• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1167-1172
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• 2008

We investigated the glass transition temperatures ($T_g$) of dendrons consisting of conformationally mobile aliphatic polyether dendritic cores plus glassy peripheral polystyrenes (PSs), and linear PSs in the molecular weight range of 1000-8500 g/mol. We compared their $T_g$ behavior depending on their polymeric architecture. The linear PSs show a typical growth of $T_g$ up to 92.5 ${^{\circ}C}$ as the molecular weight increases to 8300 g/mol, while the dendrons display nearly constant $T_g$ values of 58-61 ${^{\circ}C}$, despite the increase of molecular weight with each generation. The striking contrast of Tg behavior would be mainly attributed to the fact that the dendrons keep the ratio of $N_e$/M ($N_e$: number of peripheral chain ends, M: molecular weight) over all the generations. Additionally, for the influence of dendritic spacers on glass transition temperature we prepared dimeric PSs with different linkage groups such as aliphatic ether, ester and amide bonds. We found that the dimer with the ether spacer exhibited the lowest glass transition at 55.4 ${^{\circ}C}$, while the amide linked dimer showed the highest glass transition temperature at 74.2 ${^{\circ}C}$. This indicates that the peripheral PS chains are effectively decoupled by the conformationally flexible ether spacer. The results from this study demonstrated that polymeric architecture and dendritic core structures play a crucial role in the determination of glass transition behavior, providing a strategy for the systematic engineering of polymer chain mobility.

• Computational Structural Engineering
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• v.6 no.4
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• pp.89-98
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• 1993

As the construction of nuclear power plants are increased, nuclear wastes disposal has been faced as a serious problem. If nuclear wastes are to be buried in the underground stratum, thermo-mechanical behavior of stratum must be analyzed, because high temperature distribution has a significant effect on tunnel and surrounding stratum. In this study, in order to analyze the structural behavior of the underground which is subject to concentrated heat sources, a coupling method of nonlinear finite elements and linear boundary elements is proposed. The nonlinear finite elements (NFE) are applied in the vicinity of nuclear depository where thermo-mechanical stress is concentrated. The boundary elements are also used in infinite domain where linear behavior is expected. Using the similar method as for the problem in mechanical field, the coupled nonlinear finite element-boundary element (NFEBE) is developed. It is found that NFEBE method is more efficient than NFE which considers nonlinearity in the whole domain for the nuclear wastes depository that is expected to exhibit local nonlinearity behavior. The effect of coefficients of the rock mass such as Poisson's ratio, elastic modulus, thermal diffusivity and thermal expansion coefficient is investigated through the developed method. As a result, it is revealed that the displacements around tunnel are largely dependent on the thermal expansion coefficients.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.540-546
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• 2008

In the near future, robots should be able to understand human's emotional states and exhibit appropriate behaviors accordingly. In Human-Human Interaction, the 93% consist of the speaker's nonverbal communicative behavior. Bodily movements provide information of the quantity of emotion. Latest personal robots can interact with human using multi-modality such as facial expression, gesture, LED, sound, sensors and so on. However, a posture needs a position and an orientation only and in facial expression or gesture, movements are involved. Verbal, vocal, musical, color expressions need time information. Because synchronization among multi-modalities is a key problem, emotion expression needs a systematic approach. On the other hand, at low intensity of surprise, the face could be expressed but the gesture could not be expressed because a gesture is not linear. It is need to decide the emotional boundaries for effective robot behavior generation and synchronization with another expressible method. If it is so, how can we define emotional boundaries? And how can multi-modality be synchronized each other?

• Korean Journal of Health Education and Promotion
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• v.22 no.1
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• pp.17-40
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• 2005

This study was aimed to analyze the status of the a health education and the health behavior, and to identify the effected factors of health promotion behavior based on Green's PRECEDE Model among high school students The data was collected by interview survey with self-administration questionnaire from the selected high school students during the end of the second semester, 2001, and 1,591 students are analyzed. The statistical method of the analysing for effected factors of health promotion behavior was used the Multiple Linear Regression Analysis by SPSS package program. The results of this study are as fellows. 1. The index of the health educational contents shows the 18.14 points per 86 points, 18.96 points in girl students, 17.53 points in boy students. 2. In the index of health promotion behaviors was 84.9 points per 140 full points in all average; 61 points per 100 points. The experienced rate of smoking was $35\%$ of all students, $38.5\%$ of boy students, $30.6\%$ of girl students each. The experienced rate of drinking was $62.2\%$ of all students, $61.6\%$ of boy students, $69.4\%$ of girl students. 3. The effected factors of the health promotions behaviors to analyse by multiple linear regression model was sports activity, the degree of satisfaction of their school life, the academic records of school, the present health conditions, their awareness for hazard of smoking for their health, the experiences of the smoking, their stresses(R$^2$ =0.174). and the factors as the experiences of drinking, their stresses, and the indexes for the health education contents in their school were added in girls students.

• Earthquakes and Structures
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• v.15 no.2
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• pp.113-122
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• 2018

This study presents a new beam-column model comprising material nonlinearity and joint flexibility to predict the nonlinear response of reinforced concrete structures. The nonlinear behavior of connections has an outstanding role on the nonlinear response of reinforced concrete structures. In presented research, the joint flexibility is considered applying a rotational spring at each end of the member. To derive the moment-rotation behavior of beam-column connections, the relative rotations produced by the relative slip of flexural reinforcement in the joint and the flexural cracking of the beam end are taken into consideration. Furthermore, the considered spread plasticity model, unlike the previous models that have been developed based on the linear moment distribution subjected to lateral loads includes both lateral and gravity load effects, simultaneously. To confirm the accuracy of the proposed methodology, a simply-supported test beam and three reinforced concrete frames are considered. Pushover and nonlinear dynamic analysis of three numerical examples are performed. In these examples the nonlinear behavior of connections and the material nonlinearity using the proposed methodology and also linear flexibility model with different number of elements for each member and fiber based distributed plasticity model with different number of integration points are simulated. Comparing the results of the proposed methodology with those of the aforementioned models describes that suggested model that only uses one element for each member can appropriately estimate the nonlinear behavior of reinforced concrete structures.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.124-133
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• 2014

This study aims to track pedestrian behavior in urban linear tourist sites and to analyse their behavioral characteristics. For these purposes, this study has adopted the direct observation, a behavioral tracking methodology, and selected Chenggyecheon in Seoul as the study site, a representative site of urban regeneration. The main results of this study can be summarized as follows: the period of stay and movement distance of pedestrians in the study area are both short and most pedestrian activities, apart from walking, are of a passive nature, such as pitching pennies, reading signs, resting and the like. Spatial points of Chenggyecheon at which pedestrians have exhibited these behaviors during their stay are summarized as 30 points and classified into 3 types: landmarks, bridges and nodes. Further research that combines several tracking methods in terms of urban pedestrian behavior is needed.

• Polymer(Korea)
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• v.27 no.5
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• pp.502-507
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• 2003

The thermal and physical properties of low density polyethylene melt-blended with Metallocene linear low density polyethylenes were investigated. Since the Metallocene polyethylenes have similar MW and MWD except m-LLDPE4, it can be said that the thermal behavior and mechanical properties of the blends depend upon the l-octene comonomer content. The melting behavior of LDPE/m-LLDPE1 blends shows two melting peaks with LDPE contents higher than 50%, while the other blends show only one melting peak. It was observed that the blends show higher crystallization temperature and higher crystallinity with lower comonomer content. Initial modulus of a blend exhibited the behavior proportional to the crystallinity and the elongation at break of the blends was increased with increasing the m-LLDPE composition. Melt indices of the blends decreased with increasing the comonomer content of Metallocene LLDPE. Melt Index values of the blends show negative deviation.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.395-404
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• 2020

This was a descriptive study to investigate the effect of social support and health literacy on sick role behaviors in hemodialysis patients. A total of 149 outpatients receiving regular hemodialysis at four dialysis centers located in J city were surveyed. Data were analyzed using descriptive statistics, t-test, one-way ANOVA, Pearson correlation coefficient, and multiple linear regression. Factors including social support (β=.37, p<.001), health literacy (β=.16, p=.035), and religion (others) (β=-.25, p=.001) had an effect on sick role behavior. The explanatory power of model in this study was 22.0%. Therefore, the improvement of sick role behavior in patients undergoing hemodialysis requires specific strategies and interventions that are effective in increasing the social support and health literacy.

• Journal of Nutrition and Health
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• v.54 no.1
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• pp.67-75
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• 2021

Purpose: The theory of planned behavior (TPB) was used to investigate how the psychological constructs of attitude, subjective norms, and perceived behavioral control (PBC) affect the individual intention of behaviors in adults. Social support is also important in enabling the stability of healthy eating. This study examined the relationship between three major constructs of TPB as well as social support and the intention of healthy dietary behaviors in adults residing in Beijing, China using the extended TPB. Methods: The study questionnaire was based on previously validated items and an online survey was conducted from October to November 2020. Using a total of 244 Chinese adults in Beijing, multiple linear regression analysis was used to test the relationships between three major constructs of TPB as well as the social support and intention of healthy eating. Results: Among the three major constructs of TPB, subjective norms (p = 0.044) and PBC (p = 0.000) were significantly related to the behavioral intention of healthy eating (p = 0.000), and the model explained 76.6% of the variance of the behavioral intention from the three constructs of TPB included in the multiple linear regression model. The additional inclusion of social support to the model did not increase the explanatory power of the model to describe the behavioral intention of healthy eating. The subjective norms (p = 0.040) and PBC (p = 0.000) were still significant where social support did not explain the variance of the behavioral intention adequately. Conclusion: The subjective norms and PBC may be potential determinants of the behavioral intention of healthy eating in adults residing in Beijing, China. These study results can be used to promote healthy eating in Chinese adults living in urban areas. Large-scale intervention studies will be needed to determine if social norms and PBC predict the actual behaviors of healthy eating in Chinese adults.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.1 s.244
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• pp.66-75
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• 2006

Nonlinear response structural optimization using equivalent static loads (NROESL) has been proposed. Nonlinear response optimization is solved by sequential linear response optimization with equivalent static loads which are generated from the nonlinear responses and linear stiffness matrix. The linear stiffness matrix should be obtained in NROESL, and this process can be fairly difficult for some applications. Proportional transformation of loads (PTL) is proposed to overcome the difficulties. Equivalent static loads are obtained by PTL. It is the same as NROESL except for the process of calculating equivalent static loads. PTL is developed for large-scale probems. First, linear and nonlinear responses are evaluated from linear and nonlinear analyses, respectively. At a DOF of the finite element method, the ratio of the two responses is calculated and an equivalent static load is made by multiplying the ratio and the loads for linear analysis. Therefore, the mumber of the equivalent static loads is as many as that of DOF's and an equivalent static load is used with the reponse for the corresponding DOF in the optimization process. All the equivalent static loads are used as multiple loading conditions during linear response optimization. The process iterates until it converges. Examples are solved by using the proposed method and the results are compared with conventional methods.