• Structural Engineering and Mechanics
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• v.89 no.1
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• pp.13-22
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• 2024

The nonlinear snap-through buckling of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) curved tubes is analytically investigated in this research. It is assumed that the FG-CNTRC curved tube is supported on a three-parameter nonlinear elastic foundation and is subjected to the uniformly distributed pressure and thermal loads. Properties of the curved nanocomposite tube are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite tube are temperature-dependent. The governing equations of the curved tube are obtained using a higher-order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the tube. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved tube. Equations of motion are solved using the two-step perturbation technique for nanocomposite curved tubes which are simply-supported and clamped. Closed-form expressions are provided to estimate the snap-buckling resistance of FG-CNTRC curved pipes rested on nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of the distribution pattern and volume fraction of CNTs, thermal field, foundation stiffnesses, and geometrical parameters on the instability of the curved nanocomposite tube.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.584-591
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• 2020

Reliability is an important factor in weapons systems. Low reliability causes the weapons system to fail to function properly, which directly leads to the weakening of combat capability. This paper classifies the structure of the 5.56 mm rifle, which is currently used by the Korean army, into a total of seven assemblies and describes the eight functions necessary for the rifle to operate normally. In addition, the concept of reliability was defined as the MRBF, and the Poisson process model and TTT plot were explained as a reliability analysis theory for the repair function system. Next, the field-data obtained by defining failure as the replacement of parts other than periodic exchange of parts were refined, and the reliability was analyzed by entering the refined field operation specifications into the Minitab program. As a result, the reliability of the rifle was determined to be 251.73. The assembly parts that required improvement was identified as the barrel, lower body, and butt stock assembly, and 10 detailed parts needed to be improved. Finally, the limits of the reliability analysis using the field-data currently available for small caliber firearms were considered.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.205-212
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• 2016

This study attempts to empirically investigate if value strategy and momentum strategy could be improved by using past financial data such as ROE and PER in the Korean stock market. The study observes that both strategies which are refined by the portfolios consisting of companies with higher ROE/PER ratio show higher positive excessive returns than the traditional value strategy and momentum strategy. The study discusses that the excessive returns could be due to investors' behavioral biases such as conservatism, anchoring, confirmation, and herding by using convergent approach based on psychology theory. The results are not consistent with the efficient market hypothesis insisting investors' rational behavior.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.11
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• pp.629-654
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• 2003

A new multiresolutional scheme that reconstructs a polygonal mesh from the set of contours is presented. In the first step, we apply a radial gradient method to extract the contours on the sampled slices from a volume data. After classifying the types of the edges on the contours, we represent the contour using the context-free grammar. The polygons between two neighboring contours are generated through the traversal of the derivation trees of the context-free grammar. The polygonal surface of the coarsest resolution is refined through the refinement of the contours, which is executed by casting more rays on the slices. The topologies between the polygonal surfaces of various resolutions are maintained from the fact that the radial gradient method preserves the topologies of the contours of various resolutions. The proposed scheme provides efficient computation and compression methods for the tiling procedure with the feature preservation.

• Journal of the Korean Society of Costume
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• v.51 no.3
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• pp.75-85
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• 2001

The system of washing and shrouding a dead body is a series of procedures for encoffining in funeral rites, which are taken after death indentification by using CHOKWANG and praying for the resurrection of a dead body by calling a soul departed from the body. The washing and shrouding a dead body (hereinafter reffered to as "YEOMSEUP") is the broad concept which contains the procedures of washing, clothing and shrouding the body. The clothing includes washing, putting rices into the mouth. and then dressing while the shrouding includes first wrapping, second-wrapping and encoffining. The clothes for YEOMSEUP (all clothes and articles for funeral rites are designated) will be put in the coffin along with a dead body according to the YEOMSEUP procedures. Dasan, a SILHAK scholar in the late Yi Dynasty, pointed out some problems of the funeral rites observed in those days. At the same time, he found that the problems had arisen from the misinterpretation of the original descriptions in Chinese characters. and had tried to correct them. The books written by Dasan basically emphasized his ideology reshaping the whole procedures by trimming and removing meaningless formalities which are too much luxurious and wasteful and making them as a part of the original principles of the funeral rites. His Intents are clearly shown in his wrings on practical ettiquttes, such as SANGRYESAJON and SANGUIJEOLYO. In its attempt, this study aims at reformulating the DASAN\\`s SANGRYESAJON in terms of YEOMSEUP methods. A lot of virtues of the Dasan, like WOOSU, SIMUI, DAEDAE, MO, SORYUMHYO and DAERYUMHYO could also be found accordingly. The merits and characteristic in funeral rites are an obedience in filial duty, the pursuit of frugality. and the efficiency of practical functions. It could be said that the resurvey of DASAN′s theory on YEOMSEUP procedures is a meaningful work today when the original meaning of funeral rites fades out. Furthermore, discussions of refined burial service and encouraging cremation designed to improve land use, which are widely spread among people, could weaken the basic philosophy of YEOMSEUP and more likely propagate the atmosphere of despising the dignity of human beings.

• Journal of Korean Society of Steel Construction
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• v.12 no.3 s.46
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• pp.317-328
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• 2000

The objective of the research is to develop an algorithm for the optimum design of two-dimensional braced steel frames using an advanced analysis, which considers both material and geometric nonlinearties. Since both nonlinearties are considered in analysis process, Optimum design algorithm which does not require to calculate K-factor is presented. A multi-level discrete optimization technique with two parameters that uses the information of structural system and separate member has been developed. The structural analysis is performed by the relined plastic-hinge method which is based on zero-length plastic hinge theory. Optimization problem are formulated by AISC-LRFD code. The feasibility, validity and efficiency of the developed algorithm is demonstrated by the results of the braced steel frame.

• Korean Journal of Health Education and Promotion
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• v.20 no.3
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• pp.145-170
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• 2003

The purpose of this study was to clarity the concept of health insensitivity using Hybrid model, which consists of three phases： theoretical, empirical, and analytic. In the theoretical phase, the definitions of health insensitivity were searched in korean dictionary and examples used in the websites because the concept of health insensitivity has never been studied before. Two dimensions of health insensitivity emerged out from this investigation were cognitive and behavioral. And then a working definition of health insensitivity was established. The sub-concepts and related factors of health insensitivity were identified through the extensive reviews of the literature focusing on two dimensions of cognitive and behavioral. In the empirical phase, in order to obtain description of health insensitivity, face-to-face in-depth interviews were conducted with nine persons who are not related to professional health care. Grounded theory approach was applied to analyze these qualitative data. In the final analytic phase, theoretical results and empirical results were analyzed in the integrated way and a theoretical framework of health insensitivity was established. A refined definition of health insensitivity was that decreased health risk perception in cognitive dimension and conduction of the unhealthy behaviors in behavioral dimension. Sub-concepts of decreased health risk perception were optimistic bias and decreased general fear. Sub-concepts of unhealthy behavior were doing health threatening behavior and not doing desirable health behavior. The contact of health information was a causal condition of health insensitivity. Optimistic disposition, health locus of control, and avoidance coping style were intervening conditions of health insensitivity. Three types of health insensitivity were identified： unconcern or ignorance type, optimistic bias type, and cognitive dissonance type. Finally, The implications of these findings for further research and nursing practice are discussed.

• Journal of Engineering Education Research
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• v.15 no.3
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• pp.47-58
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• 2012

The purpose of this paper is to verify the education effects of program for engineering students and extract the essential components to be included in the learning contents. For this, we investigated the lecture contents critically and analyzed the evaluation result of questionnaire to examine the students' learning satisfaction and learners' needs concerning the effectiveness of course. The survey using two types of questionnaires was conducted with 210 junior and senior students taking lectures of ${\ll}$Presentation and Debate Skills${\gg}$ in the college of engineering at Pusan National University. According to the evaluation result, students experienced various speech education's effects concerning (1) verbal components, (2) non-verbal components, (3) problem solving competence, (4) teamwork skills, etc. On the other side there have been pointed out as problems in the ${\ll}$Presentation and Debate Skills${\gg}$ class, such as (1) a large number of assignments, (2) insufficiency of more refined evaluation method for the individuals and (3) a well-balanced arrangement between 'theory' and 'practice' was needed. However more importantly, the individual students can not do practice sufficiently owing to the large scale of class. Therefore the various and effective ways to help students improve their communicative competence have to be developed further. Finally, there have been extracted several essential components to be included in the class and implications for ameliorating the class were discussed and suggested in detail.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.31-36
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• 2006

Tritium has been used to directly measure the exchangeable hydrogen in bleached softwood kraft pulp. The hydrogen atoms associated with hydroxyl groups in pulp or with water contained in the pulp can dissociate and exchange with the hydrogen atoms in bulk water. Tritium is a radioactive isotope of hydrogen and behaves almost identically to it. The distribution of tritium between pulp and water ($k_{pw}$) can be easily measured and becomes an index of the protons available fur hydrogen bonding. Bleached kraft pulp was refined in a PFI mill to a range of freenesses. Tritiated water was added and the amount exchanged measured. There was a slight steady increase in $k_{pw}$ until approximately 300 CSF; $k_{pw}$ then rose sharply between 300 CSF and 100 CSF. This rise appears to correlate with FSP. It is likely that the action of refining on the fiber reaches a threshold at about 300 CSF causing the fiber surface to break open creating exponentially more surface area. This theory is visually confirmed through light microscopy. The slow increase in fibrillation of the fibers above 300 CSF correlates with the increase in $k_{pw}$. Beyond the threshold of 300 CSF a dramatic difference in fibrillation is shown, also corresponding with the large increase in $k_{pw}$. The freeness difference around 300 CSF is small, but the change in fiber properties is extreme within this region. This change in properties could lead to sheet breaks and other disruptions when producing products around the threshold. This study leads to a better understanding of how fiber changes during refining, resulting in a practical benefit of target freeness determination. Presently, freeness is selected based on product quality and on some measure of runnability. Yet, there are other considerations, demonstrated by the extreme change in fiber properties around 300 CSF.

• Korean Journal of Acupuncture
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• v.19 no.2
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• pp.87-96
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• 2002

Objective : To study of Literature on the Ying Qi and Wei Qi One of thing that is among basis theory of Oriental medicine is Vital Essence, Vitality, Qi and Blood(精神氣血) justly. Results : Physiological special quality of Ying Qi(營氣) first, flows within Blood Circulation and the temper is mild and second, transform blood and grow up whole body, and follow through Pectoral Qi(宗氣). Wei Qi(衛氣) means running regeneration of material that do guard action of human body as refined nutritious substances transformed in food. Physiological special quality of Wei Qi(衛氣) first, nature is fast, smooth, and sharp. And it flows outside Blood Circulation. Second, go on muscslar gap without following through Pectoral Qi(宗氣). Ying blood(營血) flows within Blood Circulation means living body ingredient which thing reveals by circulation of the blood change phenomenon. Ying Qi(營氣) is Ying(營) in meaning which go on meridians, therefore meridians as wandering living body reaction route mean. This Ying Qi(營氣)'s physiology transform blood and grows up whole body and flows within Blood Circulation. It becomes most important ingredient of composition of blood, Wei Qi(衛氣) transforms and becomes nutrition constantly by running regeneration of material which transform in Jungcho(中焦) and spread by spreading action of upper chest exhaust in lower belly above the blader of apriority, Kidney-yang.