• Advances in aircraft and spacecraft science
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• v.7 no.1
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• pp.79-90
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• 2020

The dynamic coupling between shaker and test-article has been investigated by recent research through the so called Virtual Shaker Testing (VST) approach. Basically a VST model includes the mathematical models of the test-item, of the shaker body, of the seismic mass and the facility vibration control algorithm. The subsequent coupled dynamic simulation even if more complex than the classical hard-mounted sine test-prediction, is a closer representation of the reality and is expected to be more accurate. One of the most remarkable benefits of VST is the accurate quantification of the frequency down-shift (with respect to the hard-mounted value), typically affecting the first lateral resonance of heavy test-items, like medium or large size Spacecraft (S/Cs), once mounted on the shaker. In this work, starting from previous successful VST experiences, the parameters having impact on the frequency shift are identified and discussed one by one. A simplified analytical system is thus defined to propose an efficient and effective way of calculating the lower bound frequency shift through a simple equation. Such equation can be useful to correct the S/C lateral natural frequency measured during the test, in order to remove the contribution attributable to the shaker in use. The so-corrected frequency value becomes relevant when verifying the compliance of the S/C w.r.t. the frequency requirement from the Launcher Authority. Moreover, it allows to perform a consistent post-test correlation of the first lateral natural frequency of S/C FE model.

• Journal of Fashion Business
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• v.13 no.6
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• pp.20-30
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• 2009

The purpose of this study is to develop the effective customized elderly fashion marketing process based on the web site, where older customer will be able to choose various fabrics and to try them out. This aims to establish new prototype of internet shopping mall for customized elderly fashion clothing. In this study, new method of product presentation on the online shopping mall is proposed to offer product information through 3D virtual reality. With the online shopping mall(SATC Mall) as a showcase, we presented virtual mapping system so that it enable the customers to select the fabrics and to see exactly how chosen fabric will look when applied to image of clothing. As an initial test of the application of simulation to measure 3D visualization of product, mapping software Vision Easy Map Pro Version 6.0(NedGraphics) Vision Easy Map Viewer Version 5.0(NedGraphics) were chosen and applied. By using this mapping system, the fabric change of the apparel product could be made on the internet shopping web site. However, this approach has been successful applied for presenting and customizing garment products. Future research will focus on the integration of mapping coordination into SATC Mall.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.3
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• pp.326-334
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• 2015

This paper describes the verification and the validation about the development of the integrated interoperability system for live, virtual, and constructive simulations on the aircraft weapon system. The proposed integrated interoperability system provides the framework and application softwares for implementing a synthetic environment emulating real-world environment among distributed simulation models, which are a mission model and an air combat model of a constructive level, an tactical simulator of a virtual level, and simulated ACMI of a live level. In this paper, we verify requested functions through an developmental test and evaluation, and validate operability and usability through conducing integrated LVC scenarios on the integrated interoperability system.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.68-74
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• 2006

The evaluation of durability performance in Virtual Testing Laboratory(VTL) is a new concept of vehicle design, which can reduce the automotive design period and cost. In this study, the multibody dynamics model of a car is built with a reverse engineering design. Hard points and masses of components are measured by a surface scanning device and imported into CAD system. In order to simulate the non-linear dynamic behavior of force elements such as dampers and bushes, components and materials are tested with specialized test equipments. An optimized numerical model for the damping behavior is used and the hysteresis of bush rubber is considered in the simulation. Loads of components are calculated in VTL and used in the evaluation of durability performance. In order to verify simulation results, loads of components in the vehicle are measured and durability tests are performed.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.205-223
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• 2018

During launch a spacecraft is subjected to a variety of dynamical loads transmitted through the launcher to spacecraft interface or air-born transmission excitations in the acoustic pressure field inside the fairing. As a result, spacecraft are tested on ground to ensure and demonstrate the global integrity of the structure against these loads, to screen the flight hardware for quality of workmanship and to validate mathematical models. This paper addresses the numerical modelling and simulation of the low frequency sine and random vibration tests performed on electrodynamic shaker facilities to comprise the mechanical-borne transmission loads through the launcher to spacecraft interface. Consequently, the paper reviews techniques and methodologies to derive a reliable and representative coupled virtual vibration testing simulation environment based on experimental data. These technologies are explored with the main objectives to ensure a stable, reliable and accurate control while testing. As a result, the use of the derived simulation models in combination with the added value of improved control and signal processing algorithms can lead to a safer and smoother vibration test control of the entire environmental test campaign.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.788-796
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• 2001

VR(Virtual reality) technologies have given engineers the ability to design, test, and evaluate engineering systems in a virtual environment. The virtual plant is the highlight of the application of the VR technology to plant engineering. Plant design, maintenance, control, management, operation are integrated in the virtual plant. The VR monitoring system including the concept of the virtual plant is developed to replace a current control room that has number of gages and warning lamps in two-dimensional panels which shows the operating status of a plant. The operating status of the plant is displayed in the VR monitoring system through the realistic computer graphics. Sophisticated, realistic and prompt control becomes possible. The VR monitoring system consists of advanced visualization, walk-through simulation and navigation. In the virtual environment, a user can navigate and interact with each component of a plant. In addition, the user can access the information by just clicking interesting component. The VR monitoring system is operated with various modules, such as (1) virtual plant constructed with Graphic Management System (GMS), (2) Touch & Tell System, and (3) Equipment DB System of Part. In order to confirm the usefulness of the VR monitoring system, a pilot gas plant which is currently being used for plant operator training is taken as application. The end of the paper gives an outlook on the future work and a brief conclusion.

• International Journal of Automotive Technology
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• v.6 no.1
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• pp.29-35
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• 2005

The structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, Noise/Vibration/Harshness (NVH), crashworthiness, and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, the Virtual Proving Ground (VPG) approach has been developed to simulate dynamic nonlinear events as applied to automotive ride & handling. The finite element analysis technique provides a unique method to create and analyze vehicle system models, capable of including vehicle suspensions, powertrains, and body structures in a single simulation. Through the development of this methodology, event-based simulations of vehicle performance over a given three-dimensional road surface can be performed. To verify the predicted dynamic results, a single lane change test was performed. The predicted results were compared with the experimental test results, and the feasibility of the integrated CAE analysis methodology was verified.

• Journal of the Ergonomics Society of Korea
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• v.29 no.2
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• pp.249-255
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• 2010

The visibility evaluation is significant for the development of construction equipment. The visibility evaluation follows the standards of ISO 5006, ISO 14401-1, and ISO 14401-2. The evaluation contains the operator's visibility and the visibility of rear-view mirrors. The operator's visibility includes the visibility test which requires the recognition of the rectangular line surrounding the machine by one meter and the circle with a 12 meter radius. This study describes the two evaluation processes for the development of the wheel loader. The first process is the light bulb shadow test by using a prototype wheel loader. The second process is based on computer simulation in virtual space. The advantages and disadvantages of computer simulation process are investigated.

• Journal of the Korean Society of Costume
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• v.66 no.8
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• pp.46-60
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• 2016

Countries have different brassiere patterns, and this study produced and compared 3/4 brassiere patterns from different countries to determine the difference in patterns, and to investigate the stress distribution and shape of cross section while wearing brassieres using 3D virtual fitting system. Despite the growing interest in underwear, there is a lack of related books and research on brassiere patterns, which causes the difference in sizes and pattern drafting methods by countries. Thus, research on this is needed. 3D virtual fitting system has been introduced to compare patterns, thereby improving visible effects and reducing the loss in cost caused by underwear pattern fitting test. According to the result of pattern analysis, The Secoli type exhibited the least breast cover rate (14.9 cm), while the largest cover rate was shown in Christina and ESMOD types (17.7 cm). It is believed that the difference in pattern drafting causes the difference in the total length of a brassiere. Furthermore, the Secoli, Moda Burgo, and ESMOD brassieres drafted from basic bodice pattern were found to be longer than the Christina and Han Sunmi brassieres attained from direct pattern drafting. Moreover, the darts' volume of upper and lower cups in Christina and Han Sunmi types was similar in shape. The shapes of cradle drafted from basic bodice pattern were a straight line, while those from direct drafting formed a curved shape. In fitting multiple cross sections, the Secoli, Moda Burgo, and ESMOD brassieres had gaps between the brassieres and the body. Among these, the largest number of gaps was observed in the ESMOD type pattern. This study aimed at performing comparative analysis of various brassieres' pattern drafting types as a basic research for developing a brassiere pattern drafting type.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.2
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• pp.132-140
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• 2002

This paper presents an ARM-based SOC bus transaction verification IP and the usage experiences in SOC designs. The verification IP is an AMBA AHB protocol checker, which captures legal AHB transactions in FSM-style signal sequence checking routines. This checker can be considered as a reusable verification IP since it does not change unless the bus protocol changes. Our AHB protocol checker is designed to be scalable to any number of AHB masters and reusable for various AMBA-based SOC designs. The keys to the scalability and the reusability are Object-Oriented Programming (OOP), virtual port, and bind operation. This paper describes how OOP, virtual port, and bind features are used to implement AHB protocol checker. Using the AHB protocol checker, an AHB simulation monitor is constructed. The monitor checks the legal bus arbitration and detects the first cycle of an AHB transaction. Then it calls AHB protocol checker to check the expected AHB signal sequences. We integrate the AHB bus monitor into Verilog simulation environment to replace time-consuming visual waveform inspection, and it allows us to find design bugs quickly. This paper also discusses AMBA AHB bus transaction coverage metrics and AHB transaction coverage analysis. Test programs for five AHB masters of an SOC, four channel DMAs and a host interface unit are executed and transaction coverage for DMA verification is collected during simulation. These coverage results can be used to determine the weak point of test programs in terms of the number of bus transactions occurred and guide to improve the quality of the test programs. Also, the coverage results can be used to obtain bus utilization statistics since the bus cycles occupied by each AHB master can be obtained.