• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.465-470
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• 2022

This paper studied the high-velocity impact behavior characteristics of metal materials by crosschecking the high-velocity impact analysis with the high-velocity impact experiment results of aluminul 6061. The coefficients of the Huh-Kang material model and the Johnson-Cook fracture model were calculated through quasi-static using MTS-810 and dynamic experimenting using the Hopkinson bar equipment for high-velocity impact analysis. The penetration velocity and shape were predicted through high-velocity impact analysis using the LS-DYNA. The resultes were compared with the experiment results using a high-velocit experiment equipment. It is intended to be used the containment evaluation research for aircraft gas turbine engine blade.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.191-202
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• 2023

This study aims to propose a framework for evaluating the impact of artificial intelligence (AI) services, based on the concept of AI service impact. It also suggests a model for evaluating this impact and identifies relevant factors and measurement approaches for each item of the model. The study classifies the impact of AI services into five categories: ethics, safety and reliability, compliance, user rights, and environmental friendliness. It discusses these five categories from a broad perspective and provides 21 detailed factors for evaluating each category. In terms of ethics, the study introduces three additional factors-accessibility, openness, and fairness-to the ten items initially developed by KISDI. In the safety and reliability category, the study excludes factors such as dependability, policy, compliance, and awareness improvement as they can be better addressed from a technical perspective. The compliance category includes factors such as human rights protection, privacy protection, non-infringement, publicness, accountability, safety, transparency, policy compliance, and explainability.For the user rights category, the study excludes factors such as publicness, data management, policy compliance, awareness improvement, recoverability, openness, and accuracy. The environmental friendliness category encompasses diversity, publicness, dependability, transparency, awareness improvement, recoverability, and openness.This study lays the foundation for further related research and contributes to the establishment of relevant policies by establishing a model for evaluating the impact of AI services. Future research is required to assess the validity of the developed indicators and provide specific evaluation items for practical use, based on expert evaluations.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.43-47
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• 2007

Based on experimental impact testing data, due to changing of velocity and mass of the impactor simultaneously under constant impact energy, crashworthiness of polyurethane foam has been observed. Dynamic tests were carried out in an instrumented impact-testing machine. Also, modified Sherwood-Frost model was proposed to investigate the crashworthy behaviour of rigid polyurethane foam under the condition of constant impact energy.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.116-125
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• 1997

An investigation was performed to study the impact damage in CFRP laminated composites subjected to impact loading. A finite element model has been developed for predicting the impact damage in laminated composite plates resulting from the ballistic impact. The finite element model was based on the higher-order shear deformation theory and was used to predict the initial intraply matrix cracking and the shape and size of interface delamination in laminated composites. Numerical simulation was performed and then the initiation of the matrix cracking and the shape and size of impacted induced delamination were predicted, and te results were compared with those of impact experiments with the same dimension and stacking sequences. A linear relationship holds between impact velocity and length and width of delamination. As impact velocity is increased, the increase of delamination length is highger than the increase of delamination width.

• Journal of the Korea Institute of Building Construction
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• v.21 no.5
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• pp.495-506
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• 2021

A Conceptual cost estimate, which is computed in the preliminary step of a project, is important for decision-making by a contractor in terms of the project budget, economic feasibility and validity analysis, and alternative comparisons. Therefore, a high error rate of a prediction model for a conceptual cost estimate can lead to various problems including excessive project expenditures and a delayed break-even point. this study proposed optimal impact factors by configuring quantitative impact factors computable in a preliminary step in various cases(combinations of impact factors). subsequently, the accuracy of different cases was comparatively analyzed by using the cases as input values of a prediction model using regression analysis. when the optimal combination of impact factors proposed in this study and other combination of impact factors were applied to the prediction model, the regression analysis-based prediction model exhibited 0.2-4.7% improvements in accuracy, respectively. the optimal combination of impact factors proposed in this study improved the accuracy of the prediction model of a conceptual cost estimate by removing unnecessary impact factor.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.135-142
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• 2007

MADYMO human model with the detail neck was used to investigate the reaction force of neck and neck injury from rear impact directions. In the validation simulation, head acceleration, thorax acceleration and the global kinematics of the head and neck were correlated well with experimental data. Acceleration data from three 15 km/h low speed car rear impact pendulum tests(rear-end, offset, oblique) were used to simulate the model. In the simulation results, the reaction force on the facet joint and discs in the oblique rear impact were higher than rear-end, offset rear impacts. Further research is still needed in order to neck injury analysis about different crash parameters.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.503-507
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• 2004

The radiated sound pressure induced by low-velocity impact is obtained by solving the Rayleigh integral equation. This paper established the sound analysis procedure using impact analysis model. For structurally radiated noise, the sound field is directly coupled to the structural motion. Therefore the impact response should be analyzed. The impact response is computed using the spring-mass model. And the influence of damage on the sound pressure and impacted force history of laminated were investigated. The results show that both radiated sound pressure and impact force history are strongly influenced by damage on laminated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.7
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• pp.1089-1096
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• 2001

This paper presents the fatigue behavior of composite materials with impact-induced damage under 2 level block loading. For this purpose, the 2 level block loading fatigue tests were performed on the impacted composite laminate. The fatigue life of the laminate under the block loading is greatly influenced by the impact damage; the effect of impact damage can be characterized by the present impact damage parameter. Based on this parameter, the model is developed to predict the fatigue life under block loading and the results by this model agree well with experimental results regardless of applied impact energy. Also, stochastic model is established to describe the variation of cumulative damage behavior and fatigue life due to the material nonhomogeneity.

• Asian Journal of Innovation and Policy
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• v.8 no.2
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• pp.274-287
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• 2019

Governments are asking policymakers to quantify the economic and social impact of those advanced technologies they support, including nanotechnology. National policymakers and researchers who participated in OECD activities cooperated to develop a model for the economic impact assessment of nanotechnology with a relevant case study. The present research contributing to some recommendations from the OECD WPN (Working Party on Nanotechnology) finds a successful example of market creation by nanotechnology, and assesses the resulting economic impact of the DEFRA (Department of Environment, Food & Rural Affairs of UK) model. This study investigates the economic impact of Quantum-dot (Qdot) nanotechnology on flat panel TV manufacturers, which is an ideal case to apply the DEFRA model for the analysis of product innovation based on nanotechnology. Findings show that Qdot nanotechnology is expected to create an economic value of $3.32 billion for Korean TV manufacturers over the next decade.

• Asian Journal of Atmospheric Environment
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• v.9 no.1
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• pp.22-30
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• 2015

This study evaluated road shape and roadside barrier impact on near-road air pollution dispersion using FLUENT computational fluid dynamics (CFD) model. Simulated road shapes are three types, namely at-grade, depressed, and filled road. The realizable k-${\varepsilon}$ model in FLUENT CFD code was used to simulate the flow and dispersion around road. The selected concentration profile results were compared with the wind tunnel experiments. The overall concentration profile results show good agreement with the wind tunnel results. The results showed that noise barriers, which positioned around the at-grade road, decrease the horizontal impact distance (In this study, the impact distance was defined as the distance from road surface origin coordinate to the position whose mass fraction is 0.1.) lower 0.33~0.65 times and change the vertical air pollution impact distance larger 2.0~2.27 times than those of no barrier case. In case of filled road, noise barriers decrease the horizontal impact distance lower 0.24~0.65 times and change the vertical air pollution impact distance larger 3.33~3.55 times than those of no barrier case. The depressed road increase 1.53~1.68 times the vertical air pollution impact distance. It contributes the decrease of horizontal air pollution impact distance 0.32~0.60 times compare with no barrier case.