• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.642-648
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• 2019

This paper presents a fast back-type transfer device for snack food processing that uses the inertia of transferred material. A conventional conveying system is a drive system that uses a belt conveyor and mechanical crank, which generate noise and vibration and cause environmental pollution. Vibration and noise are reduced in the proposed fast back feeding device by using a counterweight. The crank drive unit was replaced with a linear servomotor, and an equilibrium device was designed to balance the force due to acceleration. This makes it is possible to adjust the forward and backward speed and acceleration through PLC control. A vibration damper device offsets the vibration force of the periodic shock form. The main cause of the vibration was identified through vibration analysis, and reduction measures were established. We verified the effectiveness of the vibration by making a prototype and performing about 10 vibration tests. Because no mechanical transducer is needed, energy loss, noise, and vibration do not occur, and the operating speed is not limited.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.604-609
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• 2019

In this study, we fabricated a capacitive humidity sensor with interdigitated (IDT) electrodes using a thermosetting polyimide as a humidifying material. First, the number of electrodes, thickness, and spacing of the polyimide film were optimized, and a mask was designed and fabricated. The sensor was fabricated on a silicon substrate using semiconductor processing equipment. The area of the sensor was $1.56{\times}1.66mm^2$, and the width of the electrode and the gap between the electrodes were each $3{\mu}m$. The number of electrodes was 166, and the length of an electrode was 1.294 mm for the sensitivity of the sensor. The sensor was then packaged on a PCB for measurement. The sensor was inserted into a chamber environment with a temperature of $25^{\circ}C$ and connected to an LCR meter to measure the change in capacitance at relative humidity (RH) of 20% to 90%, 1 V, and 20 kHz. The results showed a sensitivity of 26fF/%RH, linearity of < ${\pm}2%RH$, and hysteresis of < ${\pm}2.5%RH$.

• Journal of vocational education research
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• v.30 no.4
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• pp.129-141
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• 2011

The aim of this study was to investigate the influence of self efficacy, emotional labor, and social support on job center workers' psychological burnout. The data in the study were collected from 132 workers who work for job center in Busan, Ulsan, Gimhae, and Jinhae, and Self-Estimate Inventory, Emotional Labor Scale, Social Support Scale, and Maslach Burnout Inventory were used. Correlation analysis and multiple regression analysis were applied for data processing. The results of the study are as follows. First, the study found a correlation between job center workers' self efficacy and psychological burnout, with higher self efficacy being less burnout. This shows that self efficacy has an meaningful influence on job center workers' psychological burnout. Second, it also found a correlation between job center workers' emotional labor and psychological burnout, with higher emotional labor being more burnout. However, multiple regression analysis indicates that frequency of emotional display, attentiveness to required display rule, and emotional dissonance which are sub-factors of emotional labor have a negative influence on psychological burnout. Third, it found a correlation between job center workers' social support and psychological burnout, with higher social support being less burnout. Among sub-factors of social support, material support and evaluative support have a meaningful influence on psychological burnout statistically. Fourth, it showed that self efficacy has a high influence on psychological burnout. This research suggests to provide basic materials which are a great help to study job center worker's psychological burnout, and proposes to arrange various program for developing human resources of job center as a public employment organization.

• Journal of Conservation Science
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• v.34 no.6
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• pp.493-502
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• 2018

Currently, the fabrication of a high-tin bronze spoon by traditional manufacturing techniques involves 10 steps in the bronze ware workshop. Hot forging has a major influence on manufacturing and involves two to three steps. The dendritic ${\alpha}$-phase in the microstructure of the high-tin bronze spoon is refined and finely dispersed through hot forging. In addition, twinning is observed in the ${\alpha}$-phase of the hammered part, and the ${\alpha}$-phase microstructure gradually transform from a polygon to a circular shape due to hammering. In this process, the adjacent ${\alpha}$-phases overlap with each other and remain combined after quenching. The microstructure with the overlapping is also observed in bronze artifacts, and this shows the correlation with technical system. The results of the experimental hot forging of Cu-22%Sn alloys show that the decrease in in the amount of the dendritic microstructure, which forms during casting, is in proportion to the number of processing steps and that the refined grain obtained by hammering contributes to the improvement in the strength of the material. From the hammering marks, which are observed on both the bronze artifact excavated from archaeological sites and on the high-tin bronze spoon produced in the traditional workshop, it is presumed that the knowledge regarding the unrecorded manufacturing system of bronze ware in ancient times has been passed down in a traditional way up to the system used currently.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.100-105
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• 2019

In this study, viable cells, coliforms and food poisoning bacteria were identified according to the pH levels of the coagulant and immersion liquid during each stage in the production of konjac, and storage stability was confirmed for 3 months. A considerable number of bacteria were found in the raw material, or powdered konjac (Amorphophallus konjac), as well as in the processing water. However, it has been shown that the plastic package were safe from microorganisms. Due to the high pH of the added coagulant [2.0% $Ca(OH)_2$], no contaminating bacteria were observed after konjac jelly formation. Coliforms were not detected any of the tested steps. During the molding process, the pH of konjac was adjusted to 9.5 ~ 12.5 at intervals of 0.5, and the number of bacteria was determined. As a result, no bacteria were detected in the alkaline range above pH 11.5. The pH of the immersion liquid was adjusted to 10.0 ~ 12.5, and after hardening, the konjac were stored at room temperature for 12 weeks. As a result, no bacteria, Escherichia coli or other food poisoning bacteria were detected at pH 11.5 or higher. Based on these results, it is expected that when the pH levels of the konjac and its immersion liquid are maintained at 11.5, it should be possible to keep the product for 3 months without additional sterilization process.

• Design & Manufacturing
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• v.13 no.2
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• pp.17-21
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• 2019

In this study, selective laser sintered 3D printing mold core and metal core were used to investigate the difference of the thickness shrinkage from the gate of the injection molded part at a constant interval. SLS 3D printing mold core was made of nylon-based PA2200 powder and the metal core was manufactured by conventional machining method. As the PA2200 powder material has low strength, thermal conductivity and high specific heat characteristics compared with metal, molding conditions were set with the consideration of molten temperature and injection pressure. Crystalline resin(PP) and amorphous resin(PS) with low melting temperature and viscosity were selected for the injection molding experiment. Cooling time for processing condition was selected by checking the temperature change of the cores with a cavity temperature sensor. The cooling time of the 3D printing core was required a longer time than that of the metal core. The thickness shrinkage of the molded part compared to the core depth was measured from the gate by a constant interval. It was shown that the thickness shrinkage of the 3D printing core was 2.02 ~ 4.34% larger than that of metal core. In additions, in the case of metal core, thickness shrinkage was increased with distance from the gate, on the contrary, in the case of polymer core showed reversed aspect.

• Korean Journal of Heritage: History & Science
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• v.42 no.4
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• pp.4-19
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• 2009

Though admitting that, in light of the recent archaeological trend, the excavation on relics of Sam-gama (a sort of kiln steaming the hemp) is increasingly reported, little efforts by far have been made not only to restore its traditional structure design but also to research hardly the change of hemp-steaming technologies in ages. In this regard, this paper shows the exploration of structural method and design as well as operability with regard to Sam-gut, traditional hemp-processing equipment that was recently reconstructed in Jungsun, Kangwon Province. Samgut, generally positioned at the waterside area, is an traditional device for steaming hemp to get bast fibers from the raw material of hemp, principally consisting of HWA-JIP(fire-place) to obtain steams by feeding fire ad Mong-got(boiling chamber) to make the hemp steamed after stacking. More specifically, thick round-logs were piled at the bottom of Hwajip prior to stacking stones around its circumferential area. When the timber positioned below gets burned with high temperature to heat stones existing in the upper side, waters then poured onto it after laying a bundle of grass and soil up to the boiled stones. If so, there generates hot vapor, which is conveyed to Monggot to steam the hemp. Functionally, it is of outstanding importance that Samgut is capable of producing high-temperature water vapors instantaneously under the intensive manpower, thus being constructed achievable for those purposes. The Samgut made by digging the ground is an instant facility that is closed after use. The remains, which were used to generate higher thermal power for steaming hemp, make it hard to excavate the historic traits because there left little vestiges in the soil, which means keen attention must be paid to find out the trace of Smgama relics. Future research stall be focused on collection of broader data regarding Samgut including technological review in extracting bas fibers from the hemp.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.517-524
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• 2019

The overdrive hub clutch is attached to a 6-speed automatic transmission to reduce fuel consumption by using the additional power of the engine. This paper proposes a means to minimize the load and roll-over ratio on the punch during the piercing process for the overdrive hub clutch product. Die clearance, shear angle, and friction coefficient, which can affect the load and roll-over ratio of the punch during processing, were set as the design variables. Sensitivity analysis was also conducted to determine the influence of each design variable on the punch load and roll-over ratio. As a result, shear angle, friction coefficient and die clearance were found to be sensitive to load and roll-over ratio. The punch load and roll-over ratio were set as the objective function and the equation of each design variable and objective function was derives using the Response Surface Method. Finally, the optimal value of the design variables was derived using the Response Surface Method. Application of this model to finite element analysis resulted in 22.14% improvement in the roll-over ratio of the punch load and material.

• Composites Research
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• v.32 no.5
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• pp.199-205
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• 2019

The composite material has the advantage that the fibers can be arranged in a desired direction and can be manufactured in one piece. However, micro voids can be formed due to micro air, moisture or improper curing temperature or pressure, which may cause the deterioration in mechanical strength. In this paper, the composite panels with different thicknesses were made by varying the curing pressure in an autoclave vacuum bag process and their microporosities were evaluated. Microporosity was measured by image analysis method, acid digestion method, and combustion method and their correlation with ultrasonic attenuation coefficient was analyzed. From the test results, it was found that the acid digestion method had the highest accuracy and the lower the curing pressure, the higher the microporosity and the ultrasonic attenuation coefficient. In addition, the microporosity and the ultrasonic attenuation coefficient were increased as the thickness of the composite panel was increased at the same curing pressure.

• The Korean Journal of Archival Studies
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• no.50
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• pp.97-138
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• 2016

This study presents the problems in the records management of special project teams at J University. Methods for the improvement plan were also proposed in this study. To achieve these objectives, five special project teams from J University, which were supported by the Ministry of Education, were selected. To collect relevant information, twelve staff members and experts were then interviewed. The records produced by the projects should be managed as evidence of the project evaluation and transparent budget execution. Proper management can be a good material for research. However, the management of project teams is vulnerable in comparison with the records of other universities. The main reason is that although the project team produces various types of records, it has not been recognized as the Department of Processing. Another reason is that the project teams are temporary institutions and do not possess authority over the entire project process. To solve the aforementioned problems, this study proposes improvement plans in the following aspects: institutional, cognitive, administrational, and systemic. In the institutional and cognitive aspects, policy and regulation were set up. In the administrational aspect, the relation and role of each element were defined. In conclusion, the plans for building the Combined Archives System were suggested. In addition the methods on how to connect with the KORUS-which will be introduced in 2017-and the system currently being used are proposed.