• Title/Summary/Keyword: Theoretical studies

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Theoretical Studies on the Base-Catalyzed Deprotonation of 4-Phenacylpyridinium Cations

  • 김왕기;전영이;손창국;김창곤;이익준
    • Bulletin of the Korean Chemical Society
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    • v.18 no.2
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    • pp.193-197
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    • 1997
  • Theoretical studies on the base-catalyzed deprotonation of 4-phenacylpyridinium cations, R1-CO-CH2-C5H4N-R2, I (R1=YC6H4 -and R2=CH3), and II (R1=C6H5 and R2=CH2C6H4Y) have been carried out with bases, NH3 and XC6H4NH2 using AM1 MO method. The Brψnsted α values are 0.20 and 0.22 and the βB values are 0.62 and 0.61, respectively for cations I and II. The negative Ⅰ (=α-βB) values obtained are in accord with the experimental results in aqueous solution, although the theoretical gas-phase α values for I are somewhat smaller than the experimental values in water due to neglect of solvation effect. It has been stressed that the Brψnsted α is distorted not only by the lag in the resonance and solvation development in the carbanion, but also by the difference in the distance between the anionic center and substituents in the TS and in the product anion.

Theoretical and practical discussion of drive-by monitoring of railway bridges using in-service vehicles

  • Achraf Zouizza;Malika Azmi
    • Structural Monitoring and Maintenance
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    • v.11 no.2
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    • pp.149-171
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    • 2024
  • Drive-by monitoring (also known as indirect monitoring or mobile sensing) of bridges has obvious advantages when compared to other approaches of Structural Health Monitoring. The underlying concept involves leveraging the coupling between the vertical vibrations of the bridge and those generated in the passing vehicle. In this scenario, the vehicle serves as both the initiator and recipient of the vibrations, which can provide information on the structural condition of the bridge. In the literature, a wide range of methods has been proposed, primarily focused on highway bridges. However, limited research has been published to assess the suitability of indirect methods for monitoring railway bridges, bounded to numerical studies based on theoretical simulations and, rarely, on experimental investigations. The aim of this work is to contribute to filling this gap and explore the feasibility of implementing drive-by monitoring for railway bridges using in-service vehicles and discuss its potential applicability, from theoretical and practical point of view, with illustration through real case studies from the Moroccan railway network.

Theoretical Grounding of Perceived Risk in Adoption of Mobile Payment System and Behavioural Intention

  • Bharti Ramtiyal;Deepak Verma;Ajay Pal Singh Rathore
    • Asia pacific journal of information systems
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    • v.31 no.4
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    • pp.543-574
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    • 2021
  • This study focuses on a better understanding of the importance of risk perception in adopting Mobile Payment Systems (MPS) by conducting a systematic literature review. From the social science field (using Scopus and Web of Science database) articles were selected. Overall, forty-four significant pieces were determined using a systematic methodology. In addition to providing a summary of the most used theories used to address perceived risk in MPS this paper also investigates the definition for the perceived risk in MPS literature. The study is performed through the identification of dominant theories used to explain perceived risk in the literature. The article gives a thematic analysis of theories and the relation of perceived risk with behavioural intention. As far as we know, this is the first effort of its kind to give a holistic, systematic literature review in light of perceived risk in MPS. Consequently, it is a crucial first step in establishing a solid theoretical framework involving the constructs of perceived risk and laying the groundwork for future research in this area.

A Study on the Social Cleavage Structure of Welfare Politics : Beyond the Limitations of Class Theories, towards a New Theoretical Framework (복지정치의 사회적 균열구조에 관한 연구 : 계급론의 한계와 새로운 분석틀)

  • Ahn, Sang-Hoon
    • Korean Journal of Social Welfare
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    • v.43
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    • pp.193-221
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    • 2000
  • The conventional framework of welfare politics, based on class concepts, tends to fail in explaining the recent social changes. Theoretical response from the social science diverges into two blocs. One is the postmodernist approach that denies possibility of structural cleavage; the other is the alternative trial that seeks to find various kinds of cleavages. The former approach is to be rejected because there is few empirical supports for it. The latter is too sparse to be applied to the studies of welfare politics that requires a comprehensive analysis. This study starts from critical investigation of such approaches, aiming at providing a theoretical framework that combines merits of existing studies on welfare politics. The theoretical framework of three statuses of welfare rights and duties, which is to be presented as an alternative to the conventional class counterpart, does not only underscore the expansion of welfare rights but also the burden of welfare duties. Hence, it can comprehensively subsume complex existence of interest cleavages of welfare politics. To make a long story short, individual interest, related to the welfare state, will effect individual attitudes toward the welfare state and their ways of political support.

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A Study on Minimization for Digital Circuits Using the Universal Logic Modules (ULM을 이용한 디지탈회로의 간소화에 관한 연구)

  • 박규태;김진복
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.13 no.4
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    • pp.12-17
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    • 1976
  • This paper deals with characteristics and analysis of the Universal Logic Modules as well as TULM, QULM and SULM. Studies are made on minimization in Storms of symmetric circuits and theoretical stuides are made by using the symmetric functions The symmetric circuits of the ULM are realized by employing 54/74 ICs, An oscillator circuit of 10KHz. is constructed based on the ULM. The experimental results gave a good agreement with the theoretical Minimization.

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Southeast Asia as Theoretical Laboratory for the World

  • Salemink, Oscar
    • SUVANNABHUMI
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    • v.10 no.2
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    • pp.121-142
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    • 2018
  • Area studies are sometimes framed as focused on specific localities, rooted in deep linguistic, cultural and historical knowledge, and hence empirically rich but, as a result, as yielding non-transferable/non-translatable findings and hence as theoretically poor. In Europe and North America some social science disciplines like sociology, economics and political science routinely dismiss any reference to local specifics as parochial "noise" interfering with their universalizing pretensions which in reality obscure their own Euro-American parochialism. For more qualitatively oriented disciplines like history, anthropology and cultural studies the inherent non-universality of (geographically constricted) area studies presents a predicament which is increasingly fought out by resorting to philosophical concepts which usually have a Eurocentric pedigree. In this paper, however, I argue that concepts with arguably European pedigree - like religion, culture, identity, heritage and art - travel around the world and are adopted through vernacular discourses that are specific to locally inflected histories and cultural contexts by annexing existing vocabularies as linguistic vehicles. In the process, these vernacularized "universal" concepts acquire different meanings or connotations, and can be used as powerful devices in local discursive fields. The study of these processes offer at once a powerful antidote against simplistic notions of "global"/"universal" and "local," and a potential corrective to localizing parochialism and blindly Eurocentric universalism. I develop this substantive argument with reference to my own professional, disciplinary and theoretical trajectory as an anthropologist and historian focusing on Vietnam, who used that experience - and the empirical puzzles and wonder encountered - in order to develop theoretical interests and questions that became the basis for larger-scale, comparative research projects in Japan, China, India, South Africa, Brazil and Europe. The subsequent challenge is to bring the results of such larger, comparative research "home" to Vietnam in a meaningful way, and thus overcome the limitations of both area studies and Eurocentric disciplines.

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A Theoretical Model of Hope Enhancing the Cancer Patients just after Surgery: Realistic Hope (수술 직후 암 환자의 희망증진 간호를 위한 이론 모델 개발 : 현실적 희망)

  • Kim, Dal Sook;Park, In Sook
    • Korean Journal of Adult Nursing
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    • v.18 no.1
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    • pp.115-124
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    • 2006
  • Purpose: The purpose of this study was to propose a theoretical model of hope commonly held by the cancer patients just after surgery, under the assumptions that hope of those patients is not only realistic and disease oriented but in dialectical circulation. Method: A theoretical model was generated through 4 steps: exploring a hope structure by synthesizing the relevant hope structures expressed in Kim and Tae's studies, in-depth literature review, examining the meanings of the concepts consisted of the structure in use and their causal relations in logical adequacy, proposing a theoretical structure through synthesizing the causal relations, and diagramming the structure. Results: The proposed theoretical model involves concepts such as Cancer Related Uncertainty (CRU), Efforts to Find out the Possibility of Cure or Recovery (EFPCR), and Hopefulness or Hopelessness. The 'EFPCR' is stipulated as 'Behaviors Related to Looking for Evidences or Cues (BRLEC)' and 'Formation of Cognitive Schema (FCS)'. In the model, Hopefulness is directly influenced by 'CRU in low', which is affected by 'FCS in good' from the result of EFPCR started with 'CRU in increase' while 'CRU with increase' from the result from EFPCR has direct effect on Hopelessness. Conclusion: The theoretical model would be used to enhancing hope of the cancer patients in post-operation.

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A Study on the Selection of Variogram Using Spatial Correlation

  • Shin, Key-Il;Back, Ki-Jung;Park, Jin-Mo
    • Communications for Statistical Applications and Methods
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    • v.10 no.3
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    • pp.835-844
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    • 2003
  • A difficulty in spatial data analysis is to choose a suitable theoretical variogram. Generally mean squares error(MSE) is used as a criterion of selection. However researchers encounter the case that the values of MSE are almost the same whereas the estimates of parameters are different. In this case, the selection criterion based on MSE should take into account the parameter estimates. In this paper we study on the method of selecting a variogram using spatial correlation.

Contemporary Issues on the Creativity Studies of Organizational Behavior (창의성중심 조직행동연구의 현황과 과제 -개인수준의 창의성을 중심으로-)

  • Sohn, Tae-Won
    • Knowledge Management Research
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    • v.6 no.2
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    • pp.123-148
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    • 2005
  • This study aims to extend the research areas of the organization behavior(OB) fields. The paper assumes that the main thrust of "Productivity through people" in the traditional OB has to be replaced by the "Creativity through people" paradigm. OB research issues and topics have not been expended or explored during the past 40 years, but been criticized such as a saturated field and even more "moribund or fallow" areas. Recently, new theoretical and research trends are identified in the area of creativity studies and in OB in general. Conceptual debates and different thoughts on the creativity studies (including creative behaviors) are reviewed selectively. Also, some theoretical issues and research implications are discussed and suggested.

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An analysis of research on the determinants of exercise behavior (운동행위 결정요인에 관한 국외문헌 분석)

  • Lee, Jong Kyung
    • Korean Journal of Adult Nursing
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    • v.12 no.3
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    • pp.356-368
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    • 2000
  • The purposes of this study were 1) to identify determinants of exercise behavior 2) to determine theoretical frameworks that were used in other research 3) to investigate the limitations of exercise research. seventy six research papers, published between 1984-1999, were selected by searching Medline for this study. Research subjects, determinants of exercise behavior, exercise measurement, the design of studies, statistical method and theoretical background were examined. The results are as follows. 1. On the research subjects, most research papers studied healthy adults. 2. Thirteen variables were identified that were used more than 5 times in various researches were self efficacy, barrier, social support, benefit, physiological characteristics, habit, personality, intention, health status, motivation, subjective norm, attitude, and affect. The most frequently supported determinant was self efficacy, the second one was social support, the third was affect and so on. But few research papers found any significant relationship between subject norms or attitude and exercise. 3. On exercise measurement, only 22.4% of research papers considered intensity, duration, frequency as elements of exercise, and 64.5% of researches were assessed by self-reported questionnaires. 4. In research design, 80.3% of research papers were survey type research. The most frequently used statistcal method was Regression. 5. 44.8% of research papers were done without any theoretical basis. Based on the above findings the following suggestions are made : 1. Research which includes diverse populations with different levels of health status needs to be studied. 2. Determinants of exercise may be dynamic and varing in their influence, therefore, stages of exercise behavior and processes of change need to be studied. 3. In research design, more prospective, longitudinal studies are needed to identify determinants of exercise habits. 4. It is necessary to develop a reliable, valid exercise measurement tool. 5. Studies are needed to develop a theoretical framework for exercise behavior.

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