• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.44-53
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• 2011

Membrane bio-reactor (MBR) has several advantages over the conventional activated sludge process, including a high biomass, low sludge production, and better permeate quality. Therefore, the MBR have gained popularity for municipal and industrial wastewater treatment. However the MBR usually were used for sewage and low streng th wastewater treatment because of membrane fouling problem and limitation of oxygen transfer into biomass. In this study, the hybrid process combining MBR and pure oxygen was tested for high strength organic wastewater treatment in the COD loading range from 2 to $10kgCOD/m^3{\cdot}day$. The hybrid process, membrane coupled pure oxygen high compact reactor (MPHCR), had been operated for one year and operation parameters, the effect of COD loading, MLSS concentration and the location of membrane module were studied for membrane fouling characteristic. Also membrane resistance test and the component of foulant was analyzed to investigate what is specific foulant in the MBR.

• Corrosion Science and Technology
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• v.20 no.3
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• pp.105-111
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• 2021

In oxidizing nitric acid solutions, stainless steel undergoes intergranular corrosion accompanied by grain dropping and changes in the corrosion rate. For the safe operation of reprocessing plants, this mechanism should be understood. In this study, we constructed a three-dimensional computational model using a cellular automata method to simulate the intergranular corrosion propagation of stainless steel. The computational model was constructed of three types of cells: grain (bulk), grain boundary (GB), and solution cells. Model simulations verified the relationship between surface roughness during corrosion and dispersion of the dissolution rate of the GB. The relationship was investigated by simulation applying a constant dissolution rate and a distributed dissolution rate of the GB cells. The distribution of the dissolution rate of the GB cells was derived from the intergranular corrosion depth obtained by corrosion tests. The constant dissolution rate of the GB was derived from the average dissolution rate. Surface roughness calculated by the distributed dissolution rates of the GBs of the model was greater than the constant dissolution rates of the GBs. The cross-sectional images obtained were comparable to the corrosion test results. These results indicate that the surface roughness during corrosion is associated with the distribution of the corrosion rate.

• Journal of Sport and Applied Science
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• v.5 no.2
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• pp.31-38
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• 2021

Purpose: A new form of sports human rights platform is needed for policy-related officials, athletes, leaders, and parents to easily share information on sports human rights and to promote communication between the sports community and the outside. Research design, data, and methodology: Participants were collected from athletes (n=3,007) who were registered in Korean Sport & Olympic Committee. Participants were asked to respond the survey items measuring their experiences of human right violations in sport. Descriptive analysis, t-test, and ANOVA were used to analyze data. Results: The platform should include information on prevention and safety of human rights violations during sports activities, procedures and methods for reporting damage, countermeasures, leader education programs, human rights protection guidelines, roles and supervision of sports organizations and institutions, and related statues. It can form a community as well as exchange information in the Internet space through the operation of bulletin boards by professional athletes, student athletes, parents, and leaders, and plays a role in crisis counseling or information provision. Given the reality that players can be blocked from the outside world, information communication channels on SNS can be a useful means of protecting and improving players' human rights. Conclusions: Therefore, it is necessary to provide a foundation for creating related platforms so that sports human rights sites or SNS can be operated voluntarily. Implications and future directions were discussed.

• The Journal of Korean Institute of Information Technology
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• v.17 no.1
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• pp.149-156
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• 2019

Mixed reality technology (MR) has become one of the fourth industrial revolution element technologies. MR technology has been widely applied not only as a digital contents industry but also in the fields of architecture, tourism, medical field, and education. In this paper, we propose a collaborative service platform for architectural applications that inter-operate with heterogeneous devices such as MR device, PC and mobile, and develop prototype system and verify it. As a result, the 3D model using the skp extension, which is mainly used in architecture design office, was created by using developed prototype system and generate the MR contents for the hololens, which is the MR device, and the conversion time and normal operation were confirmed.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.1-10
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• 2021

The type approval system for railway vehicle has been in effect since 2016 in order to establish a regular safety management system to secure railway safety and enhance the technological competitiveness of the railway industry, abolished the conventional performance test system through the reform of the Railroad Safety Act in 2012. Until now, there has been appreciated it has been making significant contributions to railway safety and industry of operation and manufacturing companies, taking their place in accordance with the implementation of the system. But there has been no case of quantitative analysis on the effectiveness of the actual system. In this study, in order to examine the full-scale performance of the approval system and quantitatively analyze effectiveness, we identified and defined the relationships with the major elements of the type approval system based on system thinking principle and determined the calculated outcomes to relevant stakeholders. A method of establishing a type approval performance management system that can be grasped, utilized, and adjusted from a point of various stakeholders' views was proposed. This is expected to be more helpful in the implementation of the system, such as improving and applying quantitative effects to analysis by closely reviewing the effects and influencing factors of the type approval system based on the data accumulated through continuous performance management and reflecting to system improvement.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.355-372
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• 2021

Recently, high-performance HMDs (Head-Mounted Display) are becoming wireless due to the growth of virtual reality technology. Accordingly, environmental constraints on the hardware usage are reduced, enabling multiple users to experience virtual reality within a single space simultaneously. Existing multi-user virtual reality platforms use the user's location tracking and motion sensing technology based on vision sensors and active markers. However, there is a decrease in immersion due to the problem of overlapping markers or frequent matching errors due to the reflected light. Goal of this study is to develop a multi-user virtual reality moving platform in a single space that can resolve sensing errors and user immersion decrease. In order to achieve this goal hybrid sensing technology was developed, which is the convergence of vision sensor technology for position tracking, IMU (Inertial Measurement Unit) sensor motion capture technology and gesture recognition technology based on smart gloves. In addition, integrated safety operation system was developed which does not decrease the immersion but ensures the safety of the users and supports multimodal feedback. A 6 m×6 m×2.4 m test bed was configured to verify the effectiveness of the multi-user virtual reality moving platform for four users.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.161-170
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• 2020

In this study, develop the seismic acceleration measurement data conversion and signal processing algorithms for improve the operational efficiency of the seismic acceleration measurement system installed for public facilities. Through the analysis of the seismic acceleration time history data, the evaluation methods and criteria and evaluating the safety of buildings were proposed. The system was applied to the test bed building to verify its operation and usability. It is expected to be used as a decision making support data and determining the direction and priority of disaster response in the event of an earthquake.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.247-255
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• 2022

This paper proposes a multiphase interleaved zero-voltage-transition boost converter with a single soft-switching cell for high-voltage DC-DC converter (HDC) of fuel cell systems. The proposed single soft-switching cell structure can reduce the system volume by minimizing the passive and active elements added even in the multiphase-interleaved structure. To analyze the feasibility of the proposed structure, this paper mathematically analyzes the operation modes of the converter with the proposed single soft-switching cell structure and presents guidelines for design and considerations. In addition, the feasibility of the 210[kW] HDC was confirmed through PSIM simulation, and the system volume reduction of up to 10.48% was confirmed as a result of the 5[kW] HDC test-bed experiment considering the fuel cell system. Through this, the validity of the proposed structure was verified.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.393-398
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• 2022

During the test operation period of the wind profiler prototype, radio frequency interference (RFI) contamination occurred in the spectrum. The reference of the RFI that removed the algorithm appearing in the wind profiler spectrum were investigated, and a new algorithm was developed to remove the RFI. First, it was filtered with a threshold value of 0.1 m/s of the spectral width, and the range of the number of gates with the same radial velocity was determined according to whether the beam was a vertical beam or an oblique beam. RFI contamination was removed through filtering and scanning of non-weather signals, and the continuity of wind vectors calculated from the improved spectral radial velocity was verified.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.1-8
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• 2022

Electronic equipment mounted on military vehicles is exposed to external shocks and vibrations. This causes problems in tactical operation and also causes cost loss in equipment maintenance. Therefore, to optimize the test standards for military vehicles with vibration, dynamic characteristics should be analyzed and standardized through actual driving tests. In this paper, the internal structure of 2.5tons military vehicle is designed in the form of a drawer and lathe, and the dynamic characteristics are identified by experiment, and the design is proposed.