• Title/Summary/Keyword: Behavior of complex system

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Vibration Reduction for a Railway Depot Building (II): Design Parameters (철도인공대지에 건설된 아파트의 방진대책(II): 설계변수)

  • Kim, Jeung Tae
    • Journal of the Korean Society for Railway
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    • v.16 no.5
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    • pp.358-364
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    • 2013
  • In the second part of the paper, a design strategy for an apartment complex constructed at a railway depot is proposed for vibration reduction purposes. Various design parameters such as the vehicle operating speeds, artificial land behavior, housing support structure, and apartment sub-structures are individually examined to reduce the transmission of vibrations through building structures. Building construction on an artificial land should be subjected to regulations that require the application of a vibration reduction scheme based on the mechanics that govern the vibration transmission phenomena. The implementation of these parameters at an early design stage will provide a quiet living environment for residents who may be exposed to excessive noise and vibration.

Status of the International Cooperation Project, DECOVALEX for THM Coupling Analysis (THM 복합거동 해석을 위한 DECOVALEX 국제공동연구 현황)

  • Kwon, Sang-Ki;Cho, Won-Jin;Choi, Jong-Won
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.4
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    • pp.323-338
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    • 2007
  • For the assessment of the performance and safety of a deep underground radioactive repository system, the thermal, hydraulic, mechanical, and chemical behaviors and their coupling should be studied. In order to analyze the THMC coupling behavior more effectively, which requires complex mathematical models and modelling techniques, DECOVALEX international cooperation project was launched in 1992. Since its beginning, four major stages of the project were successfully completed and THMC modelling techniques for various conditions could be developed. In this study, the current status and major achievements from the project were reviewed and possible benefits of the participation to the project were discussed.

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Synergistic Surface Activities and Phase Behavior in Mixtures of a Diglyceryl Cationic Surfactant and a Conventional Anionic Surfactant (디글리세릴계 양이온계면활성제와 일반 음이온계면활성제 혼합물에서의 계면활성 상승효과와 상거동)

  • Choi, Jeong-Jin;Cho, Wan-Goo;Rang, Moon-Jeong
    • Korean Chemical Engineering Research
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    • v.46 no.4
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    • pp.799-805
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    • 2008
  • In general, anionic and cationic surfactants are incompatible because their mixtures form insoluble complexes and precipitate in the water. There are, however, some equimolar complexes of anionic and cationic surfactant that are soluble and behave like regular surfactants, specifically like nonionic surfactants, thus named pseudo-nonionic surfactant complexes. Pseudo-nonionic complexes are more effective and efficient in surface activities than their ionic surfactant components as shown by their equilibrium and dynamic surface tensions. They pack at the interface more than their ionic components. When a novel cationic surfactant, diglyceryl dodecyl dimethyl ammonium chloride(DGDAC), having the polyhydroxyl group at the hydrophilic head group, was mixed with a conventional anionic surfactant (sodium dodecyl sulfate; SDS) at equimolar ratio, we found that the aqueous equimolar mixture showed strong positive synergism in which molecular interaction parameter ${\beta}^M$ was very low, -17.2. According to the studies of equilibrium phase behavior and microscopy, this mixed system could form homogenous solutions containing vesicles.

A Study on Applying Amphibious Warfare Using EINSTein Model Based on Complexity Theory (복잡계이론 기반하 EINSTein 모형을 이용한 상륙전 적용에 관한 연구)

  • Lee, Sang-Heon
    • Journal of the military operations research society of Korea
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    • v.32 no.2
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    • pp.114-130
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    • 2006
  • This paper deals with complexity theory to describe amphibious warfare situation using EINSTein (Enhanced ISAAC Neural Simulation Tool) simulation model. EINSTein model is an agent-based artificial "laboratory" for exploring self-organized emergent behavior in land combat. Many studies have shown that existing Lanchester equations used in most war simulation models does not describe changes of combat. Future warfare will be information warfare with various weapon system and complex combat units. We have compared and tested combat results with Lanchester models and EINSTein model. Furthermore, the EINSTein model has been applied and analyzed to amphibious warfare model such as amphibious assault and amphibious sudden attack. The results show that the EINSTein model has a possibility to apply and analyze amphibious warfare more properly than Lanchester models.

A Study on Growth Type of Comic strips Heroes through Journey of Life (삶의 여정을 통한 만화 히어로 성장유형 연구)

  • Kim, MiRim
    • Cartoon and Animation Studies
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    • s.29
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    • pp.173-207
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    • 2012
  • The four-phased plot which consists of introduction, development, turn and conclusion in the long-story structure tends to be patterned and schematized. The behavior of characters is in line with the beginning of human beings and the plot of comic strips basically has four phases. It is, however, not a simple arrangement but a complex one which was developed by organizing patterns of human power, behavior and emotions. With the results from a survey with college students studying comic strips, this study aims to categorize four characters from the archetypal system by Carol Pearson, four phases of the hero's journey by Joseph Campbell, and the four phases of the plot based on Aristotle's theory, which is the frame of the comic strip structure through supporting evidence extracted from comic strips in an integrated way. In this study, the categorization is performed by simplifying and systemizing a character's life cycle, which is a factor of a story structure in complex comic strips. This study is to identify what comic strip writers express by using the metaphor in the complicated long-story structure of comic strips This study reveals that the structure of introduction, development, turn and conclusion based on the plot theory by Aristotle is the metaphor of human life and fate and that the phases of development in the archetypal system by Carol Pearson, a Jung researcher influenced by Jung's theory are the metaphor of human life and fate. Also, the theories of Joseph Campbell, who also was influenced by Jung, are the metaphor of human life and fate as they projected complex emotions of joy, anger, sorrow, and pleasure onto the archetype of heroes and used the metaphor of the hero's journey. Lastly, the theories are introduced with the approach of 'guide to screenwriters' by Christopher Vogler. Meanwhile, this metaphor is the objective and goal of this study. The comic strips selected for this study seem to have long complex stories which have characters leaving their homes, going through adventures and difficulties, meeting the world in another way, experiencing tension, competition, wars, and hardship and returning home with compensation. They grow mentally and psychologically through their journeys and finally become heroes. They express the meaning of our introspection in a narrative through plots and images of comic strips. This appears complex but the basic structure of long comic strips has four phases of plot. The life style of an extraordinary character traveling for adventures and growing in long comic strips can be divided into four phases symbolizing childhood, adolescence, adulthood, and senescence and it is a psychological growth process. The archetypes of the character can be divided into four phases and the growth process can be explained. The hero's journey symbolized by the character can be also divided into four phases. Through theories, the complex arrangement of four-phased plots in comic strips corresponds with the growth process of introduction, development, turn and conclusion through the stages of life. At the same time, this study found that the characters becoming heroes are the metaphor of introspection and that the characters' growth and life correspond with the four phases in life through long comic strips. Long stories in long comic strips written by comic strip writers show that characters go on their journeys and change their lives through hardship and difficulty by logical construction of plot and their growth processes are presented in archetypal images and they reach introspection as heroes. The readers share time and space through images in comic strips and realize that they had the same experience as the characters emotionally by being moved by the stories.

The Stability Evaluation Methods of Embankment on Soft Clay (연약지반 성토의 안정평가 방법)

  • Kang, Yea Mook;Lee, Dal Won;Kim, Ji Hoon;Kim, Tae Woo;Lim, Seong Hun
    • Korean Journal of Agricultural Science
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    • v.25 no.2
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    • pp.260-270
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    • 1998
  • The field tests were performed to suggest the rational method for stability evaluation of soft clay. The behavior of settlement-displacement obtained by field monitoring system was to compare and analyze the results of the observationed method, and to investigate the complex behavior of soft clay with filling height. The results of this study are summarized as follows. 1. The horizontal displacement was suddenly increased when physical properties of soft clay showed maximum values and the part of the turning point. The values of these properties were available to the fundamental data for stability evaluation. The shear deformation appeared that difference of the horizontal displacement was maximum values. 2. Although the stability of embankment by step filling showed the unstable part over the failure standard line, the embankment was confirmed stable. So the evaluation of the stability of embankment is reasonable to use the inclination of curve than failure standard line. 3. The horizontal displacement and relative settlement were increased as same ratio at improvement ground. Estimation of shear deformation using Terzaghi's modified bearing capacity should consider the relations of embankment load and undrained shear strength at nonimprovement ground, and minimum safety factor is recommended to use larger than 1.2. 4. Excess pore water pressure was increased with increasing of filling height and decreased with maintain the filling height. The embankment was unstable when filling height was exceed the evaluation standard line, and the behavior of excess pore water pressure and horizontal displacement could use as a standard of judgement of the filling velocity control because their behavior were agree with each other.

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A comprehensively overall track-bridge interaction study on multi-span simply supported beam bridges with longitudinal continuous ballastless slab track

  • Su, Miao;Yang, Yiyun;Pan, Rensheng
    • Structural Engineering and Mechanics
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    • v.78 no.2
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    • pp.163-174
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    • 2021
  • Track-bridge interaction has become an essential part in the design of bridges and rails in terms of modern railways. As a unique ballastless slab track, the longitudinal continuous slab track (LCST) or referred to as the China railway track system Type-II (CRTS II) slab track, demonstrates a complex force mechanism. Therefore, a comprehensive track-bridge interaction study between multi-span simply supported beam bridges and the LCST is presented in this work. In specific, we have developed an integrated finite element model to investigate the overall interaction effects of the LCST-bridge system subjected to the actions of temperature changes, traffic loads, and braking forces. In that place, the deformation patterns of the track and bridge, and the distributions of longitudinal forces and the interfacial shear stress are studied. Our results show that the additional rail stress has been reduced under various loads and the rail's deformation has become much smoother after the transition of the two continuous structural layers of the LCST. However, the influence of the temperature difference of bridges is significant and cannot be ignored as this action can bend the bridge like the traffic load. The uniform temperature change causes the tensile stress of the concrete track structure and further induce cracks in them. Additionally, the influences of the friction coefficient of the sliding layer and the interfacial bond characteristics on the LCST's performance are discussed. The systematic study presented in this work may have some potential impacts on the understanding of the overall mechanical behavior of the LCST-bridge system.

Fused Deposition Modeling of Iron-alloy using Carrier Composition

  • Harshada R. Chothe;Jin Hwan Lim;Jung Gi Kim;Taekyung Lee;Taehyun Nam;Jeong Seok Oh
    • Elastomers and Composites
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    • v.58 no.1
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    • pp.44-56
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    • 2023
  • Additive manufacturing (AM) or three-dimensional (3D) printing of metals has been drawing significant attention due to its reliability, usefulness, and low cost with rapid prototyping. Among the various AM technologies, fused deposition modeling (FDM) or fused filament fabrication is receiving much interest because of its simple manufacturing processing, low material waste, and cost-effective equipment. FDM technology uses metal-filled polymer filaments for 3D printing, followed by debinding and sintering to fabricate complex metal parts. An efficient binder is essential for producing polymer filaments and the thermal post-processing of printed objects. This study involved an in-depth investigation of and a fabrication route for a novel multi-component binder system with steel alloy powder (45 vol.%) ranging from filament fabrication and 3D printing to debinding and sintering. The binder system consisted of polyvinyl pyrrolidone (PVP) as a binder and thermoplastic polyurethane (TPU) and polylactic acid (PLA) as a carrier. The PVP binder held the metal components tightly by maintaining their stoichiometry, and the TPU and PLA in the ratio of 9:1 provided flexibility, stiffness, and strength to the filament for 3D printing. The efficacy of the binder system was examined by fabricating 3D-printed cubic structures. The results revealed that the thermal debinding and sintering processes effectively removed the binder/carrier from the cubic structures, resulting in isotropic shrinkage of approximately 15.8% in all directions. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) patterns displayed the microstructure behavior, phase transition, and elemental composition of the 3D cubic structure.

Slope stability prediction using ANFIS models optimized with metaheuristic science

  • Gu, Yu-tian;Xu, Yong-xuan;Moayedi, Hossein;Zhao, Jian-wei;Le, Binh Nguyen
    • Geomechanics and Engineering
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    • v.31 no.4
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    • pp.339-352
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    • 2022
  • Studying slope stability is an important branch of civil engineering. In this way, engineers have employed machine learning models, due to their high efficiency in complex calculations. This paper examines the robustness of various novel optimization schemes, namely equilibrium optimizer (EO), Harris hawks optimization (HHO), water cycle algorithm (WCA), biogeography-based optimization (BBO), dragonfly algorithm (DA), grey wolf optimization (GWO), and teaching learning-based optimization (TLBO) for enhancing the performance of adaptive neuro-fuzzy inference system (ANFIS) in slope stability prediction. The hybrid models estimate the factor of safety (FS) of a cohesive soil-footing system. The role of these algorithms lies in finding the optimal parameters of the membership function in the fuzzy system. By examining the convergence proceeding of the proposed hybrids, the best population sizes are selected, and the corresponding results are compared to the typical ANFIS. Accuracy assessments via root mean square error, mean absolute error, mean absolute percentage error, and Pearson correlation coefficient showed that all models can reliably understand and reproduce the FS behavior. Moreover, applying the WCA, EO, GWO, and TLBO resulted in reducing both learning and prediction error of the ANFIS. Also, an efficiency comparison demonstrated the WCA-ANFIS as the most accurate hybrid, while the GWO-ANFIS was the fastest promising model. Overall, the findings of this research professed the suitability of improved intelligent models for practical slope stability evaluations.

Dynamic Value Chain Modeling of Knowledge Management (지식경영의 동태적 가치사슬 모형 구축)

  • Lee, Young-Chan
    • The Journal of Information Systems
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    • v.17 no.3
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    • pp.205-233
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    • 2008
  • This study suggests the dynamic value chain model, that will be able to not only show changing processes to organization's significant capital by integrating an individual, implicit, and explicit knowledge which affect organizational decision making, but also distinguish the key driver for raising organizational competitive power because it makes possible to analyze sensitivity of performance along with decision making alternatives and policy changes from dynamic view by connecting knowledge management capability, knowledge management activity, and relations with organizational performance with specific strategic map. Recently, a lot of organizations show interest in measuring and evaluating their performance synthetically. In organizations taking knowledge management, they introduce effective value chain model like a dynamic balanced scorecard (DBSC), and therefore they can reflect their knowledge management condition as well as show their changes by checking performance of established vision and strategy periodically. Furthermore, they can ask for their inner members' understanding and participation by communicating with and inspiring their members with awareness that members are one of their group, present a base of benchmarking, and offer significant information for later decision making. The BSC has been a successful framework for measuring an organization's performance in various perspectives through translating an organization's vision and strategy into an interrelated set of key performance indicators and specific actions. The BSC, while having significant strengths over traditional performance measurement methods, however, has its own limitations, due to its static nature, such as overlooking two-way causation between performance indicators and neglecting the impact of delayed feedback flowing from the adoption of new strategies or policy changes. To overcome these limitations, this study employs SD, a methodology for understanding complex systems where dynamic feedback among the interrelated system components significantly impact on the system outcomes. The SD simulation model in the form of DBSC would serve as a useful strategic teaming tool for facilitating an organization's communication process through various scenario analyses as well as predicting the dynamic behavior pattern of their key performance measures over a future time frame. For the demonstration purpose, this study applied the DBSC model to Prototype of Korea manufacturing and service firm.