• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.49-55
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• 2016

To separate the CM and DM noise in the EMI generated in various electrical electronic systems, passive and active separators have been researched. These separators are an important part of an effective active EMI-filter. The passive separator has some advantages, in that it is easy to realize at a low price and its structure is very simple. However, its major drawback is that its accurate inductor realization and accurate core selection are very difficult. The active separator is smaller in size and more accurate, but its main drawback is that an op-amp which has a broad band frequency response is necessary, its cost is high, and a DC power circuit is required. This paper compares the characteristics of EMI filters which apply the existing passive separator and proposed active separator. It was concluded that an active separator is needed for expensive and accurate equipment, whereas a passive separator is sufficient for inexpensive and general purpose EMI filters.

• Safety and Health at Work
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• v.9 no.1
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• pp.95-100
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• 2018

Background: Respiratory protection equipment (RPE) is the last resort to control exposure to workplace air pollutants. A comprehensive respiratory protection program (RPP) ensures that RPE is selected, used, and cared properly. Therefore, RPP must be well integrated into the occupational health and safety requirements. In this study, we evaluated the implementation of RPP in Iranian petrochemical industries to identify the required solutions to improve the current status of respiratory protection. Methods: This cross-sectional study was conducted among 24 petrochemical industries in Iran. The survey instrument was a checklist extracted from the Occupational Safety and Health Administration respiratory protection standard. An index, Respiratory Protection Program Index (RPPI), was developed and weighted by analytic hierarchy process to determine the compliance rate (CR) of provided respiratory protection measures with the RPP standard. Data analysis was performed using Excel 2010. Results: The most important element of RPP, according to experts, was respiratory hazard evaluation. The average value of RPPI in the petrochemical plants was $49{\pm}15%$. The highest and lowest of CR among RPP elements were RPE selection and medical evaluation, respectively. Conclusion: None of studied petrochemical industries implemented RPP completely. This can lead to employees' overexposure to hazardous workplace air contaminants. Increasing awareness of employees and employers through training is suggested by this study to improve such conditions.

• Journal of the Korea Society of Computer and Information
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• v.24 no.10
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• pp.243-249
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• 2019

In this paper, we proposes a comprehensive analysis of the characteristics, selection procedures, and management perspectives of each university's financial support project, and derivation of a plan to integrate the information system of the university's financial support project. To this end, we analyze the current status of business operations before and after restructuring university financial support projects, and identified the characteristics, commonalities, and differences of each project. Individual projects are promoted segmentally, evaluation indicators and evaluation methods are different for each business, standardization is difficult, and in the absence of integrated governance, sympathy and will of the system integration of the government and the managing agency cannot be found. In order to integrate the system, the business management process must be integrated and standardized, and the system equipment such as budget category adjustment must be complemented, and a stable budget for system integration must be secured.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.138-139
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• 2019

In the era of the 4th industrial revolution, automated technology innovation is emerging, and container terminals are being developed to introduce automation equipment and systems. With the advent of ultra-large vessels, terminals around the world are seeking to build port infrastructure by combining automated technology in order to attract more cargo and to enhance competitiveness to provide prompt service. To introduce automated technology that is emerging as a high-tech industry, this study proposes a structural equation model for the decision to introduce automated container terminal and conducts a questionnaire survey on workers engaged in terminal operators for empirical analysis. This paper presents the role and direction of guidelines for introduction of automated container terminal through decision model.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.705-711
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• 2019

Currently, the brain CT scan of the latest equipment lacks the study of parameter change and dose change and especially of noise, uniformity analysis and dose change. Therefore, this study attempted to study the phenomenon that occurs at this time by analyzing tube voltage, slice thickness, and pitch change in exposure parameters when using high specification CT. Experimental results show that uniformity is better when using high voltage, thick slice thickness selection, and minimum pitch. As a result of the combination, the most uniformity condition was 140 kVp, 10 mm and pitch 0.5. Noise was found to be improved regardless of pitch by increasing tube voltage and slice thickness. The radiation dose increased linearly with tube voltage and pitch. Therefore, the results of this study will serve as a reference for the use of High specification brain CT.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.173-181
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• 2021

Purpose : The purpose of this study is to compare muscle activity after applying two muscle energy techniques (MET) to subjects with forward head posture to see if the post isometric relaxation (PIR) technique is more effective than the reciprocal inhibition (RI) technique. Methods : The muscle activity was measured using EMG after applying the PIR and RI techniques to 30 adults at K College. Subjects were selected for forward head posture whose ear center was 2.5 ㎝ front of the center of the shoulder. EMG equipment was used to measure muscle activity, and the measurement sites were measured in cervical flexor and extensor muscles. The experiment period was performed once a week for a total of two weeks, and after the pre-measurement was performed for 5 minutes PIR and RI exercise. In the PIR technique, the head is tilted back in a sitting position, and the experimenter applies resistance with the same force for 7~10 seconds and repeats 3-5 times after rest. In the RI technique, in a sitting position, the subject gives the force to bend the head forward, and the experimenter applies resistance with the same force for 7 to 10 seconds, and repeats 3 to 5 times after rest. Results : The result is same as the following. In the comparison of muscle activity, there was a significant decrease in both PIR and RI at 1 and 2 weeks. And there was a greater decrease in muscle activity in PIR. There was no difference in the comparison of decrease in muscle activity at 1 week and 2 week. Conclusion : Both PRI and RI can be said to be effective in improving the function of the forward head posture in the neck muscles. Therefore, the selection of the two techniques in clinical practice should be appropriately performed under the judgment of experts according to the patient's situation.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.92-97
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• 2021

The importance of processes in cryogenic environments is increasing in a way to address problems such as critical dimension (CD) narrow and bottlenecks in micro-processing. Accordingly, in this paper, we proceed with the design and analysis of Electrostatic Chuck(ESC) and Coolant in cryogenic environments, and present optimal model conditions to provide the temperature distribution analysis of ESC in these environments and the appropriate optimal design. The wafer temperature uniformity was selected as the reference model that the operating conditions of the refrigerant of the liquid nitrogen in the doubled aluminum path were excellent. Design of simulation (DOS) was carried out based on the wheel settings within the selected reference model and the classification of three mass flow and diameter case, respectively. The comparison between factors with p-value less than 0.05 indicates that the optimal design point is when five turns of coolant have a flow rate of 0.3 kg/s and a diameter of 12 mm. ANOVA determines the interactions between the above factor, indicating that mass flow is the most significant among the parameters of interests. In variable selection procedure, Case 2 was also determined to be superior through the two-Sample T-Test of the mean and variance values by dividing five coolant wheels into two (Case 1 : 2+3, Case 2: 3+2). Finally, heat transfer analysis processes such as final difference method (FDM) and heat transfer were also performed to demonstrate the feasibility and adequacy of the analysis process.

• Journal of Drive and Control
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• v.17 no.4
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• pp.125-132
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• 2020

The objective of this study was to analyze the axle load of a rice transplanter when planting rice seedlings at different working load conditions to select a suitable gear stage and a constant planting depth for rice seedlings. In this study, there are four levels of planting distances (26, 35, 43, and 80 cm) and three planting depths (low, medium, and high) with two gear stages (1.3 and 1.7 m/s). Axle loads and required planting pressures were analyzed statistically. It was observed that axle torques were increased with increasing planting depths for both gear stages, meaning that axle torques were directly proportional to planting depths for both gear stages. It was also observed that required planting pressures had a significant difference between planting distances. Planting pressures also showed significant difference according to gear stage and planting depth. These results indicate that planting pressures were directly proportional to both gear stage and planting depth. Results revealed that the automatic depth control system of a rice transplanter could not guarantee a constant planting depth as supplied pressures were variable. This indicates that a control algorithm is needed to ensure a constant planting depth. In the future, a control algorithm will be developed for an automatic depth control system of a rice transplanter to improve its comprehensive performance and efficiency.

• Geomechanics and Engineering
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• v.27 no.6
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• pp.537-550
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• 2021

There are various technical problems need to be solved in the construction process of pre-setting an isolation wall into a double lane in the outburst prone mine. This study presents a methodology that pre-setting an isolation wall into a double lane without a coal pillar. This requires the excavation of two small section roadways to dig a wide section roadway, followed by construction of the separation wall. During this process the connecting lane is reserved. In order to ensure the stability of the separation wall, the required bearing capacity of the isolation wall is 4.66 MN/m and the deformation of the isolation wall is approximately 25 cm. To reduce the difficulty of implementing support the roadway is driven by 5 m/d. After the construction of the separation wall, the left side coal wall is brushed 1.5 m to make the width of the gas roadway reach 2.5 m and the roadway support utilizes anchor rod, ladder beam, anchor cable beam and net configuration. During construction, the concrete pump and removable self-propelled hydraulic wall mold are used to pump and pour the concrete of the isolation wall. In the process of mining, the stress distribution of coal body and isolation wall is detected and measured on site. The results demonstrate that the deformation of the surrounding rock of roadway and separation of roof in the roadway is small. The stress of the bolt and anchor cable is within equipment tolerance validating their selection. The roadway is well supported and the intended goal is achieved. The methodology can be used for reference for similar mine gas control.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.132-133
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• 2021

In recent years, energy harvesting from natural sources and waste heat has been attracting more attention from researchers in response to ever-growing energy demands, high energy prices, and climate-change-mitigation purposes. It is also an important step towards future sustainable energy usages. In thermal dynamic cycles, expanders are playing as the most important equipment for waste heat recovery and energy harvesting as well. As a kind of expander, the bladeless turbine has a promising future and more widely using owning its advantages on relatively long life, good off-design performance, easy operation cleaning and maintenance, a simple structure, no blade corrosion, and low manufacturing costs. There are numerous studies about using the Tesla Turbine as a key technology for energy harvesting in a wide range of applications and conditions. They are presented to help identify technologies that have sufficient potential for applicating to our life and marine industrial engineering. This review paper, initially, presents an overview of current studies both theoretical and experimental of Tesla Turbine usage for waste heat recovery alongside its challenges and investigation on the effect of its configuration, working fluid selection as well. To conclude, future perspectives besides possible ways of transforming waste heat energy to electricity or work, which leads to circular energy, are discussed. The ambition of this paper is to act as a first-hand reference, through the well-defined possible directions, to the young researchers and senior scientists.