• Steel and Composite Structures
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• 제38권5호
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• pp.477-496
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• 2021

The main objective of this paper is to study vibration of sandwich open cylindrical panel with damaged core and FG face sheets based on three-dimensional theory of elasticity. The structures are made of a damaged isotropic core and two external face sheets. These skins are strengthened at the nanoscale level by randomly oriented Carbon nanotubes (CNTs) and are reinforced at the microscale stage by oriented straight fibers. These reinforcing phases are included in a polymer matrix and a three-phase approach based on the Eshelby-Mori-Tanaka scheme and on the Halpin-Tsai approach, which is developed to compute the overall mechanical properties of the composite material. Three complicated equations of motion for the panel under consideration are semi-analytically solved by using 2-D differential quadrature method. Several parametric analyses are carried out to investigate the mechanical behavior of these multi-layered structures depending on the damage features, through-the-thickness distribution and boundary conditions. It is seen that for the large amount of power-law index "P", increasing this parameter does not have significant effect on the non-dimensional natural frequency parameters of the FG sandwich curved panel. Results indicate that by increasing the value of isotropic damage parameter "D" up to the unity (fully damaged core) the frequency would tend to become zero. One can dictate the fiber variation profile through the radial direction of the sandwich panel via the amount of "P", "b" and "c" parameters. It should be noticed that with increase of volume fraction of fibers, the frequency parameter of the panels does not increase necessarily, so by considering suitable amounts of power-law index "P" and the parameters "b" and "c", one can get dynamic characteristics similar or better than the isotropic limit case for laminated FG curved panels.

• 한국재료학회지
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• 제33권2호
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• pp.54-62
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• 2023

The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin²ψ method. When X-rays were used the relationship of ε_φψ-sin²ψ measured on the surface layer of the processing metal did not show linearity when the sin²ψ method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray, σ_φ becomes a sin²ψ function. Since σ_φ cannot be used as a constant, the relationship in ε_φψ-sin²ψ cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren's diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 I_max max height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.

• 한국유통학회지:유통연구
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• 제17권5호
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• pp.85-111
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• 2012

본 연구는 대형할인점의 PB(Private Brand)상품에 대한 소비자의 지각특성과 관계지속의도 간의 영향관계를 규명하는 것으로서 설문조사에 의한 실증적 연구를 토대로 하였다. 실증적 연구를 위해 선행연구를 바탕으로 하여 PB상품에 대해 소비자가 지각하는 특성으로서의 지각품질, 점포이미지, 브랜드이미지, 지각가치 등의 요인을 도출하고 이들 선행요인이 PB상품의 브랜드신뢰와 브랜드자산을 매개로 하여 관계지속의도에 어떠한 영향을 미치는가를 구조적으로 규명하고자 하였다. 실증적 연구를 위한 설문조사는 2012년 1월부터 2012년 5월 말까지 경기 및 부산지역의 소비자를 대상으로 실시하였다. 설문은 전체 300부를 배부하여 253부(84.3%)를 회수하였으며, 그 중 응답이 누락되었거나 불성실한 설문을 제외한 245부(81.6%)를 유효 표본으로 최종분석에 활용하였다. 연구결과 PB상품에 대한 선택속성으로서의 지각품질, 브랜드이미지 및 지각가치는 브랜드신뢰 및 브랜드자산에 유의적인 정(+)의 영향을 미치는 것으로 나타났으며, 나아가 이들 브랜드신뢰와 브랜드자산은 관계지속의도에 유의적인 정(+)의 영향을 미치는 것으로 나타났다. 그러나 PB상품을 판매하는 할인점의 점포이미지는 브랜드신뢰에는 정(+)의 영향을 미치지만 브랜드자산에는 유의적인 영향을 미치지 않는 것으로 분석되었다. 즉, 전반적으로 PB상품에 대해 소비자가 지각하는 품질, 점포이미지, 브랜드이미지 및 지각가치와 관계지속의도간의 관계에서 브랜드신뢰 및 브랜드자산 요인이 이들 관계를 매개하고 있음을 구조적으로 확인할 수 있었다. 이러한 연구결과를 바탕으로 볼 때 PB상품에 대한 소비자의 관계지속의도를 극대화하고 재구매를 지속적으로 유도하기 위해서는 PB상품의 품질향상, 브랜드이미지 개선 및 브랜드가치를 향상시키는 기본적 노력 위에 PB상품의 브랜드에 대한 신뢰와 자산가치를 극대화시키는 전략적 접근이 요구된다고 할 수 있다.

• 대한화학회지
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• 제40권5호
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• pp.295-301
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• 1996

$CaGa_1-xFexO_3-y$계의 x=0.25, 0.50, 0.75 및 1.00에 해당하는 고용체를 $1150^{\circ}C$, 대기압하에서 제조하였다. X-선 회절분석, Mohr염 정정, Mossbauer 분광분석을 수행하여 합성된 고용체들의 구조, 비화학량론적 화학식 및 양이온들의 분포를 결정한 후 전기전도도와 자기측정을 수행하여 물성에 관한 논의를 하였다. X-선 회절분석으로부터 얻은 모든 조성의 결정계는 브라운밀러릿 사방정계이다. 환산 격자부피는 단위세포의 차원이 다른 X=0.25의 조성을 제외하고 x값이 증가함에 따라 직선성을 가지고 증가한다. Mohr염분석 결과 고용체들은 $Fe^{4+}$ 이온을 포함하지 않고 산소공위의 몰수인 y값은 0.50으로 고정된 값을 가진다. Mossbauer 분광분석으로부터 Fe 이온의 산화상태, 배위상태, 브라운밀러릿 구조 및 $Ga^{3+}$와 $Fe^{3+}$ 이온의 분포를 논의하였다. 전기전도도와 활성화에너지는 x값이 증가함에 따라 각각 증가와 감소하고 이들로부터 전자 전기전도 메커니즘을 제안한다. x=0.50~1.00의 조성을 냉각하면서 자기측정을 수행할 때 열적 자기 히스테리시스가 나타나며 이러한 현상을 공간군과 Dzyaloshinsky-Moriya 상호작용을 기초로 논의하였다.

• 한국통신학회논문지
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• 제35권7B호
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• pp.991-1000
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• 2010

HMIPv6는 로컬 네트워크상에 이동성 지원 포인트(Mobility Anchor Point ; MAP)라는 기능을 도입하여 MAP 하부에서의 이동은 MAP가 관리함으로써 지연과 오버헤드를 줄이고 이동 노드의 핸드오프를 효율적으로 관리하는 방법이다. 그러나 이동 노드가 새로운 도메인에 들어올 경우 최상위 MAP에 이동 노드의 등록이 집중되어 성능을 저하시키는 단점이 있다. 본 논문에서는 게임이론 중에서 내쉬 교섭 해(Nash Bargaining Solution ; NBS) 이론을 적용하여 HMIPv6상에서 상위 MAP에 이동 노드의 등록이 집중되지 않고 거리(Distance), 등록된 노드 수, 데이터 전송량 등의 MAP 자원 사용 비율에 따라 여러 MAP로 부하를 분산시키는 알고리즘을 제안하였다. 시뮬레이션을 통해 상위 MAP로의 부하 집중을 방지할 수 있었고, MAP자원의 사용비율에 따라 가중치를 실시간으로 그리고 능동적으로 부여함으로써 도메인내의 MAP를 효율적으로 사용하여 성능을 향상시킬 수 있었다.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.109-114
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• 2020

The aim of this study is to develop basic artificial neural network models in forecasting the in-sample gross domestic product (GDP) of Malaysia. GDP is one of the main indicators in presenting the macro economic condition of a country as set by the world authority bodies such as the World Bank. Hence, this study uses an artificial neural network-based approach to make predictions concerning the economic growth of Malaysia. This method has been proposed due to its ability to overcome multicollinearity among variables, as well as the ability to cope with non-linear problems in Malaysia's growth data. The selected inputs and outputs are based on the previous literatures as well as the economic growth theory. Therefore, the selected inputs are exports, imports, private consumption, government expenditure, consumer price index (CPI), inflation rate, foreign direct investment (FDI) and money supply, which includes M1 and M2. Whilst, the output is real gross domestic product growth rate. The results of this study showed that the neural network method gives the smallest value of mean error which is 0.81 percent with a total difference of 0.70 percent. This implies that the neural network model is appropriate and is a relevant method in forecasting the economic growth of Malaysia.

• 한국주거학회논문집
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• 제27권6호
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• pp.19-29
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• 2016

As a lifeway and social change, the neighborhood build up around elementary school based on Perry's Neighbourhood Unit becomes change. Elementary School does not function as a center of residents' activity or community any longer. Activities occurred near the school move to the community streets that many facilities are distributed to, while utilization of facilities near schools becomes lower. On the bases of the current states, this study aims to draw a practical neighborhood center of residential areas by case study. The research is being mainly about low-rise residential areas in Seoul which includes one elementary school at least. In order to deduct the center of neighborhood, the survey takes two steps. At the preliminary survey, conduct the observation and do an interview to investigate awareness and actual status. Also to analyze practical center, do a main survey about land value, pedestrian volume, distribution of public transit and facility density. The research result shows that there is another activated center street not nearby elementary school in every case. This study assumes that the neighborhood center is not limited around elementary school and could variously build up by circumstances. It has significance that we present a question about the traditional theory and also could be references of the future city maintenance in the long term.

• 대한조선학회지
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• 제20권4호
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• pp.33-40
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• 1983

The drift force acting on a freely-floating sphere in water of finite depth is studied within the framework of a linear potential theory. A velocity potential describing fluid motion is determined by distribution pulsating sources and dipoles on the immersed surface of the sphere. Upon knowing values of the potential, hydrodynamic forces are evaluated by integrating pressures over the immersed surface of the sphere. The motion response of the sphere in water of finite depth is obtained by solving the equation of motion. From these results, the drift force on the sphere is evaluated by the momentum theorem, in which a far-field velocity potential is utilized in forms of Kochin function. The drift force coefficient Cdr of a fixed sphere increases monotononically with non-dimensional wave frequency ${\sigma}a$. On the other hand, in freely-floating case, the Cdr has a peak value at ${\sigma}a$ of heave resonance. The magnitude of the drift force coefficient Cdr in the case of finite depth is different form that for deep water, but the general tendency seems to be similar in both cases. It is to note that Cdr is greater than 1.0 when non-dimensional water depth d/a is 1.5 in the case of freely-floating sphere.

• The Journal of Asian Finance, Economics and Business
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• 제6권4호
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• pp.189-199
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• 2019

The objectives of this study are to propose the Integrated Waqf Environmental Protection Model (IWEP) and investigate the farmers' intention to adopt it. In developing the IWEP model and investigating farmers' willingness to adopt it, this study surveyed 400 farmers in Kedah. The intention of the farmers to adopt the proposed model was analysed by adding perceived barriers and socio-economic variables into the theory of reasoned action (TRA) model. The collected data were processed using structural equation modelling (SEM). The SEM results show that the subjective norm is positive and has a significant impact on the intentions of low-income farmers to accept the IWEP model. This indicates that the decision of the low-income farmers to accept the IWEP model is significantly influenced by their family members, neighbours and friends. Furthermore, awareness and perceived barriers have a greater impact on the elderly, highly educated and wealthy farmers. The findings indicate that the elderly, highly educated and wealthy farmers are aware of climate change and they perceive higher risks or barriers to climate change. As a result, they are more likely to have an adaptation intention. If we encourage people to create waqf fund, we can increase the value of the farmer and the country's total GDP.

• The Journal of Asian Finance, Economics and Business
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• 제7권1호
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• pp.229-238
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• 2020

A model is presented in this paper to provide understanding of the supply chain integration and supply chain information practices' impact on the manufacturing industries. The supply chain information practices play a crucial role in sharing information between the members of SC network. Thus, it is important to develop a comprehensive understanding of the differences and similarities among ISI and information management. It will allow firms to systematically evaluate and carefully choose the information strategy. The empirical findings of this research offer essential and interesting insights about what role SCI, supply chain information and Supply chain ISI play in determining Malaysia's financial performance. The theoretical gaps addressed in this study are of significant importance, since a little empirical evidence is available regarding system infrastructure and supply chain information management's effectiveness. This research provides further paths of exploring system infrastructure and information management, thereby defining the manufacturing industries' next step in SCM struggle i.e. modifying total integrated SC principle in other manufacturing firms. The Resource-based theory discovered organizational resources as an essential organizational success ingredient. Therefore, in order to recognize its potential value, internal resources, for instance, information system and management must be fully utilized.