• Journal of Environmental Science International
• /
• v.27 no.11
• /
• pp.1007-1021
• /
• 2018

Community dynamics of benthic macroinvertebrates and biological evaluation of water quality were investigated at Gigyecheon of Pohang and Gyeongju, Korea. The survey was carried out at 8 sites from May to October, 2017. As a result, total of 104 species under 54 families, 15 orders, 8 classes in 4 phyla with 5,052 individuals were revealed. The number of species was the most abundantly identified in aquatic insects, 76 species under 34 families, 6 orders. Among them, the order Odonata was the most abundant taxon as 21 species(20.2%). The most abundant individuals were collected in the phylum Mollusca as 1,453 individuals(28.8%). Various species appeared dominantly at each site by season, and the most dominant species was Caridina denticulata denticulata belonging to the class Malacostraca with 0.08 of dominance index. According to the results of community structure analyses, the diversity and richness indices were the highest at site II, the evenness index was the highest at site I, and the dominance index was the highest at site IV. The number of species and individuals of gathering collectors were the highest among functional feeding groups. Those of sprawlers were the highest among habitat orientation groups. The ESB showed a tendency to change according to season and site, and it was the highest in May at most surveyed sites. The KSI was also somewhat fluctuated according to season and site. From these indices, average biological water quality was evaluated as class II.

• Journal of Environmental Science International
• /
• v.32 no.5
• /
• pp.395-401
• /
• 2023

In this study, 12 environmental factors were used to evaluate the potential habitat of Pteromys volans living around some development areas. The analyzed value ranged from 0 to 20.1, and the area with a score of 10 or less was analyzed to have a low possibility of inhabiting Pteromys volans. To verify the analyzed results, a field survey was conducted on areas with 10 or more scores, and traces of habitat of Pteromys volans were confirmed in areas with 16 or more scores. All the areas with an evaluation score of 16 or higher showed high crown density and age class. However, despite the high crown density and age class, the evaluation score in some areas was low owing to the influence of other environmental factors. Therefore, in evaluating Pteromys volans habitats, it is necessary to apply various and complex criteria suitable for field conditions rather than applying uniform and fragmentary environmental factors only.

• Journal of Engineering Education Research
• /
• v.26 no.2
• /
• pp.45-53
• /
• 2023

This study conducted and evaluated the PBL-based team activity classes in contact and untact learning. Appropriate subject (Engineering communication) was also selected and evaluation methods were improved. In the qualitative evaluation results, in contact learning, similar score ranges were formed for each task, and the variability of scores for each task was not large. In untact learning, the difference in scores for each task was rather large, and the variability of scores for each task was large, indicating a large difference between teams that performed well and teams that did not. In the quantitative evaluation, contact learning showed a little low grades, but untact learning showed relatively high grades, but there were limitations in showing the conclusion that the untact learning effect was very good. As a result of the survey, there were more positive responses to the degree of understanding of the class conducted online, the degree of help to improve competence, and the team activity. However, if untact learning continues, it was analyzed that it is necessary to prepare appropriate measures to enhance learning effects and efficiently conduct team activities.

• The International Journal of Costume Culture
• /
• v.9 no.2
• /
• pp.104-112
• /
• 2006

The studies on impression formation usually have focused on the effect of certain appearance features which elevates perceptual evaluation. This study tried to find out whether there is a consensus on impression formation between the perceived person and the perceiver and if the gender is any significant variable to cast any difference on the impression evaluation. Seven photos of voluntary students in ppt file were projected to 143 students attending a university psychology class and were subjected to a impression evaluation questionnaire consisting of 28 adjective scales. The analysis of result revealed: 1) There was a significant difference between the impression evaluation scores of the perceivers and the perceived; the self evaluation of the perceived person was higher than the perceivers' evaluation. 2) There was also a significant evaluation score difference between the genders of the perceivers; the female perceivers rated the stimuli higher than the male perceivers. There was no interaction effect between the genders of the perceivers and the perceived.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.5
• /
• pp.29-38
• /
• 2013

The G-class cement is commonly used in practice for geothermal well cementing in order to protect a steel casing that is designed to transport hot water/steam from deep subsurface to ground surface during operating a geothermal power plant. In order to maintain optimal performance of geothermal wells, physical properties of the cementing material should be satisfactory. In this paper, relevant factors (i.e., groutability, uniaxial compression strength, thermal conductivity and free fluid content) of the G-class cement were experimentally examined with consideration of various water-cement (w/c) ratios. Important findings through the experiments herein are as follows. (1) Groutability of the G-class cement increases by adding a small dose of retarder. (2) There would be a structural defect caused when the w/c ratio is kept higher in order to secure groutability. (3) Thermal conductivity of the G-class cement is small enough to prevent heat loss from hot steam or water to the outer ground formation during generating electricity. (4) The G-class cement does not form free water channel in cementing a geothermal well. (5) The Phenolphthalein indicator is applicable to the distinction of the G-class cement from the drilling mud.

• 대한공업교육학회지
• /
• v.37 no.2
• /
• pp.147-160
• /
• 2012

The purpose of this study was to examine the effects on the academic achievement and learning satisfaction according to the presentation method of the multimedia materials for 'transportation technology' units of technology home economics subject. The subjects were assigned in third conditions; Text type explanation class, multimedia class and multimedia video class with narration. The data of six evaluation questions obtained from the survey of 93 high school girl were analyzed using SPSS program. The results of the study were as follows : First, in the learning satisfaction average level(M) of the students' overall responses to the questions, multimedia teaching learning class(experimental group 1) is the first(M=4.14), multimedia video class with narration(experimental group 2) is the second(M=3.16), and instructor-led class(control group) is the third (M=2.63). Therefore, the teaching learning multimedia class(experimental group 1) was most effective. Second, looking at the correlations between the students' responses to the questions, in an interesting class, the students have a retentive memory and comprehension, but a lower concentration can not a retentive memory. Third, multimedia teaching learning class(experimental group 1) has the best degree at the level of academic achievement, but instructor-led class(control group) and multimedia video class with narration(experimental group 2) have similar degree in the second place. To increase academic achievement, an instructor-led class is important to arouse interest and a multimedia video class with narration is required ways to improve level of concentration.

• Journal of Korean Society of Transportation
• /
• v.17 no.4
• /
• pp.85-97
• /
• 1999

The Purpose of this Paper is the development of the day-to-day dynamic combined model on the evaluation of traveller's traffic information for multi-mode and multi-class environments. Information is assumed to be provided for multi-mode such as bus and automobile. and multi-class such as a driver with and without route guidance equipment when they depart for their trips. The information provision strategies have been developed in the base of user equilibrium, system optimum and in between them. The Sioux Falls network is used for the evaluation of the model and information provision strategies. In the numerical analysis, a Braess' paradox for the information provision, which is the increase of travel time even though the number of information usage level and user are increased, has been occurred so that these kinds of information strategies should be implemented with special care.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.4
• /
• pp.108-116
• /
• 2018

A firing test of the 75 tonf-class liquid rocket engine to be used as the first and second stage engines of the KSLV-II was carried out at the rocket engine test facility(RETF). Since this engine uses liquid oxygen as the oxidizer, which is a cryogenic fluid, it is essential that the chill down of the supply pipe line and engine proceed for the firing test; thus, the given inlet requirements must be met. Moreover, it is important to understand the chill down characteristics of the facility and the engine and the amount of liquid oxygen consumed in the chill down process for efficient test operation in the future. In this paper, chill down characteristics of the supply pipe and the engine were evaluated through the investigation of the chill down process of the 75 tonf-class liquid rocket engine at each stage before and after run tank pressurization. In addition, the amount of liquid oxygen consumed was also evaluated.

• Journal of Biomedical Engineering Research
• /
• v.44 no.1
• /
• pp.1-10
• /
• 2023

With the announcement of MEDICAL DEVICE REGULATION 2017/745 (MDR) on April 5 2017, medical device manufacturers shall apply ISO 14971:2019 (3^rd) revised in December 2019. However, there is not much related information and guidance available to medical device manufacturers, especially single use medical device. Risk management process basically follow 5 steps which are Risk Analysis, Risk Evaluation, Risk Control, Evaluation of overall residual risk and post-production activities. The purpose of this study is to provide a guidance of from risk analysis with Failure Mode and Effects Analysis (FMEA) table to overall residual risk evaluation for the single use medical device and to reflect it in a Periodic Safety Update Reports (PSUR) to satisfy with MDR requirements with single use medical device which are widely used and manufactured FDA class 2 or CE class IIb as examples. For this study, single use medical device manufacturer can adopt ISO 14971:2019 in accordance with MDR requirements and it can be extended to the PSUR. But there are still limitations to adopt to the all-single use medical device especially high class, private device and implantable device. So, Competent Authority (CA) shall publish more guidance for the single use medical device.

• The Journal of the Korea Contents Association
• /
• v.8 no.12
• /
• pp.449-456
• /
• 2008

The purpose of this study was to study the student cognition toward the subject of physical education and toward the method of teaching in the class. For the statistical measurement, the population has been chosen as the fifth and sixth grade 319 students(160 male; 159 female) from four different elementary schools in Seoul, Korea. In terms of the teaching method and management of students, the results show that they agree with controlled participation in class and appreciate teachers ability such as explanation, skill demonstration, knowledge, evaluation, maintaining order and participating class. However, there were no statistical difference male and female except for teacher's explanation. This study clearly indicates that the students want more affirmative and cooperative class environment and they expect to be evaluated not only by skill itself, but also by class participation and activity in their physical education class. The cognition and preference toward the class between male and female students did not show any difference in this study. After all, Teachers need to have more understanding, more compassion and more sensitivity towards their elementary students for interesting, effective and affirmative class.