 13 August to 3 September 2010. Two kinds of urban effect were detected. First, weak rainfall (${\leq}1\;mm\;hr^{-1}$) was observed more frequently in the downwind area of Seoul than any other area of the country. The high frequency of weak rainfall in the downwind area was also confirmed from the recent five years of observational data (2006-2010). Because the high frequency was more apparent in mountainous regions during nighttime, the weak rainfall seems to be caused by a combined effect of urbanization and topography. Second, sporadically, a convective system was developed rapidly in the downwind area of Seoul, causing heavy rainfall (${\geq}10\;mm\;hr^{-1}$). It can be most clearly seen in series of radar images around 1300-1500 KST 27 August 2010. We investigated in detail the synoptic and local weather and upper air conditions. As a result, not only urban-induced high sensible heat but also conditionally unstable atmosphere (especially unstable in low level) and low level moisture were pointed out as important factors that contributed to urban-induced heavy rainfall.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.151-160
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• 2017

Among the methods of developing tourist spots and culture as the experience contents, it is a common method to display high-quality video images on a large display, and it is necessary to make a special difference between the participant's active participation and the visual experience in other regions. In this paper, using the single molecular OLED and active type, the regional tourist spots blend transparent OLED dual-layer display systems with the extended image implementation and augmented interaction techniques to give the participants a real-world experience, such as directing to new experiences and beautiful sights. In this paper, additional images and UI layers are applied to the layers of the images to allow visitors to experience sightseeing information, weather, maps, accommodations, festivals and photo materials with image. In addition to the dual-layer system, it also added a multi-display system that additionally has one vertical 55-inch display on each side, adding to the experience the immersive experience and interface interlocking fun. By using transparent OLED, dual layer panel and 3-channel Multi-image playback technique, the augmented type experience contents which can experience the local attractions in Jeollanamdo province in Korea at all time without any limitation of time and space were developed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.228-233
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• 2007

Pear psylla, Caccopsylla pyricola (Homoptera: Psyllidae), is a serious insect pest in pear orchards. C. pyricola overwinters as adults under rough bark scales of pear trees. When the weather warms up in the spring, the overwintered adults become active, climb up to the tree branches, and inhabit on fruit twigs to lay eggs. This study was conducted to develop a forecasting model for the onset of upward-movement of overwintered C. pyricola adults to control them by timely spraying of petroleum oil. The adult population densities were observed under rough barks (B) and on fruit twigs (T) of pear trees. Relative upward-movement rates (R) were calculated as T/(B+T). Low threshold temperatures for the activation of overwintered C. pyricola adults were selected arbitrarily from 5 to $9^{\circ}C$ at a $1^{\circ}C$ interval. Then, the days (D) when daily maximum air temperatures were above each low threshold temperature were counted from 1 February until to the dates with R $\geq$ 0.8. The same methods were applied for the prediction of the first observation of eggs. The variation of coefficients (CV) for the mean Des were lowest with the low threshold temperature of $6^{\circ}C$. At this selected threshold temperature, the upward movement of C. pyricola adults occurred with 12 D and they started laying eggs with 25 D. In the field validation, the model outputs with the $6^{\circ}C$ threshold temperature reasonably well explained the observed data in Suwon and Cheonan in 2002. Practical usages of the model were also discussed.

• The Korean Journal of Ecology
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• v.28 no.1
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• pp.45-53
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• 2005

Urban stream is an important place supporting urban ecosystem. This study was carried out to clarify the role of Jungrangchun for wintering waterbirds in Seoul. We monitored the fluctuation of waterbirds population using our census data (1997/98 winter) and pervious census data (the Ministry of Environment and National Institute of Environmental Research $1999{\sim}2004$). Wintering behaviours of common teals (Anas crecca) were also observed to understand the habitat use of waterbirds in this area. As a result of this, Jungrangchun was an important place to support $3,004\sim8,237$ wintering birds, mainly dabbling ducks and diving ducks. The population of diving ducks showed high annual fluctuation whilst the population of dabbling ducks regularly used this area every year The maximum number of waterbirds foraged and rested in late January and late February. In daily use, the number of waterbirds increased on afternoon and rapidly increased after sunset. It is assumed that waterbirds used this area not only as a nocturnal feeding site but also daytime feeding site. Thus, this result suggest that Jungrangchun is important for not only the daily use but also the nocturnal use of wintering waterbirds. The number of diving ducks was increased with low temperature and high wind speed. Therefore, this area was also a shelter of diving ducks on chilly and windy day.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.717-724
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• 2020

In general, the factors affecting the heat transfer of asphalt pavement are divided into weather factors and pavement materials. Among them, material factors include the thermophysical and surface properties. An experiment was conducted on the thermal-physical factors of asphalt, which are the basis for the pavement failure model. The thermal conductivity, specific heat capacity, thermal diffusivity, and thermal emissivity were evaluated as the thermo-physical properties of asphalt. The specimens (WC-2 & PA-13) used in the experiment were compacted with a Gyratory Compactor. The experimental results of WC-2 and PA-13 showed a thermal conductivity of 1.18W/m·K and 0.9W/m·K, specific heat capacity of 970.8J/kg·K and 960.1J/kg·K, thermal emissivity of 0.9 and 0.91, and thermal diffusivity of 5.15㎡/s and 4.66㎡/s, respectively. Experiments on the heat transfer characteristics (thermo-physical properties) of asphalt pavement that can be used for thermal failure modeling of asphalt were conducted.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1083-1094
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• 2021

In order to monitor nuclear activity in inaccessible areas, it is necessary to establish a methodology to analyze changesin nuclear activity-related objects using high-resolution satellite images. However, traditional object detection and change detection techniques using satellite images have difficulties in applying detection results to various fields because effects of seasons and weather at the time of image acquisition. Therefore, in this paper, an object of interest was detected in a satellite image using a deep learning model, and object changes in the satellite image were analyzed based on object detection results. An initial training of the deep learning model was performed using an open dataset for object detection, and additional training dataset for the region of interest were generated and applied to transfer learning. After detecting objects by multitemporal and multisensory satellite images, we tried to detect changes in objects in the images by using them. In the experiments, it was confirmed that the object detection results of various satellite images can be directly used for change detection for nuclear activity-related monitoring in inaccessible areas.