• Title/Summary/Keyword: Pendulum

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Field Application and Performance Measurements of Precast Concrete Blocks Developed for Paving Roadways Capable of Solar Power Generation (태양광 도로용 프리캐스트 콘크리트 블록 포장의 현장 적용과 계측)

  • Kim, Bong-Kyun;Lee, Byung-Jae;Kim, Yun-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.5
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    • pp.69-76
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    • 2020
  • Global warming is a very important problem as it causes rapid climate change and natural disasters. Therefore, researches related to renewable energy are being actively conducted while promoting policies such as reducing carbon dioxide emission and increasing the proportion of renewable energy. Solar power generation is being applied in urban areas like BIPV as well as existing idle areas outside the city. Therefore, in this study, precast concrete blocks developed for paving roadways capable of solar power generation were designed and constructed. For the evaluation of field applicability for 6 months, skid resistance and block settlement were measured. As a result of the experiment, it was found that skid resistance satisfies the standard of general roadway in Korea, but not the standard of highway. The skid resistance tended to decrease as time passed. In addition, the settlement of the block gradually increased slightly, but it is much smaller than the allowable settlement of the roadway. Therefore, it is necessary to establish a maintenance period and method based on the periodic measurement results in the future.

Fabrication of Three-Dimensional Scanning System for Inspection of Mineshaft Using Multichannel Lidar (다중채널 Lidar를 이용한 수직갱도 조사용 3차원 형상화 장비 구현)

  • Soolo, Kim;Jong-Sung, Choi;Ho-Goon, Yoon;Sang-Wook, Kim
    • Tunnel and Underground Space
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    • v.32 no.6
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    • pp.451-463
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    • 2022
  • Whenever a mineshaft accidentally collapses, speedy risk assessment is both required and crucial. But onsite safety diagnosis by humans is reportedly difficult considering the additional risk of collapse of the unstable mineshaft. Generally, drones equipped with high-speed lidar sensors can be used for such inspection. However, the drone technology is restrictively applicable at very shallow depth, failing in mineshafts with depths of hundreds of meters because of the limit of wireless communication and turbulence inside the mineshaft. In previous study, a three-dimensional (3D) scanning system with a single channel lidar was fabricated and operated using towed cable in a mineshaft to a depth of 200 m. The rotation and pendulum movement errors of the measuring unit were compensated for by applying the data of inertial measuring unit and comparing the similarity between the scan data of the adjacent depths (Kim et al., 2020). However, the errors grew with scan depth. In this paper, a multi-channel lidar sensor to obtain a continuous cross-sectional image of the mineshaft from a winch system pulled from bottom upward. In this new approach, within overlapped region viewed by the multi-channel lidar, rotation error was compensated for by comparing the similarity between the scan data at the same depth. The fabricated system was applied to scan 0-165 m depth of the mineshaft with 180 m depth. The reconstructed image was depicted in a 3D graph for interpretation.

View of the God in Daesoon Thoughts viewed from Perennial Philosophy (영원의 철학(Perennial Philosophy)으로 본 대순사상의 신관)

  • Heo, Hoon
    • Journal of the Daesoon Academy of Sciences
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    • v.25_2
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    • pp.177-213
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    • 2015
  • We live in two giant pendulum in called 'science' and 'religion'. But science and religion are contained in disparate information with each other, Those two is not easy to achieve convergence. But if you accept the ontological scheme of Great Chain of Being(存在의 大連鎖) in the Perennial philosophy(永遠의 哲學), Debate between religion and science is meaningless 'Great Nest of Being(存在의 대둥지, Great Chain of Being)' is similar to the multiple concentric circles, there are different dimension that the each top level to subsume surrounding the lower level. For example, upper zone 'Mysticism(神秘主義)' includes but transcends(or transcends but includes.) the sub-region theology, psychology, biology and physics. The Perennial philosophy is the great spiritual teachers of the world, philosophers and thinkers have adopted a common worldview, a religious views. Philosophers of the perennial philosophy seem to match the cross-cultural almost unanimous about the general level of the 'Great Nest of Being' for the past 3,000 years. The perennial philosophy made the conclusion that God exists in the world. Several types of view of God existing religions in the world have 'Monotheism(一神論)', 'Pantheism(汎神論)' and 'Panentheism (汎在神論)'. Although traditionally the God of the philosophers is the classical Theism, theological trends of today it is moving in the direction of Panentheism. Panentheism see that god is immanent and transcendent. also Daesoon Thoughts is the position of the Panentheism. so this paper points out the fact that the view of God of the perennial philosophy is precisely consistent with the view of God of Daesoon Thoughts. Wilber says 'envelopment [transcend and include]'. The word translates as 'powol(包越)' in Korean. 'Powol(包越)' means that all the developmental evolution is to surround the sub-region developed into the higher realms. View of the God in the perennial philosophy is 'powol theism(包越的 有神論)'. but 'powol immanent God(包越的 內在神論)' rather than building regulations as 'powol theism(包越的 有神論)'. It would have to be a more accurate representation of it. Because in the existing 'theism(有神論)' the god and humans are thought to exist apart. However, Daesoon Thoughts are deemed to also recognize another universal laws. also Sangje(上帝, the Supreme God) is recognized as a cosmic existence that transcends the laws. This point, as the characteristics of the Daesoon Thoughts, In other religions can not be found. Therefore, More specifically represent(More accurately represent), Sangje of the Daesoon Thoughts can be described as 'powol theism' or 'transcendental and included deism(包越的 理神論)'. Importantly, The idea of God can be captured directly by the discipline. In this sense, In terms of the other religions have no discipline law, the practice [discipline] of the Daesoon Thoughts required in the present age. It has the absoluteness.

Performance Evaluation for All-In-One Construction Method of Curbstone and Gutter Using Formwork Rail and Jig (거푸집 레일과 지그를 이용한 경계석 및 측구의 일체형 시공법에 대한 성능평가)

  • Choi, Jae-Jin;Ko, Man-Gi;Kim, Kyoung-Ju;Choi, Khyung-Dong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6A
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    • pp.525-534
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    • 2010
  • A road curbstone is a structure installed at the boundary of the sidewalk and the street with the objectives of road drainage, drawing attention and such. The current general construction method of curbstones places foundation concrete for the curbstones first, waits until the concrete reaches the strength to support the curbstones, places the curbstones on top, and then places the gutter and rear filling concrete. Such method has the issues of poor compaction and weakened bond strength of concrete due to split placing of concrete, and causes the curbstones to easily separate due to vehicle impact or earth pressure, in turn creating maintenance costs and spoiling the aesthetics. To improve such conventional construction methods, an all-in-one method was developed using formwork rail and jig where both the curbstones and gutter can be worked at the same time, and to evaluate the structural performance, static tests of lateral loading test, pullout test, and bending test were executed, and dynamic tests such as pendulum test and actual vehicle impact test were executed. In all tests, the all-in-one construction method using formwork rail and jig was shown to be superior to the conventional construction method by the increase of construction quality and bond strength of concrete.

Effects of impact by mechanical harvesting on storability of onions (Allium cepa L.) (기계수확 시 발생한 충격이 양파(Allium cepa L.)의 저장성에 미치는 영향)

  • Young-Kyeong Kwon;Yong-Jae Lee
    • Food Science and Preservation
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    • v.30 no.5
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    • pp.811-821
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    • 2023
  • This study investigated the storability of onions according to manual and mechanical harvesting. Moreover, we simulated the onion-to-onion impact during the mechanical harvesting process and investigated the storability after artificially subjecting the onions to impact treatment. The onion harvesting methods included hand plucking + manual collection, digger + manual, and digger + mechanical collection. The maximum impact height during the mechanical harvesting process was 0.5 m. Immediately after harvesting, no significant difference in the bruise and wound rate among the harvesting methods was observed. Any increased bruise or wound rate because of mechanical harvesting was presumed to be influenced by soil conditions, such as the presence of gravel, and machine operation factors. Furthermore, the storability during the 8.5 months storage showed no significant difference according to the harvesting methods. In treatments by simulating the impacts during the mechanical harvesting process, the impact heights were 0.0 m (0.0 J), 0.25 m (0.86 J), 0.5 m (1.72 J), and 0.75 m (2.57 J), each performed once, and four times at the same position (3.43 J) and four times at different positions (3.43 J) at 0.25 m. Throughout all the treatments, there were no significant differences in the storability during the 8.5 months storage period.

Trends and Issues of the Korean National Curriculum Documents' Subject-Matter Content System Table: Focusing on the Science Subject Case (우리나라 국가 교육과정 문서상 교과 내용 체계표의 변천과 쟁점 -과학과 사례를 중심으로-)

  • Gyeong-Geon, Lee
    • Journal of The Korean Association For Science Education
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    • v.44 no.1
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    • pp.87-103
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    • 2024
  • The content system table of the subject-matter curriculum is considered important in the Korean national curriculum, textbook writing, and teaching and learning in the classroom. However, studies that comprehensively organize the issues concerning the format of the subject-matter curriculum content system have been scarce. This study scrutinized the evolution of the content system from its inception in The 6th Curriculum to the most recent 2022 Revised National Curriculum, focusing on science curricular. The following issues and suggestions were derived for the format of the subject content system. First, caution should be exercised in using terms such as "domain," "field," and "category," and it should be clarified whether these terms are intended simply for logical differentiation or to serve as a content organizer with a specific emphasis. Second, the nature of components such as "core ideas," which can serve as innovative content organizers, should be strictly defined. Third, while the introduction of three-dimensional content elements such as "knowledge and understanding," "process and skill," and "value and attitude" is viewed positively, it is suggested that a further delineation be made, elaborating how each can be utilized to form core competencies. Fourth, the construction of the subject-specific content system in national curriculum needs caution because whether it will resolve or exacerbate the 'disparity between general curriculum and subject-matter curriculums' is uncertain. Finally, as an apparent pendulum motion of the subject-matter content system is observed in national curriculum documents, efforts should be made to ensure that it does not result in meaningless repetition, but instead achieves meaningful dialectical progress.

Design of a Decentralized Controller for Deep-sea Mining System (심해저 채광시스템에 대한 분산제어기 설계에 관한 연구)

  • Yeu, Tae-Kyeong;Park, Soung-Jea;Hong, Sup;Kim, Hyung-Woo;Choi, Jong-Su
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.13 no.3
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    • pp.252-259
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    • 2008
  • The deep-sea mining system is generally composed of surface vessel, lifting system, buffer, flexible pipe and miner. The mining system can be regarded as a large-scale system in which each subsystem is interconnected to other ones. In order to control a large-scale system, decentralized control approaches have been proposed recently. In this paper, as a basic study on application of decentralized control, firstly, the mining system was modeled in a simplified way. Lifting system and buffer were regarded as a spherical pendulum and the flexible pipe was taken as a two-dimensional linear spring connection. Based on the simplified model dynamics, the mining system can be decentralized two subsystems, the one consisting of surface vessel, lifting system and buffer, and the other, the miner. Next, this paper proposed the design of controller for each decentralized subsystem by regarding the interacting terms as disturbances. The controllers kept the constant distance between two subsystems during the miner was moving on the specified track. Finally, the efficiency of proposed controller was proven through the numerical simulation of the derived model.

Cephalometric study on head posture according to the Classification of Malocclusion (부정교합 분류에 따른 두경부 위치의 두부방사선 계측학적 연구)

  • Hwang, Chung-Ju;Kim, Suk-Hyun;Kil, Jae-Kyung
    • The korean journal of orthodontics
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    • v.27 no.2
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    • pp.221-230
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    • 1997
  • It has been known that head posture may influence directly and/or indirectly the growth and development of craniofacial morphology and can also be influenced by the funtional demand of physiologic activity. It was reported that facial morphology has close relationships with hyoid bone position and head posture. In many previous studies, Natural Head Posture(NHP) was guided, and also it was shown that NHP has high degree of reproducibility. Otherwise, There was few study about the relationship of head posture, with routine cephalometric film which is used for clinical orthodontic purpose. In this study, according to the Wits and ANB of initial cephalometric film which was taken with vertical pendulum as representative of true vertical reference line. We classified the subjects which is comprised of 60 adult female patients into Class I, II, III (Cl I, II, III)and we tried to find out the correlation of head posture and hyoid bone position according to the classification of malocclusion. As a result of our research, we found the followigs. 1. In comparison of vertical position of hyoid bone relative to the cranial base. the position of hyoid bone of Cl III was lower than that of Cl II. 2. In comparison of anteriorpostes or position of hyoid bone, relative to the cervical column. The position of hyoid bone of Cl III was more anterior than that of a II 3. in comparison of vertical position of hyoid bone relative to mandible. There was no significant correlation aumoug the groups of malocclusion. 4. ANB and Wits showed no significant correlation with hyoid bone position. 5. The relative extension of head, which was noted in Cl II, showed negative with Sum, ANB. 6. In Cl II and Cl III, Post to Ant facial height showed positive correlation with NSL/VER.

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A Study of formative character of Art Nouveau Through the works of $Ren{\acute{e}}$ Lalique, Emile Galle, Louis Comfort Tiffany, Victor Horta (아르누보양식의 조형적 특성연구 - 르네랄리크.에밀갈레.루이스 컴포트 티파니.빅토르오르타의 작품을 중심으로 -)

  • Kim, Bun-Jung
    • Journal of Science of Art and Design
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    • v.11
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    • pp.5-35
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    • 2007
  • When it comes to art, the two conflicting themes of 'scientific progress' and the 'nature' have often motivated the advent of the new mode of arts. By the late 20th century, uniform and simplified mode of arts, inspired by scientific and technological progress of that time, was gradually disillusioned by the contemporaries due to the adverse effect of science on human life. In this context, naturalism pursuing for harmony of human and the nature came up as an alternative to those living in the 21st century. The pendulum has swung from minimalism to naturalism. Though the quantitative improvement of human life cannot be denied, the uprise of such problems as environmental pollution and exhaustion of natural resources degraded the quality of human life, which, eventually, shifted the attention to the theme - 'revival of naturality.' Therefore, this thesis intends to represent the modem interpretation of the 'revival of naturality' by applying the major expressions of Art Nouveau that also emphasized naturalism. Art Nouveau found its motifs from organic figures of natural beings and put them to designs of decorative arts. This carries a historical significance in that Art Nouveau boldly revolutionized historicism, which only repeated adoption and modification of the existing modes of arts, and opened it to the modem design with new attempts to practical applications of the arts. Art Nouveau, which means 'new art', prospered from the late 19th century to the early 20th century, and even after one century, it is highly appreciated, reviving as novel and vivid forms in this contemporary art. Art Nouveau based on naturalism has revisited our contemporary period when naturalism and feminized romanticism came into fashion and its common motifs revive in different jenre of arts such as fashion, furniture, glass works, and jewelry works. This study illustrates and analyzes the works of four major artists who gave a specific attention to botanical motifs of Art Nouveau and applies decorative beauty of highly sophisticated and organic curved lines and the expressional forms of botanical figures to design. Art Nouveau proved this; the nature herself is as beautiful as she can be. Within Art Nouveau, the true humanism can be revitalized with the 'revival of naturality'. This study rediscovered the boundless potential of modern interpretation and application of Art Nouveau in decorative art and design.

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Improving Curing Rate and Physical Properties of Korean Dendropanax Lacquer with Thermal and Photo Initiator by Dual Curing (이중경화법을 이용한 열개시제 및 광개시제가 배합된 황칠도료의 경화속도 촉진 및 물성향상 연구)

  • Hwang, Hyeon-Deuk;Moon, Je-Ik;Park, Cho-Hee;Kim, Hyun-Joong;Hwang, Baik
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.4
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    • pp.333-340
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    • 2010
  • The Korean Dendropanax lacquer, made from a natural resinous sap from Dendropanax orbifera Lev., was used as a golden and transparent varnish for the traditional artifacts (armor uits, helmets, arrowheads, etc.) to make them be brilliant golden color. The cured film of the acquer has excellent protective properties such as weatherability, water resistance, and nticorrosive. But, one of disadvantages is that takes a long time and much energy to fulfill curing the lacquer. The chemical constituents of the lacquer contained conjugated diene compounds s the photopolymerizable monomers. These monomers easily polymerized in sunlight to form olden-colored, hard-coating films in a short time. Photooxidation may be one of the most mportant reactions in the chemistry of the lacquer. Although the Korean Dendropanax Lacquer hould be dried to a thoroughly dry stage to achieve optimal film properties, curing with elevated emperatures may be required for the protracted curing time at atmospheric temperature. So we ntended to accelerate the curing rate of the lacquer by dual curing of thermal and radiation uring. The effect of thermal initiator on the thermal curing reaction was evaluated by monitoring he changes in double bond peak with FT-IR. Then the curing rate of the lacquer blended with hermal initiator and photoinitiator together was measured during dual curing using a RPT with V spot curing machine. Thermal initiator not only accelerated the curing rate but also improved he physical property. And the curing rate of the Korean Dendropanax lacquer was improved by ual curing method of thermal and UV curing. According to these results, the application area of he Korean Dendropanax lacquer could be expanded to surface coatings for electronic devices uch as mobile phones or electronics.