• Title/Summary/Keyword: Clock distribution

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Obstacle Avoidance Algorithm for a Network-based Autonomous Mobile Robot

  • Sohn, Sook-Yung;Kim, Hong-Ryeol;Kim, Dae-Won;Kim, Hong-Seok;Lee, Ho-Gil
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.831-833
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    • 2004
  • In this paper, an obstacle avoidance algorithm is proposed for a network-based robot considering network delay by distribution. The proposed algorithm is based on the VFH(Vector Field Histogram) algorithm, and for the network-based robot system, in which it is assumed robot localization information is transmitted through network communication. In this paper, target vector for the VFH algorithm is estimated through the robot localization information and the measurement of its delay by distribution. The delay measurement is performed by time-stamp method. To synchronize all local clocks of the nodes distributed on the network, a global clock synchronization method is adopted. With the delay measurement, the robot localization estimation is performed by calculating the kinematics of the robot. The validation of the proposed algorithm is performed through the performance comparison of the obstacle avoidance between the proposed algorithm and the existing VFH algorithm on the network-based autonomous mobile robot.

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The clinical research of dementia assessment examination-focused on the diagnosis of dementia for patient of Cheongju district. (치매평가검진 환자에 관한 임상연구 (청주 지역사회 환자의 치매진단을 중심으로))

  • Jung, In-Chul
    • Journal of Haehwa Medicine
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    • v.15 no.1
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    • pp.1-9
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    • 2006
  • For this study, we carried out dementia assessment examination of 74 patients with memory disturbance who have come to Cheongju oriental hospital of Daejeon university from April 2005 to February 2006. This study classified the patients as none-dementia(ND), questionable dementia(QD), and dementia(DA) groups and analyzed the result of examination. As a result, the following conclusion was drawn. 1. Among the 3 groups, there was no significant differences in the sex distribution. But according to age distribution, the age of QD and DA groups showed significant difference from that of ND group. 2. MMSE-K and HDS-K scores showed the significant differences among all groups, and 7 MS result showed the significant difference between ND and the other groups. 3. The DA group significantly got lower scores than ND group in the items of the MMSE-K, Orientation, Registration, Recall, Attention, Copy two pentagons and Comprehension. Especially, significant difference also was shown in the orientation item between QD and DA groups. 4. The scores in the items of 7 MS, Benton temporal orientation, Enhanced cued recall and Clock drawing showed significant difference among all groups. Category fluency score showed significant difference between ND and the other groups. 5. The results of Brain CT and clinical chemistry test didn't show significant difference among all groups.

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Obstacle Avoidance Algorithm Development for Network-Based Autonomous Mobile Robots (네트워크 기반 자율이동로봇의 장애물 회피 알고리즘 개발)

  • Sohn, Soo-Kyung;Kim, Joo-Min;Kim, Hong-Ryeol;Kim, Dae-Won;Yang, Kwang-Woong
    • Proceedings of the KIEE Conference
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    • 2004.07d
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    • pp.2435-2437
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    • 2004
  • In this paper, an obstacle avoidance algorithm is proposed for a network-based robot considering network delay by distribution. The proposed algorithm is based on the VFH(Vector Field Histogram) algorithm, and for the network-based robot system, in which it is assumed robot localization information is transmitted through network communication. In this paper, target vector for the VFH algorithm is estimated through the robot localization information and the measurement of its delay by distribution. The delay measurement is performed by time-stamp method. To synchronize all local clocks of the nodes distributed on the network, a global clock synchronization method is adopted. With the delay measurement, the robot localization estimation is performed by calculating the kinematics of the robot. The validation of the proposed algorithm is performed through the performance comparison of the obstacle avoidance between the proposed algorithm and the existing VFH algorithm on the network-based autonomous mobile robot.

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A New Fast Algorithm for Short Range Force Calculation (근거리 힘 계산의 새로운 고속화 방법)

  • Lee, Sang-Hwan;Ahn, Cheol-O
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.383-386
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    • 2006
  • In this study, we propose a new fast algorithm for calculating short range forces in molecular dynamics, This algorithm uses a new hierarchical tree data structure which has a high adaptiveness to the particle distribution. It can divide a parent cell into k daughter cells and the tree structure is independent of the coordinate system and particle distribution. We investigated the characteristics and the performance of the tree structure according to k. For parallel computation, we used orthogonal recursive bisection method for domain decomposition to distribute particles to each processor, and the numerical experiments were performed on a 32-node Linux cluster. We compared the performance of the oct-tree and developed new algorithm according to the particle distributions, problem sizes and the number of processors. The comparison was performed sing tree-independent method and the results are independent of computing platform, parallelization, or programming language. It was found that the new algorithm can reduce computing cost for a large problem which has a short search range compared to the computational domain. But there are only small differences in wall-clock time because the proposed algorithm requires much time to construct tree structure than the oct-tree and he performance gain is small compared to the time for single time step calculation.

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Deep Brain Photoreceptors and Photoperiodism in Vertebrates

  • Oishi, Tadashi;Haida, Yuka;Okano, Keiko;Yoshikawa, Tomoko;Kawano, Emi;Nagai, Kiyoko;Fukada, Yoshitaka;Tsutsui, Kazuyoshi;Tamotsu, Satoshi
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.5-8
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    • 2002
  • Photoperiodism is an important adaptive phenomenon in various physiological parameters including reproduction to cope with seasonal changes. Involvement of extraretinal photoreceptors in the photoperiodism in non-mammalian vertebrates has been well established. In addition, circadian clock system is known to be involved in the photoperiodic time measurement. The pathway consists of light-input system, time measurement system (circadian clock), gonadotropin releasing hormone (GnRH) production in the hypothalamus, luteinizing hormone (LH) and follicle stimulating hormone (FSH) production in the pituitary, and final gonadal development. Recently, several laboratories reported photopigments newly cloned in the pineal, eyes and deep brain in addition to already known visual pigments in the retina. These are pinopsin, parapinopsin, VA-opsin, melanopsin, etc. All these photopigments belong to the opsin family having retinal as the chromophore. However, the function of these photopigments remains unknown. I reviewed the studies on the location of the photopigments by immunocytochemistry. I also discussed the results on the action spectra for induction of gonadal development in relation with the location of the photoreceptors. Various physiologically active substances distribute in the vertebrate brain. Such substances are GnRH, GnIH, neuropeptide Y, vasoactive intestinal peptide, c-Fos, galanin, neurosteroids, etc. I summarized the immunhistochemical studies on the distribution and the photoperiodic changes of these substances and discussed the route from the deep brain photoreceptor to GnRH cells.

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Improved the Noise Immunity of Phase-Locked Loop

  • Intachot, Terdsak;Panaudomsup, Sumit;Prempraneerach, Yothin
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1643-1647
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    • 2003
  • This paper, we propose a new high noise immunity phase-locked loop(PLL) which can suppress the high incident noise coupling with large amplitude and long period to the input frequency of PLL and keeps constant frequency and phase of the VCO output for providing the high stability distribution clock pulse.

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On-chip Decoupling Capacitor for Power Integrity (전력 무결성을 위한 온 칩 디커플링 커패시터)

  • Cho, Seungbum;Kim, Sarah Eunkyung
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.3
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    • pp.1-6
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    • 2017
  • As the performance and density of IC devices increase, especially the clock frequency increases, power grid network integrity problems become more challenging. To resolve these power integrity problems, the use of passive devices such as resistor, inductor, and capacitor is very important. To manage the power integrity with little noise or ripple, decoupling capacitors are essential in electronic packaging. The decoupling capacitors are classified into voltage regulator capacitor, board capacitor, package capacitor, and on-chip capacitor. For next generation packaging technologies such as 3D packaging or wafer level packaging on-chip MIM decoupling capacitor is the key element for power distribution and delivery management. This paper reviews the use and necessity of on-chip decoupling capacitor.

The Study on Distribution Clock Synchronization of EtherCAT Communication System (이더캣 통신시스템에서 분산 클럭 동기화에 관한 연구)

  • Moon, Yongseomn;Vo, Trong Tuan Anh;Lee, Youngpil;Cha, Hyunrok
    • The Journal of the Korea institute of electronic communication sciences
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    • v.4 no.4
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    • pp.293-300
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    • 2009
  • In this paper, we describe a method for synchronization protocol method used in control system based on network and IEEE 1599 synchronization method which used for implementation of synchronization technology of advanced industrial Ethernet. We also implement and perform the experiment for synchronization technology of EtherCAT communication which is one of the industrial Ethernet technology used IEEE 1599 synchronization technology based on time. And we describe an evaluation for experiment result, improve the problem and future plan.

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Design and Implementation of Xcent-Net

  • Park, Kyoung;Hahn, Jong-Seok;Sim, Won-Sae;Hahn, Woo-Jong
    • Journal of Electrical Engineering and information Science
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    • v.2 no.6
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    • pp.74-81
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    • 1997
  • Xcent-Net is a new system network designed to support a clustered SMP called SPAX(Scalable Parallel Architecture based on Xbar) that is being developed by ETRI. It is a duplicated hierarchical crossbar network to provide the connections among 16 clusters of 128 nodes. Xcent-Net is designed as a packet switched, virtual cut-through routed, point-to-point network. Variable length packets contain up to 64 bytes of data. The packets are transmitted via full duplexed, 32-bit wide channels using source synchronous transmission technique. Its plesiochronous clocking scheme eliminates the global clock distribution problem. Two level priority-based round-robin scheme is adopted to resolve the traffic congestion. Clear-to-send mechanism is used as a packet level flow control scheme. Most of functions are built in Xcent router, which is implemented as an ASIC. This paper describes the architecture and the functional features of Xcent-Net and discusses its implementation.

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Developmental Characteristics and Spatial Distribution of Mango Shield Scale, Protopulvinaria mangiferae (Green) (Homoptera : Coccidae) on Elaeocarpus sylvestris (Lour.) (담팔수깍지벌레의 충태별(蟲態別) 생육(生育) 특성(特性)과 수상분포양식(樹上分布樣式))

  • Kim, Jong-Kuk
    • Journal of Forest and Environmental Science
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    • v.11 no.1
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    • pp.40-49
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    • 1995
  • This study was carried out to investigated the developmental characteristics and spatial distribution of mango shield scale, Protopulvinaria mangiferae injuring to Elaeocarpus sylvestris(Lour.) This mango shield scale is parthenogentic. The oviparous female have three larval stages and adult. This species has two generation a year. The crawlers of the 1st generation emerged from late may to middle July, and those of the 2nd generation from early August to early October. Their emergence reached its peak in early part of the occurrence period. The crawlers disperse from 10 to 14 o'clock from ventral side of the adult and more than 90% had settled with in 8 hours on the leaves of E. sylvestris. The larvae and adults were distributed contagiously between trees. The adult densities were higher in the lower part of the crown than those in the middle or upper parts. But differents in densities were not significant among four directions. The distribution of the adult scales per leaf cluster showed an aggregation with a slightly colonized pattern.

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