• Title/Summary/Keyword: moving velocity

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Design of S-Shaped Path and Velocity Profile of Moving Stage Using Three Point Locations (3 점을 이용한 이동 무대의 S 곡선 경로 설계)

  • Jung, Kwang-Oh;Oh, Se-Kyu;Kim, Dong-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.1
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    • pp.67-76
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    • 2011
  • An exact curved path has to be fixed and velocity profile for travelling on the curved path is required by a moving stage. In this study, we decide the curved path on the basis of the information on three point locations. The path of the moving stage is traced by simulating the designed curve path and the velocity profile, and the results are compared with the given three points to determine how closely the moving stage follows the given path. Further, we propose a method to calibrate a curved path and velocity profile. The proposed moving paths were evaluated by performing experiments. Finally, the designed curved path and the actual path were compared.

Measurement and Analysis of Moving Velocity of Elementary School Students Under a Escape Drill (초등학생의 피난 훈련 상황하에서의 이동속도 측정 및 분석에 관한 연구)

  • 김응식;이정수;김수영
    • Fire Science and Engineering
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    • v.17 no.4
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    • pp.1-6
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    • 2003
  • This study measures the various moving velocities of elementary school children under situation of fire drill and suggests the methods of analysis. The velocities are such as the exiting velocity at the door of the classroom, personal walking velocity at corridor, velocity according to density of crowd and personal walking velocity at stairway. For these measurement an elementary school in Daejeon is chosen and 15 girls and 15 boys are selected in each grade. Finally speed data of the children is obtained and we can apply this data for the evacuation simulation of a school.

Vibration Characteristics of the Axially Moving Continuum with Time-Varying Length: Spagetti Problem (축방향으로 이동하며 길이가 변하는 연속체의 진동특성: 스파게티 문제에 응용)

  • 사재천;이승엽;이민형
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.385-392
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    • 2001
  • Time-dependent frequency and energy of free vibration of the Spagetti problem, that is the axially moving continuum with time-varying length, are investigated. Exact expressions for the natural frequency and time-varying vibration energy are derived by dealing with traveling waves. When the string length is increased, the vibration period increases, but the free vibration energy varies as a function of both translating velocity and boundary velocity of the continuum. However, when the string undergoes retraction, the vibration energy increases with time, String tension together with non-zero instantaneous velocity at the moving boundary results in energy variation.

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The Estimation of Moving Velocity of Viewer by Using Two Eyes Image for 3D Display for Multiple Viewers

  • Park, Se-Hyuk;Park, Young-Bin;Huh, Kyung-Moo
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.1045-1048
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    • 1999
  • In this paper, we calculate the moving velocity of viewer by using two eye images obtained at different time through the camera. This process is necessary for future 3D display technique, in which moving viewer can see 3D image continuously We firstly extract two eyes image and calculate the pixel coordinate of center point between two eyes. Next, we calculate the moving velocity in two dimension by comparing two center point coordinates obtained at different time.

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A Study on Dynamic Behavior of Simply Supported Fluid Flow Pipe with Crack and Moving Mass (크랙과 이동질량을 가진 유체유동 단순지지 파이프의 동특성에 관한 연구)

  • Son, In-Soo;Ahn, Sung-Jin;Yoon, Han-Ik
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1625-1630
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    • 2003
  • An iterative modal analysis approach is developed to determine the effect of the transverse open cracks and the moving mass on the dynamic behavior of simply supported pipe conveying fluid. The equation of motion is derived by using Lagrange's equation. The influences of the velocity of moving mass, the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. that is, the crack is modelled as a rotational spring. Totally, as the velocity of fluid flow is increased, the mid-span deflection of simply supported pipe conveying fluid is increased. The position of the crack is middle point of the pipe, the mid-span deflection of simply supported pipe presents maximum deflection.

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A Study on Dynamic Behavior of Simply Supported Fluid Flow Pipe with Crack and Moving Mass (크랙과 이동질량을 가진 유체유동 단순지지 파이프의 동특성에 관한 연구)

  • Yoon, Han-Ik;Jin, Jong-Tae;Son, In-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.4
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    • pp.419-426
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    • 2004
  • In this paper, studied about the effect of open crack and the moving mass on the dynamic behavior of simply supported pipe conveying fluid. The equation of motion is derived by using Lagrange's equation. The influences of the velocity of moving mass, the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. Therefore, the crack is modelled as a rotational spring. Totally, as the velocity of fluid flow is increased, the mid-span deflection of simply supported pipe conveying fluid is increased. The position of the crack is located in the middle point of the pipe, the mid-span deflection of simply supported pipe presents maximum deflection.

Intelligent Optimal Route Planning Based on Context Awareness (상황인식 기반 지능형 최적 경로계획)

  • Lee, Hyun-Jung;Chang, Yong-Sik
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.117-137
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    • 2009
  • Recently, intelligent traffic information systems have enabled people to forecast traffic conditions before hitting the road. These convenient systems operate on the basis of data reflecting current road and traffic conditions as well as distance-based data between locations. Thanks to the rapid development of ubiquitous computing, tremendous context data have become readily available making vehicle route planning easier than ever. Previous research in relation to optimization of vehicle route planning merely focused on finding the optimal distance between locations. Contexts reflecting the road and traffic conditions were then not seriously treated as a way to resolve the optimal routing problems based on distance-based route planning, because this kind of information does not have much significant impact on traffic routing until a a complex traffic situation arises. Further, it was also not easy to take into full account the traffic contexts for resolving optimal routing problems because predicting the dynamic traffic situations was regarded a daunting task. However, with rapid increase in traffic complexity the importance of developing contexts reflecting data related to moving costs has emerged. Hence, this research proposes a framework designed to resolve an optimal route planning problem by taking full account of additional moving cost such as road traffic cost and weather cost, among others. Recent technological development particularly in the ubiquitous computing environment has facilitated the collection of such data. This framework is based on the contexts of time, traffic, and environment, which addresses the following issues. First, we clarify and classify the diverse contexts that affect a vehicle's velocity and estimates the optimization of moving cost based on dynamic programming that accounts for the context cost according to the variance of contexts. Second, the velocity reduction rate is applied to find the optimal route (shortest path) using the context data on the current traffic condition. The velocity reduction rate infers to the degree of possible velocity including moving vehicles' considerable road and traffic contexts, indicating the statistical or experimental data. Knowledge generated in this papercan be referenced by several organizations which deal with road and traffic data. Third, in experimentation, we evaluate the effectiveness of the proposed context-based optimal route (shortest path) between locations by comparing it to the previously used distance-based shortest path. A vehicles' optimal route might change due to its diverse velocity caused by unexpected but potential dynamic situations depending on the road condition. This study includes such context variables as 'road congestion', 'work', 'accident', and 'weather' which can alter the traffic condition. The contexts can affect moving vehicle's velocity on the road. Since these context variables except for 'weather' are related to road conditions, relevant data were provided by the Korea Expressway Corporation. The 'weather'-related data were attained from the Korea Meteorological Administration. The aware contexts are classified contexts causing reduction of vehicles' velocity which determines the velocity reduction rate. To find the optimal route (shortest path), we introduced the velocity reduction rate in the context for calculating a vehicle's velocity reflecting composite contexts when one event synchronizes with another. We then proposed a context-based optimal route (shortest path) algorithm based on the dynamic programming. The algorithm is composed of three steps. In the first initialization step, departure and destination locations are given, and the path step is initialized as 0. In the second step, moving costs including composite contexts into account between locations on path are estimated using the velocity reduction rate by context as increasing path steps. In the third step, the optimal route (shortest path) is retrieved through back-tracking. In the provided research model, we designed a framework to account for context awareness, moving cost estimation (taking both composite and single contexts into account), and optimal route (shortest path) algorithm (based on dynamic programming). Through illustrative experimentation using the Wilcoxon signed rank test, we proved that context-based route planning is much more effective than distance-based route planning., In addition, we found that the optimal solution (shortest paths) through the distance-based route planning might not be optimized in real situation because road condition is very dynamic and unpredictable while affecting most vehicles' moving costs. For further study, while more information is needed for a more accurate estimation of moving vehicles' costs, this study still stands viable in the applications to reduce moving costs by effective route planning. For instance, it could be applied to deliverers' decision making to enhance their decision satisfaction when they meet unpredictable dynamic situations in moving vehicles on the road. Overall, we conclude that taking into account the contexts as a part of costs is a meaningful and sensible approach to in resolving the optimal route problem.

Dynamic Responses and Fuzzy Control of a Simply Supported Beam Subjected to a Moving Mass

  • Kong, Yong-Sik;Ryu, Bong-Jo;Shin, Kwang-Bok;Lee, Gyu-Seop;Lee, Hong-Gi
    • Journal of Mechanical Science and Technology
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    • v.20 no.9
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    • pp.1371-1381
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    • 2006
  • This paper deals with the active vibration control of a simply-supported beam traversed by a moving mass using fuzzy control. Governing equations for dynamic responses of a beam under a moving mass are derived by Galerkin's mode summation method, and the effect of forces (gravity force, Coliolis force, inertia force caused by the slope of the beam, transverse inertia force of the beam) due to the moving mass on the dynamic response of a beam is discussed. For the active control of dynamic deflection and vibration of a beam under the moving mass, the controller based on fuzzy logic is used and the experiments are conducted by VCM (voice coil motor) actuator to suppress the vibration of a beam. Through the numerical and experimental studies, the following conclusions were obtained. With increasing mass ratio y at a fixed velocity of the moving mass under the critical velocity, the position of moving mass at the maximum dynamic deflection moves to the right end of the beam. With increasing velocity of the moving mass at a fixed mass ratio ${\gamma}$, the position of moving mass at the maximum dynamic deflection moves to the right end of the beam too. The numerical predictions of dynamic deflection of the beam have a good agreement with the experimental results. With the fuzzy control, more than 50% reductions of dynamic deflection and residual vibration of the tested beam under the moving mass are obtained.

Development of a High Power SONAR System Measuring Velocity by Using Two Gated Sinusoidal Signals (두 개의 정현 신호를 이용한 속도 측정용 고전력 쏘나 시스템 개발)

  • 장순석;안흥구;이제형
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.1036-1041
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    • 1999
  • This paper aims for the development of the high power sonar system for measuring the velocity of a moving object. The high power sonar system transmits two gated 190 kHz sinusoidal signals with 1.6 [ms] time interval to the moving object. Then the sonar system detects and calculates the changed time delay of the reflected ultrasonic signals in order to derive the velocity of the moving object. The transmission part uses a high power amplifier so that 250 W gated sinusoidal signals can be transmitted to the transmitter. 1M RAM is utilized for transmitting and storing of the ultrasonic signals. The time delay is calculted by the cross-correlation technique between the transmitted signals and the received signals. The measured value from the high power sonar system is compared with directly measured values by photo diodes. The result confirms the adjacency to 0.3% error.

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Influence of Two Successively-moving Spring-mass Systems with Initial Displacement on Dynamic Behavior of a Simply-supported Beam Subjected to Uniformly Distributed Follower Forces (초기 변위를 가지고 연속 이동하는 스프링-질량계가 등분포종동력을 받는 단순지지보의 동특성에 미치는 영향)

  • 윤한익;강혁준;유진석
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.3
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    • pp.202-209
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    • 2003
  • A simply supported beam subjected to a uniformly distributed tangential follower force and the two successively moving spring-mass systems upon it constitute this vibration system. The influences of the velocities of the moving spring-mass system, the distance between two successively moving spring-mass systems and the uniformly distributed tangential follower force have been studied on the dynamic behavior of a simply supported beam by numerical method. The uniformly distributed tangential follower force is considered within its critical value of a simply supported beam without two successively moving spring-mass systems, and three kinds of constant velocities and constant initial displacement of two successively moving spring-mass systems are also chosen. Their coupling effects on the transverse vibration of the simply supported beam are inspected too. In this study the simply supported beam is deflected with small vibration proportional to natural frequency of the moving spring-mass systems. According to the increasing of initial displacement of the moving spring-mass systems the amplitude of the small vibration of the simply supported beam is increased due to the spring force. The velocity of the moving spring-mass system more affect on the transverse deflection of simply supported beam than other factors of the system and the effect is dominant at high velocity of the moving spring-mass systems.