• Title/Summary/Keyword: Obstacle-cross

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Development of 3-D Volume PIV (3차원 Volume PIV의 개발)

  • Choi, Jang-Woon;Nam, Koo-Man;Lee, Young-Ho;Kim, Mi-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.6
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    • pp.726-735
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    • 2003
  • A Process of 3-D Particle image velocimetry, called here, as '3-D volume PIV' was developed for the full-field measurement of 3-D complex flows. The present method includes the coordinate transformation from image to camera, calibration of camera by a calibrator based on the collinear equation, stereo matching of particles by the approximation of the epipolar lines, accurate calculation of 3-D particle positions, identification of velocity vectors by 3-D cross-correlation equation, removal of error vectors by a statistical method followed by a continuity equation criterior, and finally 3-D animation as the post processing. In principle, as two frame images only are necessary for the single instantaneous analysis 3-D flow field, more effective vectors are obtainable contrary to the previous multi-frame vector algorithm. An Experimental system was also used for the application of the proposed method. Three analog CCD camera and a Halogen lamp illumination were adopted to capture the wake flow behind a bluff obstacle. Among 200 effective particle s in two consecutive frames, 170 vectors were obtained averagely in the present study.

Development of Stable Traveling Systems for Stairs and Off-road (굴곡지형 안전주행시스템의 개발)

  • Choe, Jung-Seob;Jun, Hyung-Gyu
    • Journal of the Korean Society of Industry Convergence
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    • v.12 no.3
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    • pp.129-135
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    • 2009
  • This paper describes traveling systems consisting of one major-wheel and three minor-wheels attached to each tip of three spokes. A link of inter-axle plays an important role of the system. It connects secondary axle to the major wheel axle. Its length is determined to ascend stably various stairs. The systems was designed to mount a cart for carrying agricultural products. The systems was applied to ascend stairs, travel on sand and cross a obstacle, despite of simple design.

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Study on Mobile Robot's Navigation Problem Using Jacobian and Fuzzy Inference System (자코비안과 퍼지 추론 시스템을 이용한 이동로봇의 주행문제에 관한 연구)

  • Choi Gyu-Jong;Ahn Doo-Sung
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.6
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    • pp.554-560
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    • 2006
  • In this paper, we propose the topological map building method about unknown environment using the ultrasonic sensors. An ultrasonic sensor inherently has the range error due to the specular reflection. To decrease this error, we estimate the obstacle states(position and velocity) using the local minimum sensor values and Jacobian. Estimated states are used to avoid the obstacles and build the topological map similar to the type that human being memorizes an environment. When a mobile robot is faced with three problems(comer way, cross way and dead end), it senses the movable directions using FIS(Fuzzy Inference System). Among these directions, it can select the target direction using binary decision tree(Turn Side Selector). Proposed algorithm has been verified with three simulations and three implementations.

Comparison of map display styles of vehicle navigation system on human factors (차량 항법장치의 화면표시형태에 대한 인간공학적 비교)

  • Jung, Beom-Jin;Baek, Seung-Ryul;Kim, Gi-Beom;Park, Beom
    • Proceedings of the ESK Conference
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    • 1995.10a
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    • pp.208-213
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    • 1995
  • The vehicle navigation system is developed for helping driver to retrieve driving information more easily and lastly. Navigation System informs driver many pieces of driving information - roadway structure and system, on-line traffic condition, the position of vehicle, route guidance, destination and other infor- mation service. As the style of information is diverse and the amount of information is large, driver may have mental and visual overload. The display of information can disturb the driver's attention and this can cause accidents. This state is caused by the defect of human-machine interactions. When the navigation system is designed, human factors - cognitive, judgment, operating -must be considered. The display style must be designed simply and easily, not to be obstacle of human - machine interface. In this study, outside- in view display style and inside-out view display style are compared each other. Tow factors are measured. One is cognitive factor-time of cognition on information that is displayed by screen display, cognition error rate. The other is image of screen display - subject's feeling about several styles of display, degree of subject's preference. The prototype of roadway is four kinds -Cross, T-cross and O-cross. Roadway display for test is taken from paper maps. Traffic condition display style, vehicle position display style and route guidance display style are taken from current display style. Traffic condition display style is symbol. vehicle position display style and route guidance display style are described as color and symbol. The test on screen display is implemented doing given tasks. Then the test is analyzed statistically. The result of test analysis gives the guideline to the designer for the map display of the vehicle navigation system.

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Comparison the Muscle Activation in the Trunk and Lower Limbs of Subjects Wearing High-Heeled or Flat Shoes While Crossing Over Obstacles of Different Heights

  • Park, Jin-Seong;Han, Jin-Tae
    • Journal of the Korean Society of Physical Medicine
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    • v.12 no.3
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    • pp.85-91
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    • 2017
  • PURPOSE: The purpose of this study was to compare muscle activation of the trunk and lower limbs of subjects wearing high-heeled or flat shoes while crossing over obstacles of different heights. METHODS: Twenty subjects participated in this study. While wearing high-heeled shoes (7 cm) or flat shoes (0 cm), the subjects were asked to cross over obstacles of different heights (10%, 20%, and 30% of their lower-limb length). Muscle activation of the trunk and lower limbs with the supported side while crossing over obstacles of different heights was measured using the electromyogram (Noraxon, DTS, Germany). Two-way repeated ANOVA was used to compare the muscle activation between high-heel shoes and flat shoes while crossing over obstacles of different heights. All statistical analyses were performed using SPSS ver. 21, and p-values less than .05 were used to identify significant differences. RESULTS: As an obstacle's height increased, muscle activation of the trunk and lower limbs with the supported side was increased while wearing either type of shoe, and it was generally higher while wearing high-heeled shoes. However, tibialis anterior muscle activity while wearing high-heeled shoes was lower than while wearing flat shoes. CONCLUSION: This study showed that muscle activation of the trunk and lower limbs was higher when subjects wore high-heeled shoes than when they wore flat shoes while crossing over obstacles of different heights. Therefore, high-heeled shoes can easily cause high muscle fatigue of the trunk and lower limbs, and the TA muscle may weaken in persons who wear high-heeled shoes.

Comparison of the Effect of Treadmill Walking Combined With Obstacles-Crossing on Walking Function in Stroke Patients (장애물 통과 트레드밀 보행훈련이 뇌졸중 환자의 보행기능에 미치는 효과)

  • Jeong, Yeon-Gyu;Jeong, Yeon-Jae;Kim, Hyun-Sook
    • Physical Therapy Korea
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    • v.20 no.3
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    • pp.9-18
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    • 2013
  • The study aimed to compare the effect of the treadmill walking training combined with obstacle-crossing (TWT-OC) and treadmill walking training (TWT) on the walking function of patients with chronic stroke. 29 subjects volunteered to participate in this study; they were randomly assigned to either TWT-OC group (15 subjects) or TWT group (14 subjects). Subjects from the TWT-OC group underwent a treadmill walking combined with obstacles-crossing for 30 minutes daily, three days a week for four weeks, whereas subjects from the TWT group received only a treadmill walking. The 10 m walk test (10MWT), 6-min walk test (6MWT), berg balance scale (BBS), timed up and go test (TUG), activities-specific balance confidence-Korean version (ABC-K), and walking ability questionnaire (WAQ) were measured before and after the 4-week training. The TWT-OC group showed significantly better functional mobility of walking and balance measured by 6MWT (p<.01), BBS (p<.01), and TUG scores (p<.05) when compared with those of the TWT group. Further, within-group comparison showed significant improvement in all variables (p<.01) except for 10MWT. These findings suggest that the TWT-OC and TWT may be helpful for improving the walking function of patients with chronic stroke, and the TWT-OC has probably more favorable outcomes for chronic stroke, however, further trials with wider range of subjects are warranted for generalization and clinical relevance.

Local Behaviour of Propagating Flames in an Explosion Chamber (폭발챔버에서 전파하는 화염의 국부 거동)

  • Park, Dal-Jae;Lee, Young-Soon
    • Journal of the Korean Society of Safety
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    • v.26 no.2
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    • pp.32-35
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    • 2011
  • Experimental studies were carried out in an explosion chamber to investigate the influences of multiple cylinder obstacles on local flame propagation. The chamber dimension is 235 mm in height with a $1,000{\times}950\;mm^2$ rectangular cross section and a large vent area of $1,000{\times}320\;mm^2$. Multiple cylinder bars with obstruction ratio of 30% were used. In order to examine the interaction between the propagating flames and the obstacles, temporally resolved flame front images were recorded by a high speed video camera. The propagation behaviour of local flame fronts around the left obstacle was analyzed in terms of two different methods such as the incremental burnt area divided by the flame front length and the average of the local propagation velocity determined at each point along the flame front. It was found that two methods give good consistency.

밀리미터파 레이다 시스템을 이용한 전력선 검출

  • Kang, Gum-Sil;Yong, Sang-Soon;Kang, Song-Doug;Kim, Jong-Ah;Chang, Young-Jun
    • Aerospace Engineering and Technology
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    • v.3 no.1
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    • pp.242-250
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    • 2004
  • This paper describes the detection method of wire-like obstacles using millimeter-wave radar system. Passive sensor like CCD camera can be used for the detection of high power electric cables on the hills or mountains and it can give very good quality of obstacle target information. But this system is very limited to use by bad weather condition. The detection capability for different diameters of wire targets using millimeter radar system have been accomplished. To simulate the target on the moving helicopter, rotating targets are used with fixed radar system. In the experiment 11mm, 16mm and 22mm diameter of wires have been detected in single, two and three wires in one position. The detected signal from single wire was very clear on gray level image. Three wires placed very closely together could be recognized in range, cross range image plane. For two and three wires, blur effect due to mutual scattering effect is observed.

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The design of 111m high steel towers with 220kv double circuits crossing 12 km wide Bangladesh River (230KV 2회선승 111M 높이 철탑설계 (I) (강폭 12km인 Bangladesh Jamana강 횡단용))

  • 이재숙
    • Journal of the Korean Professional Engineers Association
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    • v.15 no.4
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    • pp.12-24
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    • 1982
  • East Parts of Bangladesh have been benifited by low cost energy generated by domestic natural gas but West parts where energy generated by imported fuel. Bangladesh Government authority has very much concerned to transmit the low cost electricity to the West from the East for past several years. To solve such concerns, cross-country 230kv double circuits Power transmission line was proposed, however there was a big obstacle for the realization of this line to cross the Jamuna river which has 12 km long width with a deep muddy river bed. A consultant engineering firm named Merz-Mclellan anyway finalized this plan and a world-wide bid was announced on June 31, 1979. Due to the expected difficulty to construct the towers on sea like area, only three construction groups have participated. including a Korean joint venture organization of Samsung-Korean Developement corporation-Kolon Electric Machinery company. After 3 months bid evaluation, contract was awarded to Korean Consosium and KEM Co was in charge of designing steel towers with anchor bolts and base plates beside to electrical engineering field. Then KEM Co have faced and over-comed many unenpected technical difficulties such as forced eccentricity joint on base plate, distorsion issue of 60mm thick plates welding, threading anchor bolts, tad heat treatment of some anchor bolts, disagreement from Consultant Engineer on multiplying factor of leg stresses for 45$^{\circ}$ wind and on reducing O.L.F for wind loads on cables for such 1220km long spans. After spending two years long period for designing and engineering towers, base plates, and anchor bolts, first shipment of tower was finally realized on Nov. 8, 1981 and on the other hand KDD has proceeded concrete caisson work on schedule at Jamuna river site and expected to complete tower erection and stringing of cables within this year of 1982 which was original completion target.

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The Ethics of the Othering in the Era of Transnationalism

  • Kim, Youngmin
    • Journal of English Language & Literature
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    • v.55 no.6
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    • pp.1013-1034
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    • 2009
  • The space of the Other assumes the space of Barthes's multiplicity and Foucault's transdiscursive position, and, therefore, aims at becoming the locus in which the speaking subject and the hearing subjects are supposed to communicate and constitute as if they were situated in the pscychoanalytic session. However, the wall of untranslatibility across language and cultures still exist there in the space of the Other in the form of trauma and aggressivity, as Lacan demonstrate perceptively through the reading of Kant avec Sade. In short, Lacan regards the moral commandment (to love one's neighbor as oneself) as the obstacle in the Freud's myth of transgression, and interprets this in terms of the emergence of the Other. Freud understands that the aggressivity in the subject's own heart was inherent in all humans, and that one's neighbor would be evil. Lacan goes beyond Freud and articulates that the aggressivity in the imaginary relation with the Other in the mirror stage insures that an evil inheres in the very being of humanity. A global phenomenon of the diasporic identities and hybridity, the phenomenon which has been represented by the complicated intermixture of terms which span from diaspora, postcolonialism, postnationalism. and transnationalism can be clarified, if they are put in the context of the ethics of Othering or becoming the Other. The ethics of Othering presupposes the situation in which the diasporic subjects encounter the lack of the cross-cultural negotiation and communication. The purpose of this paper is to demonstrate how the poetics of Other and the logic of the ethics of Othering can explain the postmodern or transmodern world which has become deterritorialized, diasporic, and transnational as well as how one can encounter the results of diasporic and postcolonial double consciousness, a consciousness which is a discursive category for multicultural or cross-cultural, focusing on the concept of liminality/interstitiality