• Proceedings of the KSME Conference
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• 2001.06c
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• pp.219-223
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• 2001

This paper introduces DS/Block-Structure - a structural analysis module of DS/Block, which is a Design System to simulate the behavior of a ship block in various crane operations and to evaluate its structural deformation using the finite element method. It runs based on a CAD program, Pro/ENGINEER, and structural analyses are performed by a developed FE code. Boundary conditions for the FE analysis of a ship block under lifting and turnover operation are also considered.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2395-2398
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• 2003

This paper focuses on lossless medical image compression methods for medical images that operate on two-dimensional(2D) reversible integer wavelet transform. We offer an application of the Set Partitioning in Hierarchical Trees(SPIHT) algorithm [1][3][9] to medical images, using a 2D wavelet decomposition and a 2D spatial dependence tree. The wavelet decomposition is accomplished with integer wavelet filters implemented with the lifting method, where careful scaling and truncations keep the integer precision small and the transform unitary. We have tested our encoder on medical images using different integer filters. Results show that our algorithm with certain filters performs as well and sometimes better in lossless coding than previous coding systems using 2D integer wavelet transforms on medical images.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.7-12
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• 2009

In JPEG2000, the Cohen-Daubechies-Feauveau (CDF) 9/7-tap wavelet filter adopted in lossy compression is implemented by the lifting scheme or by the convolution scheme while the LeGall 5/3-tap wavelet filter adopted in lossless compression is implemented just by the lifting scheme. However, these filters are not optimal in terms of Peak Signal-to-Noise Ratio (PSNR) values, and irrational coefficients of wavelet filters are complicated. In this paper, we proposed a method to optimize image quality based on wavelet filter design and on wavelet decomposition. First, we propose a design of wavelet filters by selecting the most appropriate rational coefficients of wavelet filters. These filters are shown to have better performance than previous wavelet ones. Then, we choose the most appropriate wavelet decomposition to get the optimal PSNR values of images.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1548-1556
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• 2006

Appropriate contact force is required for the pantograph on the high speed train to collect current from the catenery system without separation. However, at high speed, large aerodynamic lifting force is generated by the contact plate and the body of pantograph, which may cause wear of the contact wire. In this study, to confirm the interface performance of the pantograph on Korea High Speed Train, a method to measure the contact force of the pantograph was proposed and the related measuring system was developed. The forces acting on the pantograph were clarified and a practical procedure to estimate the forces was proposed. A special device was invented and applied to measure the aerodynamic lifting force. Measured contact forces were displayed by the developed system and evaluated based on the criteria.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.648-654
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• 2018

In order to maintain manholes installed on the road, the manhole should be easy to open and close. Manhole covers under harsh conditions require that they can be lifted when attempting to open the manhole because the frame and cover are stuck and difficult to open and close. In this study, the design of a lifting mechanism was carried out to improve and integrate the locking type manhole. The mechanism of the locking manhole is that when the bolt located at the center is turned, the hub connected with the bolt descends, and the hook connected to the hub is rotated. The end of the hook is hooked to the manhole frame. The auxiliary device was installed on the hook so that the manhole cover can be lifted. The structure was designed to endure about 300kg of lifting force based on 70% of the yield stress of the hook to perform lifting function. The shape design was performed through the structural analysis using the finite element method. First, the basic design was performed with the simplified 2-dimensional model and the attachment position and shape were designed through the 3-dimensional model. In order to find out the structural problems of the designed shape, the scale downed model was fabricated through 3D printing and confirmed that the lifting function worked. Finally, it was confirmed that both the locking and the average lifting of about 6.1 mm can be done by applying the lifting mechanism through the machining and applying it to the existing locking manhole.

• International Journal of Aeronautical and Space Sciences
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• v.1 no.1
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• pp.29-35
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• 2000

A numerical method to simulate Wing-In-Ground(WIG) effects for the wings moving near ground is developed. The aerodynamic analysis scheme for the wings is based on a compressible non-planar lifting surface panel method and the WIG effect is included by images. The thickness-induced effect is implemented into the lifting surface panel method by using the teardrop theory. The numerical simulation is done for the rectangular wings by varying the ground proximity. The present method is validated by comparing the calculated aerodynamic coefficients with other numerical results and measured data, showing good agreements.

• Journal of the Korea Society of Computer and Information
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• v.23 no.7
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• pp.49-56
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• 2018

Virtual object weight perception is an important topic, as it heightens the believability of object manipulation in immersive virtual environments. Although weight perception can be achieved using haptic interfaces, their technical complexity makes them difficult to apply in immersive virtual environments. In this study, we present a visual pseudo-haptic feedback system that simulates and depicts the weights of virtual objects, the effect of which is weight perception. The proposed method recognizes grasping and manipulating hand motions using computer vision-based tracking methods, visualizing a Force Arrow to indicate the current lifting forces and its difference from the standard lifting force. With the proposed Force Arrow method, a user can more accurately perceive the logical and unidirectional weight and therefore control the force used to lift a virtual object. In this paper, we investigate the potential of the proposed method in discriminating between different weights of virtual objects.

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.1
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• pp.83-101
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• 2016

This paper suggests an event-based scenario manager capable of creating and editing a scenario for shipbuilding process simulation based on multibody dynamics. To configure various situation in shipyards and easily connect with multibody dynamics, the proposed method has two main concepts: an Actor and an Action List. The Actor represents the anatomic unit of action in the multibody dynamics and can be connected to a specific component of the dynamics kernel such as the body and joint. The user can make a scenario up by combining the actors. The Action List contains information for arranging and executing the actors. Since the shipbuilding process is a kind of event-based sequence, all simulation models were configured using Discrete EVent System Specification (DEVS) formalism. The proposed method was applied to simulations of various operations in shipyards such as lifting and erection of a block and heavy load lifting operation using multiple cranes.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.4
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• pp.283-289
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• 2015

RGT(Riser Guide Tube) is a part of mooring on the bottom of a turret system to be connected with a production riser, and DBSC(Diverless Bend Stiffener Connector) is a latching component between them. In this paper, appropriate lug arrangement is decided mathematically for the case that a DBSC is lifted and installed on a RGT under the water while FPSO is under construction. Considering asymmetric arrangement & position of RGT and initial lug position, additional lug positions are determined by using an optimization method. The modified installation scheme with new lug points is investigated with a lifting simulation system, SIMSON. The simulation result shows that the installation of DBSC on RGT under the given conditions is quite feasible; therefore the mathematical method is proven to be appropriate.

• Archives of Plastic Surgery
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• v.47 no.3
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• pp.256-262
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• 2020

Background Most women consider an oval-shaped face to be youthful and beautiful. In recent years, demand has grown for surgical procedures with a shorter downtime and fewer complications. These minimally invasive procedures include botulinum toxin type A (BoNTA) injection, filler injection, suction-assisted liposuction (SAL), laser-assisted lipolysis (LAL), thread lifting, and fat grafting. This study aims to introduce an effective method for creating an aesthetically pleasing lower face using a combination of minimally invasive procedures. Methods From March 2017 to March 2019, 94 patients simultaneously underwent LAL, SAL, and thread lifting. Ancillary procedures such as BoNTA injections, hyaluronic acid filler injections, and removal of the buccal fat pad (BFP) were selectively performed according to the patient's condition. Results Patients rated their postoperative satisfaction as very satisfied, satisfied, dissatisfied, or very dissatisfied. Approximately 83% of all respondents were satisfied with the results, whereas the remaining respondents had complaints regarding the outcomes. The most common reasons for dissatisfaction were a longer-than-expected recovery time and undercorrection, and the most severe complaint was skin depression as a result of overcorrection. Conclusions Our method of simultaneously performing LAL, SAL, and thread lifting, while adding BoNTA, filler injections, and BFP removal as needed, was capable of producing consistent and reliable aesthetic outcomes for the lower face.