• 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.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.302-311
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• 2022

Sound barrier walls are one of the most effective alternatives for reducing environmental noise on roads and railways in the city center. The insertion loss of the sound barrier against road traffic noise is the sum of the sound transmission loss, sound absorption loss, and sound energy reduction due to the diffraction attenuation of the sound barrier. The sound transmission loss of the sound barrier is one of the important factors that determine the insertion loss of the sound barrier and is a basic indicator that determines the performance of the sound barrier. Nevertheless, there is not a separate standard in Korea for measuring the acoustic transmission loss of sound barrier panels. There are only a few conditions in KS F 4770 series that stipulates on the general material of sound barrier panels. This thesis examines the necessity of the acoustic transmission loss measurement and evaluation standards of sound barrier walls, and seeks a measurement method in a free sound field (anechoic chamber) sound receiving room considering the characteristics of sound barrier walls installed in external spaces, unlike indoor building materials. In addition, a single number evaluation method using a reference spectrum was proposed so that the sound insulation effect according to various installation places such as roadside or railroad side can be easily displayed.

• Korean Journal of Comparative Education
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• v.19 no.1
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• pp.25-58
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• 2009

This study aimed to establish a conceptual scheme of the quality of university and to develop a set of structured indicators for assessing the quality of university based on the result of comparative analysis of major approaches in foreign countries. Reviewing extensive literatures regarding the quality of higher education, a conceptual scheme of the quality of university, in which three representative approaches such as a goal-accomplishment approach, a customer-satisfaction approach, and a value-added approach were emphasized, was proposed and the quality of university was defined as a function of harmonization of input-process-output elements of universities. To develop indicators for assessing the quality of university, four types of approaches including university accreditation system, commercially-producted university ranking system, college student survey, and direct assessment of students' learning outcomes were reviewed. Finally thirteen sets of evaluation indicators out of six countries were comparatively analyzed. The analyses focused on the format, the content, and the primary concept of the quality in each instrument and a draft of the assessment indicators were structured. The draft of the assessment indicators were verified through a panel of professionals. The final indicators assessing the quality of university consist of three dimensions and seven areas. The input dimension comprised institutional goals, human resources, and physical resources. In the process dimension, curriculum and learning process areas were included. And, finally, the output dimension consists of educational outputs and research outputs. Based on the outcomes of the study, the recommendations were suggested for improving and utilizing the assessment indicators of the quality of university.

• Korea Trade Review
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• v.48 no.1
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• pp.215-241
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• 2023

As competition between ports intensifies, port efficiency has always been a hot topic in the port and shipping economy. Boosting regional and national economies by improving port efficiency and promoting sustainable development of ports is also a concern for port operators and local and national governments. In this situation, this study has the following objectives. First, using panel data from 2010 to 2017, the efficiency of 14 major inland ports along the Yangtze River was analyzed, and changes in port efficiency over time were examined. Second, 14 inland ports are divided into the middle, upper, and lower Yangtze River port groups to compare and review differences in efficiency levels of ports by basin. For the study, we applied a three-step DEA analysis method, which evaluated the pure relative efficiency of the port itself by removing the effects of environmental factors and statistical noise that could affect the efficiency evaluation and presented the results. As a result, it was confirmed that there was a clear difference in the efficiency value of the port between the first-stage and the third-stage efficiency evaluation result. In addition, the downstream ports showed relatively high efficiency compared to the middle and upstream ports.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.4
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• pp.365-384
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• 2024

The development of scanning technology is accelerating for safer and more efficient automated inspection than human-based inspection. Research on automatically detecting facility damage from images collected using computer vision technology is also increasing. The pixel size, quality, and quantity of an image can affect the performance of deep learning or image processing for automatic damage detection. This study is a basic to acquire high-quality raw image data and camera performance of a mobile tunnel scanning system for automatic detection of damage based on deep learning, and proposes a method to quantitatively evaluate image quality. A test chart was attached to a panel device capable of simulating a moving speed of 40 km/h, and an indoor test was performed using the international standard ISO 12233 method. Existing image quality evaluation methods were applied to evaluate the quality of images obtained in indoor experiments. It was determined that the shutter speed of the camera is closely related to the motion blur that occurs in the image. Modulation transfer function (MTF), one of the image quality evaluation method, can objectively evaluate image quality and was judged to be consistent with visual observation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.1
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• pp.47-53
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• 2014

Varietal difference of eating quality by milling degree was investigated for total nine rice varieties comprised of three varieties each as excellent, good, and normal according to sensory evaluation results of cooked rice. Nine varieties were analyzed for their physicochemical properties and for the sensory evaluation according to five different degree of milling(5.5~13.5% based on brown rice). Overall score obtained through sensory evaluation was found the best in the milling degree at 9.5% and 11.5%. The overall score by rice variety was categorized into type A that showed high score at milling degree 9.5%, type B at milling degree 11.5%, and similar type C at both milling degrees 9.5% and 11.5%. The best eating quality was observed in Ilmibyeo and Koshihikari having overall eating quality excellent at milling degree 9.5% and in Chucheongbyeo and Dongjinbyeo having overall eating quality good at milling degree 11.5%. While, Palgongbyeo and Nonghobyeo having eating quality normal showed the best eating quality at milling degree 9.5% and 11.5%. Correlation analysis between overall score and physicochemical properties and five sensory evaluation items by three types of rice showed that Mg content and stickiness of type A, protein content and taste of type B, and K content and appearance of type C were highly significant correlation on overall score by panel test. Therefore, Mg contents might have affected on the stickiness of cooked rice in type A, protein contents on the taste in type B, and K contents on the appearance in type C, respectively.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.55-60
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• 2008

Purpose: This study is to decide a quality control and calibration period of LCD display devices used for reading diagnostic images. Materias and Methods: The assessment test of 20 flat panel LCD color display devices used for reading diagnostic images were performed based on AAPM TG 18 protocol over the total six sessions at one month intervals from three months after primary calibration, in terms of geometric distortion, reflection test, luminance response evaluation, luminance uniformity, resolution, noise, veiling glare and chromaticity test. Results: The results of geometric distortion, reflection test, luminance uniformity, resolution, noise, veiling glare and chromaticity test were within the criteria recommended by AAPM TG 18, except for luminance response evaluation. In the measured luminance deviation of luminance response evaluation, 4(25%) of 20 display devices were passed a criterion from four months after calibration, and 11 (55%) were passed from eight months. Also in the contrast response of the luminance response evaluation, 1(5%) display device was passed a criterion from four months after calibration, and 3(15%) were passed from eight months. Conclusion: Considering the passing deviation after calibration, the time required and a manpower, the quality control and calibration period of LCD display devices used for reading diagnostic images should be a three months and six months after calibration.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.203-207
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• 2010

Purpose: Hepatitis B is infection caused by Hepatitis B virus (HBV). Currently, there are several methods, Kits and equipments for conducting Hepatitis B test. Due to ununiformed methods, it would cause some differences. To manage these differences, it needs process evaluating function of test system and reagent using particular standard substance. The aim of this study is to investigate tendency of RIA method's reagent used in Asan Medical Center through comparing several other test reagents using national standard substance. Materials and Methods: The standard substance in National Institute of Food and Drug Safety Evaluation's biology medicine consists of 5 things, 4 antigens and 1 antibody. We tested reagents using A, B company's Kits according to each test method. All tests are measured repeatedly to obtain accurate results. Results: Test result of "HBs Ag Mixed titer Performance panel" is obtained match rate compared S/CO unit standard with RIA method and EIA 3 reagents, CIA 2 reagents is that company A's reagent is 94.4% (17/18), 83.3% (15/18), B is 88.9% (16/18), 77.8% (14/18). Test result of "HBs Ag Low titer Performance panel" is obtain that EIA 2 reagents is shown 7 posive results, CIA 3 reagents is 11, and RIA method's company A's reagent is 3, B is 2 of 13 in low panel. "HBV surface antigen 86.76 IU/vial" tested dilution. A is obtain positive results to 600 times(0.14 IU/mL), B is 300 times (0.29 IU/mL). Case of "HBV human immunoglobulin 95.45 IU/vial", A is shown positive result to 10,000 times (9.5 mIU/mL) and B is 4,000 times (24 mIU/mL). Test result of "HBs Ag Working Standards 0.02~11.52 IU/mL" is shown that Company A's kit concentration level was 0.38IU/mL, company B was 2.23 IU/mL and higher level of concentration was positive results. Conclusion: When comparing various test reagents and RIA method according to National Standard substances for Hepatitis B test, we recognized that there were no significant trends between reagents. For hepatitis B virus antigen-antibody titers even in parts of the test up to 600 times the antigen, antibodies to 10,000 times the maximum positive results could be obtained. Therefore, we confirmed that results from Asan Medical Center are performed smoothly by reagents and system for hepatitis B virus test.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.500-506
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• 1994

For comparison of beef quality, four kinds of beef (Korean native cattle beef, dairy cattle beef, imported beef, cross-bred beef) were investigated through tenderness, juiciness and flavor related components measurement and organoleptic tests. Flavor related chemical components such as NPN, IMP, free fatty acid and free amino acids were analyzed, water holding capacity, contents of hydroxyproline and intramuscular fat were measured for evaluation of beef tenderness. Instron was also used for measuring beef tenderness as an objective method. Triangle test and descriptive analysis test were conducted for comparison and evaluation of preference of various beef samples. In hardness analysis using Instron, imported and cross-bred beefs had higher value than that of Korean native cattle or dairy cattle beef. Water holding capacity and pH of Korean cattle beef was higher than that of others. The intramuscular fat content of Korean cattle beef was highest, so it was expected juicier than other beef. In flavor related compound analysis, NPN content of Korean native cattle beef was the lowest, which shows it spent the least time among sample meats after slaughter. IMP, hypoxantine and inosine were most abundant in Korean native cattle beef. In free amino acids analysis showed that the proportion of basic acid and aromatic acid content of Korean native cattle beef was highest, whereas that of sulfur containing amino acid of imported beef was highest. TBA value of Korean native cattle beef was the lowest, and analysis of fatty acid composition revealed that the proportion of unsaturated fatty acid of Korean native cattle beef was higher than imported and dairy cattle beef, but similar to cross-bred beef. Organoleptic test was performed by triangle test and descriptive analysis. In triangle test, most panelist could distinguish Korea native cattle beef from imported beef and cross-bred beef, imported beef from cross-bred beef. In descriptive analysis which relys on subjective standards of panelists, there was no difference among beef in aroma, flavor and tenderness except juiciness. Even though contents of non volatile flavor compounds in Korean native cattle beef were higher than those of other beef samples, there were no significant differences in subjective panel test. The results showed that Korean consumers do not have common standards for beef quality evaluation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.674-680
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• 2005

The purposes of this study were to compare the effect of several reheating treatments (heating in the frying pan, convection oven and microwave oven) on sensory characteristics and to evaluate the safety during storage period of cook/chill Pajeon. The sensory evaluations were made on 5 sensory attributes by a 9-member panel using quantitative descriptive analysis (QDA). The fresh cooked Pajeon and the Pajeon reheated in the frying pan obtained a significantly (p<0.01) higher score in taste than the ones reheated in a convection oven and microwave oven. The reheated cook/chill Pajeon had a significantly (p<0.01) lower score in flavor than the freshed cooked one. Regardless of the reheating methods, sensory scores in texture of the Pajeon reheated at $v$ for 1 day were not different from that of fresh cooked one. However, the scores of the reheated ones in a convection oven and in a microwave oven decreased with storage time up to 5 days at $3^{\circ}C$. On the other hand, the Pajeon reheated in the frying pan, even after 3 days' storage at $3^{\circ}C$, was not found to be inferior to the freshed cook one in every quality attributes except flavor. Therefore, the reheating treatment in frying pan may be superior to those in a convection oven and a microwave oven. The safety of Pajeon was also evaluated by measuring total count, coliform count, psychrotrophic count, acid value and peroxide value during 5 days of storage periods at $4^{\circ}C$. Total counts of Pajeon was ranged from not detectable to $5.2\times10^2$ CFU/g. The coliform and psychrotroph were not detected at all experiments. The acid values were ranged from 1.90 to 4.03 mg of KOH/g of fat until 5 days at $4^{\circ}C$. And the peroxide values were ranged from 3.63 to 12.50 meq of peroxide/kg of fat until 5 days of storage period. Therefore, these results demonstrated that Pajeon is microbiologically and chemically safe during 5 days of storage period at refligeration temperature.