• Title/Summary/Keyword: science theories

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Application of aerospace structural models to marine engineering

  • Pagani, A.;Carrera, E.;Jamshed, R.
    • Advances in aircraft and spacecraft science
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    • v.4 no.3
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    • pp.219-235
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    • 2017
  • The large container ships and fast patrol boats are complex marine structures. Therefore, their global mechanical behaviour has long been modeled mostly by refined beam theories. Important issues of cross section warping and bending-torsion coupling have been addressed by introducing special functions in these theories with inherent assumptions and thus compromising their robustness. The 3D solid Finite Element (FE) models, on the other hand, are accurate enough but pose high computational cost. In this work, different marine vessel structures have been analysed using the well-known Carrera Unified Formulation (CUF). According to CUF, the governing equations (and consequently the finite element arrays) are written in terms of fundamental nuclei that do not depend on the problem characteristics and the approximation order. Thus, refined models can be developed in an automatic manner. In the present work, a particular class of 1D CUF models that was initially devised for the analysis of aircraft structures has been employed for the analysis of marine structures. This class, which was called Component-Wise (CW), allows one to model complex 3D features, such as inclined hull walls, floors and girders in the form of components. Realistic ship geometries were used to demonstrate the efficacy of the CUF approach. With the same level of accuracy achieved, 1D CUF beam elements require far less number of Degrees of Freedom (DoFs) compared to a 3D solid FE solution.

A Critical Review on Behavioral Economics with a Focus on Prospect Theory and EBA Model (프로스펙트 이론과 속성별 제거모형을 중심으로 한 행동경제학에 대한 비판적 고찰)

  • Won, Jee-Sung
    • Journal of Distribution Science
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    • v.11 no.5
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    • pp.63-76
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    • 2013
  • Purpose - For the past several decades, behavioral economics or behavioral decision theory has undergone rapid development. This study provides a critical review of the development of behavioral economics with a focus on what are deemed to be core theories in the field. Starting from the utility function proposed by Daniel Bernoulli in the 18th century, the development history of utility functions until the emergence of the prospect theory is thoroughly reviewed. Some of the experimental results violating the traditionally assumed utility function and supporting the prospect theory value function are summarized. The most representative principles of rational choice are transitivity, independence from irrelevant alternatives (IIA), and regularity. The development of behavioral economics has been triggered by finding counter-examples to these principles. Some of the choice behaviors discussed in this study as counter-examples to the traditional theories of rational choice are the St. Petersburg paradox; the Allais paradox; gambling behavior; and the various context effects including the similarity effect, attraction effect, and the compromise effect. The Elimination-by-Aspects (EBA) model, which was proposed as an explanation for the similarity effect, is discussed in detail as well. Based on the literature review and further analysis, this study summarizes the relationship between the context effects, prospect theory, and EBA model. Research design, data, and methodology - This study provides an extensive literature review on several important theories in the field of behavioral decision theory and adds some critical comments to the theories and the relationships among them. This study first reviews the development of utility functions. Daniel Bernoulli introduced the concept of utility function to solve the St. Petersburg paradox. In the mid-20th century, Herbert Simon proposed the "satisficing" heuristic and presented a value function with a shape different from traditional utility functions. This study highlights the strengths and weaknesses of several utility functions proposed until the emergence of the prospect theory value function. Results - This study posits that prospect theory and EBA model are the two most important theories in the field of behavioral decision theory. They can explain various choice behaviors that traditional utility maximization analysis has been unable to. The application of these models to various fields is further increasing nowadays. This study explains how prospect theory and the EBA model can be used to explain the context effects. Conclusions - The traditional economic theory relies on a single variable called "utility" in explaining consumer choice. However, this study argues that, in investigating consumer choice, several other variables should also be considered. These are the similarity among alternatives, an alternative's prototypicality within the category, the dominance relationship between alternatives, and the reference point in evaluating alternatives. Due to the development of behavioral economics, we are now closer to a more complete understanding of consumer choice behavior than in the past when we had only a single tool called utility.

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The Approaches of Cultural Studies to Theatre -The Limits of Theory Application- (연극에 대한 문화연구적 접근 -'이론' 도입의 한계를 중심으로-)

  • Kim, Yongn Soo
    • Journal of Korean Theatre Studies Association
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    • no.40
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    • pp.307-344
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    • 2010
  • Cultural Studies built on the critical mind of New Left exposes the relationship between culture and power, and investigates how this relationship develops the cultural convention. It has achieved the new perspective that could make us to think culture and art in terms of political correctness. However, the critical voices against the theoretical premises of Cultural Studies have been increased as its heyday in 1980s was nearly over. For instance, Terry Eagleton, a former Marxist literary critic, declared in 2003 that the golden age of cultural theory is long past. This essay, therefore, intends to show the weak foundations on which the approaches of cultural studies to theatre rest and to clarify the general problem of their introduction to theatre studies. The approach of cultural studies to theatre takes the form of 'top-down inquiry' as it applies a theory to a particular play or historical period. In other word, from the theory the writer moves to the particular case. The result is not an inquiry but rather a demonstration. This circularity can destroy the point of serious intellectual investigation as the theory dictates answers. The goal-oriented narrow viewpoint as a logical consequence of 'top-down inquiry' makes the researcher to favor the plays or the parts of a play that are proper to test a theory. As a result it loses the fair judgment on the artistic value of a play, and brings about the misinterpretation. The interpreter-oriented reading is the other defect of cultural studies as it disregards the inherent meaning of the text, distorting a play. The approach of cultural studies also consists of a conventionality as it arrives at a stereotyped interpretation by using certain conventions of reasoning and rhetoric. The cultural theories are fundamentally the 'outside theories' that seek to explain not theatre but the very broad features of society and politics. Consequently their application to theatre risks the destructive criticism, disregarding the inherent experience of theatre. Most of, if not all, cultural theories, furthermore, are proven to be lack of empirical basis. The alternative method to them is a 'cognitive science' that proves scientifically our mind being influenced by bodily experience. The application of cultural materialism to Shakespeare's is one of the cases that reveal the limits of cultural studies. Jonathan Dollimore and Water Cohen provide a kind of 'canonical study' in this application that is imitated by the succeeding researchers. As a result the interpretation of has been flooded with repetitive critical remarks, revealing the problem of 'top-down inquiry' and conventional reasoning. Cultural Studies is antipodal to theatre in some respect. It is interested chiefly in the social and political reality while theatre aims to create the fiction world. The theatre studies, therefore, may have to risk the danger of destroying its own base when it adopts cultural studies uncritically. The different stance between theatre and cultural theories also occurs from the opposition of humanism vs. antihumanism. We have to introduce cultural theories selectively and properly not to destroy the inherent experience and domain of theatre.

Competition and Coexistence of Visual Representations: Controversies about the Mechanism of Face Recognition in Neuroscience (시각화를 통한 재현의 경쟁과 공존: 신경과학의 얼굴 인식 메커니즘에 관한 논쟁을 중심으로)

  • Chang, Ha-Won
    • Journal of Science and Technology Studies
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    • v.10 no.2
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    • pp.107-141
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    • 2010
  • Visualization techniques are transformed into reliable representations through socio-technological processes which include the agreement on the instrument and the embodiment of practices in relevant scientific communities. Visual representations thus produced are justified by realistic and epistemic virtues in science. This paper analyzes different visual images presented in the scientific papers of two research groups who argue different theories about the mechanism of face perception. These two scientific groups use the same fMRI technology; yet, different experimental paradigms and visual stimuli change their hypotheses into distinct testable theories, which in turn lead to different evidences to support their own theories. Visual evidences are intermediate representations which lie between fMRI brain images and scientific theories, and theoretical models obtain the scientific value based on the consistency in the chain of visual representations. This study shows that representations in science tend to be good representations within the context of scientific communities. It will provide a chance to think of the value and limit of the scientific knowledge

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Varied Flavonoid Contents of Citri Unshii Pericarpium Extracted from Several Traditional Herbal Prescriptions (진피의 복합처방에 따른 유효성분 추출율의 변화)

  • Kim Jin-Ju;Cho Sung-One;Lee Ho Young;Ha Hye-kyung;Oh Ju-hee;Yang In-cheol;Choi Hwan-Soo;Lee Je-Hyun
    • The Journal of Korean Medicine
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    • v.26 no.2 s.62
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    • pp.195-200
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    • 2005
  • Objecitves: Peel of Citrus unshiu (Rutaceae) has been used in traditional herbal prescriptions. Hesperidin and naringin contents of Citri Unshii Pericarpium were determined and compared to herbal prescriptions. Then, the different extractions from prescriptions are explained with traditional herbal theories. Methods: The herb and herbal prescriptions were extracted in boiled water. A quantitative analysis was made of hesperidin and naringin using HPLC with-reversed-phase CIS column and a UV detector at 204nm. Elution was carried out at 1.0ml/min with $38\%$ methanol. Results and Conclusions: The extract of Citri Unshii Pericarpium for 180 min was the better method for extracting naringin and hesperidin. The flavonoid contents in remedies are different among several traditional herbal prescriptions. The reason for the difference can be explained with traditional drug interaction theories.

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Free vibration analysis of functionally graded plates with temperature-dependent properties using various four variable refined plate theories

  • Attia, Amina;Tounsi, Abdelouahed;Bedia, E.A. Adda;Mahmoud, S.R.
    • Steel and Composite Structures
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    • v.18 no.1
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    • pp.187-212
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    • 2015
  • In this paper, various four variable refined plate theories are presented to analyze vibration of temperature-dependent functionally graded (FG) plates. By dividing the transverse displacement into bending and shear parts, the number of unknowns and governing equations for the present model is reduced, significantly facilitating engineering analysis. These theories account for parabolic, sinusoidal, hyperbolic, and exponential distributions of the transverse shear strains and satisfy the zero traction boundary conditions on the surfaces of the plate without using shear correction factors. Power law material properties and linear steady-state thermal loads are assumed to be graded along the thickness. Uniform, linear, nonlinear and sinusoidal thermal conditions are imposed at the upper and lower surface for simply supported FG plates. Equations of motion are derived from Hamilton's principle. Analytical solutions for the free vibration analysis are obtained based on Fourier series that satisfy the boundary conditions (Navier's method). Non-dimensional results are compared for temperature-dependent and temperature-independent FG plates and validated with known results in the literature. Numerical investigation is conducted to show the effect of material composition, plate geometry, and temperature fields on the vibration characteristics. It can be concluded that the present theories are not only accurate but also simple in predicting the free vibration responses of temperature-dependent FG plates.

The three most significant contributions of criminological theories to our theoretical understanding of criminal behavior made since 1985 (범죄학 이론의 발전에 영향을 미친 이론들에 대한 고찰: -1985년 이후의 중요한 범죄이론을 중심으로-)

  • Jang, Duck-Hyung
    • Korean Security Journal
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    • no.42
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    • pp.449-468
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    • 2015
  • It is important to identify and discuss what the most vial contributions of criminological theories. In the field of criminology, most significant contributions or advancement have been made on the various issues such as age, the integration of structural and procedural level theories, other theoretical integration debates. However, it is hard to find ant systematic study exploring such a contribution in criminological theories. This study, therefore, has a purpose to discuss three most significant contributions to our theoretical understanding of criminal behavior made since 1985. To accomplish the study purpose, this study choose the followed three theoretical contributions; the emergence of life course theory, the revision of social disorganization theory, and the introduction of social structure and social Learning (SSSL) model. The three theoretical works will be introduced and discussed regarding other theoretical integration trends in the body of this study. The conclusion, contribution of this current study has been discussed in the last conclusion and discussion section.

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Exploring Preservice Science Teachers' Views of the Nature of Science: Biology vs. Non-Biology Teachers (예비 과학교사의 과학의 본성에 대한 인식 조사: 생물과 비생물 교사와의 비교)

  • Kim, Sun-Young
    • Journal of The Korean Association For Science Education
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    • v.30 no.2
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    • pp.206-217
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    • 2010
  • This study aims to explore preservice teachers' overall views of nature of science and compare their views by gender and certificate area (biology vs. non-biology teachers). In addition, a comparison with American preservice teachers' views was also implemented. The Views of Nature of Science (Abd-El-Khalick, 1998), an openended questionnaire, is utilized to explore participants' views of nature of science. Along with 'definition of science', six aspects of the nature of science, (1) theories and laws, (2) tentativeness, (3) social and cultural embeddedness, (4) creativity, (5) theory-laden, and (6) inference, were investigated. The qualitative result indicates that the participants' first image of science was about the method of science such as observations and experiments. Furthermore, these preservice science teachers particularly have a difficulty in differentiating between scientific theories and laws, and understanding the importance of creation and imagination in developing scientific knowledge. In addition, compared to American preservice teachers' view of the nature of science, Korean preservice teachers possess naive views in creative and imaginative aspect. Interestingly, biology teachers demonstrated lower understanding in theories and laws as well as tentativeness of scientific knowledge. However, there is no difference by gender.

High School Students' Views about Some Topics of the Epistemology of Science (과학인식론의 일부 주제에 대한 고등학생들의 견해)

  • Woo, Jong-Ok;Soh, Won-Joo
    • Journal of The Korean Association For Science Education
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    • v.15 no.3
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    • pp.349-362
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    • 1995
  • As science programs emphasize an understanding of the nature of science, it is needed to assess students' views on a wide range of science-technology-society topics. The purpose of this study is to investigate the views of high school students about some selected topics of the epistemology of science. The selected topics include the meaning of science, scientific assumptions, values in science, conceptual inventions in science, scientific method, consensus making in science, and characteristics of the knowledge produced in science. Identified preconceptions in the study are as follows: Science was seen as improving the world(20%), and technology was defined as the application of science(35%). Almost half of the sample(49%) subscribed to a view consistent with a creationist posture and large group of students(46%) expressed a purely ontological view. Only minority of the students(5%) discounted the role played by private science values, but one half of the sample denied the fact that gender-related values can influence the knowledge that scientist construct(53%). Only a small potion of the sample(5%) held a view contrasting to contemporary epistemology of science, but the majority(67%) expressed a simplistic hierarchical relationship in which hypotheses become theories and theories become laws. One third of the students(33%) held a preconception that the scientific method composed of questioning, hypothesizing, collecting data, and concluding. Students did not appreciate the role of consensus making in science(33%). An out-dated epistemic perspective describes the progress of science as simply an accumulation of knowledge(4%). In general, it was concluded that most high school students did not hold efficient understanding on the nature of science. It can be said that no adequate and consistent instruction took place to provide students with an authentic view of the nature of science.

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Water Vapor Adsorption on Soils. -I. Surface areas and adsorption energies as calculated by the BET and a new Aranovich theories (토양에서의 수증기 흡착 -I. BET와 Aranovich식에 의한 한국토양에서의 수증기흡착 등온식으로 토양표면적과 흡착에너지 산정)

  • Jozefaciuk, G.;Shin, Jae-Sung
    • Korean Journal of Soil Science and Fertilizer
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    • v.29 no.2
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    • pp.86-91
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    • 1996
  • Water vapor adsorption isotherms were measured for samples of the A horizons of five typical Korean soils. The experimental data were fitted to the BET and Aranovich adsorption equations. The adsorption isotherms studied followed the BET equation for the relative water vapor pressures in 0.03-0.33 range and the Aranovich equation in 0.03-0.6 range. The calculated surface areas were higher for Aranovich than for BET and opposite relations were found for adsorption energies. For the description of the water adsorption on soils, the use of the Aranovich theory is recommended.

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