• Title/Summary/Keyword: look-ahead point

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Autonomous Navigation of Nonholonomic Mobile Robots Using Generalized Voronoi Diagrams (일반화된 보로노이 다이어그램을 이용한 논홀로노믹 모바일 로봇의 자율 주행)

  • Shaoa, Minglei;Shin, Dongik;Shin, Kyoosik
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.1
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    • pp.98-102
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    • 2015
  • This paper proposes an autonomous navigation method for a nonholonomic mobile robot, based on the generalized Voronoi diagram (GVD). We define the look-ahead point for a given motion constraint to determine the direction of motion, which solves the problem of a minimum turning radius for the real nonholonomic mobile robot. This method can be used to direct the robot to explore an unknown environment and construct smooth feedback curves for the nonholonomic robot. As the trajectories can be smoothed, the position of the robot can be stabilized in the plane. The simulation results are presented to verify the performance of the proposed methods for the nonholonomic mobile robot. Furthermore, this approach is worth drawing on the experience of any other mobile robots.

Activity Segmentation and 3D-Visualization of Pusher-Loaded Earthmoving Operations from Position Data

  • Ahn, Sanghyung;Dunston, Phillip S.;Kandil, Amr;Martinez, Julio C.
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.328-332
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    • 2015
  • By logging position data from GPS-equipped construction machines, we re-create daily activities as 3D animations to analyze performance and facilitate look-ahead scheduling. The 3D animation enables going back to any point in time and space to observe the activities as they took place. By segmenting data into a set of activities, it is possible to obtain actual measures of performance such as cycle times, production, speed profiles and idle times. The measures of performance can then be compared to those expected (e.g., theoretical speed profiles vs. observed profiles), and instances of significant difference can be flagged for further investigation. Idle times and queues that exceed prescribed thresholds can also be identified. In general, many of the traditional real-time performance analyses can be performed after the fact. Situations of interest can be identified automatically and the events in this manner enhances effective performance improvement in construction. The proposed research is explained and demonstrated using a real push-loaded earthmoving operation.

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Real-Time Seam Tracking System Using a Visual Device with Vertical Projection of Laser Beam (레이저빔 수직투사 구조의 시각장치를 이용한 실시간 용접선추적 시스템)

  • Kim, Jin-Dae;Lee, Jeh-Won;Shin, Chan-Bai
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.10
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    • pp.64-74
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    • 2007
  • Because of the size and environment in the shipbuilding process, the portable type robot is required for the automatic seam tracking. For this reason, the structure of laser sensor should be considered in the initial design step and the coordinate transformation between welding robot and laser sensor, which is joint finder, must be identified exactly and the real time tracking algorithm based on these consideration could be developed. In this research, laser displacement sensor in which its structure is laser beam's vertical projection, is developed to recognize the location of weld joint. In practical applications, however, images of weld joints are often degraded because of the surface specularity or spatter. To overcome the problem, the constrained joint finding algorithm is proposed. In the approach of coordinate conversion rule for the visual feedback control among welding torch, robot body and laser sensor is applied by the same reference point method. In the real time seam tracking algorithms we propose constrained sampling method which uses look ahead distance. The RLS(Recursive Least Square) filter is applied to obtain the smooth tracking path from the sensitive edge data. From the experimental results, we could see the possibility that the developed laser sensor with proposed processing algorithm and real time seam tracking method can be used as a welding under the shipbuilding condition.

Nonlinear Time Series Prediction Modeling by Weighted Average Defuzzification Based on NEWFM (NEWFM 기반 가중평균 역퍼지화에 의한 비선형 시계열 예측 모델링)

  • Chai, Soo-Han;Lim, Joon-Shik
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.4
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    • pp.563-568
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    • 2007
  • This paper presents a methodology for predicting nonlinear time series based on the neural network with weighted fuzzy membership functions (NEWFM). The degree of classification intensity is obtained by bounded sum of weighted fuzzy membership functions extracted by NEWFM, then weighted average defuzzification is used for predicting nonlinear time series. The experimental results demonstrate that NEWFM has the classification capability of 92.22% against the target class of GDP. The time series created by NEWFM model has a relatively close approximation to the GDP which is a typical business cycle indicator, and has been proved to be a useful indicator which has the turning point forecasting capability of average 12 months in the peak point and average 6 months in the trough point during 5th to 8th cyclical period. In addition, NEWFM measures the efficiency of the economic indexes by the feature selection and enables the users to forecast with reduced numbers of 7 among 10 leading indexes while improving the classification rate from 90% to 92.22%.

The Study of Exposure and Concealment in Fashion - Focusing on the Freud's Psychoanalysis - (패션의 노출과 은폐에 관한 고찰 - Freud의 정신분석학을 중심으로 -)

  • 임성민;박민여
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.11
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    • pp.1395-1403
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    • 2004
  • Exposure and Concealment have been continued as important way to express fashion and theme as well, especially in women fashion. Exposure can make themselves attractive, and concealment emphasizes this way of being attractive by exposure. Besides the temptable effect of exposure, the ideology which put women next men in society has made a prominence on the fact exposure is significant theme in women fashion. It means that women's image of 'Being seen as Object' (this can be explained by relation passive between active) in society has driven female emphasize in using and focusing on exposure to be attractive. Also the other important thing in women fashion has been considered is concealment. The fact that society has demand women more chaste duty in detail may have meaningful thing in the condition that instigates women take off being attractive to the subject, considering ideology, men. Therefore attractive femininity has to be suggested by virtue and temptation, it is common sense that looking just shallow or too strict are far from criteria of ideal beauty. Namely, the concept for exposure coexists with concealment not only constructively but also naturally in fashion. Technique that can be accentuate for effective exposure differently from method to show unilaterally is needed, and this technique can promote new fashion. And according to the theory of Freud, women means' Absence (lacking penis)', this female's Lack Image induces male castration complex therefore 'Fetishistic Look' which transfers something phallic into specific things or parts of body is adopted, sort of object cathexis. This is revealed as some parts of women body are diverted into object for sexual love, symbolic equivalent. For example, women's parts like legs or breast are remarked as erotogenic zone and as time goes, when no more the zone are felt sexual by exposure, other somewhere felt mysterious (felt something sexual) used to be stressed by exposing. As it were, it can be possible that exposing part on women body (sexual part) moved as time passed because of what previously stated. Especially, the concept of exposure and concealment in women fashion should explain not only from a point of view of style for the beautifulness but also from wearer's immanent intention, further more relationship with ideology. About the present situation becoming bolder in women fashion, it is said that women express confidence as the position of women is elevated higher socially, the more women get freedom. But if we consider this psychoanalysis opinion mentioned ahead, the possibility can not be excluded that the exposure can get emphasizing according as the need of feminine modesty gets decreasing from ideal femininity society, men want. This study about exposure and concealment was made progressed through the theory of Freud who originated psychoanalysis, presented many theories. But nowadays contradictions are being brought up against Freud's theory including conventional philosophy like male chauvinism and adjust studies get suggested. Hereupon, there may be limitation in making no allowance of contradiction and following his theory.

The study of the usage of Jiu-Zhen (九鍼) (구침(九鍼)에 관(關)한 연구(硏究))

  • Jeong Ki-Jin;Jo Hyeon-Seok;Yoon Jong-Hwa
    • Journal of Korean Medical Ki-Gong Academy
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    • v.2 no.2
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    • pp.185-199
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    • 1998
  • Going back to long chinese medical history, there were many different methods of treatment according to the origin of local chinese areas, such as Bian-Shi(?石) from east, herbal therapy from west, acupuncturing from south, moxibustion from north, and mainpulating therapy from middle china. In the midst of these therapies, acupuncture needling had developed very much both in theories, shapes, usages and also in theraputic boundray. Historical books dealing with acupuncture had introduced and used Jiu-Zhen as a tool for acupuncture needling in common. But there are some differences between each texts about in shape, use, and there are also another different point of view about the interrelationship between Bian-Shi and Ji-Zhen. So the author, in this research, tried to look for how Jiu-Zhen had took on its real kinds, adaptive usages, theraputic boundaries, many different skills of needing. By researching over ${\ulcorner}$ Ling-Shu, Jiu-Zhen(靈樞,九鍼)${\lrcorner}$, ${\ulcorner}$ Ling-Shu, Jiu-Zhen-Shi- Yi-Yuan(靈樞,九鍼十二原)${\lrcorner}$, ${\ulcorner}$ Ling-Shu, Guan-Zhen(靈樞,官鍼)${\lrcorner}$, and by compar- ing them with the contents of Jiu-Zhen in ${\ulcorner}$ Zhen-Jiu-Yi-Jing(鍼灸甲乙經)${\lrcorner}$ ${\ulcorner}$Zhen-Jiu-Da-Cheng (鍼灸大成)${\lrcorner}$, the author discovered small conclusions such as following. 1. Taking Jiu-Zhen in a narrow sense, it only repesents nine different needle used in different cases. But in large sense, this means nine different deedling methods using each different needles which is represented in the form of Wu-Ci ( 五剌 ), Shi-Yi-Ci ( 十二剌 ) in ${\ulcorner}$ Ling-Shu, Guan-Zhen ${\lrcorner}$ 2. Jin-Zhen has been first originated from stone age as a substitute for Bian-Shi and through bronze and iron age, it followed a process of it's own shape and applicating functions. As an example, the moxibustional therapies shown in ${\ulcorner}$ Zu-Bi-Shi-Yi-Mai- Jiu-Jing ( 足臂十一脈灸經 )${\lrcorner}$ ${\ulcorner}$ Yin-Yang-Shi-Yi-Mai-Jiu-Jing ( 陰陽十一脈灸經)${\lrcorner}$ in ahead of ${\ulcorner}$ Nei-Jing ( 內經 )${\lrcorner}$ era, was relationship in acupuncturing skills and shape. So Jiu-Zhen had been originated on the base of Bian-Shi in ancient times to develop into delicate shape, skill, and theraputic foundation of modern oriental medicine.