• Korean Journal of Weed Science
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• v.31 no.1
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• pp.89-95
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• 2011

In present study we focused on the weed occurrence and diversity in rice field according to methods of weed control. Experiments comprised of no herbicide treatment (NHT), herbicide treatment (HT) and golden apple snail treatment (GAST) within the three months (July to September) of growing rice. According to results, five to seven different weed species were found in NHT, while two to four different weed species were found in HT and GAST. Monochoria vaginalis was dominant species during growing period in NHT and HT while Lemna paucicostata was the dominant in July but Persicaria hydropiper was dominant for August and September. Simpson's dominance index was highest in GAST(0.96) compared with other treatments (NHT 0.27 and HT : 0.51). The similarity coefficient was 50.31%, 4.65% and 0.38% for NHT versus HT, NHT versus GAST and HT versus GAST, respectively. In conclusion, the weed species diversity, dominance and similarity coefficient were varied in different weed control methods of rice growing.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.70-80
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• 2019

Ichthyofauna and community structure of fish were studied for two fisheries resource reserves, Chuncheon reservoir and Andong reservoir from 2017 to 2018. Fish were sampled 8 times at each reservoir. In Chuncheon reservoir, total number of fish sampled was 1,197 representing 34 species and 13 families. Dominant species and sub-dominant species were Lepomis macrochirus (23.2%) and Zacco platypus (17.4%), respectively. In Andong reservoir, total number of fish sampled was 1,393 representing 24 species and 9 families. Dominant species and sub-dominant species were L. macrochirus (15.7%) and Carassius carassius (15.2%), respectively. The diversity index of two sampling site increased compared to previous investigation. The evenness index was not changed much in Andong reservoir but increased in Chuncheon reservoir. Ichthyofauna and community structure of fish at sampling sites in both reservoirs maintained stable except high proportion of exotics species with needed to be reduced by consistent effort. For better fish population in these communities, however, various efforts such as seed stocking and installment of artificial spawning ground should be provided to these reservoirs.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.160-169
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• 2019

The migration status of waterbirds inhabiting the 10 coastal wetlands in the south and west coasts (Jangbongdo, Muuido, Daecheoncheon estuary, Seocheon tidal flat, Yubudo, Gomso bay, Hauido, Jeungdo, Doam bay, Gangjin bay) was examined from May 2008 to March 2013. For the most dominant taxonomical group, shorebirds accounted for 37.5% of the number of species and 67.1% of the total population, followed in the order of dabbling ducks, herons, and seagulls. The dominate species were Calidris alpina, Larus crassirostris, Limosa lapponica, Charadrius alexandrinus, and Calidris tenuirostris. Shorebirds were observed most at Seocheon Tidal Flats and Yubudo Island, and dabbling ducks were found most in Doam Bay. Diving ducks were observed most at Gangjin Bay and seagulls were seen most frequently at Seocheon Tidal Flats. The ten coastal wetlands of the western and southern coasts were divided into three groups according to the similarity index of waterbirds (Ro). Group 1 was the area where dabbling ducks and diving ducks were dominant, group 2 was the area where shorebirds were dominant, and group 3 was the area where seagulls were dominant. It was evident that there were differences in species composition depending on the regional environments.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.1
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• pp.30-37
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• 2004

This study investigated the structural characteristics of Taxus cuspidata communities on Mt. Hambaek. The vegetation consisted of 9 species in the T$_1$(tree) layer, 35 species in the T$_2$(subtall tree) layer, 28 species in the S(shrub) layer, and 69 species in the H(herb) layer. The dominant species of the T$_1$ layer was Taxus cuspidata and that of the T$_2$ layer was Acer tschonoskii var, rubripes. The dominant species of the S layer was Tripterygium regelii, and the dominant species of the H layer was Pseudostellaria palibiniana. The diameter distribution of the dominant five species in the T$_1$ and T$_2$ layers indicates that these Taxus cuspidata forests may be gradually dominated by Quercus mangolica and by Tripterygium regelii. The composition of biological type was Ph-D$_1$-R$_{5}$-e.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.89-98
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• 2020

PURPOSE: This study investigated the effects of unilateral static stretching on the flexibility and symmetry of the lower leg, and temporal gait variables in gait asymmetry people. METHODS: Twenty gait asymmetry people were divided into a unilateral static stretching group (USG, n = 10) and control group (CON, n = 10). The USG performed unilateral static stretching for 60 minutes, three times a week, and eight weeks. The flexibility of the lower leg (SR), and symmetry (BR), and temporal gait variables (Step length; SL, gait speed; GS) were measured before, after four and eight weeks of unilateral static stretching. Moreover, SI (symmetry index; SI) was calculated from the measured SL value. Statistical analyses were conducted using one-way ANOVA and two-way ANOVA with repeated measures, a paired t-test, and multiple comparisons according to Scheffe. RESULTS: SR and BR in the dominant and non-dominant side, and GS were increased significantly at USG after eight-weeks compared to before unilateral static stretching (p < .05). The difference in BR in the dominant and non-dominant side, and step length (SI) decreased significantly at USG after eight-weeks compared to before unilateral static stretching (p < .05). CONCLUSION: Unilateral static stretching improves the flexibility and symmetry of the lower leg, and temporal gait variables in gait asymmetry people.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.94-104
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• 2020

An ecological study for species composition and abundance of the fish assemblages in the coastal waters of Gujora and Mangchi of Geoje, Korea was conducted using monthly larval collection by an RN80 net from June, 2018 to May, 2019. A total of the 5 Orders, 15 Families, 21 species were collected. The dominant species were Ammodytes japonicus and Engraulis japonicas. Gobiidae was the most dominant species in June, Spratelloides gracilis in July, Chelidonichthys sp. in August, Gobiidae in September, Repomucenus beniteguri in October, Sebastiscus marmoratus in November, Sebastiscus marmoratus and Hexagrammos otakii in December of 2018, Pleuronectes yokohamae in January, Ammodytes japonicus in Febraury, Engraulis japonicus in March, Sebastes sp. and Gobiidae in April and Engraulis japonicus in May of 2019. The highest number of species and individuals were found in July and the smallest in August. Thus, the diversity index was the highest in July and the lowest in August. As a result of the similarity by month was divided into Group I in January and February and Group II in April, June and September. The most dominant species in the Group I were the Ammodytes japonicus and Sebastes inermis, and the most dominant species in the Group II was Gobiidae.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.511-516
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• 2013

Objective: The objective of this study is designing an optimal hand tool through maximum grip force study accordance to the hand grip span. Background: In order to prevent musculoskeletal diseases, studies on hand tool design are proceeding based on grip strength, finger force, and contribution of individual finger force on total grip strength. However, experimental apparatus using a tool that is actually used in work place was almost non-existent. Method: 19 males were participated in an experiment. Using the load cell inserted real plier, finger force, grip strength, and subjective discomfort rate of both hands (dominant and non-dominant) were measured in 5 different hand grip span(45mm, 50mm, 60mm, 70mm, and 80mm). Results: There was significant difference(p<0.001) of total grip strength, individual finger force and subjective discomfort rating according to various hand grip span(45, 50, 60, 70, and 80mm). Also, statistically significant different(p<0.001) was shown between the dominant hand and non-dominant hand. In addition, individual finger force in maximum grip was in order of middle finger, ring finger, index finger, and little finger. Conclusion: Optimal grip span of pliers that exerting maximum grip strength is 50~60mm. Application: This finding is expected to be used for designing proper pliers.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.185-199
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• 2023

This study aimed to predict the effects of water ecology on the supply of hydrothermal energy to model a housing complex in Eco Delta Smart Village in Busan. Based on the results, engineering measures were recommended to minimize problems due to possible temperature variations on the supply of hydrothermal energy from the river. The current distribution of fish, benthic macroinvertebrates, and phytoplankton in the Pyeonggang Stream was monitored to determine their effects on water ecology. In the research area, five species and three families of fish were observed. The dominant species was Lepomis macrochirus, and the subdominant species was Carassius auratus. Twenty-five species and 21 families of benthic macroinvertebrates were found. The distribution of aquatic insects was poor in this area. The dominant species were Chironomidae sp., Lymnaea auricularia, Appasus japonicus, and Caridina denticulata denticulata in February, May, July, and October. Dominant phytoplankton were Aulacoseira ambigua and Nitzschia palea in February and May. Microcystis sp. was dominant in July and October. The health of the ecology the Pyeonggang Stream was assessed as D (bad) according to the benthic macroinvertebrate index (BMI). Shifts in the location of the discharge point 150 m downstream from intake points and discharge through embedded rock layer after adding equal amounts of stream water as was taken at the beginning were suggested to minimize water temperature variations due to the application of hydrothermal energy. When the scenario (i.e., quantity of water intake and dilution water, 1,600 m³/d and water temp. difference ±5 ℃) was realized, variations in water temperature were assessed at -0.19 ℃ and 0.59 ℃ during cooling and heating, respectively, at a point 10 m downstream. Water temperatures recorded at -0.20 ℃ and 0.68 ℃ during cooling and heating, respectively, at a point 10 m upstream. All stream water temperatures after the application of hydrothermal energy recovered within 24 hours. Future work on the long-term monitoring of ecosystems is suggested, particularly to analyze the influence of the water environment on hydrothermal energy supply operations.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.235-243
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• 2007

Macrobenthos were collected in each season by SCUBA diving to investigate the benthic faunal assemblages in the coastal water of Chagwido from September 2004 to August 2005. A total of 201 macrobenthos identified, 74 species (37.2%) of Mollusca were found; 43 species of Arthropoda (19.2%); 34 species of Cnidaria (16.7%) and others including 18 species of Porifera (9.8%). Mean density and biomass were estimated to be 455 individual/$m^2$ and 15,565.0 $g/m^2$, respectively. Whereas annelids was predominant in biomass (1,558.8 g), gastropods were the most dominant faunal group in terms of abundance (5,391 individuals) and the number of species. The dominant species were Trochus sacellus, Batillus cornutus, Pagurus gracilipes, and Cantharus cecillei. The seasonal variation of the number of species and individual Mollusca and Arthropoda was observed. There was a slow increase in spring, the peak in summer, and a slow decrease in autumn and winter. The dominance index was the highest in Gosan and lowest in Yongdang. The biodiversity indice (H') were 1.760-3.497 in each station. Mean biodiversity index was 2.858 (H'). The diversity index, the eveness index (E'), and the dominance index (R) were 3.218-3.743, 0.648-0.720, 17.690-22.826, respectively, in each station.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.293-301
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• 2014

15 artificial ponds in Seoul have been examined to find out the characteristics of Odonata community according to age and size of pond. We found 6 Families 36 Species of Odonata community, and Libellulidae was the most frequent and 19 Species were observed among Libellulidae. Considering relative importance with frequency of appearance and density, Ischnura asiatica and Orthetrum albistylum was the most frequent. Also, 16 Species including Lestes temporaris, Sympetrum parvulum, and Anax nigrofasciatus were relatively rare. The result of dominant species tells that Ischnura asiatica in 1 ~ 3 year old ponds, Pantala flavescens-Orthetrum albistylum-Crocothemis servilia mariannae in order of mention in 4 ~ 6 year old ponds, Platycnemis phyllopoda-Ischnura asiatica in order of mention in 10 or more year old ponds are the dominant species. Species diversity index regarding age of pond has been researched, and species diversity index in 10 year old pond was higher than that of in 1 ~ 3 year old pond. Having done the analysis of variance for types of spawn, there are many species Endophytic egg-layers and pasting in mud or sand in 10 year old artificial ponds. The wider ponds get, the higher species diversity index gets. And, we suggest that desirable size for making artificial ponds to increase the species diversity index of Odonata is $100{\sim}300m^2$.