• Journal of Environmental Science International
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• v.18 no.6
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• pp.633-644
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• 2009

The vascular plants in the Gyeryongsan National Park were listed 227 taxa; 71 families, 148 genera, 196 species, 1 subspecies, 26 varieties and 4 forms, Among them, trees and herbs were 103 taxa (45.4%), 124 taxa (54.6%), respectively. The rare plants were identified 6 taxa such as Paeonia obovata (Legal protection species), Viola albida, Acanthopanax chiisanensis, Lilium distichum, Lilium callosum and Goodyera schlechtendaliana by the Korea Forest Service. Based on the list of Korean endemic plants, 8 taxa were recorded; Cephalotaxus koreana, Pseudostellaria multiflora, Thalictrum uchiyamai, Indigofera koreana, Acanthopanax chiisanensis, Asperula lasiantha, Weigela subsessilis and Carex okamotoi. Based on the list of approved for delivering overseas of plants, 6 taxa were recorded; Viola albida, Acanthopanax chiisanensis, Asperula lasiantha, Carex okamotoi, Lilium distichum and Lilium callosum. Specific plant species by floral region were total 21 taxa (9.3%); Paeonia obovata in class V, 5 taxa (Betula davurica, Acer palmatum, Asperula lasiantha, Lonicera subhispida, Phaenosperma globosa) in class III, 4 taxa (Viola orientalis, Acanthopanax chiisanensis, Ostericum melanotilingia, Lilium distichum) in class II and 11 taxa (Cephalotaxus koreana, Betula schmidtii, Quercus variabilis, Aphananthe aspera, Ilex macropoda, Meliosma oldhamii, Tilia amurensis, Lilium callosum, Erythronium japonicum, Polygonatum inflatum, Hosta capitata) in class I. It is important that relationship between national and local government will be needed for preservation of natural environment of Gyeryongsan National Park. As well, a long time of monitering and systematical management counterplan will be required.

• Journal of Forest and Environmental Science
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• v.31 no.3
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• pp.164-176
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• 2015

Cyathea gigantea is a tree fern distributed throughout humid tropical regions of northeast India and other parts of the country. However, wild populations of this species are largely affected by various natural and anthropogenic activities. Therefore, an attempt was made to study the population structure and regeneration status of C. gigantea in and around greater Itanagar area of Papum Pare district, Arunachal Pradesh. Altogether 45 patches, ranging from 19.63 to $260m^2$ of area, were randomly sampled to study population structure and regeneration status of the species. Population study showed highest number of youngs in the height class of 0.50-0.75 m while, immatures were recorded highest in the height class of 2.0 to 2.5 m. Majority of the matures belonged to 6-9 m height class while it was recorded maximum in the diameter class of 10-15 cm. Average density of C. gigantea was $0.07individuals\;ha^{-1}$ which varied greatly among different patches with a range of 2 to 14. Significant correlations were found between patch size and density of youngs, immatures, matures and total density. Maximum concentration of youngs was observed in patch size $60-140m^2$, while for immatures, it was highest in patch size $20-160m^2$. Similarly, highest concentration of matures was observed in patch size $20-80m^2$ and $80-180m^2$. Population structure of the total population exhibited inverted pyramid shaped distribution. Population structure consisting of youngs, immatures, matures showed that around 60% patches lack of regenerating individuals which depict very poor natural regeneration of the species. Effective conservation strategies are therefore to be formulated to save C. gigantea from the threat of extinction in near future.

• Journal of Oral Medicine and Pain
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• v.24 no.1
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• pp.37-47
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• 1999

This study was performed to investigate the factors related to vibration of temporomandibular joint during mandibular opening movement. For this study, 144 patients with temporomandibular disorders were randomly selected. Angle's classification, lateral guidance pattern, range of maximal mouth opening, preferred chewing side, and affected side were investigated clinically. Mandibular torque rotational movement during opening was recorded with $BioEGN^{(R)}$ and vibration of temporomandibular joint during opening was recorded with $Sonopak^{(R)}$. After clinical diagnosis was made, visual analogue scale(VAS) was used for evaluation of clinical progress of the subject's chief complaints. The author calculated VAS treatment index(VAS Ti) from the record of VAS. The more VAS Ti was, the less remission of subjective symptom was, The data were analyzed with SAS/Stat program and the results of this study were as follows: 1. There were no significant difference in all the variables of joint vibration by age and sex. 2. Integral and peak amplitude in patients of Angle's class I were higher than those of class II or III patients. Integral in patients of group function was higher than that in patients of canine guidance or other types of lateral excursion. 3. As to Angle's classification or lateral guidance type, there were almost not significant difference between subgroup of same class or type and subgroup of different class or type on both sides. And there were also almost not difference between one side and the other side related to preferred chewing side or affected side. 4. Patients with disk displacement with reduction showed higher value of integral and peak amplitude than any other patients. 5. Joint vibration variables significantly correlated with VAS Ti of pain. with clinical range of mouth opening, and with ingredients of mandibular torque rotational movement.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.4
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• pp.13-23
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• 2006

The vascular plants of the studied area in the Mt. Bangjang was listed 422 taxa : 106 families, 299 genera, 372 species, 1 subspecies, 46 varieties and 3 forms. Based on the list of the rare plants by the Forest Research Institute, 5 taxa were recorded in the studied areas; Lilium distichum(Preservation priority order : No. 159), Tricyrtis dilatata (No. 97), Aristolochia contorta (No. 151), Prunus yedoensis (No. 110), Patrinia saniculaefolia (No. 122) and based on the list of Korean endemic plants, 9 taxa were recorded; Cephalotaxus koreana, Carex okamotoi, Populus tomentiglandulosa, Salix purpurea var. japonica, Prunus yedoensis, Forsythia koreana, Paulownia coreana, Weigela subsessilis, Patrinia saniculaefolia. Specific plant species by floral region were total 29 taxa; Prunus yedoensis in class V, 3 taxa(Acer palmatum, Asperula lasiantha, Lonicera subhispida ) in class III, 5 taxa(Lilium distichum, Potentilla dickinsii, Caryopteris incana, Patrinia saniculaefolia, Ligularia fischeri) in class II, 20 taxa(Ulmus parvifolia, Clematis patens, Aconitum jaluense, Ilex macropoda, Grewia biloba var. parviflora etc.) in class I. The naturalized plants in this site were 13 families, 31 genera, 36 species, 2 varieties, 38 taxa and naturalization rate was 9.0% of all 422 taxa vascular plants. Because of recent rapid increase of cars and people around here, analysis shows many naturalized plants and high naturalized ratio. And wild plants disturbing ecosystem like Ambrosia artemisiifolia var. elatior have been increasing. So, it needs continuing control and conservation measures on the plant ecosystem.

• Journal of Engineering Education Research
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• v.24 no.2
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• pp.20-28
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• 2021

In 2020, the COVID-19 pandemic has brought dramatic changes in the field of engineering education. Contrary to the traditional engineering education emphasis on content-oriented, design-based, hands-on, experimental, and field experience, most of engineering classes in 2020 had to be undertaken remotely online. However, it has not been explored how professors and students perceive about such a shift in engineering education. The aim of the current study was to investigate the perceptions of professors and students on online classes in engineering colleges during spring Semester 2020. Questionnaire data were collected from 100 professors and 4,152 students in the college of engineering. The results of this study were as following: Students were less satisfied with the online classes than professors. The online lecture method that students were most satisfied with was the recorded lecture. This is likely due to the fact that the recorded lectures can be repeated multiple times anytime, anywhere. Moreover, the experimental classes, which conventionally has more of an emphasis on the hands-on experience, also had to be conducted remotely, showing even lower satisfaction among students. Most of professors reported that the average hours they spent on preparing for online lecture increased compared to face-to-face class. Both professors and students preferred in-person exam as a desirable method of end-of-semester assessment for grading. The results of the current study have important implications for the improvement of online course environments. It is important for professors to design a structured class suitable for online education and understand the challenges students encounter during online classes. Also, professors should communicate more openly about their expectations and rubrics for class goals and assignments. Schools also needs to make effort to provide the support for the internet environment of students.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.293-302
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• 2013

The present study summarizes the occurrence, distribution and autecology of 12 taxa of the class Cyanophyceae collected from several swamps, reservoir and highland wetlands in South Korea from 2009 to 2012. A new species, Anabaena koreana sp. nov. and 11 taxa of blue-green algae newly recorded are described and illustrated. Anabaena koreana is similar to A. oumiana, A. spiroides and A. crassa in that the trichomes form regular coils. However, A. koreana is distinguished from these three species by the morphological characteristics of the vegetative cell, heterocyst, and akinet shape and size. This study considers 12 blue-green algal species, including a new species, Anabaena koreana sp. nov. and 11 species that are recorded for the first time in the Korean freshwater algal flora. Among them, the genus Nostochopsis Wood ex Bornet et Flahault 1886 had not previously been recorded in Korea.

• The korean journal of orthodontics
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• v.16 no.1
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• pp.107-118
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• 1986

This study was designed to investigate the variation of mandibular pattern and cranial base and their association in the craniofacial malocclusion. The material was the 165 cephalometric radiographs taken from craniofacial malocclusion. The sample was devided into two groups by age child group aged from 10 to 13 years and adult group aged over 18 years, and each group was devided into 3 types of malocclusion; class I, Class II div. 1 and Class III malocclusion. Child group consist of 35 samples and adult group consist of 20 samples in each malocclusion type. Various angular and linear measurements on the cephalometric radiographs were recorded and statistically analyzed. The results of the study were as follows; 1. The cranial base angle was largest in Class II div. 1 malocclusion and smallest in Class III malocclusion 2. The anterior cranial base length was largest in Class II div. 1 malocclusion but posterior cranial base length did not show statistical difference. 3. The mandibular body length of Class III malocclusion was larger than those of Class I and Class II div. 1 malocclusion in the adult group but did not shown difference in the child group. The ramus height of Class III malocclusion was larger than those of Class I and Class II div. 1 malocclusion in the child and adult group, but there were no difference between Class I and Class II div. 1 malocclusion. 4. The mandibular position was showed low correlation with the cranial base angele.

• Imaging Science in Dentistry
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• v.46 no.2
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• pp.117-125
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• 2016

Purpose: This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Materials and Methods: Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Results: Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. Conclusion: In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.30 no.1
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• pp.13-24
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• 1994

Purse seiner detects a fish school navigating in full speed with the aid of fish finder, sonar, helicopter, etc., and casts a net quickly to enclose the fish school in purse seine net according to the movement of the fish school, wind, and current. At this moment, if the time of casting a net, direction, speed, and turning circle are net suitable, it is unavoidable to lose fish school founded with hard efforts and we only consume our efforts of casting and hauling the net. Therefore, in order to enclose the fish school to enhance the amount of fish for each casting, the author investigated the type of ships equipped with purse seiners and examined maneuvering tests so that we provide some basic information to figure out the ability of steerage correctly. The results obtained are summarized as follows: 1. Block coefficients of pelagic tuna purse seiners with gross tonnage between 500 and 1500 tons are recorded between 0.50 and 0.55 which are greater than those of off shore purse seiners recorded as between 0.44 and 0.54 and less than those of various cargo ships recorded as between 0.56 and 0.84. 2. L/B, L/D, B/D, B/T, and T/D of the class of gross tonnage between 75 and 130 tons are respectively 4.49, 11.00, 2.45, 2.85 and 0.86 as their average and those of the class of between 500 and 1500 tons are 4.89, 10.53, 2.15, 2.73 and 0.75 respectively, which are quite different from those of various cargo ships recorded as 6.0~7.5, 11.0~12.0, 1.6~2.0, 2.2~2.8 and 0.65~0.75 respectively. 3. Rudder area ratio of purse seiners of the class of between 75 and 130 tons is 1/24~1/31 and that of the clase of between 500 and 1500 tons is 1/36~1/42 which is greater than that of various cargo ships recorded as 1.45~1.75. 4. On speed-length ratio of purse seiners. 111 Dong-a has the biggest value 2.94 the class of 130 tons has 2.52 the class of between 75 and 100 tons has 2.30~2.35 and the class of between 500 and 1500 tons has 1.99~2.05. 5. Turning circle of stern trawlers Pusan 404 and Haelim 3 are measured as below according to rudder angles 5$^{\circ}$, 15$^{\circ}$, 25$^{\circ}$ and 35$^{\circ}$ respectively. Advances are 11.3~13.6, 6.0~7.1, 3.6~4.8 and 2.5~3.5 times of LPP respectively. Tactial diameters are 15.2~18.6, 6.9~8.0, 4.2~4.9 and 2.9~3.5 times of LPP. Purse seiner 111 Dong-a with rudder angle 35$^{\circ}$ has a good yaw with quick responsibility since its advance is 2.2~2.3 times of LPP and since its tactial diameter is 2.0~2.1 times of LPP. 6. In full ahead going of purse seiner 111 Dong-a, it takes about 2 minutes and 10.6 times of LPP from the reverse turning its engine into full astern to the ship speed 0. In its full astern going, it takes about 1 minute and 5.1 times of LPP from the reverse turning its engine into full ahead to the ship speed 0. In its full ahead going, it takes about 2 minutes and 50 seconds and 12.3 times of LPP from stopping its engine to the dead slow ahead speed 3.2 knots.

• Earthquakes and Structures
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• v.13 no.1
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• pp.67-77
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• 2017

Oil storage tanks are vital life-line structures, suffered significant damages during past earthquakes. In this study, a numerical model for an unanchored vertical vaulted-type tank was established by ANSYS software, including the tank-liquid coupling, nonlinear uplift and slip effect between the tank bottom and foundation. Four actual earthquakes recorded at different soil sites were selected as input to study the dynamic characteristics of the tank by nonlinear time-history dynamic analysis, including the elephant-foot buckling, the liquid sloshing, the uplift and slip at the bottom. The results demonstrate that, obvious elephant-foot deformation and buckling failure occurred near the bottom of the tank wall under the seismic input of Class-I and Class-IV sites. The local buckling failure appeared at the location close to the elephant-foot because the axial compressive stress exceeded the allowable critical stress. Under the seismic input of Class-IV site, significant nonlinear uplift and slip occurred at the tank bottom. Large amplitude vertical sloshing with a long period occurred on the free surface of the liquid under the seismic wave record at Class-III site. The seismic properties of the storage tank were affected by site class and should be considered in the seismic design of large tanks. Effective measures should be taken to reduce the seismic response of storage tanks, and ensure the safety of tanks.