• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.564-565
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• 2019

사물인터넷 기술은 4차 산업 혁명의 원동력이 될 차세대 주축기술로 평가되고 있다. 사물인터넷 응용을 위한 엔터티 들의 특징은 기존 보다 활동적이고 능동적으로 변해가고 있어서, 보다 세분화된 접근제어가 필요하지만 기존의 접근제어 기술은 사용자를 중심으로 설계되어 절차가 복잡하고 가변적인 내용을 적용하기에 시스템 부하가 심해, 시스템의 부하가 적으면서 효율성과 보안성을 유지할 수 있는 접근제어 기법이 필요하다. 따라서 사물인터넷 엔터티에 적합한 역할기반 접근제어에 대한 연구가 반드시 필요하다. 본 연구에서는 사물인터넷 엔터티 들의 접근제어 연구를 위한 관련 연구와 사물인터넷 내의 다양한 엔터티들의 속성을 정의할 수 있는 RBAC와 AC 방식에 대하여 분석하였다.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2625-2634
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• 2022

Discretization errors are extremely challenging conundrums of discrete ordinates calculations for radiation transport problems with void regions. In previous work, we have presented a multi-collision source method (MCS) to overcome discretization errors, but the efficiency needs to be improved. This paper proposes a goal-oriented algorithm for the MCS method to adaptively determine the partitioning of the geometry and dynamically change the angular quadrature in remaining iterations. The importance factor based on the adjoint transport calculation obtains the response function to get a problem-dependent, goal-oriented spatial decomposition. The difference in the scalar fluxes from one high-order quadrature set to a lower one provides the error estimation as a driving force behind the dynamic quadrature. The goal-oriented algorithm allows optimizing by using ray-tracing technology or high-order quadrature sets in the first few iterations and arranging the integration order of the remaining iterations from high to low. The algorithm has been implemented in the 3D transport code ARES and was tested on the Kobayashi benchmarks. The numerical results show a reduction in computation time on these problems for the same desired level of accuracy as compared to the standard ARES code, and it has clear advantages over the traditional MCS method in solving radiation transport problems with reflective boundary conditions.

• Molecules and Cells
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• 제45권1호
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• pp.26-32
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• 2022

Living cells generate, sense, and respond to mechanical forces through their interaction with neighboring cells or extracellular matrix, thereby regulating diverse cellular processes such as growth, motility, differentiation, and immune responses. Dysregulation of mechanosensitive signaling pathways is found associated with the development and progression of various diseases such as cancer. Yet, little is known about the mechanisms behind mechano-regulation, largely due to the limited availability of tools to study it at the molecular level. The recent development of molecular tension probes allows measurement of cellular forces exerted by single ligand-receptor interaction, which has helped in revealing the hitherto unknown mechanistic details of various mechanosensitive processes in living cells. Here, we provide an introductory overview of two methods based on molecular tension probes, tension gauge tether (TGT), and molecular tension fluorescence microscopy (MTFM). TGT utilizes the irreversible rupture of double-stranded DNA tether upon application of force in the piconewton (pN) range, whereas MTFM utilizes the reversible extension of molecular springs such as polymer or single-stranded DNA hairpin under applied pN forces. Specifically, the underlying principle of how molecular tension probes measure cell-generated mechanical forces and their applications to mechanosensitive biological processes are described.

• Journal of Trauma and Injury
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• 제35권3호
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• pp.145-150
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• 2022

This paper aims to summarize why I write, how to find a motif, and how to polish and finish a manuscript. For William Carlos Williams, practicing medicine and writing poetry were two parts of a single whole, not each of the other. The two complemented each other. Medicine stimulated Williams to become a poet, while poetry was also the driving force behind his role as a doctor. Alexander Pope, the 18th century English poet, wrote a poem entitled "The Epistle to Dr. Arbuthnot" that was dedicated to a friend who was both a poet and a physician. In this poem, we receive an answer to the questions of "Why do you write? Why do you publish?" Pope writes, "Happy my studies, when by these approv'd! / Happier their author, when by these belov'd! / From these the world will judge of men and books." When I write, I first reflect on whether I only want to write something for its own sake, like "a dog chasing its own tail," instead of making a more worthwhile contribution. When my colleagues ask me, "Why do you write essays as well as scientific papers?" I usually answer, "Writing is a process of healing for me-I cannot bear myself unless I write." When the time comes to sit down and put pen to paper, I remind myself of the saying, festina lente (in German, Ohne Hast, aber ohne Rast, corresponding to the English proverb "more haste, less speed"). If I am utterly exhausted when I finish writing, then I know that I have had my vision.

• 품질경영학회지
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• 제50권3호
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• pp.533-543
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• 2022

Purpose: The purpose of this study is to identify and resolve the causes of defects in the unmanned aerial vehicle launch system(propulsion wire fracture, rear rail deformation) and to prevent recurrence. Methods: The causes of the two defects were derived through fault tree analysis for each of the two defects and fault reproduction tests. In the case of propulsion wire, the installation of a high speed camera to check the behavior of wire was the driving force behind the defect resolution. Results: The results of this study are as follows; It was determined that the thickness of the washer was less than the maximum tolerance of the pulley was the cause of the propulsion wire fracture defect. Failure to comply with the launch procedure and insufficient safety margin were judged as the cause of the rear rail deformation defect. Accordingly, the configuration was changed to remove each defect. Conclusion: The case of this study was conducted to eliminate defects in the launch system for UAV. The causes of defects were estimated through fault tree analysis. After the configuration change, Structural analysis and launch tests were performed to demonstrate the safety and effectiveness of the modified configuration. As a result, the effect of the modified configuration was verified.

• 품질경영학회지
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• 제50권2호
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• pp.251-264
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• 2022

Purpose: This study aims to contribute to the research flow on the relationship between win-win supportive collaboration and safety, while noting that win-win supportive collaboration affects corporate safety-related factors such as climate, safety prevention, and behavior from the perspective of domestic small and medium-sized logistics companies that have signed contracts with large logistics companies, Methods: Based on responses from 147 small and medium-sized logistics companies, structural equation modeling is performed to examine the relationship among the factors such as supportive collaboration, safety climate, safety prevention, safety behavior. Results: Study results are as follows. Supportive collaboration of large logistics companies influence the formation of a safety climate and safety behavior within logistics SMEs positively. In addition, safety prevention and safety behavior are affected by safety climate in a positive way. Conclusion: Win-Win supportive collaboration is a driving force behind safety management practices in the supply chain leading to safety management performance, so it is necessary to consider it for the growth of the sustainable supply chain.

• 한국정밀공학회지
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• 제12권5호
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• pp.88-97
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• 1995

The leaf spring is used in the suspension of most buses and trucks due to its compactness, which reduces the shock-force and the vibration from the road, and increases passenger comfortability and carlife. Of the various kinds of leaf springs, the leaf spring without eyes can be found easily in the heavy duty truck, and has different characteristics to the leaf spring with eyes in the case of large free camber. Because of radius change, the leaf without eyes slips on the supports, which makes the deflection. The difference is due to this deflection. In this paper, we show the general method of characteristic analysis, for example, Pandan method, can be no more applicable to these springs. Thus considering the geometry deflection by slip, we have developed the equation of the characteristic of the leaf spring without eyes and prove the effectiveness of this equation by experiment. From the result, at large camber the slip deflection is large and as camber smaller, this is smaller. At the camber behind some value, the effect of slip no longer influence to the characteristic of leaf springs.

• 한국지반공학회논문집
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• 제22권10호
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• pp.131-138
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• 2006

페이스볼트의 타설각도는 현재 수평타설을 기준으로 하고 있으나 실제로는 수평으로부터 벗어나는 경우가 많이 발생하고 있다 본 논문에서는 페이스볼트의 타설각도가 지반보강 효과에 미치는 영향에 대하여 실내실험과 수치해석을 통해 분석하였다. 페이스볼트에 의해 굴착부근의 지표면 침하 및 막장 수평변위를 억제하려고 하는 경우는 가능한 한 수평으로 타설하는 것이 유리하며, 수평으로부터 벗어나는 경우는 타설본수를 추가하여야 하는 것으로 나타났다.

• 대한조선학회논문집
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• 제60권4호
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• pp.240-247
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• 2023

In this study, morphological and hydrodynamic characteristics of the non-axisymmetric supercavity generated behind a disk-shaped cavitator were examined. By extending the previous study on axisymmetric supercavitating flow based on a boundary element method, hydrodynamic forces acting under the angle of attack condition of 0 to 30 ° and shape characteristics of the supercavity were analyzed. The results revealed that increasing the angle of attack by 30 ° reduced the length and width of the cavity by about 15% and the volume by about 40 %. An empirical formula that can quantitatively estimate the geometrical characteristics and change of the cavity was derived. It is expected that this method can be used to evaluate the shape information and force characteristics of the supercavity for the control of the vehicle in a very short time compared to the viscous analysis in the initial design stage of the supercavity underwater vehicle.

• 영어영문학
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• 제56권2호
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• pp.255-276
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• 2010

Despite some critics' efforts to highlight Shelley's political fruitfulness, they tend to disregard meaningful differences that Shelley has from other Jacobin radicals of his times. Accordingly, the critics tackle his apparent incoherence revealed in A Philosophical View of Reform; the first two sections contain a keen insight into the socio-political injustice prevalent in Britain and the reasons behind it, while the third section withdraws from the previous radical position and settles with a moderate electorate reform. This paper argues that recent developments in post-structuralist and post-Marxist theory help to clearly assess Shelley's political position. Emphasizing that the Jacobin concept of revolution is incompatible with the plurality and opening which a radical democracy requires, post-marxists such as Ernest Laclau and Chantal Mouffee claim that a more viable form of political resistance is to expose repression and force involved in hegemonic articulations. For them, dislocation, a distabilization of a discourse that results from the emergence of events which cannot be domesticated, symbolized, or integrated within the discourse, opens up the possibility of freedom for agents. A Philosophical View of Reform is an attempt to dislocate the discourses of monarchy and paper money by exposing their social and historical constructiveness and their repressive exclusion of alternative discourses. The political goal of this essay is to awaken subjects within a hegemonic structure by decentering the structure and to make them act by stimulating new discoursive constructions.