• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.41-47
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• 2011

With the world-wide demand on the emission minimization, the needs on the diesel aftertreatment devices with high efficiency are also increasing. In order to effectively develop or design a high-performance diesel particulate filter, a clear understanding on the deposition and regeneration mechanism is required. In the present study, a theory on the lumped parameter model for wall-flow type diesel particulate filters is described focusing on the deposition efficiency, pressure drop inside the filter. The fourth order explicit Runge-Kutta method is utilized for the mass flow rate computation. Engine operation modes with controlled and uncontrolled regeneration options are selected. The computational lumped parameter model is validated by comparing the computed results with the measured data.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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• pp.149-155
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• 2001

The use of primitive cell volume and zero order Laue (ZOLZ) pattern is proposed to identify phase in a complex microstructure. Single convergent beam electron pattern containing higher order Laue zone ring from a nanosized region is sufficient to calculate the primitive cell volume of the phase, while ZOLZ pattern is used to determine the zone axis of the crystal. A computer program is used to screen out possible phases from the value of measured cell volume from convergent beam electron diffraction (CBED) pattern. Indexing of ZOLZ pattern follows in the program to find the zone axis of the identification from a single CBED pattern. An example of the analysis is given from the rapidly solidified $Al-Al_3Ti$ system.

• Steel and Composite Structures
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• v.33 no.2
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• pp.163-180
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• 2019

A semi analytical method is employed to analyze free vibration characteristics of uniform and stepped functionally graded circular cylindrical shells under complex boundary conditions. The analytical model is established based on multi-segment partitioning strategy and first-order shear deformation theory. The displacement functions are handled by unified Jacobi polynomials and Fourier series. In order to obtain continuous conditions and satisfy complex boundary conditions, the penalty method about spring technique is adopted. The solutions about free vibration behavior of functionally graded circular cylindrical shells were obtained by approach of Rayleigh-Ritz. To confirm the dependability and validity of present approach, numerical verifications and convergence studies are conducted on functionally graded cylindrical shells under various influencing factors such as boundaries, spring parameters et al. The present method apparently has rapid convergence ability and excellent stability, and the results of the paper are closely agreed with those obtained by FEM and published literatures.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.251-260
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• 2019

In order to ensure second-order multi-agent systems (MAS) realizing consensus more quickly in a limited time, a new protocol is proposed. In this new protocol, the gradient algorithm of the overall cost function is introduced in the original protocol to enhance the connection between adjacent agents and improve the moving speed of each agent in the MAS. Utilizing Lyapunov stability theory, graph theory and homogeneity theory, sufficient conditions and detailed proof for achieving a finite-time consensus of the MAS are given. Finally, MAS with three following agents and one leading agent is simulated. Moreover, the simulation results indicated that this new protocol could make the system more stable, more robust and convergence faster when compared with other protocols.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.151-158
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• 2019

In this paper, we analyzed the relationship between employment stability, wage level, welfare system, working condition, job satisfaction and organizational commitment in order to find out ways to develop and competitiveness of the nano-convergence industries. Through this study, we conducted the possibility of deriving organizational commitment by job satisfaction which is given through employment stability, wage level, welfare system, and working condition for continuing their work life. In order to find relationships between each concepts, we used a multiple regression analysis with job satisfaction and commitment as dependent variable and employment stability, wage level, welfare system, and working condition as independent variables. Through this study, it was expected to increase the organizational commitment through the job satisfaction of the employees if a changing method of employees management is centered on some tasks suggested for the sound working condition and efficient utilization policies.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.1
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• pp.45-51
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• 2021

The purpose of this study is to suggest the optimal shape for a local air ventilation system for fume removal, which is operated in a zinc galvanizing factory, and to propose the improvement plan for a ventilation system used in a zinc galvanizing factory through flow analysis. A part of the air sprayed by an air curtain goes out. It will be necessary to research the position of an air curtain, its spray angles, and its nozzle shape. In addition, additional research needs to be conducted on the shape of the fan installed before a hood in order to make it easy to induce fume. In a local air ventilation system, air is inhaled from the outside. The higher an inlet negative pressure is, the easier fume is removed. It was found that it was necessary to install an appropriate hole in the wall on the back of a push nozzle in order to reduce an inlet negative pressure.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.143-150
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• 2014

A high power amplifier(HPA) has widely been used in wireless communications. In order to have a maximum power efficiency, the HPA uses a saturation domain having nonlinear characteristics, which generates nonlinear distortions to decrease the transmission efficiency. In order to solve this problem, various methods to linearize HPA have been reported until now, and the pre-distorter method is very attractive among them. In this paper, a new enhanced adaptive pre-distorter method was proposed to be applied for compensating nonlinear distortions of HPA. Through computer simulations as well as the analytical analysis, it could be shown that it is possible for both conventional adaptive pre-distorter and proposed adaptive pre-distorter, to be applied for linearizing HPA. Also, the simulations results demonstrated that the proposed adaptive pre-distorter may have faster convergence speed and better capability of compensating the nonlinear distortion than the conventional adaptive pre-distorter with nearly equal computation complexity.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.1
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• pp.111-119
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• 2022

This paper is about power transfer between heterogeneous systems in zero-energy buildings. Currently, electricity used in buildings, from renewable energy generation power in buildings, consists of alternating current networks. In order to use electricity, alternating current must be converted to direct current, which typically results in a loss of 10%. In order to solve this problem, research is needed to reduce power loss as much as possible by implementing both a DC network and an AC network in a zero-energy building. Therefore, in this paper, an inter-link converter capable of bidirectional power transfer between DC and AC networks applied to zero-energy buildings is developed. The structure of the inter-link converter to be developed was proposed and its feasibility was verified through simulations and experiments.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.969-977
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• 2022

Currently, in Korea, aerial photogrammetry is being studied for cadastral boundaries and numerical maps. Since the announced value of cadastral survey is closely related to ownership, the accuracy and reliability of the published value should be emphasized above all else. However, although aerial photogrammetry has great advantages in economic feasibility and surveying efficiency, it has many limitations when extracting the boundary of cadastral survey based on the acquired image. In order to improve these limitations, in this study, an aerial target was applied to obtain reliability improvement. Therefore, in order to examine the usefulness of aerial photogrammetry for cadastral survey application, cadastral boundary extraction and accuracy comparison analysis were conducted.

• Smart Media Journal
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• v.11 no.6
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• pp.51-63
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• 2022

Metaverse provides a simulated environment where a large number of users can participate in various activities. In order for Metaverse to be sustainable, it is necessary to study ethics that can be applied to a Metaverse service platform. In this paper, Metaverse ethics and the rules for applying to the platform are explored. And, in order to judge the ethicality of avatar actions in social Metaverse, the identity, interaction, and relationship of an avatar are investigated. Then, an action-based audit approach to avatar interactions (e.g., dialogues, gestures, facial expressions) is introduced in two cases that an avatar enters a digital world and that an avatar requests the auditing to subjects, e.g., avatars controlled by human users, artificial intelligence (AI) avatars (e.g., as conversational bots), and virtual objects. Pseudocodes for performing the two cases in a system are presented and they are examined based on the description of the avatars' actions.