• Title/Summary/Keyword: Shape Space

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Obstacle Avoidance Method for Multi-Agent Robots Using IR Sensor and Image Information (IR 센서와 영상정보를 이용한 다 개체 로봇의 장애물 회피 방법)

  • Jeon, Byung-Seung;Lee, Do-Young;Choi, In-Hwan;Mo, Young-Hak;Park, Jung-Min;Lim, Myo-Taeg
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.12
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    • pp.1122-1131
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    • 2012
  • This paper presents obstacle avoidance method for scout robot or industrial robot in unknown environment by using IR sensor and vision system. In the proposed method, robots share the information where the obstacles are located in real-time, thus the robots can choose the best path for obstacle avoidance. Using IR sensor and vision system, multiple robots efficiently evade the obstacles by the proposed cooperation method. No landmark is used at wall or floor in experiment environment. The obstacles don't have specific color or shape. To get the information of the obstacle, vision system extracts the obstacle coordinate by using an image labeling method. The information obtained by IR sensor is about the obstacle range and the locomotion direction to decide the optimal path for avoiding obstacle. The experiment was conducted in $7m{\times}7m$ indoor environment with two-wheeled mobile robots. It is shown that multiple robots efficiently move along the optimal path in cooperation with each other in the space where obstacles are located.

Design Support Based on 3D-CAD System using functional Space Surrounding Design Object (설계대상물의 외부공간을 이용한 3차원 CAD 시스템에 의한 설계지원)

  • Nahm, Yoon-Eui;Ishikawa, Haruo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.32 no.1
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    • pp.102-110
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    • 2009
  • Concurrent Engineering(CE) has presented new possibilities for successful product development by incorporating various product life-cycle functions from the earlier stage of design. In the product design, geometric representation is vital not only in its traditional role as a means of communicating design information but also in its role as a means of externalizing designer's thought process by visualizing the design product. During the last dozens of years, there has been extraordinary development of computer-aided tools intended to generate, present or communicate 3D models. However, there has not been comparable progress in the development of 3D-CAD systems intended to represent and manipulate a variety of product life-cycle information in a consistent manner. This paper proposes a novel concept, Minus Volume (MV), to incorporate various design information relevant to product lift-cycle functions. MV is a functional shape that is extracted from a design object within a bounding box. A prototype 3D-CAD system is implemented based on the MV concept and illustrated with the successful implementation of concurrent design and manufacturing.

Noise Source Identification and Acoustic Radiation Power Reduction of Hard Disk Drive Using Sound Intensity (음향 인텐시티를 이용한 하드디스크 드라이브의 소음원 파악 및 음향파워 제어)

  • Kang, Seong-Woo;Han, Yun-Sik;Hwang, Tae-Yeon;Son, Young;Koo, Ja-Choon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1540-1548
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    • 2000
  • Sound intensity techniques and ODS(Operational Deflection Shape) techniques are applied to identify the acoustic noise source of a hard disk drive and its control system. The sound intensity is used to visualize the noise source locations, and the ODS information to visualize the vibration pattern and to obtain the dynamic characteristics of the noise sources. The measurement systems are customized to accurately measure the sound intensity and ODS distributions of HDD system in space domains as well as frequency domains. The measurement systems for the sound absorption and transmission loss of materials are also used to support the background data for the efficient noise control. Using the visual information of source locations and its dynamic characteristics, the partial noise barrier structure and optimum absorption are designed and its controlled sound power level is proved to be under 3.1 Bel(Idle)/3.3Bel (Seek) which is the lowest level in the disk drive industry.

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Effects of the Gap and the Speed on the Lap-Joint $CO_2$ Laser Welding of Automotive Steel Sheets (자동차용 강판의 겹치기 $CO_2$ 레이저 용접에서 용접속도와 판재간격에 따른 용접특성 연구)

  • 이경돈;박기영;김주관
    • Journal of Welding and Joining
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    • v.20 no.4
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    • pp.510-516
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    • 2002
  • Recently the laser welding technology has been applied increasingly for the automotive bodies. But the lap joint laser welding for 3 dimensional automotive body is new while the butt joint laser welding is well known as the tailored blank technology. In this study, the process window was found for the full penetration welding of the lap joint of the 1mm-thick high strength steel sheets. The limit curves and characteristic curves were suggested to define the boundaries and the contour lines in a space of the welding speed and the gap size. The characteristics of the weld sectional geometry were used to determine the limit curves. They are bead width, penetration depth and sectional area. After the observed data was analysed carefully, it was noticed that there was a transition point at which the sectional shape was changed and the bead area jumped as the welding speed was increased. Also a new concept of 'input energy Per volume' was suggested to distinguish the difference at the transition Point. The difference of sectional areas at the transition point can be related to the dynamic keyhole phenomena.

A study on Applicable to Advanced treatment of using Side Stream Plug-Flow Reactor (효과적 공간활용을 위한 Side Stream Plug-Flow Reactor를 이용한 하수 고도처리 공정 적용에 관한 연구)

  • Kim, samju;Hyun, InHwan;Dockko, Suk
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.3
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    • pp.367-372
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    • 2008
  • This study configured the conventional $A^2O$ (Anaerobic-Anoxic-Aerobic bioreactor) system which the fixed media immersed into the anoxic reactor(Named PFR system : Plug Flow Reactor) for evaluating the removal efficiency of nitrogen in the wastewater. The experimental equipment was a cylinder which was consist of 4 pleated PE Pipes(Length 330M, Diameter 100mm) including 2 rope shape media. As a result, the average effluent T-N removal efficiency of the conventional $A^2O$ system was 17.9, 40.3, 50.6, 44.6% in each mode, but the average effluent T-N removal efficiency of the PFR system could achieve 38.8, 57.1, 71.8, 65.4% in each mode. It indicated that the PFR system caused to the increasing of C/N ratio that effected to the increasing of the denitrification efficiency. Not only the effective T-N removal efficiency but also the controllable install space will give advantages for retrofitting of the wastewater treatment plant with the conventional treatment system to the PFR system.

MOLECULAR LINE STUDY OF L1014 WITH SRAO 6M TELESCOPE (L1014 분자운 핵에 대한 SRAO 6m 망원경을 이용한 분자선 관측연구)

  • Lee, Chang-Won
    • Publications of The Korean Astronomical Society
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    • v.20 no.1 s.24
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    • pp.1-5
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    • 2005
  • We report molecular line observations of CO(1-0), $^{13}CO(1-0)$, CS(2-1), and HCN(1-0) with SRAO 6m telescope toward L1014-IRS which is thought to be a very faint infrared source embedded in previously known 'starless' core L1014. The CO(1-0) observations find several components with different velocities along the line of sight of L1014, $4km\;s^{-1}$ and between $40{\sim}50km\;s^{-1}$. We find a parsec scale CO molecular outflow at the $4km\;s^{-1}$ component for the first time the direction of which is coincident with that of the small scale (${\sim}500pc$) outflow previously found. Although the observation is not covered for whole area of the outflow, the size of the molecular outflow seems not very inconsistent with the expected age of L1014-IRS. More accurate size and shape of the molecular outflow from L1014-IRS will be determined from the full coverage mapping in CO over the outflow region in very near future.

THE STUDY OF SCATTERING IN THE ISM WITH HIGH RESOLUTION OBSERVATIONS OF OH MASERS

  • Migenes, Victor;Slysh, V.I.;Velasco, A.E.Ruis;Villalpando, S.
    • Journal of The Korean Astronomical Society
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    • v.40 no.4
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    • pp.131-132
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    • 2007
  • The research of OH maser emission sources with high angular resolution is complicated by the effects of interstellar scattering: more over, most of the OH maser sources are located in the galactic plane where the scattering is largest. However, the data available from pulsar studies on the spatial distribution of the amount of scattering indicate that there is a strong non-uniformity in the distribution of the amount of scattering material. There are directions in the galactic plane where the scattering is an order of magnitude higher than the average, as well as directions where the scattering is much lower. The latter provide an opportunity to investigate OH masers with the full angular resolution offered by very long baseline interferometry instruments, like the VLBA, and measure their true angular size, shape and brightness temperature. We have observed approximately 100 OH maser sources, distributed all over the northern hemisphere, with the VLBA in order to study the scattering properties of the interstellar medium.

TEMPORAL VARIATION OF HCO+ 1-0 GALACTIC ABSORPTION LINES TOWARD NRAO 150 AND BL LAC

  • Han, Junghwan;Yun, Youngjoo;Park, Yong-Sun
    • Journal of The Korean Astronomical Society
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    • v.50 no.6
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    • pp.185-190
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    • 2017
  • We present observations of $HCO^+$ 1-0 absorption lines toward two extragalactic compact radio sources, NRAO 150 and BL Lac with the Korean VLBI Network in order to investigate their time variation over 20 years by Galactic foreground clouds. It is found that the line shape of $-17kms^{-1}$ component changed marginally during 1993-1998 period and has remained unaltered thereafter for NRAO 150. Its behavior is different from that of $H_2CO$ $1_{10}-1_{11}$, suggesting chemical differentiation on ~ 20 AU scale, the smallest ever seen. On the other hand, BL Lac exhibits little temporal variation for the $HCO^+$ and $H_2CO$ lines. Our observation also suggests that Korea VLBI Network performs reliably in the spectrum mode in that the shapes of the new $HCO^+$ 1-0 spectra are in good agreement with the previous ones to an accuracy of a few percent except the time varying component toward NRAO 150.

What would we meet for the implant dentistry: A Case Report (임플란트를 하면서 만나게 되는 문제들: 증례보고)

  • Lee, Jung-Sam
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.24 no.1
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    • pp.49-67
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    • 2015
  • Since the implant became the important treatment modality in dentistry, the research and clinical effort to mimic natural tooth appearance have been pursued. While the rehabilitation of mastication and occlusal appearance was focused in the past, more esthetic and functional restoration was preferred recently. To fulfill this demand, the clinicians should consider the axial contour, papilla space, subgingival appearance, as well as the shape of occlusal surface. In the surgery part, there have been significant advances in the adequate formation of bone and soft tissue through the careful reflection on the surgery time and incision. When the dentist has good knowledge about this aspect and passion for the final product, he or she can acquire better results.

An Anisotropic Hardening Constitutive Model for Dilatancy of Cohesionless Soils : I. Formulation (사질토의 체적팽창을 고려한 비등방경화 구성모델 : I. 정식화)

  • 오세붕;박현일;권오균
    • Journal of the Korean Geotechnical Society
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    • v.20 no.6
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    • pp.75-83
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    • 2004
  • This study is focused on the constitutive model in order to represent brittleness and dilatancy of cohesionless soils. The constitutive model was proposed on the basis of an anisotropic hardening rule with generalized isotropic hardening rule. The shape of yield surface is a simple cylinder type in stress space and it makes the model practically useful. Flow rule was approximated by a concrete function on dilatancy. A peak stress ratio was defined to model brittle stress-strain relationships. The proposed model was formulated and implemented to calculate the stress-strain relationship from triaxial tests. In the companion paper the proposed model will be verified by comparison with the triaxial test results.