• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.197-210
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• 2015

The purpose of this study is to find out subjective perception types and needs of interested group on the employment supporting for students with disabilities in college by Q methodology, then to search for political measures to support employment for students with disabilities in the implication of the sorted subjective perception types. The result of the study showed that there are four major sorts of subjectivities on the employment supporting for students with disabilities in college : external dependence(Type1), disability-friendly (Type2), demand tailored(Type3), internal role emphasis(Type4). The result of the study could check that there was necessary reconstruction to disability-friendly infrastructure based on interset and willness on the employment supporting for students with disabilities in college. In addition to that there was necessary to job creation of government, to build network of industry to successful labor market entry of students with disabilities.

• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.65-76
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• 2021

There is a possibility of cavities occurring inside and behind the lining of an aged tunnel structure. In most cases, it is not easy to check the cavity because it exists in a place where visual inspection is impossible. Recently, attempts have been made to evaluate the condition of the tunnel lining and the backfill materials using non-destructive tests such as Ground Penetrating Radar, and various related model tests and numerical analysis studies have been conducted. In this study, the GPR signal characteristics for tunnel lining model testing were analyzed using gprMax software, which was compared with model test results. The numerical model applied to the model test reasonably simulated the electromagnetic wave signal according to the change of the material such as tunnel lining and internal cavity. Using the verified GPR model, B-scan data for the development of the GPR signal analysis technique were obtained, which can evaluate the thickness of the tunnel lining, the presence of the cavity, the effect of the waterproof membrane, and the frequency band.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.637-643
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• 2019

To verify internal movements of the body, a DICOM file obtained from CT and a Geant4 code were used to simulate lung cancer patients. In addition, the method is applied to measure the movement of tumor when the movement of t he tumor is located inhale and exhale by creating a virtual tumor in the self-produced moving phantom, and to check the distribution of dose in the treatment plan and the accuracy of tumor in PTV for respiratory and lung cancer patients. It was confirmed that 97% or more respiratory control radiation therapy was effective even if the moving area was more than 3cm, in the 40% to 70% range. Dose distribution with respiratory radiation therapy applied to moving targets, measured by film in the actuation phantom, was shown to be within a 3mm margin of error for dose distribution containing 90%. It was confirmed that for actual patient breathing curves, the treatment time may be shorter than that due to the longer expiratory time.

• Journal of Oral Medicine and Pain
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• v.44 no.3
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• pp.92-102
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• 2019

Purpose: To investigate the masticatory function of patients with different temporomandibular disorders (TMD) phenotypes, and to explore the risk factors for the masticatory function of TMD patients among multiple biopsychosocial variables using patient-reported outcomes (PROs). Methods: Clinical features and TMD diagnoses of 250 cases were investigated by reviewing medical records. Psychosocial factors were evaluated using four questionnaires representing pain severity and pain interference (Brief Pain Inventory), pain catastrophizing (Pain Catastrophizing Scale, PCS), psychological distress (Symptom Check List-90-Revised, SCL-90R) and kinesiophobia (Tampa Scale for Kinesiophobia for Temporomandibular Disorders, TSK-TMD). Masticatory function, as a dependent variable, was determined using the Jaw Functional Limitation Scale (JFLS). Kruskal-Wallis test and Spearman's rank correlation were used for analyses. Results: A total of 145 cases were included and classified into four subgroups including group 1: TMD with internal derangement without pain (n=14), group 2: TMD with muscle pain (n=32), group 3: TMD with joint pain (n=60) and group 4: TMD with muscle-joint combined pain (n=39). Pain severity (p=0.001) and interference (p=0.022) were the highest in group 2, but the mean global score of JFLS was the highest in group 3, followed by group 4, group 2, and group 1 (p=0.013). Pain severity, pain interference, the mean global score of PCS and the mean global score of TSK-TMD showed significant and moderate correlation with the mean global score of JFLS. All subdimensions and the global severity index of SCL-90R had significant, but weak correlations with all scores of JFLS. Conclusions: The results suggest that masticatory functional limitation depends on the TMD phenotypes. Among the various PROs, pain perception, pain catastrophizing and kinesiophobia seem to be more influential risk factors on jaw function than psychological distress, such as depression and anxiety.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.26-34
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• 2019

In this paper, a coarse lunar soil model is developed using discrete element method and its computed physical properties are compared with those of the actual lunar soil for its validation. The surface of the actual moon consists of numerous craters and rocks of various sizes, and it is covered with fine dry soil which seriously affects the landing stability of the lunar lander. Therefore, in consideration of the environment of the lunar regolith, the lunar soil is realized using discrete element method. To validate the coarse model of lunar soil, the simulations of the indentation test and the direct shear test are performed to check the physical properties(indentation depth, cohesion stress, internal friction angle). To examine the performance of the proposed model, the drop simulation of finite element model of single-leg landing gear is performed on proposed soil models with different particle diameters. The impact load delivered to the strut of the lander is compared to test results.

• Journal of Drive and Control
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• v.18 no.1
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• pp.1-8
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• 2021

This paper presents research on methods for the reduction of forklifts' noise level for the increased comfort and safety of its operator. A cooling fan with a high air volume flow rate installed in the forklift acts as an important design parameter which efficiently cools the heat exchanger system, helping to transfer internal heat from the engine room to the outdoors with both transmitted and diffracted opening noises. The cooling fan contributes significantly to both the forklift's emitted sound power and the operator room's noise level, thereby necessitating research on the forklift's reduction of acoustic power level and transmission. A noise analysis for various fan models with a biomimetic design based on eagle-wing geometry was conducted. In addition to the acoustic power generation, the aerodynamic performance of the cooling blade is also strongly influenced by the design of airfoil distribution, thereby requiring optimization. The cooling fans were fabricated and installed in the forklift in order to check the efficacy of the forklift engine's cooling, and the final version of the fan was measured for its ability to lower acoustic power level and cool the engine room. This study explains the aerodynamic and acoustic features of the designed fans with the use of BEM analysis and forklift test results.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.85-92
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• 2020

Wet Scrubber reacts the incoming pollutant gas with cleaning water (water + absorbent) to absorb pollutants and release the clean air to the atmosphere. Wet scrubbers and packed tower scrubbers using this principle are widely used in businesses that emit acid gases. In particular, in the etching process using hydrochloric acid (HCl), alkaline washing water (NaOH) having a pH of about 8 to 11 is used to absorb a large amount of acid gas. However, These salts are attached to the injection nozzle (nozzle), filling material (packing), and the demister (Demister), causing air pollution, human damage, and inoperability due to clogging and acid gas discharge. Therefore, In this study, an improvement plan was proposed to manage the washing water with pH 3~4 acidic washing water. The test method takes samples from the Wet Scrubber flue measurement laboratory twice a month for 1 year. Hydrogen chloride (HCl) concentration (ppm) was measured, and nozzle clogging and scale conditions were measured, compared, and analyzed through a differential pressure gauge and a pressure gauge. As a result of the check, it was visually confirmed that the scale was reduced to 50% or less in the spray nozzle, filler, and demister. In addition, the emission limit of hydrogen chloride in accordance with the Enforcement Regulation of the Air Quality Conservation Act [Annex 8] met 3 ppm or less. Therefore, even if the washing water is operated in an acidic pH range of 3 to 4, it is expected to reduce air pollution and human damage due to clogging of internal parts, and it is expected to reduce maintenance costs such as regular cleaning or replacement of parts.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.773-779
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• 2021

CNG, which has recently been attracting attention as an alternative fuel in the transportation field to reduce emissions caused by global warming, is natural gas with abundant reserves and mainly composed of methane. Being in a gaseous state, natural gas requires the compression and liquefaction processes for transportation. Until now, general shut-off valves for liquid and gas piping have been developed in Korea, but there are few studies on shut-off valves for high pressures of about 200 bar. Currently, research on the flow analysis of valves is being actively conducted around the world. However, there are relatively many studies on large valves such as low-pressure valves or shipbuilding and marine, and the safety factor through structural analysis to check the structural integrity of the valve is checked at the design stage. Since it is necessary to have a fast response speed while minimizing pressure and speed loss due to flow change, basic research was conducted on the flow analysis of the valve to secure design data, and the numerical analysis was performed on high-pressure automatic shut-off valves applied to CNG refueling stations. After securing the basic valve shape through reverse engineering for advanced products, we compared the valve flow coefficient Cv coefficient with advanced products. As a result, it was found that the reverse engineering model was at the level of about 60%. However, we compared the Cv coefficient by modifying the reverse engineering model, and the result showed that it was improved to about 96%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.1-7
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• 2021

This study attempted to detect possible collapse and fire accidents in facilities for disaster monitoring of large facilities, and to develop a customized beacon to recognize the internal situation of an IoT-based facility when a disaster occurs. In the case of data measurement using the existing strain gauge sensor, the strain gauge sensor was connected by wire to measure it, but this study changed it to wireless so that the presence and absence of structural deformation can be monitored in real time. In this process, in order to use the Wheatstone bridge, a strain sensor module that can be connected to a customized beacon was manufactured, and a system configuration was conducted to remotely check the measurement data. To verify measurement data, 10 customized beacons and 2 gateways were installed on the 15th floor of the Advanced Institue of Convergence Technology, and as a result of analysis of measurement data, it was confirmed that the strain data values were distributed between 7 and 8.

• Tribology and Lubricants
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• v.37 no.6
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• pp.246-252
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• 2021

Among the engine components of an internal combustion engine, the valve train is a series of systems that supply intake gas to the combustion chamber and operate intake and exhaust valves that discharge exhaust gas. If excessive wear occurs in the valve train system, the suction and exhaust valves do not open and close on time, which leads to abnormal combustion and exhaust gas. In this study, we conduct experiments and analyses on friction and wear characteristics of the valve train system. Moreover, we experimentally study the correlation between the pinball and pinball cap on engine oil lubrication, friction experiment, wear amount analysis, and surface analysis. Specifically, we experiment using Ball on reciprocating tribo-tester and apply commercial engine oil sold on the market engine oil. We construct the experimental conditions for each new oil and oil. Accordingly, the completed specimen was subjected to a confocal microscope to check the wear volume, observe the surface of the specimen, and confirm the elemental components using a scanning microscope (SEM) and an energy dispersion X-ray spectrometer (EDS). Through this experiment, we analyze the friction and wear characteristics of valve train components according to engine oil grade, and the obtained data serve as an effective engine oil management method.