• Korea-Australia Rheology Journal
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• 제18권2호
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• pp.67-81
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• 2006

Using a strain-controlled rheometer, the dynamic viscoelastic properties of aqueous xanthan gum solutions with different concentrations were measured over a wide range of strain amplitudes and then the linear viscoelastic behavior in small amplitude oscillatory shear flow fields was investigated over a broad range of angular frequencies. In this article, both the strain amplitude and concentration dependencies of dynamic viscoelastic behavior were reported at full length from the experimental data obtained from strain-sweep tests. In addition, the linear viscoelastic behavior was explained in detail and the effects of angular frequency and concentration on this behavior were discussed using the well-known power-law type equations. Finally, a fractional derivative model originally developed by Ma and Barbosa-Canovas (1996) was employed to make a quantitative description of a linear viscoelastic behavior and then the applicability of this model was examined with a brief comment on its limitations. Main findings obtained from this study can be summarized as follows: (1) At strain amplitude range larger than 10%, the storage modulus shows a nonlinear strain-thinning behavior, indicating a decrease in storage modulus as an increase in strain amplitude. (2) At strain amplitude range larger than 80%, the loss modulus exhibits an exceptional nonlinear strain-overshoot behavior, indicating that the loss modulus is first increased up to a certain strain amplitude(${\gamma}_0{\approx}150%$) beyond which followed by a decrease in loss modulus with an increase in strain amplitude. (3) At sufficiently large strain amplitude range (${\gamma}_0>200%$), a viscous behavior becomes superior to an elastic behavior. (4) An ability to flow without fracture at large strain amplitudes is one of the most important differences between typical strong gel systems and concentrated xanthan gum solutions. (5) The linear viscoelastic behavior of concentrated xanthan gum solutions is dominated by an elastic nature rather than a viscous nature and a gel-like structure is present in these systems. (6) As the polymer concentration is increased, xanthan gum solutions become more elastic and can be characterized by a slower relaxation mechanism. (7) Concentrated xanthan gum solutions do not form a chemically cross-linked stable (strong) gel but exhibit a weak gel-like behavior. (8) A fractional derivative model may be an attractive means for predicting a linear viscoelastic behavior of concentrated xanthan gum solutions but classified as a semi-empirical relationship because there exists no real physical meaning for the model parameters.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.1089-1097
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• 2020

Nowadays, technology and information are developing rapidly. It compels an organization or a company strive to excel in its field. In the Industrial Revolution 4.0 era, companies must maintain their assets and technology to face the competition. One asset that should be paid attention to is human resources. Human resource has two important variables, namely Organizational Citizenship Behavior (OCB) and Employee Engagement (EE). This study aims to analyze the relationship between OCB and EE on Employee Performance (EP) in the manufacturing industry in Tangerang. This study is conducted using a quantitative method with 200 respondents. The data is collected by distributing questionnaires to respondents, which is then analyzed using Structural Equation Modeling (SEM) with AMOS 23 software. The result of this study indicates that OCB has a significant effect on EE and EP. This study also finds that employee engagement has a significant effect on employee performance and can mediate the relationship between OCB and EP. From these results, the implication that can be taken is that the manufacturing industry in Tangerang must pay attention to their employees for them to develop OCB and EE, and eventually increase their performance towards the organization.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2679-2683
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• 2014

Mechanisms underlying the impacts of interactions between carbon nanoparticles (CNPs) and ionic liquids (ILs) on the physicochemical behavior of CNPs need to be more full worked out. This manuscript describes a theoretical investigation at multiple levels on the interactions of fullerene $C_{60}$ with 21 imidazolium-based ILs of varying alkyl side chain lengths and anionic types and their impacts on $C_{60}$ dispersion behavior. Results show that ${\pi}$-cation interaction contributed to mechanism of the $C_{60}$-IL interaction more than ${\pi}$-anion interaction. The calculated interaction energy ($E_{INT}$) indicates that $C_{60}$ can form stable complex with each IL molecule. Moreover, the direction of charge transfer occurred from IL to $C_{60}$ during the $C_{60}$-IL interaction. Quantitative models were developed to evaluate the self-diffusion coefficient of $C_{60}$ ($D_{fullerene}$) in bulk ILs. Three interpretative molecular descriptors (heat of formation, $E_{INT}$, and charge) that describe the $C_{60}$-IL interactions and the alkyl side chain length were found to be determinants affecting $D_{fullerene}$.

• The Journal of Asian Finance, Economics and Business
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• 제7권6호
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• pp.399-407
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• 2020

The paper examines social entrepreneurial intention through outcome expectations. The proposed model incorporates outcome expectations from social cognitive career theory and theory of planned behaviors. The study also introduces a scale for outcome expectations in social entrepreneurship, including solving social problems, innovation, family tradition of social involvement, meaning in life, prestige and social recognition, competitive and favorite job and wealth. A survey of 279 students was conducted through face-to-face structured interviews. The confirm factor analysis and technique of structural equation modeling were used to explore relationships among latent constructs. Research results show that the outcomes impact only through three determinants of theory of planned behavior and do not have significant impact to social entrepreneurial intention. It suggests that outcome expectations may be a flexible factor. Individual outcome expectations can shift to motivations when facing favorable conditions such as family support, government support, etc. The findings suggest that the ability to predict social entrepreneurial intention of attitude toward behavior, subjective norms, and perceived behavioral control. The proposed model in this study contributes importantly to the emerging literature on entrepreneurial intention, particularly to social entrepreneurial intention. This study is also the first quantitative study to measure the impact of outcome expectations on social entrepreneurial intention.

• 한국지반환경공학회 논문집
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• 제8권3호
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• pp.19-25
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• 2007

쇄석말뚝은 느슨한 사질토지반이나 점토지반에 치환법에 의해 다져진 자갈이나 쇄석을 연약한 지반에 삽입하여 개량하는 공법이다. 쇄석말뚝 공법은 흙과 말뚝 접촉면에서 압밀거동이 다양한 인자에 의해 영향을 받게 되어 정량적인 해석에 많은 어려움이 있다. 본 연구에서는 재하시험을 통해 선단지지 군말뚝의 거동에 대한 다양한 인자의 영향을 조사하였다. 궁극적으로 연약지반의 개량 특성과 설계인자의 영향력을 PR값을 사용하여 평가하였다. 실험결과와 계산된 PR 값으로부터 쇄석말뚝의 침하거동이 근입비나 매트의 설치여부 보다는 말뚝의 직경이나 복합지반의 치환율에 의해 영향을 받고 있음을 알 수 있다.

• 한국의류산업학회지
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• 제15권1호
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• pp.46-56
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• 2013

This study categorizes online fashion shopping malls according to consumer store patronage behavior as well as classifies consumer groups by online shopping mall patronage to understand the unique characteristics in each phases of purchase. A quantitative survey was conducted using 487 questionnaires from women in their 20s and 30s. The data were analyzed using frequency analysis, cross-tabulations, factor analysis, T-test, ANOVA, cluster analysis, and ${\chi}^2$-test. The findings of this study are as follows. First, online shopping malls were classified into three types of 'integrated mall', 'open market' and 'specialized fashion mall'. Second, based on one of the three types of categorization consumer groups patronizing each type turned out as follows: integrated mall patrons (141, 28.95%), open market patrons (226, 46.41%) and the specialized mall patrons (119, 24.64%). Third, the characteristics of each group had significant differences according to clothing shopping orientation, information search, shopping mall behavior, spending on online shopping, and e-loyalty.

• 한국실내디자인학회논문집
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• 제19권6호
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• pp.197-205
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• 2010

For the spatial experience of spectators visiting a museum, the route search of trying to follow the spatial structure or production of exhibition and the information search of trying to see are accomplished at the same time. In such process, the spectator's reaction of visual perception produces the result of emotional reaction and action exchanged between human and space by going through the recognition and perception on the target of environment factor. For the spatial experience of a spectator, the reaction of visual perception which interacts according to the exhibit and exhibition environment within space according to viewing purpose, interest and concern of spectator comes out as visual activity which is an activity to understand the spatial information shown as various activities according to spatial structure and unfolding characteristics of the display. The purpose of this study is to identify The Correlation of Spectator Movement Created According to Structural Form of Exhibition Area Based on Interaction between Exhibition Area Structure and Spectator to utilize as basic material while designing museum exhibition using isovist field which is a quantitative analysis tool of spectator's visual behavior and spatial structure at each exhibition area.

• 디자인학연구
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• 제20권2호
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• pp.129-140
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• 2007

With the overall revision of the Welfare of the Aged Act in 1997, elderly welfare facilities have developed differently according to the size of locality, capacity, and social and economic characteristics. In response to the problem, various plans are being executed for expanding services and facilities for the aged. However, such efforts by the government have been focused on quantitative increase rather than on qualitative improvement, and there are not many high-quality elderly welfare facilities that meet the needs of the consumers, namely, the aged. In contrast, elderly welfare centers in Japan began to be founded from the 1960s and increased significantly from the 1970s and, as a result, 2,214 elderly welfare centers were in operation in 1995, maintaining a high level in quantity as well as in quality. Therefore, the present study surveyed using a checklist how elderly welfare centers in Japan, which are playing central roles in welfare facility services for the aged in Japan, design their indoor spaces reflecting elders' behavior and characteristics and, based on the results of the survey, classified spaces into shared spaces and individual service spaces and analyzed the spaces of each center using the checklist. The results from this case study will be used as basic data to establish standards for the space composition of elderly welfare facilities in Korea, which has 10 years' short history of elderly welfare facilities.

• Macromolecular Research
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• 제11권4호
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• pp.283-290
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• 2003

Organic drugs including aspirin, omeprazole, and naproxen with three different levels of octanol/water partition coefficient were examined for their release behavior from the amphiphilic PCL-b-PEO-b-PCL (PCEC) matrix. Scanning electron micrograph (SEM) of PCEC illustrated a well defined two-phase morphology consisted of dispersed poly(ethylene oxide) (PEO) domain and continuous polycaprolactone (PCL) phase. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) experiments veri tied that three model drugs are dissolved as a molecular dispersion in PCEC matrix. The release of hydrophilic aspirin closely followed the water absorption profile of the matrix indicating that its major fraction is present in PEO domain. However, substantial amount of aspirin present in less hydrophilic region displayed discontinuous biphasic release pattern. In the case of omeprazole with intermediate hydrophobicity consistent release behavior was observed for a period of 24 hrs after the rapid liberation of ca. 10% of the drug presumably partitioned in PEO phase. It was ascribed to the fact that the progressive hydration of PCEC matrix gradually increased the chance of drug/water exposure to compensate the exhaustion of device. Naproxen with the highest octanol/water distribution coefficient among three model drugs exhibited a limited release of 35% for 24 hrs. Finally, hydroxypropyl methylcellulose phthalate (HPMCP)/PCEC blend matrix demonstrated an accelerated and quantitative release of hydrophobic naproxen by generating high porosity and thereby expanding polymer/water interface.

• 한국시뮬레이션학회논문지
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• 제22권2호
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• pp.33-40
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• 2013

본 논문은 에이전트 기반 모델링 및 시뮬레이션을 바탕으로 한 한국군 GOP 경계시스템에 관한 연구이다. 에이전트 기반 모델링 및 시뮬레이션 기반 소프트웨어인 MANA를 이용하여 다양한 시나리오를 모델링하고 유전학적 알고리즘을 통해 침투 양상이 변화하는 적에 대해 분석하였다. 우리는 유전학적 알고리즘을 이용하여 침투하는 적의 최적화된 행동에 근사하는 값을 구하기 위해 최적화 모델을 구성하였다. 그 결과는 GOP 경계시스템에서 침투하는 적의 행동에 대한 최적화가 경계시스템의 효과성에 현저한 차이를 가져온다는 점과 침투하는 적의 아군 자산에 대한 회피 정도는 각각의 자산의 중요성을 반영한다는 점에서 두 가지 중요한 통찰력을 제공한다.