• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2021-2032
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• 1992

A redundant sensor system, which consists of two incremental encoders and a gyro sensor, has been proposed for the estimation of the posture of mobile robots. A hardware system was built for estimating the heading angle change of the mobile robot from outputs of the gyro sensor. The proposed hardware system of the gyro sensor produced an accurate estimate for the heading angle change of the robot. A sensor data fusion algorithm has been developed to find the optimal estimates of the heading angle change based on the stochastic measurement equations of our readundant sensor system. The maximum likelihood estimation method is applied to combine the noisy measurement data from both encoders and gyro sensor. The proposed fusion algorithm demonstrated a satisfactory performance, showing significantly reduced estimation error compared to the conventional method, in various navigation experiments.

• Journal of Auto-vehicle Safety Association
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• v.8 no.1
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• pp.13-18
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• 2016

More than 80 percent of traffic accidents related with lane departure believed to be the result of crossing the lane due to either negligence or drowsiness of the driver. Lane-departure related accident in the highway usually involve high fatality. Even though LDWS is believed to prevent accident 25% and reduce fatalities by 15% respectively, its effectiveness in performance is yet to be confirmed in many aspects. In this study, the vehicle lateral locations relative to warning zone envelop (earliest and latest warning zone) defined in ISO standard, ECE and NHTSA regulations are compared with respect to various factors including delays, vehicle speed and vehicle heading angle with respect to the lane. Since LDWS is designed to be activated at the speed over 60 km/h, vehicle speed range for the study is set to be from 60 to 100 km/h. The vehicle heading angle (yaw angle) is set to be up to 5 degree away from the lane (abrupt lane change) considering standard for lane change test using double lane-change test specification. The TLC is calculated using factors like vehicle speed, yaw angle and reaction time. In addition, the effect of vehicle type and reaction time have been considered to assess LDWS safety.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.80-80
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• 2022

Estimation of heading date of paddy rice is laborious and time consuming. Therefore, automatic estimation of heading date of paddy rice is highly essential. In this experiment, deep learning classification models were used to classify two difference categories of rice (vegetative and reproductive stage) based on the panicle initiation of paddy field. Specifically, the dataset includes 444 slanted view images belonging to two categories and was then expanded to include 1,497 images via IMGAUG data augmentation technique. We adopt two transfer learning strategies: (First, used transferring model weights already trained on ImageNet to six classification network models: VGGNet, ResNet, DenseNet, InceptionV3, Xception and MobileNet, Second, fine-tuned some layers of the network according to our dataset). After training the CNN model, we used several evaluation metrics commonly used for classification tasks, including Accuracy, Precision, Recall, and F1-score. In addition, GradCAM was used to generate visual explanations for each image patch. Experimental results showed that the InceptionV3 is the best performing model in terms of the accuracy, average recall, precision, and F1-score. The fine-tuned InceptionV3 model achieved an overall classification accuracy of 0.95 with a high F1-score of 0.95. Our CNN model also represented the change of rice heading date under different date of transplanting. This study demonstrated that image based deep learning model can reliably be used as an automatic monitoring system to detect the heading date of rice crops using CCTV camera.

• Journal of Life Science
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• v.30 no.10
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• pp.844-850
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• 2020

Disaster-related extreme weather is rapidly increasing due to climate change. In Korea, typhoons accompanied by rainfall usually approach in August and September, causing great damage. The purpose of this study is to find a gene that regulates the heading date of rice in order to avoid loss of harvest from climate change and typhoons. Cheongcheong/Nagdong doubled haploid (CNDH) was used as the plant material to investigate the location of heading-related genes using QTL and sequence analysis by cloning the gene. In the distribution chart, the heading dates, culm lengths, panicle lengths, numbers of panicles, and 1,000-grain weights all have normal distributions. QTL analysis found 13 contigs on chromosome 8. One QTL, named qHd8, was detected on chromosome 8. The range at qHd8 was approximately 7.7 cM, with RM72 and RM404 markers near the peak. There were 13 contigs and 1 ORF. Protein sequence analysis showed that rice was similar to Os08g0341700, AtSFH13, and AtSFH7 proteins. Os08g0341700, which is involved in signal transduction, is similar to phosphatidylinositol transfer-like protein II, and complete information is not available, but it is believed to play a role in the phosphatidylinositol-specific signaling pathway related to Sec14P.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.170-179
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• 1997

This paper presents a hybrid navigation system for AUV to locate its position precisely in rough sea. The tracking system is composed of various sensors such as an inclinometer, a tri-axis magnetometer, a flow meter, and a super short baseline(SSBL) acoustic position tracking system. Due to the inaccuracy of the attitude sensors, the heading sensor and the flowmeter, the predicted position slowly drifts and the estimation error of position becomes larger. On the other hand, the measured position is liable to change abruptly due to the corrupted data of the SSBL system in the case of low signal to noise ratio or large ship motions. By introducing a sensor fusion technique with the position data of the SSBL system and those of the attitude heading flowmeter reference system (AHFRS), the hybrid navigation system updates the three-dimensional position robustly. A Kalman filter algorithm is derived on the basis of the error models for the flowmeter dynamics with the use of the external measurement from the SSBL. A failure detection algorithm decides the confidence degree of external measurement signals by using a fuzzy inference. Simulation is included to demonstrate the validity of the hybrid navigation system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.259-267
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• 2010

This study was performed at Rice and Winter Cereal Crops Department of NICS during 2007 and 2008 to investigate the characteristics of rice leaf emergence and to obtain basic data which can be used for rice growth simulation model by which we can forecast rice growth stage and heading date accurately under different cultivars, transplanting date, and climatic conditions. To confirm leaf emergence rate according to rice maturing ecotype, we surveyed the leaf emergence rate and heading date of Unkwangbyeo, Hwayoungbyeo and Nampyeongbyeo which are early maturing, medium maturing and medium-late maturing cultivars, respectively, according to seedling raising duration and transplanting time. When seedling duration was 15 days, the growth duration between transplanting time and completion of flag leaf emergence on main culm were 51.5~78.3 days in Unkwangbyeo, 55.3~87.9 days in Hwayoungbyeo and 58.4~98.4 days in Nampyeongbyeo, respectively. When seedling duration was 30 days, they were 50.1~75.5 days in Unkwangbyeo, 52.4~84.7 days in Hwayoungbyeo and 56.4~93.8 days in Nampyeongbyeo, respectively. As transplanting time delayed, the emerged leaf number after transplanting decreased in all rice cultivars. The cumulative temperature between transplanting time to completion of flag leaf elongation on main culm were $1,281^{\circ}C{\sim}1,650^{\circ}C$ in Unkwangbyeo, $1,344^{\circ}C{\sim}1,891^{\circ}C$ in Hwayoungbyeo and $1,454^{\circ}C{\sim}2,173^{\circ}C$ in Nampyeongbyeo, respectively. Leaf emergence rate on main culm were precisely represented by equation, y = $y_0$ + a / [1 + exp( - (x - $x_0$) / b)]^c, when we used daily mean temperature as variable.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.17-28
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• 2007

This study was conducted to analyze the optimum heading period according to the recent climatic change for improvement of rice yield and grain quality in the Yeongnam area. We analyzed climatic elements including daily mean air temperature, daily range of air temperature, sunshine hours, and amount of precipitation from 1996 to 2005 in comparison with those of the 1971 to 2000 normal. Daily mean air temperature and amount of precipitation in the recent 10 years increased, but daily range of air temperature and sunshine hours decreased in comparison with the norm. Also, monthly mean air temperature was lowered remarkably in July and August. The monthly amount of precipitation largely increased in August and September. The daily range of air temperature and sunshine hours were greatly decreased from August to October, Possible cultivation periods for rice in the recent 10 years ranged from 171 days in Boughwa to 228 days in Busan and was expanded about $1{\sim}13$ days in comparison with the normal. Optimum heading date by local regions for the maximum climatic yield potential was estimated as July 31 at Bonghwa to September 7 at Busan, Masan, and Tongyeong in the recent 10 years. There was a wide difference in optimum heading date according to local legions of the Yeongnam area. Compared to the normal, optimum heading date in the recent 10 years was delayed about I~8 days in most local regions except Bonghwa, Mungyeong, and Yeongdeok. These results suggested that it is necessary to develop late maturity rice cultivars for producing high yield and quality rice grain due to the recent climatic change. Moreover, it is still more important to select the most suitable cultivation period appropriate to the changed climate of each local region in Yeongnam area.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.177-189
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• 2010

These studies were conducted to analysis for weather reaction on the growth and yield component according to meterological elements used Vector Autoregressive Regression(VAR) Model at Daejeon, Hongseong, Geumsan, Nonsan, and Yesan to core of center to Chungnam area in Rice. Reaction of cultivars according to change of meterological elements for growth and yield component effected on heading time in Gancheokbyeo and Mananbyeo, grain number of a spike in Gancheokbyeo, ratio of ripeness in Gancheokbyeo and Geumobyeo 1, amount of milled rice in Geurubyeo and Ansanbyeo, and 1,000 grains weight in Gancheokbyeo, Dasanbyeo, and Hwajinbyeo. An effect on the growth and yield components of meterological elements were influenced by heading date, 1,000 grain weight and ratio of repening as sunshine hours. The cultivars in sensitive reaction for change of weather condition were classified to 14 varieties including Gerubyeo et al., insensitive cultivars were classified to 66 varieties including Gyehwabyeo et. al.

• Journal of the Korean Society for Library and Information Science
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• v.48 no.2
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• pp.177-199
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• 2014

The purpose of this study is to propose the expansion of headings for digital trends of Korean Decimal Classification. In order to achieve the purpose, this study first analyzed the change process of classification items related to digital resources in DDC and KDC. Second, subject names related to digital in LCSH and Korean National Library Subject Heading were analyzed. Third, comparisons between the items related to digital of DDC 23rd with LCSH and KDC with Korean National Library Subject Heading were conducted. The result of comparative analysis was identified that KDC 6th edition faces with difficulties in reasonable classification because item names related to digital of KDC 6th edition have 11 items. Therefore, the item related to digital has to be expanded to new classification item name and has to add include notes and class here notes in KDC.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.323-330
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• 2009

This paper proposes a methodology for automatic hierarchy classification of subtitles in a engineering document by the a fact that heading symbols of subtitles represent a hierarchical structure of the document. The proposed methodology is composed of two methods: extracting subtitles from plan text document and determining hierarchical structure of the subtitles. The subtitles in a document is extracted by comparing heading symbol patterns with predefined heading symbol groups, and the depth levels of the subtitles are determined by analyzing relative location of subtitles according to change of the heading symbol patterns. A prototype module, which can transform a plain text document into a structured XML document in accordance with a hierarchical structure of subtitles, is developed based on the proposed methodology, and the performance of the module is analyzed with 20 engineering documents.