• Bulletin of the Korean Chemical Society
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• 제29권6호
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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.

• 전산구조공학
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• 제6권4호
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• pp.89-98
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• 1993

최근 원자력의 사용이 증가함에 따라 핵폐기물을 효과적으로 처리하는 문제에 관심이 집중되고 있다. 이러한 핵폐기물을 지층내에 저장할 경우 고온의 열에 의해 핵폐기물 구조체에 지대한 영향을 미치므로 지반의 열력학적 거동을 분석할 필요성이 요구된다. 본 연구는 지반내에 처분된 고온의 사용후 핵연료에 의한 열역학적인 응력이 집중되어 비선형 거동이 예상되는 저장구조체 주변에는 비선형 유한요소를 적용하고 선형거동이 예상되는 무한영역에는 선형경계요소를 사용하여, 일반적인 역학적 계와 동일한 방법으로 비선형 유한요소와 경계요소를 조합한 프로그램을 개발하였다. 사용후 핵연료 폐기구조체와 같이 국부적인 비선형거동이 예상되는 구조물에서는 조합방법이 전 영역을 비선형 유한요소로 모형화하여 해석하는 것보다 효율적임을 알 수 있었다. 또한, 지층내 지반에 영향 미치는 주요 지반계수를 변화시킨 경우, 터널경계의 변위에 이러한 계수들이 어떠한 영향을 미치는가를 개발된 방법을 사용하여 검토하였다. 검토결과, 다른 계수들의 변화보다 열팽창계수의 변화가 터널주위의 변위에 상당한 영향을 미침을 알 수 있었다.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.540-546
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• 2008

미래에는 로봇이 사람의 감정 상태를 이해하거나 적절하게 자신의 행동을 표현하는 기능은 중요해 질 것이다. 사람간의 교류에서 메세지의 93%가 행동 표현에 있으며, 바디 랭귀지는 감정의 양을 표현하므로 행동 표현은 중요한 감정 표현 수단이다. 최근의 로봇들은 얼굴, 제스처, LED, 소리 등의 복합적 방법을 이용하여 사람과 교류하고 있지만 포즈는 위치와 방위, 얼굴이나 제스처는 속도, 말이나 색 풍은 시간에 대한 정보가 필요하기 때문에 하나의 모델로 통합하거나 동기화 시키기 어렵다. 한편 작은 세기의 감정에서, 얼굴은 쉽게 표현이 가능하지만 제스처는 표현이 힘들다. 또한 기존의 감정 경계는 같은 형태와 크기를 가지거나, HHI 분야에 국한되어 연구되어 왔다. 본 논문에서는 정서 공간에서 감정의 경계를 어떻게 정의할 것이며, 복합적 표현 방법을 시스템적으로 어떻게 동기화할 수 있을지를 제안한다.

• 보건교육건강증진학회지
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• 제22권1호
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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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• 제15권2호
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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.

• 한국조경학회지
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• 제42권5호
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• pp.124-133
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• 2014

본 연구는 도심 선형 여가공간 내 보행자의 행태를 추적하고, 그들의 행태특성을 분석하는 것을 목적으로 한다. 이를 위해 본 연구는 행태추적 방법의 하나인 직접관찰법을 도입하였고, 대표적인 선형 도시재생 사례인 서울 청계천을 연구대상지로 선정하였다. 주요 연구결과를 요약해 보면 대상지내 보행자들의 체류시간과 이동거리는 매우 짧았고, 도보를 제외한 주요 행태는 동전던지기, 안내판 읽기, 휴식 등의 소극적인 특성을 보였다. 또한 보행자들의 주요 행위지점을 살펴보면 30개 지점으로 종합되었으며, 랜드마크, 교량, 결절점의 세 유형으로 구분되었다. 추후 도시 보행자들의 행태에 대해 다양한 행태추적 방법이 융합된 연구들이 진행되기를 고대한다.

• 폴리머
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• 제27권5호
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• pp.502-507
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• 2003

메탈로센 선형 저밀도 폴리에틸렌 (m-LLDPE)과 저밀도 폴리에틸렌 (LDPE)을 용응 블렌딩 방법으로 블렌드를 제조하여 열적 거동 및 물성을 관찰하였다. LDPE/m-LLDPE1 블렌드는 LDPE조성이 50% 이상이면 두 개의 용융 피크가 관찰된 반면 다른 블렌드들은 단일한 용융 피크를 나타내었다. m-LLDPE에서 공단량체 함량이 감소할수록 용융 온도와 상대 결정화도가 증가하였다. 공단량체 함량이 2 wt%인 m-LLDPE1이 초기 탄성률이 가장 높게 관찰되었고, 공단량체 함량이 증가함에 따라 감소하였다. 블렌드에서 조성에 따른 초기 탄성률의 변화는 상대 결정화도의 거동과 유사하게 나타났다. 블렌드의 파괴 신율은 LDPE/m-LLDPE1과 LDPE/m-LLDPE2 블렌드에서 평균값보다 낮은 파괴 신율을 나타내었었다. m-LLDPE2의 용융 지수가 가장 높게 관찰되었고 공단량체 함량이 증가함에 따라 감소하는 경향을 나타내었다.

• 한국융합학회논문지
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• 제11권9호
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• pp.395-404
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• 2020

본 연구는 혈액투석 환자의 사회적 지지, 건강정보 이해능력, 환자역할행위 이행의 정도와 환자역할행위 이행에 미치는 영향을 파악하기 위한 서술적 조사연구이다. J시에 위치한 투석실 4곳에서 정기적인 혈액투석을 받는 외래환자 149명을 대상으로 조사하였다. 자료는 기술통계, t-test, one-way ANOVA, Pearson correlation, multiple linear regression으로 분석하였다. 혈액투석 환자역할행위 이행에 미치는 영향은 사회적 지지(β=.37, p<.001), 건강정보 이해능력(β=.16, p=.035), 종교(기타)(β=-.25, p=.001)가 유의한 것으로 나타났으며, 본 연구에 적용한 분석모델의 설명력은 22%로 나타났다. 이러한 결과로 보아 환자역할행위 이행의 증진을 위해 사회적 지지와 건강정보 이해능력을 높여 줄 수 있는 구체적인 전략과 효과적인 중재방안 모색이 필요하다.

• Journal of Nutrition and Health
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• 제54권1호
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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.

• 대한기계학회논문집A
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• 제30권1호
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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.