• Title/Summary/Keyword: Time and Motion Studies

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Analysis of Clinical and Radiographic Outcome of the Reconstructive Surgery for the Cavovarus Foot Deformity (요내반족 변형에 대한 재건수술의 임상적 및 방사선학적 결과 분석)

  • Jung, Hong-Geun;Park, Jae-Yong;Lee, Dong-Oh;Eom, Joon-Sang;Chung, Seung-Hee
    • Journal of Korean Foot and Ankle Society
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    • v.18 no.2
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    • pp.62-67
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    • 2014
  • Purpose: Reconstructive surgeries for equinocavovarus foot deformities are quite variable, including hind-midfoot osteotomy or arthrodesis, soft tissue procedure, tendon transfers, etc. Comprehensive evaluation of the deformity and its etiology is mandatory for achievement of successful deformity correction. Few studies in this field have been reported. We report on the clinical and radiographic outcome of reconstruction for cavovarus foot deformities. Materials and Methods: The study is based on 16 feet with cavovarus foot deformities that underwent bony and soft tissue reconstructive surgery from 2004 to 2008. We evaluated the etiologies, varieties of surgical procedures performed, pain score, functional scores, and patient satisfaction and measured the radiographic parameters. Results: The average age at the time of surgery was 39.4 years old, with a male/female ratio of 9/4 and an average follow-up period of 23.9 months (range, 12~49 months). The etiologies of the cavovarus deformity were idiopathic 7 feet, residual poliomyelitis 5 feet, Charcot-Marie-Tooth disease 2 feet, and Guillain-Barre syndrome and hemiplegia due to cerebrovascular accident sequela 1 foot each. Lateral sliding calcaneal osteotomies were performed in 12 feet (75%), followed by Achilles tendon lengthening and plantar fascia release in 11 feet (69%), and first metatarsal dorsiflexion osteotomy/arthrodesis and tendon transfer in 10 feet (63%). Visual analogue scale pain score showed improvement, from an average of 4.2 to 0.5 points. American Orthopaedic Foot and Ankle Society ankle-hindfoot score showed significant improvement, from 47.8 to 90.0 points (p<0.05). All patients were satisfied. Ankle range of motion improved from $27.5^{\circ}$ to $46.7^{\circ}$. In radiographic measurements, calcaneal pitch angle improved from $19.1^{\circ}$ to $15.8^{\circ}$, Meary angle from $13.0^{\circ}$ to $9.3^{\circ}$, Hibb's angle from $44.3^{\circ}$ to $37.0^{\circ}$, and tibio-calcaneal axis angle from varus $17.5^{\circ}$ to varus $1.5^{\circ}$ Conclusion: We achieved successful correction of cavovarus foot deformities by performing appropriate comprehensive reconstructive procedures with improved functional, radiographic measures and high patient satisfaction.

Prediction of Structural Performance of an Automotive Ball Joint (자동차용 볼조인트의 구조적 성능 예측)

  • Kim, Seong-Uk;Jeong, Gyeong-Il;Lee, Kwon-Hee;Lee, Dong-Jin;Lee, Myeong-Gon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.1
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    • pp.705-713
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    • 2018
  • An automotive ball joint connects the suspension system to the steering system and helps to enable rotational and linear motion between the two elements for steering. This study examines a ball joint used in medium and large-sized pickup trucks. Ball joints consist of a stud, socket, bearing, and plug. The main structural performance metrics of ball joints are the pull-out strength and push-out strength. These structural parameters must meet certain criteria to avoid serious accidents. Test and simulation methods are used to investigate the design requirements, but tests are time-consuming and costly. In this study, we modeled ball joints in SolidWorks and performed a finite element analysis in Abaqus to predict structural performance. The analysis was used to obtain the structural performance required for the static analysis of a 2D axisymmetric model. The uncertainties in the manufacturing of the ball joint were assumed to be the manufacturing tolerances, and the dimensional design variables were identified through case studies. The manufacturing tolerances at each level were defined, and the results were compared with experimental results.

Development of Sailing Algorithm for Ship Group Navigation System (선박 그룹항해시스템의 항법 알고리즘 개발)

  • Wonjin, Choi;Seung-Hwan, Jun
    • Journal of Navigation and Port Research
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    • v.46 no.6
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    • pp.554-561
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    • 2022
  • Technology development related to maritime autonomous surface ships (MASS) is actively progressing around the world. However, since there are still many technically unresolved problems such as communication, cybersecurity, and emergency response capabilities, it is expected that it will take a lot of time for MASS to be commercialized. In this study, we proposed a ship group navigation system in which one leader ship and several follower ship are grouped into one group. In this system, when the leader ship begins to navigate, the follower ship autonomously follows the path of the leader ship. For path following, PD (proportional-derivative) control is applied. In addition, each ship navigates in a straight line shape while maintaining a safe distance to prevent collisions. Speed control was implemented to maintain a safe distance between ships. Simulations were performed to verify the ship group navigation system. The ship used in the simulation is the L-7 model of KVLCC2, which has related data disclosed. And the MMG (Maneuvering Modeling Group) standard method proposed by the Japan Society of Naval Architects and Ocean Engineering (JASNAOE) was used as a model of ship maneuvering motion. As a result of the simulation, the leader ship navigated along a predetermined route, and the follower ship navigated along the leader ship's path. During the simulation, it was found that the three ships maintained a straight line shape and a safe distance between them. The ship group navigation system is expected to be used as a navigation system to solve the problems of MASS.

Response Analysis of RC Bridge Piers due In Multiple Earthquakes (연속지진하중에 의한 철근콘크리트 교량 교각의 응답해석)

  • Lee Do-Hyung;Jeon Jong-Su;Park Tae-Hyo
    • Journal of the Korea Concrete Institute
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    • v.16 no.3 s.81
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    • pp.357-367
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    • 2004
  • In this paper, the effect of cumulative damage for reinforced concrete bridge piers subjected to both single and multiple earthquakes is investigated. For this purpose, selected are three set of accelerograms one of which represents the real successive input ground motions, recorded at the same station with three months time interval. The analytical predictions indicate that piers are in general subjected to a large number of inelastic cycles and increased ductility demand due to multiple earthquakes, and hence more damage in terms of stiffness degradation is expected to occur. In addition, displacement ductility demand demonstrates that inelastic seismic response of piers can significantly be affected by the applied input ground motion characteristics. Also evaluated is the effect of multiple earthquakes on the response with shear. Comparative studies between the cases with and without shear indicate that stiffness degradation and hence reduction in energy dissipation capacity of piers are pronounced due to the multiple earthquakes combined with shear. It is thus concluded that the effect of multiple earthquakes should be taken into account for the stability assessment of reinforced concrete bridge piers.

Numerical Analysis of Vortex Induced Vibration of Circular Cylinder in Lock-in Regime (Lock-in 영역에서 원형실린더의 와류유기진동 전산해석)

  • Lee, Sungsu;Hwang, Kyu-Kwan;Son, Hyun-A;Jung, Dong-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.1
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    • pp.9-18
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    • 2016
  • The slender structures such as high rise building or marine riser are highly susceptible to dynamic force exerted by fluid-structure interactions among which vortex-induced vibration(VIV) is the main cause of dynamic unstability of the structural system. If VIV occurs in natural frequency regime of the structure, fatigue failure likely happens by so-called lock-in phenomenon. This study presents the numerical analysis of dynamic behavior of both structure and fluid in the lock-in regimes and investigates the subjacent phenomena to hold the resonance frequency in spite of the change of flow condition. Unsteady and laminar flow was considered for a two-dimensional circular cylinder which was assumed to move freely in 1 degree of freedom in the direction orthogonal to the uniform inflow. Fluid-structure interaction was implemented by solving both unsteady flow and dynamic motion of the structure sequentially in each time step where the fluid domain was remeshed considering the movement of the body. The results show reasonable agreements with previous studies and reveal characteristic features of the lock-in phenomena. Not only the lift force but also drag force are drastically increasing during the lock-in regime, the vertical displacement of the cylinder reaches up to 20% of the diameter of the cylinder. The correlation analysis between lift and vertical displacement clearly show the dramatic change of the phase difference from in-phase to out-of-phase when the cylinder experiences lock-in. From the results, it can be postulated that the change of phase difference and flow condition is responsible for the resonating behavior of the structure during lock-in.

Valuing the Risks Created by Road Transport Demand Forecasting in PPP Projects (민간투자 도로사업의 교통수요 예측위험의 경제적 가치)

  • Kim, Kangsoo;Cho, Sungbin;Yang, Inseok
    • KDI Journal of Economic Policy
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    • v.35 no.4
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    • pp.31-61
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    • 2013
  • The purpose of this study is to calculate the economic value of transport demand forecasting risks in the road PPP project. Under the assumption that volatility of the road PPP project value occurs only in regard with uncertainty of traffic volume forecasting, this study calculates the economic value of the traffic forecasting risks in the case of the road PPP project. To that end, forecasted traffic volume is assumed to be a stochastic variable and to follow the Geometric Brownian motion as time passes. In particular, this study attempts to differentiate itself from existing studies that simply use an arbitrary assumption by presenting the application of different traffic volume growth volatility and the rates before and after the ramp-up period. Analysis of the case projects reveals that the risk premium related to traffic volume forecast of the project turns out as 7.39~8.30%, without considering option value-such as minimum revenue guarantee-while the project value volatility caused by transport demand forecasting risks is 17.11%. As the discount rate grows higher, the project value volatility tends to decrease and volatility in project value is always suggested to be larger than that in transport volume influenced by leverage effect due to fixed expenditure. The market value of transport demand forecasting risk-calculated using the project value volatility and risk premium-is analyzed to be between 0.42~0.50, implying that a 1% increase or decrease in the transport amount volatility would lead to a 0.42~0.50% increase or decrease in risk premium of the project.

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A Study on Gardening Theories of Li, Yu in 'Xian Qing Ou Ji' (한정우기(閑情偶寄)를 통해 본 이어(李漁)의 조원(造園) 이론)

  • Zhang, Lin;Jung, Woo-Jin;Sung, Jong-Sang
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.3
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    • pp.137-148
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    • 2018
  • Li Yu's Xian Qing Ou Ji was written during the late Ming and early Qing Dynasty when material culture flourished due to the development of the commercial economy. Xian Qing Ou Ji is considered a retrospective work that reflects the rich material society at that time. This study focuses on his gardening theories through the interpretation and analysis of these two texts of 'Jushibu(居室部)' and 'Zhongzhibu(種植部)' in Xian Qing Ou Ji. The results are summarized as follows. First, he explained the method of garden configuration and orientation according to the topography utilizing the theory of 'suiting one's measures to local conditions(因地制宜)'. He emphasized the detailed understanding of topography as the starting point for all the gardening theories. It stated that he tried to adjust the height of the terrain artificially to create an ideal form of 'anterior high and posterior low(前低後高)'. The successful arrangement of houses, pavilions, rockery and waterways et al. was able to be achieved because of his accurate understanding of topography. Second, 'borrowing scenery(取景在借)' means 'borrowing the outside scenery to the inside'. He applied this theory by 'viewing in motion(動觀)' and 'viewing in repose(靜觀)'. 'Viewing in motion' is seen as a positive methodology for landscape enjoyment. For example, the view through a window changes with movements of the boat, and it can portray thousands of landscape paintings which can be seen through the windows. In the case of 'viewing in repose', the window is regarded as a means of attracting outside garden views to the inside. Third, he emphasized 'the firmness of objects(制體宜堅)', where the design of windows and railings must be considered ahead of others. Fourth, he interpreted the contents of 'the pursuit of novelty(創異標新)'. This generalizes the characteristics of his gardening theory. The contents included 'hall wall(廳壁)', 'variable sun visor(活?)', 'hanging boards and couplets(聯?)' and 'method of supporting vines with bamboo screen(竹屛扶植法)'.

An Archaeology of Cinema as a Real/Imaginary Narrative Medium (상상적/실제적 서사 미디어로서 영화에 대한 미디어고고학)

  • Jeong, Chan-Cheol
    • Journal of Popular Narrative
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    • v.25 no.4
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    • pp.361-395
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    • 2019
  • This paper take a media archaeological approach to cinema transformed into a narrative medium during its transitional period, 1903-1915. To accomplish this, I will explore the question of as which narrative medium cinema was imagined and also how it was institutionalized as a narrative medium with authorship. I will explain that the imaginary and real ideas and changes on cinema resonated with each other on the foundation of its technological aspects such as indexicality, 23 frames/sec. and montage. It was during the transitional period that cinema was transformed from a medium representing spectacle to a medium of narration. The establishment of the American film copyright law in 1912 was an institutional, real outcome from the contemporary understanding of cinema as a narrative medium. At the same time, various ideas emerged that led to imagining of cinema as a complete narrative medium, incomparable to any other. From a media archaeological perspective, the imaginary ideas of media resonate with their actual course of development. These imaginary ideas are not just imaginary, but rather reflect the contemporary desire for the medium. This paper looks into the transitional period based on this media archaeological point of view. To this end, this paper will briefly introduce the notion of media archaeology as a media theory and then discuss Eric Kluitenberg's concept of 'an archaeology of imaginary media' and its methodologies. Second, it will explore literary and cinematic imagining of cinema as a powerful medium of storytelling, while discussing the ways in which cinema's technological characteristics played a decisive role in these imaginings. Also to show the techno-deterministic role of cinema in the real world, this paper will explore how its technological characteristics were considered as an important element in the processes through which America's first motion picture copyright was institutionalized in 1912 after two historical copyright cases: one is Edison v. Lubin in 1903 and Kalem v. Harper Brothers in 1909. Ultimately, this paper will lead us to an understanding of the history of cinema as a medium and its developments in more multi-layed way, as communication between the real and imaginary, and give us perspectives toward what cinema is.

The Problem of Theodicy in Daesoon Jinrihoe (대순진리회에서 신정론 문제)

  • Cha, Seon-keun
    • Journal of the Daesoon Academy of Sciences
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    • v.33
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    • pp.257-286
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    • 2019
  • This study aims to explain theodicy in Daesoon Jinrihoe using established theodicies. Theodicy in Daesoon Jinrihoe can be described as follows: within the worldview of Daesoon Jinrihoe, the problems of evil and suffering are better addressed by analyzing the problem of mutual contention. Accordingly, theodicy in Daesoon Jinrihoe is a matter which should be discussed only in regards to the time period known as the Former World and the transition period after the Reordering Works that leads up to the Later World. The Later World does not operate under patterns of mutual contention. Consequently, there will be no suffering. Therefore, issues of theodicy are irrelevant in the Later World. Theodicy should be dealt differently as it pertains to the Former World and the previously mentioned transition period. Daesoon Thought posits that there is an underlying principle presides over the cosmos, and the divine beings act in accordance with it and perform specific duties in their own subdivisions. The cosmic principle is able to contain cycles of both Sanggeuk ('mutual destruction' in general usage, but 'mutual contention' in Daesoon Thought related to the Former World) and sangsaeng ('mutual generation' in general usage and 'mutual beneficence' in Daesoon Thought related to the Later World). Suffering came into being due to mutual contention. However, mutual contention was not set into motion maliciously, but was arranged instead to facilitate the realization of greater values such as growth and development. In other words, mutual contention are not products of a moral value the nature of which is bad or wrong. Yet, since the world has operated under mutual contention from time immemorial, a nearly incalculably vast multitude of grievances have accumulated. In addition, the divine beings who had operated under mutual contention often made mistakes and spread confusion. This extreme situation resulted in tremendous disasters breaking out all over the world. Perhaps this particular theodicy could be named "Dualistic Sanggeuk Theology (Dualistic Theodicy of Mutual Contention)." After the divine beings reported to the Supreme God that the world had fallen into a serious crisis, the Supreme God penetratingly examined the circumstances of the world and then descended to Earth as a human being named Jeungsan. As Jeungsan practiced the Reordering Works of Heaven and Earth, the Great Opening was preordained by Him. As a result, the transition period started, and from that point onward, theodicy should be described differently. It is presumed that all creatures will be judged at the time of the Great Opening. This will result in the annihilation of all wicked beings including both divine beings and humans. There will also be the establishment of an earthly paradise as well as grievance resolution for all beings prior the Great Opening. This can also be called "The Eschatological Theodicy of the Resolution of Grievances." Theodicy in Daesoon Jinrihoe adopts the two theodicies mentioned above. In addition to that, various theodicies from other traditions such as Irenaean ("soul-making") Theodicy, Free Will Theodicy, Recompense Theodicy, Afterlife Theodicy, Karma Samsara Theodicy, theodicy of participation, and Communion Theodicy can all potentially be applied on a case by case basis.

The new explore of the animated content using OculusVR - Focusing on the VR platform and killer content - (오큘러스 VR (Oculus VR)를 이용한 애니메이션 콘텐츠의 새로운 모색 - VR 플랫폼과 킬러콘텐츠를 중심으로 -)

  • Lee, Jong-Han
    • Cartoon and Animation Studies
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    • s.45
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    • pp.197-214
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    • 2016
  • Augmented Reality, virtual reality in recently attracted attention throughout the world. and Mix them mixed reality etc., it has had a significant impact on the overall pop culture beyond the scope of science and technology. The world's leading IT company : Google, Apple, Samsung, Microsoft, Sony, LG is focusing on development of AR, VR technology for the public. The many large and small companies developed VR hardware, VR software, VR content. It does not look that makes a human a human operation in the cognitive experience of certain places or situations or invisible through Specific platforms or program is Encompass a common technique that a realization of the virtual space. In particular, out of the three-dimensional image reveals the limitations of the conventional two-dimensional structure - 180, 360 degree images provided by the subjective and objective symptoms such as vision and sense of time and got participants to select it. VR technology that can significantly induce the commitment and participation is Industry as well as to the general public which leads to the attention of colostrum. It was introduced more than 10 related VR works Year 2015 Sundance Film Festival New Frontier program. The appearance VR content : medical, architecture, shopping, movies, animations. Also, 360 individuals can be produced by the camera / video sharing VR is becoming an interactive tunnel between two possible users. Nevertheless, This confusion of values, moral degeneration and the realization of a virtual space that has been pointed out that the inherent. 4K or HUD, location tracking, motion sensors, processing power, and superior 3D graphics, touch, smell, 4D technology, 3D audio technology - It developed more than ever and possible approaches to reality. Thereafter, This is because the moral degeneration, identity, generational conflict, and escapism concerns. Animation is also seeking costs in this category Reality. Despite the similarities rather it has that image, and may be the reason that the animation is pushed back to the VR content creation. However, it is focused on the game and VR technology and the platform that is entertaining, but also seek new points within the animation staying in the flat Given that eventually consist of visual images is clear that VR sought. Finally, What is the reality created in the virtual space using VR technology could be applied to the animation? So it can be seen that the common interest is research on what methods and means applied.