• Title/Summary/Keyword: Physically based simulations

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SIMULATING NONTHERMAL RADIATION FROM CLUSTER RADIO GALAXIES

  • TREGILLIS I. L.;JONES T. W.;RYU DONGSU
    • Journal of The Korean Astronomical Society
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    • v.37 no.5
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    • pp.509-515
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    • 2004
  • We present results from an extensive synthetic observation analysis of numerically-simulated radio galaxy (RG) jets. This analysis is based on the first three-dimensional simulations to treat cosmic ray acceleration and transport self-consistently within a magnetohydrodynamical calculation. We use standard observational techniques to calculate both minimum-energy and inverse-Compton field values for our simulated objects. The latter technique provides meaningful information about the field. Minimum-energy calculations retrieve reasonable field estimates in regions physically close to the minimum-energy partitioning, though the technique is highly susceptible to deviations from the underlying assumptions. We also study the reliability of published rotation measure analysis techniques. We find that gradient alignment statistics accurately reflect the physical situation, and can uncover otherwise hidden information about the source. Furthermore, correlations between rotation measure (RM) and position angle (PA) can be significant even when the RM is completely dominated by an external cluster medium.

Application of SWAT model to Gyeongancheon watershed for estimating stream flows and sediment yields (SWAT 모형을 이용한 경안천 유역의 유출 및 유사량 추정)

  • Kim, Chul-Gyum;Kim, Hyeon-Jun
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2003.10a
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    • pp.527-530
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    • 2003
  • In this study, physically based SWAT model was applied to estimate the daily stream flows and sediment yields in Gyeongancheon watershed. The calibration and validation of the model outputs have been performed with yearly and daily measured stream flows of the time period 1988-1991 and 2001. The application results showed a good agreement with the simulated and observed stream flows, and similar trend with simulated and observed sediment yields. Overall, SWAT is a reasonable watershed scale model on long-term simulations of stream flows and sediment yields for management purposes.

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Transferring Skin Weights to 3D Scanned Clothes

  • Yoon, Seung-Hyun;Kim, Taejoon;Kim, Ho-Won;Lee, Jieun
    • ETRI Journal
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    • v.38 no.6
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    • pp.1095-1103
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    • 2016
  • We present a method for transferring deformation weights of a human character to three-dimensional (3D) scanned clothes. First, clothing vertices are projected onto a character skin. Their deformation weights are determined from the barycentric coordinates of the projection points. For more complicated parts, such as shoulders and armpits, continuously moving planes are constructed and employed as projection reference planes. Clothing vertices on a plane are projected onto the intersection curve of the plane with a character skin to achieve a smooth weight transfer. The proposed method produces an initial deformation for physically based clothing simulations. We demonstrated the effectiveness of our method through several deformation results for 3D scanned clothes.

Comparison of Efficiency of Flash Memory Device Structure in Electro-Thermal Erasing Configuration (플래시메모리소자의 구조에 대한 열적 데이터 삭제 효율성 비교)

  • Kim, You-Jeong;Lee, Seung-Eun;Lee, Khwang-Sun;Park, Jun-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.5
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    • pp.452-458
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    • 2022
  • The electro-thermal erasing (ETE) configuration utilizes Joule heating intentionally generated at word-line (WL). The elevated temperature by heat physically removes stored electrons permanently within a very short time. Though the ETE configuration is a promising next generation NAND flash memory candidate, a consideration of power efficiency and erasing speed with respect to device structure and its scaling has not yet been demonstrated. In this context, based on 3-dimensional (3-D) thermal simulations, this paper discusses the impact of device structure and scaling on ETE efficiency. The results are used to produce guidelines for ETEs that will have lower power consumption and faster speed.

Comparative Evaluation on Collision and Particle Separation Efficiency between CO2 Bubbles and Air Bubbles Using Contact Zone Model of Flotation Process (부상분리 공정의 접촉영역 모델을 이용한 이산화탄소와 공기 기포의 충돌 및 입자 분리효율 비교 평가)

  • Yang, Jong-Won;Choi, Yong-Ho;Chae, In-Seok;Kim, Mi-Sug;Jeong, Yong-Hoon;Kim, Tae-Geum;Kwak, Dong-Heui
    • Journal of Korean Society on Water Environment
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    • v.35 no.1
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    • pp.64-71
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    • 2019
  • In recent years, carbon dioxide ($CO_2$) bubbles emerged as the most widely applied material with the recycling of sequestrated storage to decrease global warming. Flotation using $CO_2$ as an alternative to air could be effective in overcoming the high power consumption in the dissolved air flotation (DAF) process. The comparison of DAF and DCF system indicated that, the carbon dioxide flotation (DCF) system with pressurized $CO_2$ only requires 1.5 ~ 2.0 atm, while the DAF system requires 3.0 ~ 6.0 atm. In a bid to understand the characteristics of particle separation, the single collector collision (SCC) model was used and a series of simulations were conducted to compare the differences of collision and flotation between $CO_2$ bubbles and air bubbles. In addition, laboratory experiments were sequentially done to verify the simulation results of the SCC model. Based on the simulation results, surfactant injection, which is known to decrease bubble size, cloud improved the collision efficiency of $CO_2$ bubbles similar to that of air bubbles. Furthermore, the results of the flotation experiments showed similar results with the simulation of the SCC model under anionic surfactant injection. The findings led us to conclude that $CO_2$ bubbles can be an alternative to air bubbles and a promising material as a collector to separate particles in the water and wastewater.

Simulations Analysis of Proposed Structure Characteristics in Shallow Trench Isolation for VLSI (고집적을 위한 얕은 트랜치 격리에서 제안한 구조의 특성 모의 분석)

  • Lee, YongJae
    • Journal of the Korea Society for Simulation
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    • v.23 no.3
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    • pp.27-32
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    • 2014
  • In this paper, We are going to propose the novel structure with improved behavior than the conventional vertical structure for VLSI CMOS circuits. For this, the proposed structure is the moat shape for STI. We want to analysis the characteristics of simulations about the electron concentration distribution, oxide layer shape of hot electron stress, potential flux and electric field flux, electric field fo themal damage and current-voltage characteristics in devices. Physically based models are the ambient and stress bias conditions of TCAD tool. As a analysis results, shallow trench structure were trended to be electric functions of passive as device dimensions shrink. The electrical characteristics influence of proposed STI structures on the transistor applications become stronger the potential difference electric field and saturation threshold voltage, are decreased the stress effects of active region. The fabricated device of based on analysis results data were the almost same characteristics of simulation results data.

Analysis of dynamic performance of redundant manipulators using the concept of aspects

  • Chung, W.J.;Chung, W.K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10b
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    • pp.1664-1670
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    • 1991
  • For kinematically redundant manipulators, conventional dynamic control methods of local torque optimization showed the instability which resulted in physically unachievable torque requirements. In order to guarantee stability of the null space vector method which resolves redundancy at the acceleration level, Maciejewski[1] analyzed the kinetic behavior of homogeneous solution component and proposed the condition to identify regions of stability and instability for this method. 'In this paper, a modified null space vector method is first presented based on the Maciejewski's condition which is a function of a manipulator's configuration. Secondly, a new control method which is based on the concept of aspects is proposed. It was shown by computer simulations that the modified null space vector method and the proposed method have a common property that a preferred aspect is preserved during the execution of a task. It was also illustrated that both methods demonstrate a drastic reduction of torque loadings at the joints in the tracking motion of a long trajectory when compared with the null space vector method, and thus guarantee the stability of joint torque.

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Simulations of Proposed Shallow Trench Isolation using TCAD Tool (TCAD 툴을 이용한 제안된 얕은 트랜치 격리의 시뮬레이션)

  • Lee, YongJae
    • Journal of the Korea Society for Simulation
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    • v.22 no.4
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    • pp.93-98
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    • 2013
  • In this paper, the proposed shallow trench isolation structures for high threshold voltage for very large scale and ultra high voltage integrated circuits MOSFET were simulated. Physically based models of hot-carrier stress and dielectric enhanced field of thermal damage have been incorporated into a TCAD tool with the aim of investigating the electrical degradation in integrated devices over an extended range of stress biases and ambient temperatures. As a simulation results, shallow trench structure were intended to be electric functions of passive, as device dimensions shrink, the electrical characteristics influence of proposed STI structures on the transistor applications become stronger the potential difference electric field and saturation threshold voltage.

Energy-Efficient Reference Walking Trajectory Generation Using Allowable ZMP (Zero Moment Point) Region for Biped Robots (2족 보행 로봇을 위한 허용 ZMP (Zero Moment Point) 영역의 활용을 통한 에너지 효율적인 기준 보행 궤적 생성)

  • Shin, Hyeok-Ki;Kim, Byung-Kook
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.10
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    • pp.1029-1036
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    • 2011
  • An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.

Geometry Cutting Solution using Vector Dot Product (벡터 내적연산을 이용한 지오메트리 절삭 솔루션)

  • Hwang, Min Sik
    • Journal of Korea Multimedia Society
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    • v.19 no.8
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    • pp.1337-1344
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    • 2016
  • As the visual effect frequently used in movies or animations, special effects are well suited for the creation of buildings or materials' destruction and collapse scenes. With the relevant programs developing technologically, the adoption of a real-time physically based-system makes it possible to realistically express dynamic simulations. In the large scale, the visual expression of such effects of destroying is satisfying enough, but most common programs of those effects fail to maximize visual effect generated with the cutting of small materials. Besides, to perform a heavy simulation process needs high-performance hardware and programs, where high costs would become a serious issue. For this reason, this paper suggests a solution optimized for the effect of small materials-cutting. The progress of each step shows technologies which trace movement with the state of the completion of the character's motions and then cut the material in real-time, finally led to the very realistic visual effect. Besides, using vector inner calculation to follow the motions of object and to realize cutting effect, this study provides an experiment that constructs visual effect for visualization from the basis of mathematical algorithm and it would be certainly as an educational material used for further researches.