• Journal of Pharmaceutical Investigation
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• 제29권3호
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• pp.193-203
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• 1999

In order to investigate systematically the steady shear flow properties of aqueous po1y(ethylene oxide) (PEO) solutions having various molecular weights and concentrations, the steady flow viscosity has been measured with a Rheometrics Fluids Spectrometer (RFS II) over a wide range of shear rates. The effects of shear rate, concentration, and molecular weight on the steady shear flow properties were reported in detail from the experimentally measured data, and then the results were interpreted using the concept of a material characteristic time. In addition, some flow models describing the non-Newtonian behavior (shear-thinning characteristics) of polymeric liquids were employed to make a quantitative evaluation of the steady flow behavior, and the applicability of these models was examined by calculating the various material parameters. Main results obtained from this study can be summarized as follows: (1) At low shear rates, aqueous PEO solutions show a Newtonian viscous behavior which is independent of shear rate. At shear rate region higher than a critical shear rate, however, they exhibit a shear-thinning behavior, demonstrating a decrease in steady flow viscosity with increasing shear rate. (2) As an increase in concentration and/or molecular weight, the zero-shear viscosity is increased while the Newtonian viscous region becomes narrower. Moreover, the critical shear rate at which the transition from the Newtonian to shear-thinning behavior occurs is decreased, and the shear-thinning nature becomes more remarkable. (3) Aqueous PEO solutions show a Newtonian viscous behavior at shear rate range lower than the inverse value of a characteristic time $1/{\lambda}_E$, while they exhibit a shear-thinning behavior at shear rate range higher than $1/{\lambda}_E$. For aqueous PEO solutions having a broad molecular weight distribution, the inverse value of a characteristic time is not quantitatively equivalent to the critical shear rate, but the power-law relationship holds between the two quantities. (4) The Cross, Carreau, and Carreau-Yasuda models are all applicable to describe the steady flow behavior of aqueous PEO solutions. Among these models, the Carreau-Yasuda model has the best validity.

• 한국재난정보학회 논문집
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• 제15권4호
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• pp.524-530
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• 2019

연구목적: 본 논문에서는 3차원 해석프로그램을 활용하여 인터페이스 요소를 구성하고, 일반적인 부재의 특성치와 강도가 보강된 부재의 특성치 등의 실제 표현할 수 있는 물성조건을 적용하여 연결체의 복합거동 안정성을 평가하고자 하였다. 연구방법: 해석 모델은 비선형적인 재료 거동을 포함한 솔리드 요소(Solid Element)를 사용하여 빔 구조 및 원형 플랜지, 볼팅 시스템 등의 부재를 설계도면과 동일한 치수로 모델링을 완성하였고 각 부재는 하나의 복합거동연결체로 조립되는 과정에서 다른 요소유형(Element Type) 접촉면의 통일성과 매쉬(Mesh) 생성을 보다 효율적으로 제어하여 분할작업(Partition)을 수행하였으며 부재들에 활용된 강재는 Gr. 50 탄소강 재질로 모델링 하였다. 연구결과: 부재별 접촉 인접부위, 하중재하부위, 고정단 부위, 취약예상부위 등으로 하여 하중단계별 변위 및 변형, 응력상태 등을 나타내고, 유한요소 해석 후 복합거동연결체의 각 하중단계에서의 변위, 변형, 응력 등의 분포도로 영향을 검증하고 설계의 타당성을 확인하였다. 결론: 따라서 이 결과를 토대로 하여 마이크로 파일의 설계 지지력이 결정되면 복합거동 연결체의 취약 지점의 파악과 보강의 정도를 파악할 수 있을 것으로 판단된다.

• Asia pacific journal of information systems
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• 제17권3호
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• pp.1-24
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• 2007

With the development of information technology (IT), various information systems (IS) such as Web-based systems and mobile systems have appeared utilizing different technologies. However, recent studies on IS use and user satisfaction rarely account for technological differences among IS and environmental characteristics where IS are intended to be used. The purpose of this research is to investigate the determinants of the use of Web-based ticketing systems for cultural activities and to empirically validate their relationships. Environmental psychology suggests that human beings respond to external stimuli from environments with their emotions, and their emotional states influence human actions, e.g., IS use in this research. Applying environmental psychology to the use of Web-based systems in the culture and entertainment industry, we propose that web site characteristics first influence a user's internal state of mind (i.e., flow) and then the flow state influences the IS use. Studies related to the state of flow collectively affirm the key role played by the flow construct in shaping individual attitudes and behaviors toward IS. Users' flow states are captured by their shopping enjoyment, perceived behavioral control, and the level of concentration on the IS use. Referring to social presence theory, we have included such web site characteristics as content quality, context of web site, and community quality. In our research model, a second order construct is utilized to represent web site quality, because flow theory suggests that holistic experiences with web-based systems (rather than individual characteristics of the web site) are important in explaining the IS use. Further, we have included trust as another important factor influencing the IS use since business transactions on the web encompass higher uncertainty comparing to offline transactions. In order to test our hypotheses, we have conducted an online survey which results in 1,141 valid responses in the final sample. The data were collected from respondents who have experiences in Internet ticketing systems. Although it was a convenient sample, the sample represents a wide variety of user demographics. Validity and reliability of the research instrument were tested and research hypotheses were examined using PLS Graph 3.0. The results indicate that web site characteristics significantly influence the level of user concentration, user's enjoyment in shopping, and perceived behavioral control. Further, the use of Internet ticketing systems is influenced by users' flow states and trust in the web channel. User satisfaction is turned out to be affected by the use of Internet ticketing systems. Unlike extant research on the relationship between web site characteristics and its use, our study has found that, in the culture and entertainment industry, the impact of web site characteristics on IS use is mediated by a user's flow state. This finding has a practical implication that web site design should include as many features that enhance shopping enjoyment and concentration. Other practical implications of these findings and future research implications are also discussed.

• 공업화학
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• 제31권2호
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• pp.147-152
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• 2020

본 연구에서는 천연오일인 cashew nut shell liquid (CNSL)의 구성성분인 cardanol을 이용하여 내화학성이 향상된 에폭시계 수지용 반응성 희석제 제조 공정을 최적화하였다. 이를 위해 반응표면분석법 중 중심합성계획법을 이용하여 최적화과정를 설계하였다. 계량인자로는 cardanol/ECH 반응몰비, 반응시간, 반응온도이고, 반응치는 수율, 에폭시 당량(EEW), 점도이다. 기초실험으로부터 계량인자 범위를 각각 cardanol/ECH 반응몰비(2~4), 반응시간(4~8 h), 반응온도(100~140 ℃)로 설정한 후 최적화과정을 진행한 결과 최적의 조건은 cardanol/ECH 반응몰비(3.33), 반응시간(6.18 h), 반응온도(120 ℃)로 산출되었으며, 이 조건에서의 예측값은 수율(100%), EEW (429.89 g/eq.), 점도(41.65 cP)로 나타났다. 실제 실험을 통해 알아본 결과 오차율은 0.3% 이하로 나타나 중심합성계획모델을 이용하여 cardanol 원료 반응성 희석제의 제조 공정을 최적화할 수 있었다.

• 한국산학기술학회논문지
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• 제17권9호
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• pp.543-551
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• 2016

최근 문화산업은 한류의 성장과 더불어 발전가능성과 함께 극적인 효과를 보여주고 있는 매력적인 산업이다. 특히 대중성을 겸비한 공연예술 산업이 유망산업으로 주목받기 시작하면서, 공연예술 시장의 마케팅 기법도 다른 상품 시장처럼 소비자의 욕구와 수요에 맞추어 변화되기 시작하였다. 소비자들의 요구가 점점 다양해지고 개성화되며 다양한 소비자의 욕구충족에 능동적으로 대처하기 위해서는 소비자들의 행동을 파악하는 것이 무엇보다 중요하다. 공연예술 시장에서는 관객에 대한 중요성을 인식하고, 이에 적합한 마케팅 기법을 적용해야 한다. 본 연구에서는 공연예술 관람객들이 가치에 대하여 지각하는지를 실증적으로 규명하고, 지각된 가치가 공연예술에 대한 태도형성과 만족도에 미치는 영향관계를 규명하기 위해 노력하였다. 공연예술에 대한 가치가 태도와 고객만족도에 미치는 영향관계를 살펴보기 위해서는 측정항목의 신뢰성과 타당성을 검정하기 위해 사용하는 신뢰도 분석(reliability analysis)과 요인분석(factor analysis)을 실시하였다. 본 연구목적을 달성하기 위한 핵심적인 분석방법은 구조방정식 모형(SEM)을 사용하였다. 그 결과 공연예술에 대한 지각된 가치와 태도가 고객만족도에 긍정적인 영향을 미치는 것으로 나타났다. 연구의 시사점은 공연을 기획하는 단체입장에서는 공연을 보러오는 관객을 중심으로 마케팅과 홍보를 진행할 수 있는 연구의 기초자료가 되어 앞으로 보다 구체적이고 세부적인 연구가 지속되어질 것을 기대해본다.

• 한국정보과학회논문지:데이타베이스
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• 제28권4호
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• pp.732-741
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• 2001

관계형 데이타베이스 시스템에서 결합 연산자는 데이타 베이스 절의를 구성하는 연산자들 중 가장 많은 처리시간을 요구한다. 따라서 이러한 결합 연산자를 효율적으로 처리하기 위해 많은 병렬 알고리즘들이 수개되었다. 그 중 다중 해쉬 결합 질의의 처리를 위해 할당트리를 이용한 방법이 가장 우수한 것으로 알려져 와싸. 그러나 이 방법은 할당 트리의 각 노트에서 필연적인 지연이 발생되는데 이는 루플 실험단계에서 외부 릴레이션을 디스트로부터 페이지 단위로 읽는 비용과 이미 읽는 페이지에 대한 해쉬 결합 비용간의 실행시간 차이에 의해 발생하게 된다. 이는 페이지 실행시간 동기화 기법을 이용하여 할당 트라 한 노드에서의 실행시간을 줄일 수 있었다. 본 논문에서는 한 노드에서의 성능 개선 효과를 할당 트리 전체로 확장하여 전체 다중 해쉬 결합의 성능 분석을 수행하였으며 한정된 프로세서 환경 하에서 입력 릴레이션 수와 할당된 프로세서 수와의 관게에 따른 효율적인 다중 해쉬 결합 알고리즘을 제안하였다. 그리고 분석적 비용 모형을 세워 기존 방식과의 다양한 성늘 분석을 통해 비용 모형의 타당성을 입증하였다.

• 유통과학연구
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• 제14권4호
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• pp.81-92
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• 2016

Purpose - In recent years, management scholars have expressed growing interest in the concept of person-Job fit because of having many benefits for employees' attitudes and behaviors. The related research is needed to determine what specific types of fit are related to each other, and to get important individual outcomes. Person-job fit of employees in service organization plays an important role in company as well as person in service industry. Person-job fit, representing the consistency between person (service provider) and job (service provided to the customers), gives significant and positive effects on the attitude and behavior of service provider. On the basis of the study background, the purpose of this study is as follows. First, we would like to examine the effects of person-job fit of service provider on their emotional intelligence. Emotional intelligence is divided into four sub-factors such as self-understanding, understanding others, emotional utilization, and emotional regulation. Second, we would like to identify the relationships between job satisfaction and sub-factors such as self-understanding, understanding others, emotional utilization, and emotional regulation. Research design, data, and methodology - We performed structural equation model using Spss 18.0 and Amos 20.0 in order to verify the hypotheses. Subjects were golf service assistants who were high-touching service with high degree in interaction and long contact time with customers. 178 out of the total 200 surveys were used in evaluation from helpers of golf service working as full-time service provider after selecting two locations of golf course located near Busan. From the evaluation of reliability and validity with variables used in this research, they satisfied and confirmed certain standard. Results - The results are as follows. First, as the results of identifying the relationships between person-job fit and emotional intelligence of service provider, person-job fit did not have positive and significant effect on self-understanding. On the other hand, it affected positively and significantly other factors in emotional intelligence such as emotion to others, emotional utilization, and emotional regulation. Second, as the results of identifying the relationship between emotional intelligence and job satisfaction, sub-factors in emotional intelligence such as emotion to others, emotional utilization, and emotional regulation except self-emotion affected significantly and positively job satisfaction. However, self-emotion did not have significant and positive effects on job satisfaction. Conclusion - These results will be valuable and used for service providers. In addition, many service providers will recognize that person-job fit is very important to get a job. This research has a purpose on the assumption that appropriateness between individual and task in service industry shall act as major influence in emotional intelligence of service provider. Recognitive ability of service provider is also very important per characteristics of service, but emotional intelligence that interacts and connected directly with most customers can be a very meaningful factor as well. Emotional intelligence allows people to recognize, understand, and empathize the emotion of customers shall be a positive reinforcement for customers to evaluate the service ultimately.

• 유통과학연구
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• 제12권8호
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• pp.43-54
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• 2014

Purpose - This study was based on a theoretical consideration of the structural relationship between the support and control of the franchisor and the satisfaction and strategic response (voice, loyalty, exit, neglect) of the franchisee. First, based on the preceding research, this study systematically organized the type of support and control of the franchisor. Second, the study examined the effects of a franchisor's support and control on the expectancy disconfirmation between affiliated franchisees' expectations before a franchise agreement and performance after operating an affiliated store. Third, the study looked into the effects of expectancy disconfirmation relating to a franchisor's support and control on an affiliated franchisees' general satisfaction. Fourth, this study examined the influence of the general satisfaction of a franchisee on affiliated franchisees' response strategies. Research design, data, and methodology - In this study, the population comprised the nation's franchisors, and the sample comprised franchisees conducting business in Seoul and Gyeonggi-do. A self-administered questionnaire was used; the author and examiner explained the study's parameters to the interviewees in advance, to lessen the rate of rejection of the answers and to maintain reliability. The author distributed 350 copies of the questionnaire and collected 327 copies (93.4%). The author removed 54 copies of the sample, as these copies belonged to franchisees that were not registered by the Fair Trade Commission and/or were thought to have either defects or inadequate answers. The author selected an effective sample of 273 copies to enter data and to do the statistical analysis. Results - Both a reliability analysis and a confirmatory factor analysis were performed to measure reliability and validity, and a structural equation model was used to conduct the hypothesis test and investigate the models. The hypothesis was tested (Table 5). The models had a suitable fit, for instance, χ² = 447.663(df = 212, p = .000), χ²/df = 2.112, GFI = .881, AGFI = .858, RMR = .083, RMSEA = .067, NFI = .932, and CFI = .961. The hypothesis test results were as follows. Hypothesis 1 was accepted (C.R. = -2.339, p = .019). Hypothesis 2 was accepted (C.R. = 15.213, p = .000). Hypothesis 3 was accepted (C.R. = -2.631, p = .006). Hypothesis 4 was accepted (C.R. = 16.271, p = .000). Hypothesis 5 was accepted (C.R. = 2.391, p = .017). Hypothesis 6 was accepted (C.R. = 5.777, p = .000). Hypothesis 7 was accepted (C.R. = 17.153, p = .000). Hypothesis 8 was accepted (C.R. = 24.746, p = .000). Hypothesis 9 was accepted (C.R. = -10.150, p = .000). Hypothesis 10 was accepted (C.R. = -12.124, p = .000). Conclusions - The research results showed that expectations for a franchisor's support and control had a significant influence on expectation disconfirmation in a negative way, whereas the performance of support and control were found to have a significant influence on expectation disconfirmation in a positive way. In addition, the expectation disconfirmation of support and control was found to have a significant influence on satisfaction of franchisees in a positive way. Generally, regarding the research on control, control is found to have a negative influence on the satisfaction of franchisees, but this study proves that control is found to affect it in a positive way through conformity.

• 사회복지연구
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• 제40권3호
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• pp.41-68
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• 2009

조손가족 청소년들은 일반 가족의 청소년들에 비해 부정적인 환경에 노출됨으로써 심리사회적으로 부정적인 영향을 받는 경향이 높기 때문에 중요하게 검토되어야 한다. 이와 관련하여 조손가족 청소년의 위험요인, 보호요인과 학교 적응유연성 간의 관계를 다룬 연구가 이루어지고 있으나, 대부분 청소년의 위험요인, 보호요인과 학교 적응유연성 간의 단편적인 관계를 설명하는데 그치고 있다. 이에 본 연구는 조손가족 청소년의 위험요인과 보호요인 간, 그리고 이들과 학교 적응유연성 간의 매개적인 경로와 인과관계를 살펴보는데 목적을 두었다. 이를 위해 전국 단위의 조손가족 청소년 328명을 대상으로 조사하였고, 분석방법은 SEM을 사용하였다. 분석결과는 다음과 같다. 조손가족 청소년의 위험요인, 보호요인과 학교적응유연성 간의 직접효과와 보호요인의 매개효과를 검증하기 위해 구조회귀모형을 검증한 결과 모형의 적합도가 타당하게 나타났다. 위험요인은 청소년의 학교적응유연성에 부정적 영향을 미치며(교사의 무관심, 부정적 애착관계, 우울불안 순), 보호요인은 학교 적응유연성에 긍정적 영향을 미쳤다(교사의 지지, 자아존중감 순). 또 보호요인은 위험요인이 학교 적응유연성에 미치는 부정적 영향을 매개하여 완화시키는 것으로 나타났다.

• 한국콘텐츠학회논문지
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• 제19권10호
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• pp.607-619
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• 2019

본 연구는 천연기념물 물거미와 그 서식 장소를 교육 콘텐츠로 하여 물거미의 생태 관찰과 가상야외학습장(VFC) 개발을 통해 과학적 소양과 은대리 습지에 대한 아름다운 추억을 가질 수 있도록 했다. 프로그램 개발을 위해 2015개정교육과정과 교과서를 분석하였고, STEAM 수업 모델에 따라 7차시 학습자료로 개발했다. 학생들은 협력학습으로 물거미에 관한 3D 파노라마 VFC를 제작하면서 물거미에 대한 의미와 가치를 감성적으로 체험할 수 있도록 했다. 6명의 교육 전문가 패널이 개발 프로그램의 타당도를 검증한 결과, 5점 리커트 척도에서 평균 4.20(CVI=.88)로 매우 합당한 것으로 평가되었다. 개발 프로그램의 현장 적합성과 실제 학교 현장에서의 불일치 정도를 줄이기 위해 중학교 과학동아리 학생들을 대상으로 예비수업에 적용한 결과, 수업 만족도는 평균 4.24이었으며 프로그램의 유용성과 참신한 학습 내용, 융합교육 수업의 적합성 등에서 매우 만족하였다. 이 연구는 청소년들을 대상으로 한 생태와 가상현실 관련 융합교육 분야에 기여할 수 있을 것이다.