• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.214-223
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• 2016

Joint time-frequency images of the broadband acoustic echoes of six fish species were obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The acoustic features were extracted by changing the sliced window widths and dividing the time window by a 0.02-ms interval and the frequency window by a 20-kHz bandwidth. The 22 spectrum amplitudes obtained in the time and frequency domains of the SPWVD images were fed as input parameters into an artificial neural network (ANN) to verify the effectiveness for species-dependent features related to fish species identification. The results showed that the time-frequency approach improves the extraction of species-specific features for species identification from broadband echoes, compare with time-only or frequency-only features. The ANN classifier based on these acoustic feature components was correct in approximately 74.5% of the test cases. In the future, the identification rate will be improved using time-frequency images with reduced dimensions of the broadband acoustic echoes as input for the ANN classifier.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.221-232
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• 2015

Broadband echoes measured in live chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, and fat greenling Hexagrammos otakii with different morphologies and internal characteristics were analyzed in time and frequency domains to understand the species-specific echo feature characteristics for classifying fish species. The mean echo image for each time-frequency representation dataset obtained as a function of orientation angle was extracted to mitigate the effect of fish orientation on acoustic scattering. The joint time-frequency content of the broadband echo signals was obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The SPWVDs were analyzed for each echo signature of the three fish species. The results show that the time-frequency analysis provided species-specific echo structure patterns and metrics of the broadband acoustic signals to facilitate fish species classification.

• Journal of Korean Elementary Science Education
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• v.26 no.3
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• pp.329-340
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• 2007

This study is to find out how well elementary school gardens work as places of observation learning. We compared the tree species planted in elementary school gardens with those which appeared in the science textbooks of the 7th Korean National Curriculum. The number of tree species are 60 throughout all the grades, specifically; 43 in the third grade, 22 in the fifth grade, 16 in the first grade, 15 in the second grade, 8 in the sixth grade, and 5 in the fourth grade, respectively. Their frequency of appearance (hereafter referred to as 'appearance frequency') throughout all the grades is 175, and the maximum frequency is 62 in the third grade. Of particular note is the fact that the appearance frequency in one grade was very high, meaning that a repeat study will not be conducted. The total number of tree species counted in the study was 13,028 and consisted of 167 species in 52 families. Only 23% of the total planted tree species, that is, 38 tree species appeared in the textbooks, so the ratio of the practical usage of school gardens was revealed to be low. In the school gardens, there are only an average of about 16 tree species per school. The fewest number of species in one school was 9 and the most was 22. The native species were 74 and the non-native species were 93. This means that almost all the planted species do not relate to observation learning in the textbooks. The 22 tree species among 60 species in the textbooks were not planted in the gardens. In conclusion, the degree of utilization of almost all the elementary school gardens examined during this investigation was very low.

• Journal of Plant Biology
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• v.12 no.3
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• pp.35-41
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• 1969

To clarify the types of brackish region of the Han River Estuary, this research was carried out, and the results obtained on the basis of salinities and phytoplankton are as follows: 1. Geomorphologically, the Han River Estuary is the drowned river valley type. 2. According to the Venice System, the estuarine extent is defined from the lower point of Jollyu-ri to Palmi Island. As a whole the estuarine region is mixo-haline including parts from oligo-haline to poly-haline. 3. In standpont of phytoplankton frequency, the frequency of fresh-water species is high in the upper region of estuary and that of marine species is high in the lower region. The rate of frequency of fresh-water species is inversely proportionate to that of marine species. The area mixedby marine and fresh-water species over estuarine boundary. 4. The frequency of some typical brackish species is very low and almost similar in the whole region.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.224-233
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• 2016

The objective of this study was to develop an artificial neural network (ANN) model for the acoustic identification of commercially important fish species in Korea. A broadband echo acquisition and processing system operating over the frequency range of 85-225 kHz was used to collect and process species-specific, time-frequency feature images from six fish species: black rockfish Sebastes schlegeli, black scraper Thamnaconus modesutus [K], chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, konoshiro gizzard shad Konosirus punctatus and large yellow croaker Larimichthys crocea. An ANN classifier was developed to identify fish species acoustically on the basis of only 100 dimension time-frequency features extracted by the principal components analysis (PCA). The overall mean identification rate for the six fish species was 88.5%, with individual identification rates of 76.6% for black rockfish, 82.8% for black scraper, 93.8% for chub mackerel, 90.6% for goldeye rockfish, 96.9% for konoshiro gizzard shad and 90.6% for large yellow croaker, respectively. These results demonstrate that individual live fish in well-controlled environments can be identified accurately by the proposed ANN model.

• Ocean and Polar Research
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• v.39 no.1
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• pp.13-21
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• 2017

Temporal changes in the number of zooplankton species are important information for understanding basic characteristics and species diversity in marine ecosystems. The aim of the present study was to estimate the optimal monitoring frequency (OMF) to guarantee and predict the minimum number of species occurrences for studies concerning marine ecosystems. The OMF is estimated using the temporal number of zooplankton species through bi-weekly monitoring of zooplankton species data according to operational taxonomic units in the Tongyoung coastal sea. The optimal model comprises two terms, a constant (optimal mean) and a cosine function with a one-year period. The confidence interval (CI) range of the model with monitoring frequency was estimated using a bootstrap method. The CI range was used as a reference to estimate the optimal monitoring frequency. In general, the minimum monitoring frequency (numbers per year) directly depends on the target (acceptable) estimation error. When the acceptable error (range of the CI) increases, the monitoring frequency decreases because the large acceptable error signals a rough estimation. If the acceptable error (unit: number value) of the number of the zooplankton species is set to 3, the minimum monitoring frequency (times per year) is 24. The residual distribution of the model followed a normal distribution. This model can be applied for the estimation of the minimal monitoring frequency that satisfies the target error bounds, as this model provides an estimation of the error of the zooplankton species numbers with monitoring frequencies.

• Journal of People, Plants, and Environment
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• v.24 no.5
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• pp.485-498
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• 2021

Background and objective: This study was conducted to find out the status of plant utilization in the current textbooks by analyzing the plants by grade and subject in the national textbooks for all elementary school grades in the 2015 revised curriculum in Korea. Methods: The data collected was analyzed using Microsoft Office Excel to obtain the frequency and ratio of collected plant data and SPSS for Windows 26.0 to determine learning content areas by grade and the R program was used to visualize the learning content areas. Results: A total of 232 species of plants were presented 1,047 times in the national textbooks. Based on an analysis of the plants presented by grade, the species that continued to increase in the lower grades tended to decrease in the fifth and sixth grades, the upper grades of elementary school. As for the number and frequency of plant species by subject, Korean Language had the highest number and frequency of plant species. The types of presentation of plants in textbooks were mainly text, followed by illustrations and photos of plants, which were largely used in first grade textbooks. In addition, as for the area of learning contents in which plants are used, in the lower grades, plants were used in the linguistic domain, and in the upper grades, in the botanical and environmental domains of the natural sciences. Herbaceous plants were presented more than woody plants, and according to an analysis of the plants based on the classification of crops, horticultural crops were presented the most, followed by food crops. Out of horticultural crops, flowering plants were found the most diversity with 63 species, but the plants that appeared most frequently were fruit trees that are commonly encountered in real life. Conclusion: As a result of this study, various plant species were included in elementary school textbooks, but most of them were horticultural crops encountered in real life depending on their use. Nevertheless, plant species with high frequency have continued a similar trend of frequency from the previous curriculums. Therefore, in the next curriculum, plant learning materials should be reflected according to social changes and students' preference for plants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.2
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• pp.195-206
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• 2017

Joint time-frequency images of the broadband echo signals of six fish species were obtained using the smoothed pseudo-Wigner-Ville distribution in controlled environments. Affine transformation and principal component analysis were used to obtain eigenimages that provided species-specific acoustic features for each of the six fish species. The echo images of an unknown fish species, acquired in real time and in a fully automated fashion, were identified by finding the smallest Euclidean or Mahalanobis distance between each combination of weight matrices of the test image of the fish species to be identified and of the eigenimage classes of each of six fish species in the training set. The experimental results showed that the Mahalanobis classifier performed better than the Euclidean classifier in identifying both single- and mixed-species groups of all species assessed.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.1
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• pp.31-50
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• 1993

This study was conducted to investigate the plants status of the woody landscape plants species of 38 elementary, middle, and high school in Iri city, and to obtain some fundamental information for development and use of native species of trees. The results are summarized as follows: 1. Landscape plants species of 38 elementary, middle and high school in Iri city was 55 families, 164 species, and 85, 045 trees and the average of landscape plants species of 17 elementary schools was 50.5 families, 3, 010 trees, on the other hand, middle and high school was 42.4 families, 1, 609 trees. 2. Plants species by type was Deciduous Broadleaved Tree 32.9%, Deciduous Broadleaved Shrub 25.6%, Evergreen Coniferous Tree 14.6%, Evergreen Broadleaved Shrub 9.7%, Vine 4.8%. Evergreen Trees on the other hand, according to the utilization rate 'others' was 32.2%. 3. The rate of plants species of the Evergreen Trees to the Deciduous (except Vine and 'others') was 34:66. on the other hand, rate of quantity was 50.5:49.5 and the rate of the trees to the shrubs(except Vine and 'others') was 58:42. to the plants species and to the quantity of the number of trees was 25.9:74.1. 4. Plants species of fruit plants of 38 elementary, middle and high school in Iri city was 31 species to the 164 species. The rate of frequency was Poncirus trifoliata 27.8%, Lycium chinense 25.1%, Ginkgo biloba 16.7%, to the quantity of the number of trees, fruit plants was 2, 605 trees to the 85, 045 trees and the frequency was 3%. 5. School trees and flowers of 38 elementary, middle and high school in Iri city were appointed 17 elementary school, on the other hand, middle and high schools were only 4 middle and high schools. Plants species of the best of frequency school tree was Zelkova serrata and school flower was Rosa spp.. 6. The rate of the native species to the introduced species was 73.8:26.2. on the other hand, the rate of quantity by the number of trees was 84.7:15.3 to the type, the rate of frequency of plants of native species Evergreen trees was Thuja orientalis, deciduous was Ginkgo biloba, Vine was Wisteria floribunda and 'others' was Sasa borealis. on the other hand, to the introduced species, Evergreen Trees was Juniperus chinensis. Deciduous Trees was Metasequoia glyptostroboides, and Vine was Vitis labrusca and 'others' was Phyllostachys pubescens. 7. As the fundament of the results of above the optimum selecting of woody landscape plants according to native species of trees was 29 families, 58 species. on the basis of 30 points, 28 points was 8 species Ginkgo biloba, Ulmus davidiana var. japonica, Parthenocissus tricuspidata, Elaeagnus umbellata, Fraxinus rhynchophylla, Weigela subsessilis, Koelreuteria paniculata, Lonicera japonica, 26 points was 27 species Thuja orientalis, Zelk ova serrata, Euonymus japonica etc., and 24 points was 23 species Populus tomen tiglandulosa, Juglans sinensis, Sophora japonica etc..

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.48-48
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• 2017

The objectives of this study were to determine the dominance frequency of plant species between spring and summer, to provide useful information toward the conservation to increasing production cattle feed in grazing area in Hiroshima, Japan. The frequency of dominant plant species can adapt in the spring and summer, that consist of Paspalum dilatatum (spring 69.32% and summer 78.98%), Paspalum notatum (spring 47.73% and summer 98.30%), Trifolium repens (spring 73.86% and summer 81.25%). The observed plant species also influenced some productivity, which consists of plant height (spring 16.64 cm and summer 21.55 cm), vegetation cover rates (spring 77.18% and summer 81.36%, chlorophyll content (spring 41.72 mg/g Fw and summer 36.28 mg/g Fw), diversity index (spring 0.94 and summer 0.80), evenness index (spring 0.93 and summer 0.67), and species numbers (spring 32.0 and summer 21.0). It is proposed that Paspalum dilatatum, Paspalum notatum, and Trifolium repens, can be used to increase productivity of plant species as cattle feeds.