• Journal of Korea Water Resources Association
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• v.55 no.8
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• pp.623-634
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• 2022

Due to river maintenance projects such as the creation of hydrophilic areas around rivers and the Four Rivers Project, the flow characteristics of rivers are continuously changing, and the risk of water quality accidents due to the inflow of various pollutants is increasing. In the event of a water quality accident, it is necessary to minimize the effect on the downstream side by predicting the concentration and arrival time of pollutants in consideration of the flow characteristics of the river. In order to track the behavior of these pollutants, it is necessary to calculate the diffusion coefficient and dispersion coefficient for each section of the river. Among them, the dispersion coefficient is used to analyze the diffusion range of soluble pollutants. Existing experimental research cases for tracking the behavior of pollutants require a lot of manpower and cost, and it is difficult to obtain spatially high-resolution data due to limited equipment operation. Recently, research on tracking contaminants using RGB drones has been conducted, but RGB images also have a limitation in that spectral information is limitedly collected. In this study, to supplement the limitations of existing studies, a hyperspectral sensor was mounted on a remote sensing platform using a drone to collect temporally and spatially higher-resolution data than conventional contact measurement. Using the collected spatio-temporal hyperspectral images, the tracer concentration was calculated and the transverse dispersion coefficient was derived. It is expected that by overcoming the limitations of the drone platform through future research and upgrading the dispersion coefficient calculation technology, it will be possible to detect various pollutants leaking into the water system, and to detect changes in various water quality items and river factors.

• The Korean Journal of Nuclear Medicine Technology
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• v.26 no.2
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• pp.15-19
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• 2022

Purpose [⁶⁸Ga]PSMA-11 is needed the high reproducibility, excellent radiochemical yield and purity. In term of radiation safety, the radiation exposure of operator for its production also should be considered. In this work, we performed a comparative study for the fully automated synthesis of [⁶⁸Ga]PSMA-11 between non-cassette type and cassette type. Materials and Methods Two different type of modules (TRACERlab FX N pro for non-cassette type and BIKBox for cassette type) were used for the automated production of [⁶⁸Ga]PSMA-11. According to the previously identified elution profile, Only 2.5 ml with high radioactivity was used for the reaction. After adjusting the pH of the reaction solution with HEPES buffer solution, the precursor was added and reacted with at 95 ℃ for 15 minutes. The reaction mixture was separated and purified using a C18 light cartridge. The product was eluted with 50% EtOH/saline solution and diluted with saline. It was completed by sterilizing filter. In the non-cassette type, the aforementioned process must be prepared directly. However, in the cassette method, synthesis was possible simply by installing a kit that was already completed. Results Both total [⁶⁸Ga]PSMA-11 production time were 25±3(non-cassette type) and 23±3 minutes(cassette type). The radiochemical yield of the non-cassette type(65.5±5.7%) was higher than that of the cassette type(61.6±4.8%) after sterilization filter. The non-cassette type took about 120 minutes of preparation time before synthesis due to washing of synthesizer and reagent preparation. However, since the cassette type does not require washing and reagent preparation, it took about 20 minutes to prepare before synthesis. Both type of synthesizer had a radiochemical high purity(>99%). Conclusion The non-cassette type production of [⁶⁸Ga]PSMA-11 showed higher radiochemical yield and lower cost than the cassette type. However, The cassette type has an advantage in terms of preparation time, convenience, and equipment maintenance.

• Journal of Intelligence and Information Systems
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• v.29 no.3
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• pp.57-78
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• 2023

COVID-19, which started in Wuhan, China in November 2019, spread beyond China in 2020 and spread worldwide in March 2020. It is important to prevent a highly contagious virus like COVID-19 in advance and to actively treat it when confirmed, but it is more important to identify the confirmed fact quickly and prevent its spread since it is a virus that spreads quickly. However, PCR test to check for infection is costly and time consuming, and self-kit test is also easy to access, but the cost of the kit is not easy to receive every time. Therefore, if it is possible to determine whether or not a person is positive for COVID-19 based on the sound of a cough so that anyone can use it easily, anyone can easily check whether or not they are confirmed at anytime, anywhere, and it can have great economic advantages. In this study, an experiment was conducted on a method to identify whether or not COVID-19 was confirmed based on a cough sound. Cough sound features were extracted through MFCC, Mel-Spectrogram, and spectral contrast. For the quality of cough sound, noisy data was deleted through SNR, and only the cough sound was extracted from the voice file through chunk. Since the objective is COVID-19 positive and negative classification, learning was performed through XGBoost, LightGBM, and FCNN algorithms, which are often used for classification, and the results were compared. Additionally, we conducted a comparative experiment on the performance of the model using multidimensional vectors obtained by converting cough sounds into both images and vectors. The experimental results showed that the LightGBM model utilizing features obtained by converting basic information about health status and cough sounds into multidimensional vectors through MFCC, Mel-Spectogram, Spectral contrast, and Spectrogram achieved the highest accuracy of 0.74.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.79-94
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• 2009

The research project was conducted to develop a paper bagging machine for grape. This technology was aimed to highly reduce a labor for paper bagging in grape and bakery. In agriculture labor and farm population has rapidly decreased since 1980 in Korea so there was so limit in labor. In particular there is highly population in women and old age at rural area and thus labor cost is so high. Therefore a labor saving technology in agricultural sector might be needed to be replaced these old age with mechanical and labor saving tool in agriculture. The following was summarized of the research results for development of a paper bagging machine for grape. 1. Development of a new paper bagging machine for grape - This machine was designed by CATIA VI2/AUTO CAD2000 programme. - A paper bagging machine was mechanically binded a paper bag of grape which should be light and small size. This machine would be designed for women and old age with convenience during bagging work at the field site. - This machine was manufactured with total weight of less than 350g. - An overage bagging operation was more than 99% at the actual field process. - A paper bagging machine was designed with cartridge type which would be easily operated between rows and grape branches under field condition. - The type of cartridge pin was designed as a C-ring type with the length of 500mm which was good for bagging both grape and bakery. - In particular this machine was developed to easily operated among vines of the grape trees. 2. Field trials of a paper bagging machine in grape - There was high in grape quality as compared to the untreated control at the application of paper bagging machine. - The efficiency of paper bagging machine was 102% which was alternative tool for the conventional. - The roll pin of paper bagging machine was good with 5.3cm in terms of bagging precision. - There was no in grape quality between the paper bagging machine and the conventional method. - Disease infection and grape break was not in difference both treatments.

• Korea Science and Art Forum
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• v.29
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• pp.305-318
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• 2017

The need for recognizing the crime in the urban spaces as a social problem and finding out specific approaches such as the study of space design and various guidelines for crime prevention is increasing. In this regard, "Crime Prevention Through Environmental Design" (marked as "CPTED") is actively underway. Yeomri-dong Salt Way is the first place to which the Seoul Crime Prevention Design Project was appled. The business objective of improving the local environment has been implemented rationally through cooperation and voluntary participation between subject of the project executives and community members. Since its efficiency has been proven, the sites have been expanded since then and becomes a benchmarking example of each local government.This kind of problem solving effort has the same context in purpose and direction of the 'Village Art Project' which has been implemented since 2009 with the aim of promoting the culture of the underdeveloped area and encouraging the participation of the residents by introducing the public art. It is noteworthy that this trend is centered around the characteristics of community functions and values. The purpose of this study is to propose the application method of community furniture as a way to increase the efficiency of CPTED to improve the 'quality of life' of residents. To do this, we reviewed CPTED, community design, public art literature and prior research, and identified the problems and implications based on the site visit Yeomri-dong of Seoul and Gamcheon Village of Pusan which is the successful model of "Seoul Root out Crime by Design" and 'Maeulmisul Art Project' respectively. The common elements of the two case places identified in this study are as follows: First, the 'lives' of community residents found its place in the center through the activation of community by collaborative activities in addition to the physical composition of the environment. Second, community design and introduction of public art created a new space, and thereby many people came to visit the village and revitalize the local economy. Third, it strengthened the natural monitoring, the territoriality and control, and the activity increase among the CPTED factors. The psychological aspect of CPTED and the emotional function of public art are fused with the 'community furniture', thereby avoiding a vague or tremendous approach to the public space through a specific local context based on the way of thinking and emotion of local people and it will be possible to create an environment beneficial for all. In this way, the possibility and implication of the fusion of CPTED and public art are expected to be able to reduce the social cost through the construction of the crime prevention infrastructure such as expansion of the CPTED application space, and to suggest a plan to implement the visual amenity as a design strategy to regenerate city.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.49-59
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• 2019

The field trial was performed to evaluate the rice growth and yield in different direct seeding methods after Italian Ryegrass Harvest The required time for seed emergence was for 7 ~ 8days in the tested direct seeding methods and there was high in seedling establishment in order of wet hill-seeding with iron-coated seeds > water seeding with iron-coated seeds > wet hill-seeding with soil coverage with pregerminated seeds. The rice plant height was shorter in the tested direct seeding methods than that of machine transplanting until 45day after seeding but there was not significant difference in terms of statistical analysis at 63day after seeding. The growth of tiller number in the rice plant was high in water seeding with iron-coated seeds and wet hill-seeding with soil coverage and low in wet hill-seeding with iron-coated seeds compared to machine transplanting. The yield component in the tested direct seeding methods was not significant difference in terms of statistical analysis. The milled rice yield in the tested direct seeding methods was higher 2 ~ 8% being with 4.94 ~ 5.24t/ha than that of machine transplanting but there was not significant difference in terms of statistical analysis. The percentage of head rice was low in the tested direct seeding methods compared to machine transplanting. The weedy rice was not occurred in the tested rice cultivation methods. In conclusion the direct seeding method would be recommended to be a suitable to in following by Italian ryegrass harvesting in southern area of Korea in terms of reduction in production cost and high income basis for rice growing farmers.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.589-597
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• 2023

Floating debris in large quantities from land during heavy rainfall has adverse social, economic, and environmental impacts, but the monitoring system for the concentration area and amount is insufficient. In this study, we proposed an efficient monitoring method for floating debris entering the river during heavy rainfall in Daecheong Lake, the largest water supply source in the central region, and applied remote sensing techniques to estimate the standing-stock of floating debris. To investigate the status of floating debris in the upper of Daecheong Lake, we used a tracking buoy equipped with a low-orbit satellite communication terminal to identify the movement route and behavior characteristics, and used a drone to estimate the potential concentration area and standing-stock of floating debris. The location tracking buoys moved rapidly during the period when the cumulative rainfall for 3 days increased by more than 200 to 300 mm. In the case of Hotan Bridge, which showed the longest distance, it moved about 72.8 km for one day, and the maximum moving speed at this time was 5.71 km/h. As a result of calculating the standing-stock of floating debris using a drone after heavy rainfall, it was found to be 658.8 to 9,165.4 tons, with the largest amount occurring in the Seokhori area. In this study, we were able to identify the main concentrations of floating debris by using location-tracking buoys and drones. It is believed that remote sensing-based monitoring methods, which are more mobile and quicker than traditional monitoring methods, can contribute to reducing the cost of collecting and processing large amounts of floating debris that flows in during heavy rain periods in the future.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.669-681
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• 2023

Studies have tried to apply remote sensing technology, a non-destructive survey method, instead of the existing destructive survey, which requires relatively large labor input and a long time to estimate chlorophyll content, which is an important indicator for evaluating the growth of fruit trees. This study was conducted to non-destructively evaluate the chlorophyll content of pear tree leaves using unmanned aerial vehicle-based hyperspectral imagery for two years(2021, 2022). The reflectance of the single bands of the pear tree canopy extracted through image processing was band rationed to minimize unstable radiation effects depending on time changes. The estimation (calibration and validation) models were developed using machine learning algorithms of elastic-net, k-nearest neighbors(KNN), and support vector machine with band ratios as input variables. By comparing the performance of estimation models based on full band ratios, key band ratios that are advantageous for reducing computational costs and improving reproducibility were selected. As a result, for all machine learning models, when calibration of coefficient of determination (R²)≥0.67, root mean squared error (RMSE)≤1.22 ㎍/cm², relative error (RE)≤17.9% and validation of R²≥0.56, RMSE≤1.41 ㎍/cm², RE≤20.7% using full band ratios were compared, four key band ratios were selected. There was relatively no significant difference in validation performance between machine learning models. Therefore, the KNN model with the highest calibration performance was used as the standard, and its key band ratios were 710/714, 718/722, 754/758, and 758/762 nm. The performance of calibration showed R²=0.80, RMSE=0.94 ㎍/cm², RE=13.9%, and validation showed R²=0.57, RMSE=1.40 ㎍/cm², RE=20.5%. Although the performance results based on validation were not sufficient to estimate the chlorophyll content of pear tree leaves, it is meaningful that key band ratios were selected as a standard for future research. To improve estimation performance, it is necessary to continuously secure additional datasets and improve the estimation model by reproducing it in actual orchards. In future research, it is necessary to continuously secure additional datasets to improve estimation performance, verify the reliability of the selected key band ratios, and upgrade the estimation model to be reproducible in actual orchards.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.1009-1029
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• 2023

Urban trees play a vital role in urban ecosystems,significantly reducing impervious surfaces and impacting carbon cycling within the city. Although previous research has demonstrated the efficacy of employing artificial intelligence in conjunction with airborne light detection and ranging (LiDAR) data to generate urban tree information, the availability and cost constraints associated with LiDAR data pose limitations. Consequently, this study employed freely accessible, high-resolution multispectral satellite imagery (i.e., Sentinel-2 data) to estimate fractional tree canopy cover (FTC) within the urban confines of Suwon, South Korea, employing machine learning techniques. This study leveraged a median composite image derived from a time series of Sentinel-2 images. In order to account for the diverse land cover found in urban areas, the model incorporated three types of input variables: average (mean) and standard deviation (std) values within a 30-meter grid from 10 m resolution of optical indices from Sentinel-2, and fractional coverage for distinct land cover classes within 30 m grids from the existing level 3 land cover map. Four schemes with different combinations of input variables were compared. Notably, when all three factors (i.e., mean, std, and fractional cover) were used to consider the variation of landcover in urban areas(Scheme 4, S4), the machine learning model exhibited improved performance compared to using only the mean of optical indices (Scheme 1). Of the various models proposed, the random forest (RF) model with S4 demonstrated the most remarkable performance, achieving R² of 0.8196, and mean absolute error (MAE) of 0.0749, and a root mean squared error (RMSE) of 0.1022. The std variable exhibited the highest impact on model outputs within the heterogeneous land covers based on the variable importance analysis. This trained RF model with S4 was then applied to the entire Suwon region, consistently delivering robust results with an R² of 0.8702, MAE of 0.0873, and RMSE of 0.1335. The FTC estimation method developed in this study is expected to offer advantages for application in various regions, providing fundamental data for a better understanding of carbon dynamics in urban ecosystems in the future.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.112-120
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• 2007

This paper reviews the use of parasites as 'biological tags' for studying stock analysis of salmonid fishes. Numerous definitions of stock concepts exist, but most of them essentially define a group of fish as having similar biological characteristics and being self-reproducing as stocks. It is important to manage fish stocks for human consumption and sustainable production and especially for salmonid fishes. Because these fry are considered as each country's property, it is necessary to identify and discriminate each fish stock in the open sea. Methods of separating fish stocks are very diverse. Artificial tags, parasites, otoliths scales and genetic characters have been used for stock analysis and each method has advantages and disadvantages. Of these parasites can be good biological tags because they are applied by nature at no cost. Parasites can be infected with susceptible host fishes when they enter into certain areas. Then if they move to the outside and are caught researchers can infer that the fish had been in the endemic area for a period of time during their life. Hence the host fish can be considered as naturally 'tagged' by parasites. However, if they do not pass the parasites-endemic. area, they will harbour no parasites. Therefore, researchers can discriminate each fish stocks and trace their migration routes with these biological tags. In this paper, several examples on the use of parasites as biological tags for studying salmonids, as well as other species, are listed. The advantages and limitations of parasites as biological tags are also discussed. Chum salmon (Oncorhynchus keta), the main salmonid species migrating to Korea, is distributed all around the North Pacific. Korean chum salmon are generally thought to move to the Sea of Okhotsk, the western North Pacific and the Bering Sea. However, there is no clear information on the distribution and migration pathways of Korean chum salmon, and no markers exist for separating them from others yet. Recent Korean chum salmon stock analysis including parasites information are mentioned.