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1,620 results on '"Lee, Y.-K."'

2. Monte Carlo calculation of organ and effective dose rates from ground contaminated by Am 241: Results of an international intercomparison exercise

Author

Eakins, J, Huet, C, Brkić, H, Capello, K, Desorgher, L, Epstein, L, Hunt, J G, Kim, H S, Krstic, D, Lee, Y-K, Manohari, M, Nikezic, D, Shukrun, R H, Souza-Santos, D., and Tymińska, K.

Subjects
Physics - Medical Physics
Abstract

An intercomparison exercise is described that examines Monte Carlo modelling of anthropomorphic voxel phantoms in an idealized ground-contamination photon exposure scenario. Thirteen participants calculated and submitted organ and effective dose rates for comparison against a set of verified reference solutions. The effective dose rates are shown to agree with the reference value to within reasonable statistical uncertainties in five of the cases, though in only one of those was similar agreement also demonstrated in the evaluation of all requested organ dose rates. Orders-of-magnitude differences in doses are seen for some of the other participants, both internally within their own dataset and also relative to the reference solutions. Following limited feedback and suggestions from the organizer, up to two sets of revised solutions were resubmitted by some of the participants; these generally exhibited improved agreement, though not always. The overall observations and conclusions from this intercomparison exercise are summarized and discussed., Comment: 19 pages, 7 figures, 3 tables

Published
2021
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3. Advanced Satellite-based Frequency Transfer at the 10^{-16} Level

Author

Fujieda, M., Yang, S-H., Gotoh, T., Hwang, S-W., Hachisu, H., Kim, H., Lee, Y. K., Tabuchi, R., Ido, T., Lee, W-K., Heo, M-S., Park, C. Y., Yu, D-H., and Petit, G.

Subjects
Electrical Engineering and Systems Science - Signal Processing, Physics - Atomic Physics
Abstract

Advanced satellite-based frequency transfers by TWCP and IPPP have been performed between NICT and KRISS. We confirm that the disagreement between them is less than 1x10^{-16} at an averaging time of several days. Additionally, an intercontinental frequency ratio measurement of Sr and Yb optical lattice clocks was directly performed by TWCP. We achieved an uncertainty at the mid-10^{-16} level after a total measurement time of 12 hours. The frequency ratio was consistent with the recently reported values within the uncertainty., Comment: 9 pages, 5 figures

Published
2017

10. $L_2$ boosting in kernel regression

Author

Park, B. U., Lee, Y. K., and Ha, S.

Subjects
Mathematics - Statistics Theory
Abstract

In this paper, we investigate the theoretical and empirical properties of $L_2$ boosting with kernel regression estimates as weak learners. We show that each step of $L_2$ boosting reduces the bias of the estimate by two orders of magnitude, while it does not deteriorate the order of the variance. We illustrate the theoretical findings by some simulated examples. Also, we demonstrate that $L_2$ boosting is superior to the use of higher-order kernels, which is a well-known method of reducing the bias of the kernel estimate., Comment: Published in at http://dx.doi.org/10.3150/08-BEJ160 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm)

Published
2009
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11. Rapidity dependence of high p_T suppression at sqrt{s_{NN}}=62.4{GeV}

Author

Arsene, I., Bearden, I. G., Beavis, D., Besliu, C., Budick, B., Bøggild, H., Chasman, C., Christensen, C. H., Christiansen, P., Cibor, J., Debbe, R., Enger, E., Gaardhøje, J. J., Hagel, K., Ito, H., Jipa, A., Jundt, F., Johnson, E. B., Jørdre, J. I., Jørgensen, C. E., Karabowicz, R., Kim, E. J., Kozik, T., Larsen, T. M., Lee, J. H., Lee, Y. K., Lindal, S., Lystad, R., Løvhøiden, G., Majka, Z., Mikelsen, M., Murray, M., Natowitz, J., Neumann, B., Nielsen, B. S., Ouerdane, D., Płaneta, R., Ramiıres, F., Ristea, C., Ristea, O., Röhrich, D., Samset, B. H., Sandberg, D., Sanders, S. J., Scheetz, R. A., Staszel, P., Tveter, T. S., Videbæk, F., Wada, R., Yin, Z., Yang, H., and Zgura, I. S.

Subjects
Nuclear Experiment
Abstract

We present measurements of charged hadron p_T spectra from Au+Au collisions at sqrt(snn)=62.4 GeV for pseudorapidities eta=0, eta=1 and eta=3.2. Around midrapidity (eta=0, eta=1) we find nuclear modification factors at levels suggesting a smaller degree of high p_T suppression than in the same reaction at higher energy sqrt(snn)=200 GeV. At the high pseudorapidity, eta=3.2, where nuclear modification factors cannot be constructed due to the lack of p+p reference data, we find a significant reduction of R_{CP} (central to peripheral ratio) as compared to midrapidity.

Published
2006

16. Design and analysis of super twisting sliding mode-PID controller for two-wheeled self-balancing robot.

Author

Chiew, T. H., Lee, Y. K., Chang, K. M., Ong, J. J., and Goh, Y. H.

Subjects
*ROBOTS, *MOBILE robots, *TRANSFER functions, *MATHEMATICAL models
Abstract

Two-wheeled self-balancing robot is one of the popular applications of the inverted pendulum concept which is unstable in nature with highly nonlinear properties. This paper presents a novel control algorithm to reduce the settling time and disturbance rejection property of the balancing robot. A mathematical model of the two-wheeled self-balancing robot was utilized as the transfer function from motor input voltage to tilt angle of the robot. Three control algorithms were designed, namely; classical proportional-integral-derivative controller, super twisting sliding mode controller, and the proposed control algorithm, a combination of both proportional-integral-derivative controller and super twisting sliding mode controller. A sinusoidal signal with zero magnitude was used as a reference input signal while an impulse signal with a magnitude of five volts was applied as a disturbance signal to the robot. The output signal, that is, the tilt angle of the robot was recorded. The control performances of the designed control algorithms based on recorded output signals were compared in terms of settling time, maximum overshoot, steady-state error, and disturbance rejection property. The comparison simulation results showed that the proposed control algorithm has good disturbance rejection property and able to improve 55.4% in settling time without overshoot and steady-state error. [ABSTRACT FROM AUTHOR]

Published
2023
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28. A Self Evolutionary Rule-Base

Author

Khattak, A. M., Pervez, Z., Khan, W. A., Lee, S. Y., Lee, Y. K., Kim, Tai-hoon, editor, Adeli, Hojjat, editor, Ma, Jianhua, editor, Fang, Wai-chi, editor, Kang, Byeong-Ho, editor, Park, Byungjoo, editor, Sandnes, Frode Eika, editor, and Lee, Kun Chang, editor

Published
2011
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44. Five decades of terrestrial and freshwater research at Ny-Ålesund, Svalbard

Author

Pedersen, Å. Ø., Convey, P., Newsham, K. K., Mosbacher, J. B., Fuglei, E., Ravolainen, V., Hansen, B. B., Jensen, T. C., Augusti, A., Biersma, E. M., Cooper, E. J., Coulson, S. J., Gabrielsen, G. W., Gallet, J. C., Karsten, U., Kristiansen, S. M., Svenning, M. M., Tveit, A. T., Uchida, M., Baneschi, I., Calizza, E., Cannone, N., de Goede, E. M., Doveri, M., Elster, J., Giamberini, M. S., Hayashi, K., Lang, S. I., Lee, Y. K., Nakatsubo, T., Pasquali, V., Paulsen, I. M.G., Pedersen, C., Peng, F., Provenzale, A., Pushkareva, E., Sandström, C. A.M., Sklet, V., Stach, A., Tojo, M., Tytgat, B., Tømmervik, H., Velazquez, D., Verleyen, E., Welker, J. M., Yao, Y.-F., Loonen, M. J. J. E., Pedersen, Å. Ø., Convey, P., Newsham, K. K., Mosbacher, J. B., Fuglei, E., Ravolainen, V., Hansen, B. B., Jensen, T. C., Augusti, A., Biersma, E. M., Cooper, E. J., Coulson, S. J., Gabrielsen, G. W., Gallet, J. C., Karsten, U., Kristiansen, S. M., Svenning, M. M., Tveit, A. T., Uchida, M., Baneschi, I., Calizza, E., Cannone, N., de Goede, E. M., Doveri, M., Elster, J., Giamberini, M. S., Hayashi, K., Lang, S. I., Lee, Y. K., Nakatsubo, T., Pasquali, V., Paulsen, I. M.G., Pedersen, C., Peng, F., Provenzale, A., Pushkareva, E., Sandström, C. A.M., Sklet, V., Stach, A., Tojo, M., Tytgat, B., Tømmervik, H., Velazquez, D., Verleyen, E., Welker, J. M., Yao, Y.-F., and Loonen, M. J. J. E.

Abstract

For more than five decades, research has been conducted at Ny-Ålesund, in Svalbard, Norway, to understand the structure and functioning of High-Arctic ecosystems and the profound impacts on them of environmental change. Terrestrial, freshwater, glacial and marine ecosystems are accessible year-round.

Published
2022

48. Monte Carlo calculation of organ and effective doses due to photon and neutron point sources and typical X-ray examinations: Results of an international intercomparison exercise

Author

Huet, Christelle, Eakins, Jonathan, Zankl, Maria, Gomez-Ros, Jose-Maria, Jansen, Jan, Moraleda, Montse, Struelens, Lara, Akar, Deepak, Borbinha, Jorge, Brkic, Hrvoje, Bui, Duc Ky, Capello, Kevin, Dang, Thi My Linh, Desorgher, Laurent, Di Maria, Salvatore, Epstein, Lior, Faj, Dario, Fantinova, Karin, Ferrari, Paolo, Gossio, Sebastian, Hunt, John, Jovanovic, Zoran, Kim, Han Sung, Krstic, Dragana, Le, Ngoc Thiem, Lee, Y. K., Murugan, Manohari, Nadar, Minal, Nguyen, Ngoc-Quynh, Nikezic, Dragoslav, Patni, Hemant, Souza Santos, Denison, Tremblay, Marilyn, Trivino, Sebastian, Tymińska, Katarzyna, Laboratoire de dosimétrie des rayonnements ionisants (IRSN/PSE-SANTE/SDOS/LDRI), Service de dosimétrie (IRSN/PSE-SANTE/SDOS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Public Health England - Centre for Radiation, Chemical and Environmental Hazards (PHE-CRCE), Helmholtz Zentrum München (HMGU), Centro de Investigaciones Energéticas Medioambientales y Tecnológicas [Madrid] (CIEMAT), Centre for Radiation, Chemical and Environmental Hazards (CRCE) (PHE), BNRC, Centre d'étude de l'énergie nucléaire (SCK*CEN), Bhabha Atomic Research Centre, Centro de Ciências e Tecnologias Nucleares, Faculty of Medicine, Institute for Nuclear Science and Technology, Health Canada, Institute of Radiation Physics, Centro de Ciências e Tecnologias Nucleares (C2TN), Soreq Nuclear Research Center, SURO (National Radiation Protection Institute), ENEA, Autoridad Regulatoria Nuclear, Instituto de Radioproteção e Dosimetria, University of Kragujevac, Korea Institute of Radiological and Medical Sciences, SERMA/LEPP, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Indira Gandhi Centre for Atomic Research, Bhabha Atomic Research Centre (BARC), Government of India, Department of Atomic Energy, CNEA, Comisión Nacional de Energía Atómica, and National Centre for Nuclear Research

Subjects
[PHYS]Physics [physics], Monte Carlo, ICRP reference phantom, Organ absorbed dose
Abstract

International audience; This paper summarizes the results of an intercomparison on the use of the ICRP Reference Computational Phantoms with radiation transport codes, which was organized by EURADOS working group 6. Three exercises are described: exposure to an anterior-posterior (AP) photon point source, exposure to an AP neutron point source, and exposure to two typical medical X-ray examinations. The three exercises received 17, 8 and 8 solutions, respectively. Participants originated from fifteen different countries, and used a wide range of Monte Carlo codes. Due to difficulties in defining the precise source location unambiguously in the exercise description, agreement to within ~10 % of the reference solution was considered satisfactory for a given participant’s results. Although some participants provided initial solutions in good agreement with the reference solutions, differences of several tens of percent, or even several orders of magnitude, were exhibited for many of the others. Following feedback and suggestions from the organizers, revised solutions were submitted by some of the participants for the photon exercises; in general, agreement was improved. The overall observations from these three intercomparison exercises are summarized and discussed.

Published
2022

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