• Coupled systems mechanics
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• 제11권4호
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• pp.285-295
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• 2022

Laminated composite plates are utilized extensively in different fields of construction and industry thanks to their advantages such as high stiffness-to-weight ratio. Additionally, they are characterized by their directional properties that permit the designer to optimize their stiffness for specific applications. This paper presents a numerical analysis and optimization study of plates made of composite subjected to low velocity impact. The main aim is to identify the optimum fiber orientations of the composite plates that resist low velocity impact load. First, a three-dimensional finite element model is built using LS DYNA computer software package to perform the impact analyses. The composite plate has been modeled using solid elements. The failure criteria of Tsai-Wu's criterion have been used to control the strength of the composite material. A good agreement has been found between the predicted numerical results and experimental results in the literature which validate the finite element model. Then, an Adaptive Simulated Annealing (ASA) has been used to optimize the response of impacted composite laminate where its objective is to maximize the safety factor by varying the ply angles. The results show that the ASA is robust in the sense that it is capable of predicting the best optimal designs.

• 정보관리학회지
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• 제27권1호
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• pp.269-287
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• 2010

최근까지 학술지의 영향력을 측정하기 위하여 Thomson Reuters(ISI)의 영향력지수(JIF: Journal Impact Factor)가 널리 사용되어왔다. 그러나, 이러한 JIF는 학술지 단위가 아니라 수록 논문의 평균 영향력을 측정하는 지표라는 근본적인 한계를 가지고 있으며, 이외에도 다양한 측면에서 많은 문제점들이 지적되었다. 특히 국내 인용색인은 국제적인 인용색인 데이터베이스에 비해서 인용 데이터의 규모가 상당히 제한적이므로, 이를 고려하여 국내 학술지 인용 환경에 적합한 지수의 적용이 필요하다. 따라서 이 연구는 최근 급속히 확산되고 있는 Hirsch 유형 지수(h-type indices)를 적용하여 국내 학술지의 영향력을 보다 더 상세하게 측정할 수 있는 실제적인 방안을 모색하였다. 결과적으로, h-지수의 변형지수($h_s$-지수, $f_s$-지수)를 사용하거나 호 단위 합산(호 기반 h-지수, 호 기반 f-지수) 방법을 통하여, 기존 Hirsch 유형 지수들의 변별력을 향상시킬 수 있음은 물론 국내 학술지의 영향력을 더욱 정밀하게 측정할 수 있는 것으로 나타났다.

• 한국경영과학회지
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• 제39권4호
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• pp.33-49
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• 2014

This study empirically examines the impact of firms' environmental (E), social (S), and governancial (G) factors on their short-term and long-term values. To measure firms' non-financial performance, we use ESG performance grades published by KCGS (Korea Corporate Governance Service). We employ stock log return as the proxy of each firm's short-term value, and Tobin's Q ratio as that of its long-term value. From a series of regression analyses, we find each of the ESG factors generally has a negative impact on stock return while it has a positive impact on the Tobin's Q ratio. These results imply that firms' effort for enhancing their non-financial performance may adversely affect their financial performance in a short term; but in the long-term point of view, firms' values increase through their good images engraved by their respective social, environmental and governancial efforts. In addition, we compare the relative strength of impact among E, S, G, the three non-financial factors on the firms' value measured in Tobin's Q ratio, and find that S (social factor) and G (governancial factor) give statistically significant impact on the firms' value respectively. This result tells us it would be advised to strategically embed CSV (creating shared value) pursuing both of profits and social responsibility in the firms' future agenda. While E (environmental factor) is shown to be an insignificant factor for the firms' value, it should be emphasized as a major concern by all the stakeholders in order to form a sound business ecosystem.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.839-843
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• 2008

Receiving room's floor impact sound level is been influenced to various factor of slab thickness, room size, structure etc. This study examined the noise of upper part slab and room mode in receiving room to be importance factor that influence in receiving room level among this factors. According to this study, vibration mode in slab and room mode are concentrated on frequency that is high level relatively. This causes bad effect in floor impact sound level. Therefore, method to reduce floor impact sound level is to change vibration mode using slab upper part's resilient material or reduce room mode in receiving room.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.837-840
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• 2002

An analysis method for rubber toughened PVC is suggested to evaluate critical dynamic strain energy release rates($G_c$) from the Charpy impact energy measurements. An instrumented Charpy impact tester was used to extract ancillary information concerning fracture parameters in addition to total fracture energies and maximum critical loads. The dynamic stress intensity factor $K_{Id}$ was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well. The fracture surfaces produced under low velocity impact fur PVC/MBS composites were investigated by SEM. The results show that MBS rubber is very effective reinforcement material for toughening PVC.C.

• International Journal of Computer Science & Network Security
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• 제21권11호
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• pp.278-286
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• 2021

The aim of this paper is to examine the importance of skills development in the process of employee performance. As part of this research, we will seek to determine the nature and extent of skills development impact in improving employee performance. This research project is one of the new themes that some researchers have started in recent years. The novelty of this theme is the inclusion of the skill development factor. This factor is likely to have a positive impact on employee motivation and performance. Some of the factors already known to have an impact on employee performance, such as motivation, career development, training, and experience, will be adopted. It is assumed that the results of this research will have a positive impact on employee performance and employee retention.

• 한국정보통신학회논문지
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• 제3권4호
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• pp.915-922
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• 1999

본 논문에서는 GaAs 풀밴드 E-k관계를 이용하여 전계방향에 따라 임팩트이온화가 전자전송에 미치는 영향을 분석하였다. E-k관계를 구하기 위하여 페르미황금법칙과 local form factor를 이용하는 의사포텐셜방법을 사용하였으며 임팩트이온화율을 구하기 위하여 브릴로우인영역을 사면체로 분할하여 각 사면체마다 적분하는 사면체방법을 이용하였다. 임팩트이온화의 이방성분석을 위하여 Monte Carlo시뮬레이션을 수행하였다. 특히 임팩트이온화의 과도상태분석을 수행한 결과, 이방성은 과도상태에서만 발생하는 것으로 나타났으며 정상상태에서는 등방성 특성을 보이는 것으로 나타났다. 본 연구에서 제시한 GaAs 임팩트이온화의 이방성특성은 GaAs 소자의 과도응답특성분석에 사용될 수 있으리라 사료된다.

• 복식
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• 제51권3호
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• pp.51-58
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• 2001

The purpose of this study was to investigate the effects of store image preferences on clothing impulse purchasing of male college students. The sample included 290 male college students, and an instrument was developed based on the previous studies. The statistical analyses used for this study were factor analysis and multiple regression. The result of factor analysis showed that store image preferences consisted of five factors : promotion, display, service, product, brand preferences. Clothing impulse purchasing consisted of product-driven impulse purchasing, situation-driven impulse purchasing, emotion-driven impulse purchasing. Multiple regression revealed that there were significant effects of store image preferences on dimensions of clothing impulse purchasing. For example, promotion preference factor had a positive impact on product-driven impulse purchasing and situation-driven impulse purchasing, but had a negative impact on emotion-driven impulse purchasing. The relative importance of store image preference factors were different according to different dimensions of clothing impulse purchasing.

• 디지털융복합연구
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• 제7권2호
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• pp.71-81
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• 2009

This paper studied the impact of Internet addiction on school life adaptation of high school students. We searched the literature on Internet addiction for such research and analyzed the impact that Internet addiction has on school life fitness. The SPSS statistics program was used for Internet addiction factor analysis and the analysis was carried out through the structure equation model. The family relation, individual relation, school relation and friend relation factor were deduced to Internet addiction as a result. It was revealed that the individual relation factor among Internet addiction factors had an influence on school life fitness. It is expected that this research will prove helpful in providing preventative education for Internet addiction

• Structural Engineering and Mechanics
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• 제27권5호
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• pp.609-623
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• 2007

The problem of a semi-infinite magneto-electro-elastically impermeable mode-III crack in a magneto-electro-elastic material is considered under the action of impact loads. For the case when a pair of concentrated anti-plane shear impacts, electric displacement and magnetic induction impacts are exerted symmetrically on the upper and lower surfaces of the crack, the magneto-electro-elastic field ahead of the crack tip is determined in explicit form. The dynamic intensity factors and dynamic energy density factor are obtained. The method adopted is to reduce the mixed initial-boundary value problem, by using the Laplace and Fourier transforms, into three simultaneous dual integral equations, one of which is converted into an Abel's integral equation and the others into a singular integral equation with Cauchy kernel. Based on the obtained fundamental solutions of point impact loads, the solutions of two kinds of different loading cases are evaluated by integration. For some particular cases, the present results reduce to the previous results.