• Steel and Composite Structures
• /
• v.19 no.6
• /
• pp.1421-1447
• /
• 2015

In this paper, the effect of material-temperature dependent on the wave propagation of a cantilever beam composed of functionally graded material (FGM) under the effect of an impact force is investigated. The beam is excited by a transverse triangular force impulse modulated by a harmonic motion. Material properties of the beam are temperature-dependent and change in the thickness direction. The Kelvin-Voigt model for the material of the beam is used. The considered problem is investigated within the Euler-Bernoulli beam theory by using energy based finite element method. The system of equations of motion is derived by using Lagrange's equations. The obtained system of linear differential equations is reduced to a linear algebraic equation system and solved in the time domain and frequency domain by using Newmark average acceleration method. In order to establish the accuracy of the present formulation and results, the comparison study is performed with the published results available in the literature. Good agreement is observed. In the study, the effects of material distributions and temperature rising on the wave propagation of the FGM beam are investigated in detail.

• Journal of the Korea Safety Management & Science
• /
• v.1 no.1
• /
• pp.101-110
• /
• 1999

QFD is a market driven design and development methodology for products and services to meet or exceed customer's needs and expectations, This method enables to specify clearly the customer's needs and then evaluate the product capability in terms of its impact on meeting those needs. Process of satisfying customers begins with effectively soliciting their different needs and wants which may be non-technical and imprecise in nature. Although the HoQ is a comprehensive tool for showing the relationships between attributes, it lacks the flexibility to deal with the inherent inexactness and vagueness in the voice of customer. In this paper, fuzzy theory is introduced to overcome this limitation. Qualitative customer requirements are interpreted quantitative data through fuzzy inference procedure, and then target value is determined.

• Journal of Digital Convergence
• /
• v.9 no.1
• /
• pp.25-36
• /
• 2011

This paper examines user's loyalty to social network sites (SNS) from switching costs (SC) incurred by both technology and social factors. We propose a research model specifying that the perceived values of resources of the factors affect the SC and the SC determine user's loyalty. Empirical results show that technology variables of ease of use and privacy controllability, and social variables such as network size, usefulness of SNS activities, and awareness of network status have significant effect on SC. In particular, ease of use is negatively associated with SC. Since it is shown that in overall the impact of social factors is stronger than that of technology factors, we can interpret that technological superiority itself does not lead to the success of SNS. Contributions of this paper are: 1) application of SC in SNS research from the resource based perspective, which can be used for developing strategies of sustainable SNS, and 2) provision of different perspective toward the variable of ease of use, which has been considered an important factor of technology acceptance.

• Journal of Digital Convergence
• /
• v.9 no.1
• /
• pp.71-87
• /
• 2011

Currently, many companies are interested in (Radio Frequency Identification (RFID). Nonetheless, technical imperfection and the uncertainty of Return on Investment (ROD is discouraging the companies' intention to implement RFID. Accordingly, while a number of companies concede the efficiency of RFID, few of them expresses enthusiasm, making a rain check to adopt RFID. Moreover, the recent economic depression has down-sized the companies' investment on Information Technology (IT), subsequently hindering RFID implementation. In adopting RFID, the collaboration of supply chain is the most importance factor. Therefore, in implementing RFID, many companies reinforced collaboration of supply chain. Therefore, this study will focus on performing an analysis on several factors which influence the intention to adoption of RFID, such as the human factor, technology factor, vender factor and task factor. The results of this study will provide useful guidelines for RFID adoption strategy to Korean companies.

• Management & Information Systems Review
• /
• v.21
• /
• pp.189-208
• /
• 2007

This study was designed to find what impacts store attributes and personal characteristics have had on customer loyalty to beauty shops. Participants were 283 men and women who had experienced services in beauty shops and selected from the Metropolitan area, Busan, Gyeongbuk area, Gyeongnam area, Chungcheong area, and other area. In conclusion, technical factor and lifestyle have had the greatest impact on customer loyalty to beauty shops. In beauty market faced with keen competition, the way to meet customers' needs is to run a distinguished beauty shop with distinct beauty techniques in consideration of individual lifestyle. This will help raise customer loyalty to beauty shops. This study has the important implication that personal characteristics as well as store attributes has been proved to be essential for increasing customer loyalty to beauty shops. I hope that future studies will continue to examine different marketing factors by different beauty shops, with additional analysis on the details, contributing to make a marketing strategy available for beauty shop owners.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2018.07a
• /
• pp.129-130
• /
• 2018

본 논문에서는 셀룰라시스템 환경에서 특히, 채널추정에러가 존재하는 환경에서 D2D 통신을 위한 전력제어 알고리즘 성능을 분석한다. 채널추정에러의 성능분석을 위해 가우시안 채널 추정에러를 모델링하였으며, 이는 SIR 성능이 확률적 분포를 가지도록 한다. 실제 전송환경에서는 송신단과 수신단 사이의 채널환경 변화로 인해 채널 추정 에러는 불가피하다. 이러한 채널추정 에러가 D2D 단말 전력제어 알고리즘에 어떻게 영향을 주는지 실험을 통하여 분석하도록 한다.

• Proceedings of the Korean Society of Environment and Ecology Conference
• /
• 2003.10a
• /
• pp.1-21
• /
• 2003

I introduce the Flexible Dam Operation (FDO) and some of sediment control techniques In dams which are implemented as trials to avoid or reduce environmental impact of dams on the downstream reaches. The FDO is a dam management method to improve river environment in the downstream reaches by means of the flushing flow, the maintenance flow and so on utilizing a vacant portion of capacity for flood control without interrupting prime flood control function during the rainy/typhoon season. It Is suggested by the guideline of the FDO that EDO should be implemented regularly after the trial for about three years. The basic conception of the FDO is described here. The example of excavation of deposited sediments in check dams and placement of sand ana gravel immediately downstream of the dams and the example of coordinated sediment flushing are described as some of sediment control techniques in dams. Now they are at the stage of experiment and trial. Therefore, it is important to increase examples and establish the technical methodology and the environmental evaluation method for them.

• Elastomers and Composites
• /
• v.33 no.1
• /
• pp.3-9
• /
• 1998

The production of polyurethane polymer has been increased because of their unique properties and variety process methods available. The generation of their wastes also increases with products. These byproducts of industrialization seriously threaten the environmental demanding. Therefore, development of the recycling technologies have been required. The main propose of this study is to develop the recycling technology of waste polyurethane from a footwear scrap. This technique is composed of the following procedure : crushing, devulcanizing, pelletizing, washing and drying. The pellet was characterized with various methods. The recycled polyurethane(RPU) was blended with HIPS(high impact polystyrene) and investigated morphologically and rheologically. The experimental results showed that the addition of 20% HIPS to RPU was limited without mechanical performance of the superial properties of a virgin polyurethane. We believe that these technical information make possible to develop a rational engineering product.

• Geomechanics and Engineering
• /
• v.9 no.1
• /
• pp.83-100
• /
• 2015

Water and energy supplies are the key factors affecting the economic development and environmental improvement of Turkey. Given their important role and the fact that a large part of Turkey is in seismically active zones dams should be accurately analyzed since failure could have a serious impact on the local population environment and on a wider level could affect the economy. In this paper, a procedure is proposed for the static, slope stability, seepage and dynamic analysis of an earth dam and the Pamukcay embankment dam. The acceleration time history and maximum horizontal peak ground accelerations of the $Bing\ddot{o}l$ (2003) earthquake data was used based on Maximum Design Earthquake (MDE) data. Numerical analysis showed that, the Pamukcay dam is likely to experience moderate deformations during the design earthquake but will remain stable after the earthquake is applied. The result also indicated that, non-linear analysis capable of capturing dominant non-linear mechanism can be used to assess the stability of embankment dams.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2519-2523
• /
• 2008

When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed will save the construction cost. However the shortening the distance between track centers may cause the stability problems due to higher wind pressure. Therefore the extensive technical review and aerodynamical study should be performed to determine the adequate distance between track centers. In this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. We conducted the parametric study of the effects of train wind on the running stability.