• Title/Summary/Keyword: Balance(Stability)

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Obstacle Avoidance Algorithm of Hybrid Wheeled and Legged Mobile Robot Based on Low-Power Walking (복합 바퀴-다리 이동형 로봇의 저전력 보행 기반 장애물 회피 알고리즘)

  • Jeong, Dong-Hyuk;Lee, Bo-Hoon;Kim, Yong-Tae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.4
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    • pp.448-453
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    • 2012
  • There are many researches to develop robots that improve its mobility to adapt in various uneven environments. In the paper, a hybrid wheeled and legged mobile robot is designed and a obstacle avoidance algorithm is proposed based on low power walking using LRF(Laser Range Finder). In order to stabilize the robot's motion and reduce energy consumption, we implement a low-power walking algorithm through comparison of the current value of each motors and correction of posture balance. A low-power obstacle avoidance algorithm is proposed by using LRF sensor. We improve walking stability by distributing power consumption and reduce energy consumption by selecting a shortest navigation path of the robot. The proposed methods are verified through walking and navigation experiments with the developed hybrid robot.

A Comparative Study Wooden Stupa of Korea, Japan and China(I) - Focused on the Corner Bracket Set - (한.중.일 목조 불탑의 비교론적 고찰(I) - 귀공포를 중심으로 -)

  • Cheon, Deuk-Youm;Yang, Tae-Hyeon;Lee, Jae-Yeon
    • Journal of architectural history
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    • v.21 no.2
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    • pp.7-20
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    • 2012
  • As the corner of wooden pagoda forms the roof by closely bordering left and right eaves on the various purlins and angle rafters, it is designed for every face to be recognized as front whose structure system increases load to bear proportionally. The corner of wooden pagoda is inseparable with the corner bracket set as it becomes stable thanks to the corner bracket set structurally and load burden under restrained structure makes the corner bracket set really important. Accordingly, this study could figure out some facts by analyzing corner bracket sets of Palsangjeon of Beobjusa Temple in Korea, Seokgatap of Bulgungsa Temple in China and Ojungtap of Beobryungsa Temple in Japan which were constructed with pure wooden structure. This study demonstrated that corner bracket set played a pivotal role in keeping balance of concentrated load of corner (corner of opening) in each floor that contributed to the stability of wooden pagoda structurally despite multiple duplications of floors and also figured out the outfit of corner bracket set was subject to the floor type and the cross section of Gongpo installed on top of Pyeongju. Wooden pagodas in 3 countries were two floor types of octagon and square, and employed different connection method between upper and lower floors. The difference between floor and duplication method determines the method of corner, but even different methods were sufficient to have entirety in every side by completing dynamic principle of corner bracket set even though old method had to solve the problem of concentrated load and it also confirms that it was essential Gongpo to prevent any deformation of corner.

패들형 블레이드를 장착한 힌지없는 로터 시스템의 회전시험

  • Song, Keun-Woong;Kim, Joune-Ho;Kim, Deog-Kwan
    • Aerospace Engineering and Technology
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    • v.3 no.2
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    • pp.217-228
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    • 2004
  • This paper presents the rotating test techniques and the results of the roating test of the small-scaled hingeless rotor system with composite paddle blades in hover and forward flight conditions. The small-scaled rotor system was designed using froude-scaled properties of full scale rotor system. Metal flexures and composite flexures were made as hub flexures by the same dynamic properties of rotor system. The rotating tests of hingeless rotor system installed in GSRTS at KARI were carried out to get lead-lag damping ratios and aerodynamic loads of the hingeless rotor system. MBA(Moving Block Analysis) technique was used for the estimation of lead-lag damping ratio. 6-components balance was installed between hub and main shaft and straingauges on blades were instrumented for the measurements of aerodynamic loads of rotor system. Tests were performed on the ground and in the wind tunnel according to the test conditions of hover and forward flight, respectively.

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A Study on Expressive Features of Embroidered Norigae in the Chosun Dynasty (조선시대 수노리개에 나타난 표현 특성에 관한 연구)

  • Yang, Suk-Hyang
    • The Korean Journal of Community Living Science
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    • v.22 no.1
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    • pp.103-113
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    • 2011
  • The purpose of the study was to examine formative features of embroidered norigae in form, color, pattern and expressive technique through positive analysis of relics and various of collections of work and to consider expressive features of embroidered norigae. The results of the study were as follows. First, embroidered norigae has handcrafted decoration. it was made by being sewed for women longing for their family's happiness. Embroidered norigae is a dress worn by women that is hung on a coat string or the waist part of a skirt. Second, it is eco-environmental. Embroidered norigae applied things seen in nature such as flowers, butterflies and bees to its pattern. Third, it has practicality. Embroidered norigae has high practical value besides a decorative function. Needle case norigae and incense case norigae provide functions in accordance with women's wisdom and skill as well as practicality. Fourth, it is praying for good luck. Women embroidered patterns symbolizing their desires in life such as their family's happiness, wealth, many sons and a long life. Fifth, it has balance and harmony. The knot of embroidered norigae has a perfect symmetry in the front/back part and in the right/left part. And the main body and tassel are symetrical in the right/left part, which gives stability and comfortableness. Embroidered norigae is classified into knot, main body and decorative part in its form. The three kinds express their unique beauty by being harmonized together. Finally, it has a property of melody. Movement of the tassel has a property of melody shaken by the wind and movement of its wearer.

Identification of DC21 as a Novel Target Gene Counter-regulated by IL-12 and IL-4

  • Kong, Kyoung-Ah;Jang, Ji-Young;Lee, Choong-Eun
    • BMB Reports
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    • v.35 no.6
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    • pp.623-628
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    • 2002
  • The Th1 vs. Th2 balance is critical for the maintenance of immune homeostasis. Therefore, the genes that are selectively-regulated by the Th1 and Th2 cytokines are likely to play an important role in the Th1 and Th2 immune responses. In order to search for and identify the novel target genes that are differentially regulated by the Th1/Th2 cytokines, the human PBMC mRNAs differentially expressed upon the stimulation with IL-4 or IL-12, were screened by employing the differential display-polymerase chain reaction. Among a number of clones selected, DC21 was identified as a novel target gene that is regulated by IL-4 and IL-12. The DC21 gene expression was up-regulated either by IL-4 or IL-12, yet counter-regulated by co-treatment with IL-4 and IL-12. DC21 is a dendritic cell protein with an unknown function. The sequence analysis and conserved-domain search revealed that it has two AU-rich motifs in the 3'UTR, which is a target site for the regulation of mRNA stability by cytokines, and that it belongs to the N-acetyltransferase family. The induction of DC21 by IL-12 peaked around 8-12 h, and lasted until 24 h. LY294002 and SB203580 significantly suppressed the IL-12-induced DC21 gene expression, which implies that PI3K and p38/JNK are involved in the IL-12 signal transduction pathway that leads to the DC21 expression. Furthermore, tissue blot data indicated that DC21 is highly expressed in tissues with specialized-resident macrophages, such as the lung, liver, kidney, and placenta. Together, these data suggest a possible role for DC21 in the differentiation and maturation of dendritic cells regulated by IL-4 and IL-12.

Efficient Green Phosphorescent OLEDs with Hexaazatrinaphthylene Derivatives as a Hole Injection Layer (Hexaazatrinaphthylene 유도체를 정공 주입층으로 사용한 고효율 녹색 인광 OLEDs)

  • Lee, Jae-Hyun;Lee, Jonghee
    • Applied Chemistry for Engineering
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    • v.26 no.6
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    • pp.725-729
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    • 2015
  • Organic light emitting diodes (OLEDs) are regarded as the next generation display and solid-state lighting due to their superb achievements from extensive research efforts on improving the efficiency and stability of OLEDs in addition to developing new materials. Herein, efficient green phosphorescent OLEDs were obtained by using hexaazatrinaphthylene (HAT) derivatives as a hole injection layer. External quantum and current efficiencies of OLEDs were enhanced from 8.8% and 30.8 cd/A to 13.6% and 47.7 cd/A, respectively by inserting a thin layer of HAT derivatives between the ITO and hole transporting layer. The enhancement of OLEDs was found to be originated from the inserted HAT derivatives, which resulted in the optimized hole-electron balance inside the emission layer.

Real time remote management for home network system using bio-physical sensor (생체 센서 시스템을 이용한 실시간 원격 홈 네트워크 시스템)

  • Kim, Jeong-Lae
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.1
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    • pp.117-124
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    • 2011
  • This study was realized the home network system for home care by bio-physical sensor system, to convey for the remote physical signal. The composition condition has four functions of displacement point for a Vision, Somatosensory, Vestibular and CNS that the basic measurement used to a Heart Rate, Temperature, Weight. Physical signal are decided to search a max and min point with adjustment of 0.01 unit in the reference level. There were checked physical condition of body balance to compounded a physical neuroceptor of sensory organ for the measurement such as a Vision, Somatosensory, Vestibular, CNS, BMI. There are to check a health care condition through a combination of physical organ with a posturography of a exercise. The service of home network system can be used to support health care management system through health assistants in health care center and central health care system. It was expected to monitor a physical parameter for the remote control health management system.

Comparison of Core Muscle Activity and Thickness According to Walking Training Method (워킹 훈련방법에 따른 복부 중심근육 활성도와 근 두께 변화 비교)

  • Lee, H.J.;Kim, Y.T.;Lee, S.J.;Kim, M.S.;Kim, S.H.;Tae, K.S.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.9 no.4
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    • pp.301-308
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    • 2015
  • The purpose of this study was to compare core muscle activity and thickness in the abdomen (internal Oblique, IO; External Oblique, EO; Transverse Abdominis, TrA) according to walking training methods. Tests were performed on 20 healthy men who randomly assigned to two groups, divided by Nordic walking (n=10) or Power walking group (n=10). They were performed Nordic walking or Power walking training for 2 weeks that is consistent with each of the assigned groups. Results demonstrated that Nordic walking was more effective than Power walking in improving IO and EO activities. Nordic walking is believed to be useful method for a variety of therapeutic exercise as a stable balance with the stick in addition to normal gait and trunk stability.

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Study on the Design and Analysis of a 4-DOF Robot for Trunk Rehabilitation (체간 재활을 위한 4-DOF 로봇의 설계 및 분석에 관한 연구)

  • Eizad, Amre;Pyo, Sanghun;Lee, Geonhyup;Lyu, Sung-Ki;Yoon, Jungwon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.7
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    • pp.41-51
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    • 2020
  • This paper presents the development of a robotic system for rehabilitation of the trunk's ability to maintain postural control under different balance conditions. The system, developed with extensive input from rehabilitation and biomedical engineering experts, consists of a seat mounted on a robotic mechanism capable of moving it with four degrees of freedom (3 rotational and 1 translational). The seat surface has built in instrumentation to gauge the movements of the user's center of pressure (COP) and it can be moved either to track the movements of the COP or according to operator given commands. The system allows two types of leg support. A ground mounted footrest allows participation of legs in postural control while a seat connected footrest constrains the leg movement and limits their involvement in postural control. The design evolution over several prototypes is presented and computer aided structural analysis is used to determine the feasibility of the designed components. The system is pilot tested by a stroke patient and is determined to have potential for use as a trunk rehabilitation tool. Future works involve more detailed studies to evaluate the effects of using this system and to determine its efficacy as a rehabilitation tool.

Comparison of Stress and Physiological Variables between Diabetic and Nondiabetic Adults

  • Han, Byung-Jo;Choi, Seok-Cheol;Moon, Seong-Min;Kim, Dae-Sik;Hyun, Kyung-Yae
    • Biomedical Science Letters
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    • v.18 no.4
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    • pp.384-390
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    • 2012
  • Diabetes mellitus (DM) is considered to be a serious metabolic disease which may cause systemic complications. The present study was designed to clarify a difference on stress, physiological variables and their correlation between diabetic (DM group) and nondiabetic adults (control group). The levels of body weight, waist circumference, blood pressure, body mass index, body fat mass, total cholesterol (TcH), triglyceride (TG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), total bilirubin (TB), autonomic balance (AB), stress index (SI), fatigue index (FI), and heart rate (HR) were all significantly higher in the DM group than in the control group. However, the levels of autonomic activity (AA), stress resistance (SR), and electrocardiac stability (ES) were significantly lower in the DM group than in the control group. The percentages of persons with abnormal levels in the Tch, high density lipoprotein, low density lipoprotein, TG, AST, ALT and GGT were significantly greater in the DM group than in the control group. In the correlation of glucose and hemoglobin A1c (HBA1c) to stress indices, the DM group had a significant relationship with AB, SR, SI, FI, ES, and HR, whereas the control group had no significant relationship with these, excepting AB. These results suggest that DM was harmfully associated with body, biochemical and stress indices and that blood glucose and HBA1c levels must be exhaustively regulated.