• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.71-83
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• 2009

Shotcrete is an important primary support for tunnelling in rock. The quality control of shotcrete is a core issue in the safe construction and maintenance of tunnels. Although shotcrete may be applied well initially onto excavated rock surfaces, it is affected by blasting, rock deformation and shrinkage and can debond from the excavated surface, causing problems such as corrosion, buckling, fracturing and the creation of internal voids. This study suggests an effective non-destructive evaluation method of the tunnel shotcrete bonding state applied onto hard rocks using the impact-echo (IE) method and ground penetration radar (GPR). To verify previous numerical simulation results, experimental study carried out. Generally, the bonding state of shotcrete can be classified into void, debonded, and fully bonded. In the laboratory, three different bonding conditions were modeled. The signals obtained from the experimental IE tests were analyzed at the time domain, frequency domain, and time-frequency domain (i.e., the Short- Time Fourier transform). For all cases in the analyses, the experimental test results were in good agreement with the previous numerical simulation results, verifying this approach. Both the numerical and experimental results suggest that the bonding state of shotcrete can be evaluated through changes in the resonance frequency and geometric damping ratio in a frequency domain analysis, and through changes in the contour shape and correlation coefficient in a time-frequency analysis: as the bonding state worsens in hard rock condition, the autospectral density increases, the geometric damping ratio decreases, and the contour shape in the time-frequency domain has a long tail parallel to the time axis. The correlation coefficient can be effectively applied for a quantitative evaluation of bonding state of tunnel shotcrete. Finally, the bonding state of shotcrete can be successfully evaluated based on the process suggested in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.525-534
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• 2010

A road curbstone is a structure installed at the boundary of the sidewalk and the street with the objectives of road drainage, drawing attention and such. The current general construction method of curbstones places foundation concrete for the curbstones first, waits until the concrete reaches the strength to support the curbstones, places the curbstones on top, and then places the gutter and rear filling concrete. Such method has the issues of poor compaction and weakened bond strength of concrete due to split placing of concrete, and causes the curbstones to easily separate due to vehicle impact or earth pressure, in turn creating maintenance costs and spoiling the aesthetics. To improve such conventional construction methods, an all-in-one method was developed using formwork rail and jig where both the curbstones and gutter can be worked at the same time, and to evaluate the structural performance, static tests of lateral loading test, pullout test, and bending test were executed, and dynamic tests such as pendulum test and actual vehicle impact test were executed. In all tests, the all-in-one construction method using formwork rail and jig was shown to be superior to the conventional construction method by the increase of construction quality and bond strength of concrete.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.169-181
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• 2023

This study was conducted to examine the remuneration curriculum of vocational ability development training teachers and instructors and to examine ways to apply micro credentials. To this end, the current status of the remuneration curriculum of vocational ability development training instructors and instructors at K University's Competency Education Development Institute, the characteristics of micro credentials, and the possibility of linking the remuneration curriculum to micro credentials are as follows. First, most of the recognition of digital certificates was positive for digital certificates such as digital credit, digital badge issuance, and recognition of the recognized qualification process of maintenance education when completing the training course. In addition, as a method of applying micro credentials to conservative education, various cases were proposed to benefit from conservative education, systematization and grading of the qualification process, and credit of the qualification process. Second, as an institutional supplement to enhance the utilization of conservative education using micro credentials, the need to expand NCS-based major conservative education, provide efficient learning contents and learning methods, and set minimum completion time. In addition, the most common response as a way to improve the understanding of teachers and instructors in vocational ability development training was the micro credential promotion plan. Third, in the role of conservative education institutions and vocational ability development training instructors and instructors, conservative education institutions mention maintaining educational quality the most, and active participation was the role of vocational ability development training instructors. Through this study, it is expected to establish a vocational training environment that can enhance expertise and provide a practical portfolio of practical competency history by linking the remuneration curriculum of vocational competency development training instructors and micro credentials.

• Journal of the Korean Geosynthetics Society
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• v.23 no.2
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• pp.63-75
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• 2024

Drinking water is an essential element to ensure the basic human right to live, and the quality of clean water must always be ensured. However, domestic water facilities, which were installed intensively in the early 2000s, are deteriorating. The accidents such as discoloration of water such as chromaticity and turbidity as well as leakage of substances frequently occur. However, since it is virtually impossible to replace all water pipes, the detailed standards for maintenance of water pipe network facilities established in 2021 require water pipe cleaning. The swab pig method, one of the water pipe cleaning methods, is a method of physically removing substances in pipes and is evaluated as having the highest cleaning efficiency. However, Swab is highly likely to be damaged or deformed during the cleaning process, and may even be lost. Therefore, in this study, the material of the pig was changed to a material with high compressibility, and it was made as close as possible to the inner wall of the water pipe. And, to maximize cleaning efficiency, a rotation swab pig with a rotation blade was developed. In addition, high-strength wire and winding equipment were additionally developed to eliminate the possibility of loss and to determine the location of the pig. The inlet and outlet are connected with wires, and after verifying the performance of each detailed technology, the technology was applied on a test bed with a 30m section. As a result of the application, the performance of the technology was verified by measuring the process time and evaluating applicability.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.106-111
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• 2008

Six standard methods for marine ecotoxicological tests were established(or applicated) using marine decomposer, primary producers and consumers. Development processes referred to the standard methods established by USEPA(United States Environmental Protection Agency), international organizations and European methods. However, the standard test species were selected among the domestic species generally found in the Korean waters and sediments. The test methods provide the culture/maintenance of test species, test methods, reproducibility and quality acceptance criteria etc. A total of nine test species were designated including bioluminescent bacteria(Vibrio fischeri), diatom(Skeletonema costatum), seaweed(Ulva pertusa), rotifer(Brachionus plicatilis), benthic copepod(Tigriopus japonicus), benthic amphipods(Mandibulophoxus mai, Monocorophium acherusicum), and fishes(Oryzias latipes, Paralichthys olivaceus). These test species represent the decomposer, primary producer and consumers in marine trophic system in Korean coastal ecosystems, and we recommend the "battery test" including at least one species from the each trophic level for marine ecotoxicological test.

• Korean Journal of Construction Engineering and Management
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• v.25 no.3
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• pp.37-46
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• 2024

Recently, 3D laser scanning technology, which can collect accurate and quick information on phenomena, has been attracting attention among smart construction technologies. 3D laser scanning technology can obtain information most similar to reality at construction sites. In this study, we would like to apply a new member identification method to an actual building and present the possibility of applying point cloud data, which can be collected using 3D laser scanning technology, to measuring progress at construction sites. In order to carry out the research, we collected location information for component identification from BIM, set a recognition margin for the collected location information, and proceeded to identify the components that make up the building from point cloud data. Research results We confirmed that the columns, beams, walls, and slabs that make up a building can be identified from point cloud data. The identification results can be used to confirm all the parts that have been completed in the actual building, and can be used in conjunction with the unit price of each part in the project BOQ for prefabricated calculations. In addition, the point cloud data obtained through research can be used as accurate data for quality control monitoring of construction sites and building maintenance management. The research results can contribute to improving the timeliness and accuracy of construction information used in future project applications.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.308-316
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• 2013

Fresh ginseng has a limited storage life due to the quality change caused by microbial spoilage as well as physiological deterioration. The present study investigated the effects of 1-methylcyclopropene (1-MCP) treatment, an inhibitor of ethylene action, on the microbial growth and quality maintenance of fresh ginseng during storage. Harvested fresh ginsengs were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP for 20 hours at $4^{\circ}C$ and then stored at room temperature (RT) for 18 days or low temperature ($4^{\circ}C$) for 160 days. After 18 days of storage at RT, the percentage weight loss in 1-MCP treated fresh ginseng (8.3%) is lower than that of control (10.1%). During long-term storage at $4^{\circ}C$, weight losses were increased slightly until 120 days without difference between non-treated and 1-MCP ginsengs. In contrast, after 120 days of storage at $4^{\circ}C$, higher increase in weight loss was observed in non-treated ginsengs than in 1-MCP treated ginsengs. Respiration rate and ethylene production of fresh ginseng were reduced by 1-MCP treatments at RT. The 1-MCP treatment also resulted in lower microbial population compared to those of non-treated ginsengs at RT. However, in ginsengs stored at $4^{\circ}C$ for short-term (45 days), no differences were noted in weight loss and microbial population between 1-MCP treated and non-treated ginsengs. Major ginsenosides was not changed by 1-MCP treatment during the 7 days of storage at RT. Results suggest that 1-MCP treatment can be used to maintain the freshness of ginseng at room temperature for short term storage and at low temperature for long term storage. 1-MCP treatment could be applied on fresh ginseng to avoid deleterious effect of exogenous ethylene during storage and shipping.

• The Journal of Internal Korean Medicine
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• v.25 no.1
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• pp.138-148
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• 2004

Objective : Insomnia is the disorder of initiation or maintenance in sleeping that results in daytime sleepiness and dysfunction, and it arises from multiple psychological, physiological and environmental factors. A number of stroke patients suffer from insomnia are classified as sleep disorder patients with physical illness. In addition, insomnia may have profound deleterious effects on the natural course of stroke. We are to assess the effectiveness of intradermal acupucture on stroke combined with insomnia. Methods : We recruited hospitalized patients with insomnia after stroke. Then, the subjects were allocated into a treatment group and a control group by randomization. The treatment group received intradermal acupuncture therapy at He-7(神門), EH-6(內關) correctly. However in control group, intradermal acupuncture were just attached to He-7(神門), EH-6(內關) without insertion. Treatment over time at first day and second day a various indexes were repeatedly checked such as sleep latency, total sleep time, sleep quality, condition on awakening, ability of concentration, morning sleepiness, Insomnia Severity Index, and Athens Insomnia Scale. In the second analysis, we divided the treatment group into a response and a non-response group by their response to intradermal acupuncture. With the acupuncture treatment, accompanied symptoms were checked Results : Among thirty two subjects, two of them were dropped out: One complained the pain from needle insertion, and the other underwent the change of his herbal medication. At baseline investigation with the residual 30 subjects, the control and the treatment group were assessed to have an equal comparability. In the treatment group, sleep latency, total sleeping time, a number of awakenings, sleep quality and ability of concentration showed improvement significantly compared with the control group. The non-response Group showed symptoms such as nausea and halitosis, belching and acid regurgitation, abundant expectoration, while Responder Group showed palpitation, oppressed feelings in chest and sleep disorder. Conclusions: The result of this clinical study suggests that the intradermal acupuncture at He-7(神門), EH-6(內關) is one of the effective treatments for the insomnia after stroke.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.2
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• pp.47-61
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• 2009

The purpose of this study was to understand the laws related to the safety management of children's play facilities(LRSMCPF) including the "Safety Supervision Law of Children's Play Facilities(SSLCPF)" and the "Quality Management and Industrial Products Safety Management Law(QMIPSAL)", in order to analyze the problems by 4 phases-development of products, landscape design, landscape construction and maintenance considering landscape project procedure-and to propose a revision of the laws. The results are as follows: 1. The various LRSMCPF, SSLCPF and QMIPSAL, as basic laws for the safety management of children's play facilities, were insufficient regarding the features of children's play facilities and play spaces, which are both comparatively varied and complex. 2. In development of products, the one-year duration of safety certification based on QMIPSAL was too short and the procedure for safety certification were redundant in both products and plants inspection, and export and import product inspection. 3. The field inspection of construction sites based on SSLCPF was repeated with quality control and a consultation of rules based on "Construction Technology Management Law". 4. There are not enough safety inspection organizations regarding children's play facilities to meet the demand of safety certification, safety inspection, and safety education in the near future. 5. For children's play safety, the establishment of a general safety management system for children's play connected with the phases is needed to ensure safe play equipment, to construct safe playgrounds, and to manage play facilities. The criteria, regulations, and procedure regarding safety certification and safety inspection of play facilities must be revised efficiently and standardized to a global level as well. To improve the system and contents of safety certification and inspection, authorization of safety inspection organizations based on landscape architecture is needed. Further study will be required to concretely analyze in detail the laws, enforcement decrees and rules, and ordinances that consider the practical experience of professional landscape architects, inspectors, and lawyers.

• Journal of Korean Academy of Nursing Administration
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• v.3 no.1
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• pp.119-133
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• 1997

Continuing shift service of clinical nurses can be not only the cause of occupational dissatisfaction by being connected with the change of circadian rhythm and the burden of duties to be applicable to such changes. But also of inviting the lowering of nursing quality by being affected to the resignation of the nurses as the threat to the health of the nurses. This study has selected 500 nurses at random under non-probability sampling who have been serving by shift in 7 general hospitals which have over 400 sickbeds for the purpose of cross-sectional survey design from Sep. 7 through 20, 1996. Standardized modification of the CMI has been used which was designed for Koreans with Cornell Medical Index developed by Broadman and his fellow workers as the study device. The structure of the device was composed of 35 questions on physical appeal(Chronbach's ${\alpha}=8507$) and 22 questions of mental appeal(Cronbach's ${\alpha}=.8166$ totalling 57 questions. The collected data has been computerrized by using SPSS. General character, present symptom, perceived symptom and others are sought by practical number and percentage, and the health condition comparison followed by general characters was conducted by t-test and ANOVA. The post test was by Duncan's test by the level of p<.05. 1) The items of the answer that they have the physical symptom presently by 50% or over of the nurses were as "Do you often have spells of severe dizziness", "Are your eyes often red or inflamed", "Does press or pain in the head often make like miserable", "Are your ankles often badly swollen", "Do pains in the back make it hard for you to keep up with your work". 2) The items of the answer by over 50% of the nurses as the mental symptom at present were "do you fell bad when criticized?", "Do you get angry when everything is against your will?", "do you get angry when ordered to do this and that?", "do you feel uneasy by such a trifle thing?", "do you tremble or are you freightened by sudden sound?". The mental and physical symptoms which have appeared presently in connection with the shift service have been agreed with each other. But the physical condition has been worse than the mental one. 3) In the physical health conditions followed by demosociological character, there were the significant differences by sex, religion and place of residence(p<.05), and in the mental health conditions, there were the significant differences by age, marital status, residence place and the required time for attending hospital(p<.05). 4) There was significant difference by the degree of satisfaction about the duty in both the physical and mental health conditions. In short, the higher the degree of duty satisfaction, the better the health conditions. 5) There were the significant difference according to the times of night duty and whether they take the drug or not or the kinds of the drugs in the physical health conditions related with the characters of night shift. Mental health conditions in the night shift case showed significant differences according to their taking drug or not or the kinds of the drugs(p<.05). I can confirm that the nurses have been affected continuously by the shift service mentally and physically. The maintenance of the physical and mental health of the nurses and its promotion are very important problem to guarantee the quality nursing in the performance of the nursing service continuously and effectively, so the hospital should make every effort to improve the duty conditions by finding out the causes affecting to their health. In the nursing management viewpoint, I think that elevating the satisfaction degree about the duty would be a great help to the promotion of physical and mental health conditions. But what is most important is that the nurses themselves should take care of themselves in maintaining the good conditions in their service in the hospital.