• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.177-188
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• 2019

The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.

• Journal of the Korean Society of Earth Science Education
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• v.11 no.3
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• pp.193-202
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• 2018

The purpose of this study was to examine the effects of creative product performance on scientific attitude, scientific self efficacy and creative problem solving ability of science-gifted elementary students. The subjects of the study were 20 students who were enrolled in science-gifted class of G elementary school. 8 period lessons of the creative product performance were given to the students after simulated creative product performance lessons. Pre and post tests were done before and after executing lessons to assess the change of students' scientific attitude, scientific self efficacy and creative problem solving ability. The findings and results of this study can be summarized as follows: First, creative product performance had meaningful effect in improving scientific attitude of science-gifted students. Second, creative product performance had meaningful effect in improving scientific self efficacy of science-gifted students. Third, creative product performance had meaningful effect in improving creative problem solving ability of science-gifted students. From questionnaire interview, we could know that subject students had difficulties in carrying out the performance at first but after the performance they came to have favorable impression and high satisfaction level about the performance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.433-452
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• 2019

This study deals with shotcrete reinforcing performance according to the amount of synthetic fiber (PP fiber) and proper evaluation method. The shotcrete compressive strength, flexural strength and flexural toughness were tested by setting the mixing amounts of steel fiber ($37.0kg/m^3$) and synthetic fiber (PP fiber) as parameters ($5.0kg/m^3$, $7.0kg/m^3$ and $9.0kg/m^3$). Particularly, circular panel flexural toughness test (Road and Traffic Authority, RTA) was performed to evaluate the shotcrete energy absorption capacity. As a result, the compressive strength and the bending strength of the steel fiber reinforced shotcrete were large, but the flexural toughness of the synthetic fibe (PP fiber) reinforced shotcrete was large. Therefore, synthetic fiber (PP fiber) reinforced shotcrete is considered to have a reinforcing effect comparable to that of steel fiber reinforced shotcrete. Analysis of the relationship between the flexural toughness and the energy absorption capacity of synthetic fiber (PP fiber) reinforced shotcrete revealed that the energy absorbing ability is exhibited at a flexural toughness lower than the allowable standard (3.0 MPa). (Class A: 2.55 MPa = 202J, Class B: 2.72 MPa = 282J, Class C: 3.07 MPa = 403J). As a result of this study, it can be concluded that the actual shotcrete support performance can be evaluated by evaluating the support performance of the shotcrete measured at less than the allowable standard (3.0 MPa) at the actual tunnel site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.406-413
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• 2019

This study is a descriptive study to investigate the relationship between communication competency, interpersonal relationship ability and self-management competency of nursing college students in graduation year. Data collection was conducted from November 1, 2016, to December 9, 2016, in 135 students of 4th grade nursing students in M and K areas. The collected data were analyzed using the SPSS WIN 21.0 program. The result of this study showed that average degree of communication competency was $3.55{\pm}.34$(5 point-scale), interpersonal relationship ability was $3.79{\pm}.50$(5 point-scale), self-management competency was $3.67{\pm}.47$(5 point-scale). The communication competency of nursing college students in graduation year showed a significant positive correlation with interpersonal relationship ability(r=.65, p<.001) and self-management competency(r=.70, p<.001). In addition, interpersonal relationship ability also showed a significant positive correlation(r=.69, p<.001) with self-management competency. Therefore, this study proposes an intervention program to help nursing graduates maintain efficient interpersonal relationships through smooth communication with patients, guardians and staff at the job site after graduation by building their own management competency in their academic life.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.145-150
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• 2019

The purpose of this study was to investigate farmers' field survey to improve animal welfare certification standards and to obtain basic data on the animal welfare level for certified farmers to develop evaluation methods of animal welfare level suitable for domestic farm environment. The subjects of the study were selected 10 animal welfare laying certified farmhouses. The farming certified farming facility survey collected breeding form, head, feed and drink space, breeding density, length and shape of perch. Animal welfare was assessed by the presence of sand bath, spawning, enrichment measures, free range, feathers pecking. The results of the study showed that most the certified animal welfare laying hens complied with the certification standards. All the farms were providing the nest box, but there were farms with more than 20% of the spawning rate. The perches were provided in sufficient length, but only three of ten farms were using rounded perches. Feather damage has been identified in most survey farms, which is likely to be due to feather damage caused by roosters producing both fertilized eggs. In this study, 10 farm households were surveyed. It was not possible to represent the whole certified farmhouse. Therefore, it should be analyzed thoroughly to evaluate the level of animal welfare.

• Journal of the Korean Geotechnical Society
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• v.35 no.7
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• pp.29-39
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• 2019

Load distributive compression anchors distribute the compressive stress in the grout and increase the pull-out capacity of the anchor by using multiple anchor bodies. In this anchor type, the spacing between the anchor bodies has a large influence on the stress in the grout. However, there are few researches about the spacing and there are no design standards. Therefore, the effect of the anchor body spacing on the grout stress was analyzed by performing finite element analyses. First, the applicability of the numerical modeling was verified by comparing with field test results of a compression anchor. Then, the parametric study was performed varying soil type, anchor body spacing, and load magnitude. The analysis results showed that the maximum compressive stress in the grout increased at the narrower spacing and the tensile stress developed at the wider spacing. Therefore, the optimum spacing was defined as the spacing, which prevents the superposition of compressive stresses and minimize the tensile stress. Finally, the optimum spacing was proposed according to the soil type and the load magnitude.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.125-133
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• 2019

A microscope is the fundamental research and diagnostic apparatus for clinical investigation of signaling transduction, morphological changes and physiological tracking of cells and intact tissues from patients in the biomedical laboratory science. Proper use, care and maintenance of microscope with comprehensive understanding in mechanism are fully requested for reliable image data and accurate interpretation for diagnosis in the clinical laboratory. The standard operating procedure (SOP) for light microscopes includes performance procedure, brief information of all mechanical parts of microscopes with systematic troubleshooting mechanism depending on the laboratory capacity. Maintenance program encompasses cleaning objective, ocular lenses and inner optics; replacement and calibration of light source; XY sample stage management; point spread function (PSF) measurement for confocal laser scanning microscope (CLSM); quality control (QC) program in fluorescent microscopy; and systematic troubleshooting. Laser safety is one of the concern for medical technologists engaged in CLSM laboratory. Laser safety guideline based on the laser classification and risk level, and advisory lab wear for CLSM users are also expatiated in this overview. Since acquired image data presents a wide range of information at the moment of acquisition, well-maintained microscopes with proper microscopic maintenance program are impulsive for its interpretation and diagnosis in the clinical laboratory.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.343-346
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• 2019

This letter describes a development of satellite-based forest withering index for detection of fire burn area and its application to the Goseong-Sokcho and Gangneung-Donghae wildfires in April 4, 2019. Withered forest has very different spectral characteristics from healthy forest. In particular, a false color composite of R-NIR-G represents such difference very clearly. Using Sentinel-2 images with the forest withering index, we derived the area burned by the wildfires: approximately 701.16 ha for Goseong-Sokcho and approximately 710.60 ha for Gangneung-Donghae, although official record will be announced by the Korean government later.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.87-92
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• 2019

In this paper, we have verified a low-voltage EM(elasto-magnetic) sensing technique for tensile force management of PSC(prestressed concrete) internal tendon in order to apply the technique to actual construction sites where stable power supply is difficult. From observation of past domestic and overseas PSC structural accident cases, it was found that PS tension is very important to maintain structural stability. In this paper, we have tried to measure the tensile force from a magnetic hysteresis curve through EM sensors according to voltage value by using relation between magnetostriction and stress of ferromagnetic material based on elastic-magnetic theory. For this purpose, EM sensor of double cylindrical coil type was fabricated and tensile force test equipment for PS tendon using hydraulic tensioning device was constructed. The experiment was conducted to confirm relationship between changes of permeability and tensile force from the measurement results of the maximum / minimum voltage amount. The change of magnetic hysteresis curve with magnitude of tensile force was also measured by reducing amount of voltage step by step. As a result, the slope of estimation equation in accordance with magnitude of magnetic field decreases with the voltage reduction. But it was confirmed a similar pattern of change of magnetic permeability for the magnetic hysteresis loop. So, in this study, it is considered that it is possible to manage the tensions of PSC internal tendon using EM sensing technique in low-voltage state.

• 한국체육학회지인문사회과학편
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• v.56 no.1
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• pp.53-65
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• 2017

This study was conducted to examine how marine sport event visitors' satisfactions and city image effect on revisit and recommendation. To do this, we analyzed the socio-statistical characteristics of spectators, and examined the influence relationship among city image, satisfaction, revisit and recommendation intention. The results were as follows: First, 'family and relatives' as the companions of spectators of yacht competition were the most, and the route of acquiring the competition information was 'the other', in other words, that most of the respondents learned directly in the field, and 'car' as transportation means was the most. In addition, "local tourism" as watching purposes was the most and 'the day' as the period of stay was the most. Second, the image and satisfaction of spectators of yacht competition showed significant influence on revisit and recommendation intention. Specifically, program satisfaction and program agent satisfaction, which are a sub-factors of satisfaction, have a significant positive effect on revisit and recommendation intention. Through these research results, we were able to confirm inadequacy(lack of attractiveness, connections and public relations) of this event, and see what parts should be improved in order to be born again a sustainable event.