• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.38-46
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• 1995

In this paper, an experimental study on the effects of the impact damage and the perforation characteristic of CFRP laminates with different fiber stacking orientation and ply number was done through an observation of interrelations between the impact energy vs. transmitted energy and the impact energy vs. absorbed energy per unit volume. The velocities of the ball before or after impact are measured by the high-speed camera. And when CFRP laminates are subjected to tranverse impact by a steel ball(${\phi}10$), the delamination shapes generated by impact damage are observed by using SAM (Scanning acoustic Microscope).

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1686-1704
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• 2021

This study addresses the numerical simulation of the shield building of an AP1000 nuclear power plant (NPP) subjected to a large commercial aircraft impact. First, a simplified finite element model (F.E. model) of the large commercial Boeing 737 MAX 8 aircraft is established. The F.E. model of the AP1000 shield building is constructed, which is a reasonably simplified reinforced concrete structure. The effectiveness of both F.E. models is verified by the classical Riera method and the impact test of a 1/7.5 scaled GE-J79 engine model. Then, based on the verified F.E. models, the entire impact process of the aircraft on the shield building is simulated by the missile-target interaction method (coupled method) and by the ANSYS/LS-DYNA software, which is at different initial impact velocities and impact heights. Finally, the laws and characteristics of the aircraft impact force, residual velocity, kinetic energy, concrete damage, axial reinforcement stress, and perforated size are analyzed in detail. The results show that all of them increase with the addition to the initial impact velocity. The first four are not very sensitive to the impact height. The engine impact mainly contributes to the peak impact force, and the peak impact force is six times higher than that in the first stage. With increasing initial impact velocity, the maximum aircraft impact force rises linearly. The range of the tension and pressure of the reinforcement axial stress changes with the impact height. The perforated size increases with increasing impact height. The radial perforation area is almost insensitive to the initial impact velocity and impact height. The research of this study can provide help for engineers in designing AP1000 shield buildings.

• Korean Journal of Applied Biomechanics
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• v.33 no.4
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• pp.164-174
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• 2023

Objective: The aim of this study was to quantitatively analyze the impact characteristics of the lower extremity on strike pattern during running. Method: 19 young subjects (age: 26.53 ± 5.24 yrs., height: 174.89 ± 4.75 cm, weight: 70.97 ± 5.97 kg) participated in this study. All subjects performed treadmill running with fore-foot strike (FFS), mid-foot strike (MFS), and rear-foot strike (RFS) to analyze the impact characteristics in the lower extremity. Impact variables were analyzed including vertical ground reaction force, lower extremity joint moments, impact acceleration, and impact shock. Accelerometers for measuring impact acceleration and impact shock were attached to the heel, distal tibia, proximal tibia, and 50% point of the femur. Results: The peak vertical force and loading rate in passive portion were significantly higher in MFS and FFS compared to FFS. The peak plantarflexion moment at the ankle joint was significantly higher in the FFS compared to the MFS and RFS, while the peak extension moment at the knee joint was significantly higher in the RFS compared to the MFS and FFS. The resultant impact acceleration was significantly higher in FFS and MFS than in RFS at the foot and distal tibia, and MFS was significantly higher than FFS at the proximal tibia. In impact shock, FFS and MFS were significantly higher than RFS at the foot, distal tibia, and proximal tibia. Conclusion: Running with 3 strike patterns (FFS, MFS, and RFS) show different impact characteristics which may lead to an increased risk of running-related injuries (RRI). However, through the results of this study, it is possible to understand the characteristics of impact on strike patterns, and to explore preventive measures for injuries. To reduce the incidence of RRI, it is crucial to first identify one's strike pattern and then seek appropriate alternatives (such as reducing impact force and strengthening relevant muscles) on that strike pattern.

• Journal of Drive and Control
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• v.16 no.2
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• pp.1-7
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• 2019

Jaw crusher is a device that breaks rock collected from mines or quarries to produce aggregates of the size desired by user. A representative method for measuring load is to measure them by attaching force sensors directly to the part where the load is generated. However, the direct method has many limitations such as high-impact loads generation in equipment or space constraints, sensor capacities and costs. Therefore, Transfer Path Analysis (TPA) was used to indirectly measure impact loads by attaching acceleration sensors. In this study, both direct and TPA methods were used to measure the impact load of Jaw crusher. This study finally quantifies the impact of the load generated by the Jaw crusher using direct method and TPA method, and comparing the impact load measured calculated the derive the error rate.

• Journal of Korean Public Health Nursing
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• v.6 no.2
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• pp.108-132
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• 1992

The purpose of this study· is to identify sources of the caregiving burden, thereby suggesting social welfare alternetives for supporting family caregivers of the elderly with dementia. 23 family caregivers who participated in self-help group of family caregivers of dementia elderly at a welfare facility for the elderly in Seoul were seleted as the study sample. Zarit caregiving burden scale and Zarit functional impairment measurement for the elderly were adapted for this study and a number of additional variables were included in this study. Correlational analysis was utilized. The results of the study were summarized as follows : 1) The impairment of activities of daily living of the elderly was significantly related to the negative elderly. caregiver-family relationship(PADL:r=.6032 IADL : r=.5930 p<.05). 2) The impact on caregiver's health was very significantly related to the impact on the caregiver's task(r=.6233 p<.001). 3) The Impact on caregiver's health was very significantly related to the impact on the caregiver's social activity restriction(r=.6851 p<.001). 4) The impact on the caregiver's social activity was very significantly related to the impact on the caregiver's task(r=.6969 p<.001). 5) Caregiver's income was significantly related to the impact on the caregiver's task(r=.5252 p<.05). 6) Compensation(interpersonal relationship between the elderly and the caregivers, social praise and appreciation of the elderly) was important variables which affect to the feeling of the caregiving burden.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.209-216
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• 2021

This study aim is to examine 1) the impact of corporate social responsibility disclosure and tax aggressiveness on firm value, 2) the impact of tax aggressiveness on firm value, and 3) the impact of corporate social responsibility on firm value. The sample of this study is 29 manufacturing companies listed on the Indonesia Stock Exchange. The period of research spans three years, from 2017 to 2019. The data is gathered from the annual report of the companies or website of companies and also the website from Indonesia Stock Exchange (IDX). This study uses Structural Equation Model with Partial Least Square. The research findings show that corporate social responsibility and tax aggressiveness have a negative and significant impact on firm value. The tax aggressiveness and firm value have a negative and significant impact. Corporate social responsibility has a positive and significant impact on firm value. This study uses the manufacturing sector, so that the findings of this study cannot be generalized to other sectors. Future research should explore other sectors such as mining, banking, etc. This study uses Effective Tax Rate (ETR) to measure tax aggressiveness. Further research should use another measurement, for instance, Current Effective Tax Rate (CETR).

• 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.

• Journal of Environmental Impact Assessment
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• v.4 no.1
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• pp.1-8
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• 1995

Environmental Impact Assessment(EIA) in Korea has developed as a tool for environmental conservation and decision making since Environmental Impact Statement(EIS) preparation in 1981. For effective implementation of it, we do system development and method enhancement continuously. The recently introduced GIS (Geographic Information System) can integrate geographic and attribute data, which will be applied to scoping, assessment, and alternative assessment, etc. in EIA. This study has three major components. First, it explains building of EIA factors of natural environment, living environment, and socio-economic environment of the study area defined in EIS preparation regulation. Second, the study presents applications of assessment method concerning suitability analysis of landfill site using GIS. Finally, it shows integration of GIS and odor impact assessment. Based on these analysis, the study makes some recommendations and conclusions.

• Journal of the Korean housing association
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• v.16 no.5
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• pp.91-98
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• 2005

The purpose of this study is to analysis of propagation characteristics for floor impact noise in attendance upon investigating standard of insulation performance, measurement and evaluation, understanding characteristics of a measuring factor for floor impact noise in apartment houses. Four cases which was before occupied apartment in Daegu was selected for experiment. Floor impact noise of measurement and evaluation method which are specified in the Korea Standard 2810-1, 2810-2, 2863-1 and 2863-2 was selected for this study. As the result of this study, 1) Especially, there is not a difference for apartment size, but the apartment of 40py type is lower than 30py's about $1\~2\;dB$ for light-weighted and heavy weighted impact sound. 2) The floor impact sound insulation performance is similar about measurement location of the same floor structure. 3) The floor impact sound insulation performance is not a difference about the slab area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.1
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• pp.52-63
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• 1998

The impact programmer for impact test was designed and the impact analysis was conducted. The effects of the material and geometric parameters on the impact force and pulse shape were investigated. The impact characteristics were examined by experimental and finite element method. The impact test was conducted with free drop impact tester. The ABAQUS/Explicit 5.5 version was used for finite element analysis. The geometric parameters of the conical and dome type impact programmer were analyzed. The polyurethane impact programmers were fabricated and tested. The effects of the hardness and thickness of the impact programmer were studied. The peak acceleration and time duration of impact programmer have close correlation with the hardness, impact energy and thickness of the impactor. The experiment was good agreement with analytical predictions. The impact pulse shape generated with polyurethane impact programmer was half sine shape. The maximum impact force was proportional to impact energy. The impact acceleration was decreased with thickness of impact programmer. The maximum impact time duration level was about 2 msec.