• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1103-1114
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• 2000

Recent attempt to enhance the safety against collision reshaped the simple shell structures into the integrated complex shell structures. Moreover, due to various regulations continuously tightened for environment protection, weight reduction of automobiles becomes an increasingly important issue. Auto parts lightening is mainly accomplished by more reasonable design, adoption of lighter materials and miniaturization of the auto bodies. Focusing on the locally enhanced design approach among the above three ways, we here attempt to develop a patching optimization method, and also to determine the thicknesses of an integrated shell structure, both bringing a specified amount of stress relaxation. We first select a cross member as a patching optimization model. Based on the finite element stress calculations, we relieve the stress of cross member by patching in two ways-nonuniform thickness patching and optimized uniform thickness patching, the latter of which is more effective in a practical point of view for the preset amount of stress relaxation. Selecting a box type subframe as another finite element analysis model, we then determine the thickness of each part by axiomatic design approach for a preset amount of stress relaxation. The patching methodology and the axiomatic approach adopted in this work can be applied to the other complex shell structures such as center member and lower control arm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.111-119
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• 2017

This paper presents a method to determine the rear steering angle in integrated chassis control with electronic stability control (ESC) and rear wheel steering (RWS). A control yaw moment needed to stabilize a vehicle should be distributed into the tire forces generated by the ESC and RWS. Weighted pseudo-inverse control allocation (WPCA) is adopted to determine the tire forces. Four methods are proposed to calculate the rear wheel steering angle. To validate the proposed methods, a simulation is performed using a vehicle simulation software package, CarSim. The simulation results show that the proposed method for determining the rear wheel steering angle improves the performance of the integrated chassis control.

• Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.261-267
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• 2015

Free-form blades are widely used in different industries, such as aero-engine and steam turbine. Blades that are damaged during service or have production deficiencies are usually replaced with new ones. This leads to the waste of expensive material and is not sustainable. However, material and costs can be saved by repairing of locally damaged blades or blades with localized production deficiencies. The blade needs to be further machined after welding process to reach the aerodynamic performance requirements. This paper outlines an adaptive location approach of repaired blade for model reconstruction and NC machining. Firstly, a mathematical model is established to describe the localization problem under constraints. Secondly, by solving the mathematical model, localization of repaired blade for NC machining can be obtained. Furthermore, a more flexible method based on the proposed mathematical model and the continuity of the deformation process is developed to realize a better localization. Thirdly, by rebuilding the model of the repaired blade and extracting repair error, optimized tool paths for NC machining is generated adaptively for each individual part. Finally, three examples are given to validate the proposed method.

• Journal of The Korea Institute of Healthcare Architecture
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• v.12 no.1
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• pp.27-39
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• 2006

This study was intended to present the proper operational scheme and present the criterion for establishment of proper convenient facilities and its planning method and the proper method of laying all sorts of teaching aids out. For this purpose, it attempted to investigate the type of crippled disorder and the behavioral characteristics of schoolchildren with crippled disorder with a focus on the descriptive study on disabled schoolchildren receiving complete integrated education. And it sought to analyze the present situation of complete integrated education and the case of integrated education and dissect the realities of its operation and the realities of the establishment of convenient facilities for disabled schoolchildren with a focus on the survey research.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.21-28
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• 2020

Integrated bidirectional OBC/LDC was developed to reduce the volume for elements, avoid space restriction, and increase efficiency in EV vehicles. In this study, a DC-DC converter in integrated OBC/LDC circuits was composed of an SRC circuit with a stable output voltage relative to an LLC circuit using a theoretical method and simulation. The resonant network of the selected circuit was optimized to minimize the power loss and element volume under constraints for the buck converter and the battery charging range. Moreover, the validity of the optimal model was verified through an analysis using a theoretical method and a numerical analysis based on power loss at the optimized resonant frequency.

• Journal of Power Electronics
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• v.15 no.2
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• pp.378-388
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• 2015

This paper proposes a pulse width modulation (PWM)-based sliding mode controller (SMC) for a full-bridge DC-DC converter that can eliminate static output voltage error. Hysteretic SMC in DC-DC converter does not have a fixed switching frequency, and applying hysteretic SMC to full-bridge converters is difficult. Fixed-frequency SMC, which is also called PWM-based SMC, based on equivalent control overcomes these shortcomings. However, the controller order reduction in equivalent control in PWM-based SMC causes static output voltage error. To resolve this issue, an integral item is added to the PWM-based SMC. Sliding mode coefficients are designed by applying a standard second-order system to the sliding mode surface. The effect of adding an integral item on the controller is analyzed, and an integral coefficient design method is proposed. Experiment results on a three-level full-bridge DC-DC converter verify the control scheme and design method proposed in this paper.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.1-23
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• 2021

The form of agri-food transaction has taken a rapid change from the existing method since Covid-19. In response to changes in the market environment such as Covid-19, the integrated marketing organization in Jeollabuk-do was diagnosed from the point of view of innovation, and the future direction was examined. In order to improve the distribution structure of the production area, an integrated marketing organization was fostered, and both quantitative and qualitative growth were brought about. However, some regions still lack willingness to participate and lack of expertise. In particular, there is no infrastructure and strategy to prepare for the increase in non-face-to-face transactions post Covid-19. Online transactions also require economies of scale, so non-face-to-face transaction capabilities must be reinforced by adding a separate organization and experts in charge of online transaction functions within the integrated marketing organization. In the future, online sales are highly likely to expand not only to transactions between producers and individual consumers (C to C), but also to mass consumer (B to B) transactions. It will be an opportunity. In addition, it is necessary to efficiently use production area distribution facilities such as sorting and packaging. Since the non-contact transaction method will increase after Corona 19, it is necessary to strengthen marketing capabilities such as expansion of utilization rate, order placement, settlement, and customer management, and reorganization of specialized organizations.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.123-133
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• 2019

Bicycle fitting used to depend on empirical adherence of bicycle Peter and intuitive judgment by hand, but recent developments in industry and the Fourth Industrial Revolution have continuously developed other related tools that can be applied to bicycle fitting. Depending on these circumstances, bicycle fitting technology is also developing, and due to the difficulty of the technicians, there is a limit to popularizing. The Bicycle Integrated Fitting System has the need for this study to make these problems easy for anyone to operate by the system of manual. The purpose of this study is to examine the methods of physical sizing among the various stages of developing these systems. Accurate physical measurements can improve the efficiency of bicycle riding and minimize the injury of bicycle risers issued by incorrect fittings. Thus, in this study, physical measurement methods for bicycle fitting were derived by body region and applied to the post-measurement fitting as well as the location and method of measurement. It has prepared a basis for establishing a core database for physical measurement of development of integrated bicycle fitting system. Research was conducted to enhance understanding and utilization of users after system development and results were derived for the purpose of the study. Research was conducted to establish a database for the development of a bicycle integrated fitting system, and future research on bicycle fitting methods, application of the system, and hardware development should be carried out.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.237-246
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• 2022

This paper proposes a method to adjust the turn ratio of a transformer for the high-efficiency operation of an LLC converter with a wide input range in a wired/wireless integrated charging system for electric vehicles. The characteristics of the inductive power transfer converter in the integrated charging system are analyzed to design the LLC converter, and the DC-link voltage range is derived. The aspect of voltage gain following each parameter of the LLC converter is analyzed, and the resonant network and transformer are designed. Based on the designed parameters, the feasibility of the design and control method is verified by implementing the operation of the LLC converter according to the DC-link and battery voltages.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.570-575
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• 2013

Enhancing utilization of buildings is gaining in importance in response to a challenging economy; thus, there is a need for a method that analyzes space, user, and user activity in an integrated way to provide project stakeholders with utilization information to support their decision-making about buildings. Conventional methods, such as architectural programming and post-occupancy evaluation, lack a formal relationship between user activity and other information, and therefore, are coarse-grained. This relationship has been formalized by two relatively new methods that provide fine-grained utilization information: workplace planning and space-use analysis. We characterize these two methods with focuses on their usage in different phases (i.e., planning, design, occupancy), required information that needs to be gathered, and the achievement and limitations in terms of three criteria, i.e., consistency, efficiency, and transparency. This characterization would not only help project stakeholders select and use a method that best meets their purposes for enhancing utilization of their buildings, but also provide researchers with promising research topics regarding enhancing utilization of buildings.