• Tribology and Lubricants
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• v.30 no.2
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• pp.116-123
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• 2014

The objective of this study is to model and simulate the nonlinear lubrication performance of the sliding part between the piston and cylinder wall in a hydrostatic swash-plate-type axial piston pump. A numerical algorithm is developed that facilitates simultaneous calculation of the rotating body motion and fluid film pressure to observe the fluid film geometry and power loss. It is assumed that solid asperity contact, so-called mixed lubrication in this study, invariably occurs in the swash-plate-type axial piston pump, which produces a higher lateral moment on the pistons than other types of hydrostatic machines. Two comparative mixed lubrication models, rigid and elastic, are used to determine the reaction force and sliding friction. The rigid model does not allow any elastic deformation in the partial lubrication area. The patch shapes, reactive forces, and virtual local elastic deformation in the partial lubrication area are obtained in the elastic contact model using a simple Hertz contact theory. The calculation results show that a higher reaction force and friction loss are obtained in the rigid model, indicating that solid deformation is a significant factor on the lubrication characteristics of the reciprocating piston part.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.25-31
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• 2011

In this paper, we propose virtual building construction plans. For this, we compose the construction materials with components and assemble components in pattern. When we change assembled constructions, we can design the building efficiently with patterns if the parts are selected. Also through information analysis of material components or patterns, we can provide information which is necessary to a reconstruction to the designer. Using steal house method, the assembly functions were comprised of a wall, a room, a window, a door, roof etc. Also We explained the materials automatic extraction method which applies steal house.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.5
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• pp.353-357
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• 2020

Fractures of the orbital floor and walls are among the most frequent maxillofacial fractures. Virtual three-dimensional (3D) planning and use of patient-specific implants (PSIs) could improve anatomic and functional outcomes in orbital reconstruction surgery. The presented case was a victim of a terrorist attack involving improvised explosive devices. This 58-year-old female suffered severe wounds caused by a single piece of metal from a bomb, shattering the left orbital floor and lateral orbital wall. Due to remaining hypotropia of the left eye compared to the right eye, late orbital floor reconstruction was carried out with a personalised 3D printed titanium implant. We concluded that this technique with PSI appears to be a viable method to correct complex orbital floor defects. Our research group noted good aesthetic and functional results one year after surgery. Due to the complexity of the surgery for a major bony defect of the orbital floor, it is important that the surgery be executed by experienced surgeons in the field of maxillofacial traumatology.

• Journal of the Korean housing association
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• v.22 no.3
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• pp.93-100
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• 2011

The objective of this study is to provide basic objective data which can be utilized as an adjustment criterion for the alleviation of the limit on the number of floors of buildings by quantitatively evaluates the effect of the alleviation of the limit on the number of floors of buildings in apartment complexes on thermal environment of apartment complexes using data obtained from apartments in a class 2 general residential area. In this study, we carried out a thermal environment analysis utilizing the simulation of a virtual object area. The result is summarized as follows: The result of analyzing the entire surface temperature showed an equal decrease of surface temperature due to shadow in all scenarios and high floors showed a tendency of low surface temperature during daytime as the rate of shadow the high floors increase. This influences not only the surface temperature but also HIP and is judged to greatly contribute to the alleviation of the heat island effect. Also, the reason why HIP at high floors shows high values before sunrise and after sunset is thought to be because the concrete wall of the building maintains a high temperature during nighttime by absorbing and storing sunlight during daytime instead of reflecting it since it has low reflectance.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.471-478
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• 2011

This UGV (Unmanned Ground Vehicle) is not only widely used in various practical applications but is also currently being researched in many disciplines. In particular, obstacle avoidance is considered one of the most important technologies in the navigation of an unmanned vehicle. In this paper, we introduce a simple algorithm for path planning in order to reach a destination while avoiding a polygonal-shaped static obstacle. To effectively avoid such an obstacle, a path planned near the obstacle is much shorter than a path planned far from the obstacle, on the condition that both paths guarantee that the robot will not collide with the obstacle. So, to generate a path near the obstacle, we have developed an algorithm that combines an edge detection method and a limit-cycle navigation method. The edge detection method, based on Hough Transform and IR sensors, finds an obstacle's edge, and the limit-cycle navigation method generates a path that is smooth enough to reach a detected obstacle's edge. And we proposed novel algorithm to solve local minima using the virtual wall in the local vision. Finally, we verify performances of the proposed algorithm through simulations and experiments.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1441-1476
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• 2021

The tracheobronchial tree is a system of airways that allows the passage of air to aerate the lungs and entire body. Several pathological conditions can affect this anatomical region. Multidetector CT (MDCT) helps identify and characterize various large airway diseases. Post-processing tools, such as virtual bronchoscopy and automatic lung analysis, can help enhance the performance of imaging studies. In this pictorial essay review, we provide imaging findings of various bronchial lesions manifested as wall thickening and endoluminal nodules on conventional MDCT and advanced image visualization and analysis.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.97-107
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• 2013

The latest programming paradigm has been mostly geared toward object-oriented programming and visual programming based on the object-oriented programming. However, object-oriented programming has a more difficult and complicated concept compared with that of existing structural programming technique; thus it has been very difficult to educate students in the IT-related department. This study designed and implemented a Java robot training kit in which the Java virtual machine is built so that it may enhance the desire and motivation of students for learning the object-oriented programming using the training kit which is possible to attach various input and output devices and to control a robot. The developed Java robot training kit is able to communicate with a computer through the USB interface, and it also enables learners to manufacture a robot for education and to practice applied programming because there is a general purpose input and output port inside the kit, through which diverse input and output devices, DC motor, and servo motor can be operated. Accordingly, facing the IT fusion era, the wall between the academic circles and the major becomes lower and the need for introducing education about creative engineering object-oriented programming language is emerging. At this point, the Java robot training kit developed in this study is expected to make a great commitment in this regard.

• Journal of KIBIM
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• v.2 no.1
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• pp.1-6
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• 2012

With the increased awareness of energy consumption as well as the environmental impact of building operations, architects, designers and planners are required to place more consideration on sustainability and energy performance of the building. To ensure most of those considerations are reflected in the building performance, critical design decisions should be made by key stakeholders early during the design development stage. The application of BIM during building energy simulations has profoundly improved the energy analysis process and thus this approach has gained momentum. However, despite rapid advances in BIM-based processes, the question still remains how ordinary building stakeholders can perform energy performance analysis, which has previously been conducted predominantly by professionals, to maximize energy efficient building performance. To address this issue, we identified two leading building performance analysis software programs, Energy Plus and IES (IES ), and compared their effectiveness and suitability as BIM-based energy simulation tools. To facilitate this study, we examined a case study on Building Performance Model (BPM) of a single story building with one door, multiple windows on each wall, a slab and a roof. We focused particularly on building energy performance by differing building orientation and window sizes and compared how effectively these two software programs analyzed the performance. We also looked at typical decision-making processes implementing building energy simulation program during the early design stages in the U.S. Finally, conclusions were drawn as to how to conduct BIM-based building energy performance evaluations more efficiently. Suggestions for further avenues of research are also made.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.101-107
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• 2020

We propose a realistic seeing through visualization methods in mixed reality environment. When a user wants to see specific location beyond a wall in indoor environment. The proposed system recognizes and registers the selected area using environment modelling and feature-based tracking. Then the selected area is diminished and the specific location is visualized in real-time. With the proposed seeing through methods, a user can understand spatial relationship of the building and can easily find the target location. We conducted a user study comparing the seeing through method to conventional indoor navigation service in order to investigate the potential of the proposed seeing through method. The proposed seeing through method was evaluated in navigation time in comparison with conventional approach. The proposed method enable users to navigate target locations 30% faster than the conventional approach.

• Korean Institute of Interior Design Journal
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• v.25 no.5
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• pp.111-120
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• 2016

Unlike the past, brick-and-mortar is no longer on the priority list for the shopping activity. Instead, it is replaced by various non-store shopping alternatives, such as Internet, TV, catalog, mobile, etc. As consumers engage digitally, they made fewer trips to stores. Especially, as mobile shopping made the price comparison possible while shopping in the store, new shopping trend of 'showrooming' came to the fore as the serious issue. In order to cope with the this crisis, many brick-and-mortar retailers utilize omni-channel strategy for their countermeasure. This research paper is to suggest the omni-channel strategy that is applicable for the brick-and-mortar retailers. The results are as follows. First, in order to set up the connected-channel shopping environment, consumers have to be exposed to the environment that can deliver the continuous brand experience under the same price policy, brand and store management, etc, as integrating the various purchasing channels into one. Especially, in-store environment needs to change for the place where consumer experience is stressed for the most as using virtual reality devices with augmented reality technology. Also, the online digital kiosk, and tablet that consumer can order the products through the online channel while shopping in-store Second, the barrier-free in-store environment should be offered in order to increase the consumer convenience. This change will allow consumer communicate with the store environment more effectively. Lastly, brick-and-mortar should extend the physical territory as utilizing the offline's advantage and disadvantage through setting up the digital interactive wall or pop-up store for increasing the opportunity of customer interaction with the store. Moreover, visiting service for the elderly, housewife with the baby, or disabled person will be one of the effective substitute.