• Title/Summary/Keyword: High Dynamic

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A Research on the Dynamic Pressure Estimation for the Control Law Design of High Speed Vehicle (초고속 비행체 제어기법 설계를 위한 비행체 동압 추정 기법 연구)

  • Park, Jungwoo;Kim, IkSoo;Park, Iksoo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.953-956
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    • 2017
  • This paper introduces general applications of vehicle's dynamic pressure information which is estimated during the flight. And a method to estimate the dynamic pressure for a high speed vehicle is suggested to sustain reliability of the flight under a high estimation accuracy of the information. The presented method is straightforward with simple relations of the compressible flow but is a still merited idea employed for the high speed vehicle control scheme with great accuracy.

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Dynamic Material Property of Mn-B Alloy High-Strength Steel (Mn-B 합금계 고강도 강의 동적 물성)

  • Choi, Chang;Hong, Sungin
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.11
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    • pp.124-131
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    • 1996
  • The dynamic material property of Mn-B ally high-strength steel is investigated through the rod impact test which is one of simple test methods for the analysis of the material behavior under high-strain-rate. Rod impact test is performed to produce the deformed shape of rod and analyzed by the one-dimensional theory based on conservation law and the two-dimensional hydrocode AUTODYN-2D. The dynamic yield stress is determined and compared with the static yield stress to investigate the strain-rate sensitivity of Mn-B alloy high-strength steel.

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Compressed Sensing Based Dynamic MR Imaging: A Short Survey (Compressed Sensing 기법을 이용한 Dynamic MR Imaging)

  • Jung, Hong;Ye, Jong-Chul
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.5
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    • pp.25-31
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    • 2009
  • The recently developed sampling theory, "compressed sensing" is gathering huge interest in MR reconstruction area because of its feasibility of high spatio-temporal resolution of dynamic MRI which has been limited in conventional methods based on Nyquist sampling theory. Since dynamic MRI usually has high redundant information along temporal direction, this can be very sparsely represented in most of cases. Therefore, compressed sensing that exploits the sparsity of unknown images can be effectively applied in most of dynamic MRI. This review article briefly introduces currently proposed compressed sensing based dynamic MR imaging algorithms and other methods exploiting sparsity. By comparing them with conventional methods, you may have insight how the compressed sensing based methods can impact nearly every area of clinical dynamic MRI.

Simplified Dynamic Analysis of High-Rise Buildings (고층건물의 단순화된 동적해석)

  • 이동근;황재호
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1993.04a
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    • pp.101-108
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    • 1993
  • A simplified dynamic analysis method for high-rise building structures is proposed in this study. In the proposed method, member forces are obtained through static analysis using story forces derived from story shear forces which are obtained using dynamic analysis procedure. Major advantage of the proposed method is in the convenience in load combinations for design analysis.

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Characteristics of Dynamic Track Tension for Three Dimensional High Mobility Tracked Vehicle (3차원 고기동 궤도차량의 동적 궤도장력 특성 연구)

  • 서문석;최진환;류한식;배대성
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.112-120
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    • 2003
  • In this paper, dynamic track tension fur high mobility tracked vehicle is investigated by multibody dynamic simulation techniques. This research focuses on a heavy military tracked vehicle which has sophisticated suspension and rubber bushed rack systems. In order to obtain accurate dynamic track tension of track subsystems, each track link is modeled as a body which has six degrees of freedom. A compliant bushing element is used to connect track links. Various virtual proving ground models are developed to observe dynamic changes of the track tension. Numerical studies of the dynamic track tension are validated against the experimental measurements. The effects of pre-tensions, traction forces, fuming resistances, sprocket torques, ground profiles, and vehicle speeds, for dynamic responses of track tensions are explored, respectively.

Mediating Effect of Operational Capabilities on the Dynamic Capabilities and Performance of Korean SMEs (동적역량과 기업성과에 대한 운영역량의 매개효과 분석)

  • Bae, Sun-Cheol;Kim, Byung-Keun
    • Journal of the Korean Operations Research and Management Science Society
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    • v.41 no.4
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    • pp.15-32
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    • 2016
  • This study examines the relationship between dynamic capabilities and operational capabilities as well as investigates the effect of these capabilities and performance. We also test these relationships on two industry groups categorized into high-tech industries and low-tech industries. We collected 221 firms' data from a questionnaire survey of small and medium-sized enterprises in Korea. Empirical results show that dynamic capabilities and operational capabilities influence performance positively. In high-tech industries dynamic capabilities directly affect performance while marketing capabilities appear to mediate the relationship between dynamic capabilities and performance. Dynamic capabilities show no significant effect on performance for low-tech industries; however, operational capabilities do mediate the relationship between dynamic capabilities and performance.

A Study on the Structural Dynamic Modification of Sub-structure of Clean Room Considering Vibration Criteria (반도체 초정밀장비의 진동허용규제치를 고려한 지지구조의 동특성 개선에 관한 연구)

  • 손성완;이홍기;백재호
    • Journal of the Semiconductor & Display Technology
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    • v.2 no.2
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    • pp.25-30
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    • 2003
  • In the case of a vibration sensitive equipment, it require a vibration free environment to provide its proper function. Especially, lithography and inspection device, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved Giga Class semi conductor wafers. This high technology equipments require very strict environmental vibration criteria in proportion to the accuracy of the manufacturing. In this paper, the dynamic analysis and modal test were performed to evaluate the dynamic properties of the constructing clean room structure. Based on these results, a structural dynamic modification(SDM) were required to satisfiy the vibration allowable limit for pression machine. Therefore, in order to improve the dynamic stiffness of clean room structure, the VSD system which can control the force applied on structure, were adopted and its utility were proved from dynamic test results of the improved structure after a modification work.

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Studies on Rheological Properties of High Solid Coating Colors(Part 2) - Effect of Rheology Modifiers on High-Shear Viscosity and Dynamic Penetration Behavior - (고농도 도공액의 유동특성에 관한 연구(제2보) - 유동성 조절제가 고전단 점도 및 동적 침투특성에 미치는 영향 -)

  • Yoo, Sung-Jong;Cho, Byoung-Uk;Lee, Yong-Kyu
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.3
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    • pp.121-127
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    • 2011
  • This study used two types of rheology modifiers including an alkali-swellable emulsion (ASE) and an surface-adhesion emulsion (SAE) to elucidate their effects on high shear viscosity and dynamic penetration behavior among the flow properties of high solids coating. Since rheology under high shear and dynamic penetration behavior significantly affect the quality of coated paper in case of high solids coating, it is very important to examine the variations in rheology of high solids coating color by rheology modifier. It was found that the high solids coating color prepared with the SAE type showed superior dynamic penetration behavior and high shear viscosity than that with the ASE type rheology modifier.

Development of fundamental technology for dynamic analysis of the high speed EMU (Electric Multiple Unit) (동력분산형 고속철도 주행성능 동역학 해석을 위한 기반기술 개발)

  • Yoon, Ji-Won;Park, Tae-Won;Jun, Kab-Jin;Park, Sung-Moon;Kim, Jung-Bum
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.380-386
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    • 2008
  • The development of a new railway vehicle is under progress through the Next Generation High-Speed Rail Development Project in Korea. Its aim is to develope fundamental technology of the vehicle that can run over 400km/h. The new distributed traction bogie system, 'HEMU'(High-speed Electric Multiple Unit), will be used and is different from that of previously developed high speed railway vehicles. Previous vehicles adopted push-pull type system, which means one traction-car drives rest all of the vehicle. Due to the difference, investigation on dynamic behavior and its safety evaluation are necessary, as a part of verification of the design specification. In the paper, current progresses of researches are presented. And the High-Speed Railway vehicle system is evaluated for a dynamic characteristic simulation. Proper dynamic models including air-suspension system, wheel-rail, bogie and car-body is developed according to the vehicle simulation scenario. The basic platform for the development of dynamic solver is prepared using nodal, modal coordinate system and wheel-rail contact module. Operating scenario is prepared using commercial dynamic analysis program and used for development of dynamic model, which contains many parts such as carbodies, bogies and suspension systems. Furthermore, international safety standard is applied for final verification of the system. Finally, the reliability of the dynamic model will be verified with test results in the further researches. This research will propose a better solution when test results shows a problem in the parts and elements. Finally, the vehicle that has excellent performance will be developed, promoting academic achievement and technical development.

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Grid Peak Power Limiting / Compensation Power Circuit for Power Unit under Dynamic Load Profile Conditions (Dynamic Load Profile 조건의 전원 장치에 있어서 계통 Peak Power 제한/보상 전력 회로)

  • Jeong, Hee-Seong;Park, Do-Il;Lee, Yong-Hwi;Lee, Chang-Hyeon;Rho, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.5
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    • pp.376-383
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    • 2022
  • The improved performance of computer parts, such as graphic card, CPU, and main board, has led to the need for power supplies with a high power output. The dynamic load profile rapidly changes the usage of power consumption depending on load operations, such as PC power and air conditioner. Under dynamic load profile conditions, power consumption can be classified into maximum, normal, and standby power. Several problems arise in the case of maximum power. Peak power is generated at the system power source in the maximum-power situation. Frequent generation of peak power can cause high-frequency problems and reduce the life of high-pressure parts (especially high-pressure capacitors). For example, when a plurality of PCs are used, system overload occurs due to peak power generation and causes problems, such as power failure and increase in electricity bills due to exceeded contract power. To solve this problem, a system peak power limit/compensation power circuit is proposed for a power supply under dynamic load profile conditions. The proposed circuit detects the system current to determine the power situation of the load. When the system current is higher than the set level, the circuit recognizes that the system current generates peak power and compensates for the load power through a converter using a super capacitor as the power source. Thus, the peak power of loads with a dynamic load profile is limited and compensated for, and problems, such as high-frequency issues, are solved. In addition, the life of high-pressure parts is increased.