• Title/Summary/Keyword: critical means

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A comparison of structural performance enhancement of horizontally and vertically stiffened tubular steel wind turbine towers

  • Hu, Yu;Yang, Jian;Baniotopoulos, Charalambos C.;Wang, Feiliang
    • Structural Engineering and Mechanics
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    • v.73 no.5
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    • pp.487-500
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    • 2020
  • Stiffeners can be utilised to enhance the strength of thin-walled wind turbine towers in engineering practise, thus, structural performance of wind turbine towers by means of different stiffening schemes should be compared to explore the optimal structural enhancement method. In this paper two alternative stiffening methods, employing horizontal or vertical stiffeners, for steel tubular wind turbine towers have been studied. In particular, two groups of three wind turbine towers of 50m, 150m and 250m in height, stiffened by horizontal rings and vertical strips respectively, were analysed by using FEM software of ABAQUS. For each height level tower, the mass of the stiffening rings is equal to that of vertical stiffeners each other. The maximum von Mises stresses and horizontal sways of these towers with vertical stiffeners is compared with the corresponding ring-stiffened towers. A linear buckling analysis is conducted to study the buckling modes and critical buckling loads of the three height levels of tower. The buckling modes and eigenvalues of the 50m, 150m and 250m vertically stiffened towers were also compared with those of the horizontally stiffened towers. The numbers and central angles of the vertical stiffeners are considered as design variables to study the effect of vertical stiffeners on the structural performance of wind turbine towers. Following an extensive parametric study, these strengthening techniques were compared with each other and it is obtained that the use of vertical stiffeners is a more efficient approach to enhance the stability and strength of intermediate and high towers than the use of horizontal rings.

A Critical Approach to the Directions of the Neoliberal Educative Policies of the Governments of Democratic Alliances of Chile (칠레 민주연합 정부의 신자유주의 교육 정책방향의 비판적 접근)

  • Ahn, Tae Hwan
    • Cross-Cultural Studies
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    • v.29
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    • pp.315-339
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    • 2012
  • The Chilean educative policies as the Voucher System and the privatization have been almost same from the Pinochet government and the ones of "Concertacion" or "Democratic Alliances" until now. Because the neoliberal regime has dominated principally in Chile the area of the education. In this study first of all I will analyze the procedures of the violent repression of the leftist politicians and the intellectuals of the universities by the Pinochet government. And the importance of the reform of the law of education in 1980 was emphasized and the other one in 1990 one day before the retirement of Pinochet. We can comprehend the fact that the education would have been used as a tool to achieve the development of the country and the economic one sacrificing the public and equalitarian values of the education. And the competence, the efficiency and the quality of the education have been emphasized through the policies as example the rights of the selection of the schools by the parents as like a product in the market. But the result was the enormorors expansion of the private education not only in the secondary schools but also in the universities. And also has been intensified "the segregation and the discrimination" of the students jerarquitized by the different social-economic levels of the parents. The Chilean people including the middle class did not realize rightly the inherent problems of the neoliberal regime having the equivocation as if the private schools should have been better than the public ones. However the high level of the public university education became to be dominated by the acomodated class. This was the cause of the last year's great scale of the demonstration of the Chilean students. The most important thing is that these matters was agravated not by the Pinochet government but by the ones of "Concertacion" or "Democratic Alliances". Because these governments tried to maintain the neoliberal regime by means of the education only arranging the small problems or contratiempos.

A Critique on Han WonJin's Theory of Mind-Nature based on the Disposition (남당(南塘) 한원진(韓元震)의 '기질(氣質)' 심성론(心性論) 비판(批判))

  • Ahn, JaeHo
    • The Journal of Korean Philosophical History
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    • no.37
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    • pp.71-96
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    • 2013
  • This research is a discussion in critical viewpoint about Han WonJin's philosophical thoughts. As everyone knows, Han WonJin emphasizes the difference of nature between human and animal, so as to try to be hardened human-being's dignity and value. But, his theoretical system can't back that purpose. First, he focused on the real world and maintains "GiseonLihoo[氣先理後]". It means that the ontological sense of Li can be unmake by Gi, then Li can't be the ultimate basis of everything under the sun and pure good moral principle. This concept is perfectly realized in the theory of Mind-Nature, the realistic nature of everything under the sun is a thing that Li had been unmade by Gi, also formed in mixing with disposition. The practical and concrete Mind only has a cognitive function which had already been decided it's superiority. How can we practice moral behavior, can secure human-being's value and dignity in being based on these Mind-Nature?

Development of 50W High Quality Factor Printed Circuit Board Coils for a 6.78MHz, 60cm Air-gap Wireless Power Transfer System (6.78MHz, 거리 60cm, 50W급 무선 전력 전송 시스템용 High Quality Factor PCB 코일 개발)

  • Lee, Seung-Hwan;Yi, Kyung-Pyo
    • Journal of the Korean Society for Railway
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    • v.19 no.4
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    • pp.468-479
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    • 2016
  • In order to supply power to online monitoring systems that are attached to high voltage catenary or overhead wires, a wireless power transfer system is required that is able to transmit power over the insulation gap. Such wireless power transfer systems have transmitter and receiver coils that have diameters of over 10cm. This paper focused on an investigation of the sources of loss in the coils when the coils are fabricated using printed circuit board technology. Using finite element simulation results, it has been shown that the dielectric loss in the substrate was the dominant source of the total loss. It has been demonstrated that the selection of a proper dielectric material was the most critical factor in reducing the loss. For further reduction of the loss, the distributed tuning capacitor method and the slotting of the inter-turn spaces have been proposed. For the evaluation of the proposed methods, four coils have been fabricated and their equivalent series resistances and quality factors were measured. Measured quality factors were greater than 300, which means that these devices will be helpful in achieving high coil-to-coil efficiency.

Effect of pre-hospital BLS simulation training on the paramedic's competency

  • Jung, Jun-Ho;Cho, Byung-Jun
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.1
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    • pp.103-109
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    • 2018
  • The purpose of the study is to investigate the effect of a simulation training of BLS in paramedics in pre-hospital situation. This a nonequivalence control quasi-experimental study. The study subjects were 8 paramedics of experimental group and 8 paramedics of control group in K fire department. An informed consent was written by the subjects after explaining of the purpose of the study. The study methods consisted of conventional education and practice training. The conventional education was done for 30 minutes and the practice training was taken by four trainees of one group and the instructor demonstrated Basic Iife Support (BLS) performance for three minutes. Each trainer peformed BLS for ten minutes. In the beginning of the course, two paramedics got off from the ambulance and performed BLS including 5 cycles of Cardiopulmonary Resuscitation (CPR). Soon after the BLS, another two paramedics performed pre-hospital BLS survey. The education was guided by two professors of emergency medical technology, two Basic Iife Support instructors, and two emergency rescue directors. Pre-hospital BLS was measured by a 5-point Likert scale. Higher score means higher performance skills. The data were analyzed using SPSS/WIN 22.0 program set at significance level of p<05. The effect of simulation education was much more significant than the conventional education in BLS. The simulation education is very important and effective in improving the clinical performance skills of paramedics than the conventional education. The simulation education can provide the virtual environment of cardiac arrest to the paramedics. In conclusion, the simulation education can provide the effective teaching methods for various practice performance skills and solution by critical thinking in the paramedics and healthcare providers in the future.

International Cases and Their Implications on School Safety in Korea (학교안전의 국제적 프로그램 사례와 국내적 함의)

  • Kim, Eun-Joo
    • Journal of the Korea Convergence Society
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    • v.12 no.9
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    • pp.261-271
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    • 2021
  • Recent accidents in school environment involving violence, and bullying indicate that school safety is exposed to a serious threat to community well-being. Such incidents come as big problem because various policies and programs have widely long been implemented in order to protect the school environment. Thus, it is critical for the local community and goverment to develop measures for prevention. However, some of the incidents are misrepresented because school environment still remains as one of the safest settings. The current study discusses successful case studies of education, policies and projects regarding school violence and safety that are enforced in many other nations. One of the most practical and concrete means of pursuing an improved level of school safety is for the local community to be actively involved in the process. And one of the key factors for the success of international programs was that it was very much an integrative approach involving a joint effort with the local communities, accompanying a strong tie between the school and its surrounding context.

Excessive soil water stress responses of sesame (Sesamum indicum L.) and perilla (Perilla frutescens L.) cultivated from paddy fields with different topographic features

  • Ryu, Jongsoo;Baek, Inyeoul;Kwak, Kangsu;Han, Wonyoung;Bae, Jinwoo;Park, Jinki;Chun, Hyen Chung
    • Korean Journal of Agricultural Science
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    • v.45 no.4
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    • pp.749-760
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    • 2018
  • In Korea, the largest agricultural lands are paddy fields which have poor infiltration and drainage properties. Recently, the Korean government has pursued cultivating upland crops in paddy fields to reduce overproduced rice in Korea. For this policy to succeed, it is critical to understand the topographic information of paddy fields and its effects on upland crops cultivated in the soils of paddy fields. The objective of this study was to characterize the growth properties of sesame and perilla from paddy fields with three soil topographic features and soil water effects which were induced by the topographic features of the sesame and perilla. The crops were planted in paddy fields located in Miryang, Gyeongnam with different topographies: mountain foot slope, local valley and alluvial plain. Soil water contents and groundwater levels were measured every hour during the growing season. The paddy field of the mountain foot slope was significantly effective in alleviating wet injury for the sesame and perilla in the paddy fields. The paddy field of the mountain foot slope had a decreased average soil water content and groundwater level during cultivation. Stress day index (SDI) from the alluvial plain paddy field had the greatest values from both crops and the smallest from the ones from the paddy field of the mountain foot slope. This result means that sesame and perilla had the smallest stress from the soil water content of the paddy field on the mountain foot slope and the greatest stress from the soil water content of the alluvial plain. It is important to consider the topography of paddy fields to reduce wet injury and to increase crop yields.

A Study of Consumer Perception on Fashion Show Using Big Data Analysis (빅데이터를 활용한 패션쇼에 대한 소비자 인식 연구)

  • Kim, Da Jeong;Lee, Seunghee
    • Journal of Fashion Business
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    • v.23 no.3
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    • pp.85-100
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    • 2019
  • This study examines changes in consumer perceptions of fashion shows, which are critical elements in the apparel industry and a means to represent a brand's image and originality. For this purpose, big data in clothing marketing, text mining, semantic network analysis techniques were applied. This study aims to verify the effectiveness and significance of fashion shows in an effort to give directions for their future utilization. The study was conducted in two major stages. First, data collection with the key word, "fashion shows," was conducted across websites, including Naver and Daum between 2015 and 2018. The data collection period was divided into the first- and second-half periods. Next, Textom 3.0 was utilized for data refinement, text mining, and word clouding. The Ucinet 6.0 and NetDraw, were used for semantic network analysis, degree centrality, CONCOR analysis and also visualization. The level of interest in "models" was found to be the highest among the perception factors related to fashion shows in both periods. In the first-half period, the consumer interests focused on detailed visual stimulants such as model and clothing while in the second-half period, perceptions changed as the value of designers and brands were increasingly recognized over time. The findings of this study can be utilized as a tool to evaluate fashion shows, the apparel industry sectors, and the marketing methods. Additionally, it can also be used as a theoretical framework for big data analysis and as a basis of strategies and research in industrial developments.

Converting Triangulated 3D Indoor Mesh Data to OGC IndooGML (삼각분할된 3차원 실내공간데이터를 OGC IndoorGML로 변환하는 방법)

  • Li, Ki-Joune;Kim, Dong Min
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.6
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    • pp.499-505
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    • 2018
  • Most of 3D indoor spatial data recently constructed by many projects merely focus on the visualization rather than geospatial information applications. The 3D indoor data for visualization in 3DS or COLLADA format are based on triangular mesh representation. In order to implement meaningful applications, we need however more meaningful information in 3D indoor spatial data than visualization data in triangular meshes. For this reason, an OGC (Open Geospatial Consortium) standard, called IndoorGML(Indoor Geographic Markup Language) was published to meet the requirements on 3D indoor spatial data for several geospatial applications for indoor space more than simple visualization. It means that it becomes a critical functional requirement to convert triangular mesh representation in 3DS or COLLADA to IndoorGML. In this paper we propose a framework of the conversion, which consists of geometric, topological, and semantic construction of data from triangular meshes. An experiment carried out to validate the proposed framework is also presented in the paper.

Root Bark of Morus Alba Suppresses the YAP Activity through Activation of Classical Hippo Signaling Pathway (상근피의 Hippo 신호전달 경로 활성화를 통한 YAP 억제 효능)

  • Cho, You Na;Choi, Da Bin;Jeong, Han Sol
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.33 no.4
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    • pp.191-197
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    • 2019
  • This study aims to evaluate the effects of the root bark of Morus alba (RMA) on the regulation of the Hippo-YAP pathway. Hippo-YAP signaling is a critical regulator in controlling organ size and tissue homeostasis. Hippo, the serine/threonine kinase phosphorylate the LATS. Phosphorylated LATS then phosphorylates and inactivates the YAP and TAZ, which are two closely related transcriptional co-activator. Here we report RMA activates the Hippo signaling, thereby inhibits the YAP/TAZ activity. First, we examine the cytotoxic effects of RMA by MTT assay. RMA was cytotoxic at concentrations higher than $50{\mu}g/ml$ in HEK293A cells. The reporter gene assay was performed to measure the activity of TEAD, a key transcription factor that controls cell growth and proliferation. RMA significantly suppressed the luciferase activity. By phos-taq gel shift assay, and western blotting, we showed that RMA enhanced the phosphorylation of YAP in wild type cells, but not in LATS1/2 knock out cells, which means RMA activates classical Hippo pathway. RMA induced the cytoplasmic sequestration of YAP. RMA also suppressed the mRNA expression of CTGF and CYR61; the two major YAP dependent genes. Taken together, RMA is considered to be a good candidate for proliferative disease such as cancer, by facilitating cell death through activating the Hippo signaling pathway.