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Volumn 36, Issue 5, 2010, Pages 1325-1332

Temporal frequency modulates reaction time responses to first-order and second-order motion

Author keywords

First order motion; Modulation depth; Reaction time; Second order motion; Temporal frequency

Indexed keywords

ARTICLE; ATTENTION; CONTRAST SENSITIVITY; DECISION MAKING; FEMALE; HUMAN; MALE; MOVEMENT PERCEPTION; ORIENTATION; PATTERN RECOGNITION; PERCEPTIVE DISCRIMINATION; PSYCHOPHYSICS; REACTION TIME;

EID: 77957375143     PISSN: 00961523     EISSN: None     Source Type: Journal    
DOI: 10.1037/a0019250     Document Type: Article
Times cited : (3)

References (60)
  • 1
    • 40149084810 scopus 로고    scopus 로고
    • First- and second-order motion mechanisms are distinct at low but common at high temporal frequencies
    • doi: 10.1167/8.2.12
    • Allard R., Faubert J. First- and second-order motion mechanisms are distinct at low but common at high temporal frequencies. Journal of Vision 2006, 8:1-17. doi: 10.1167/8.2.12.
    • (2006) Journal of Vision , vol.8 , pp. 1-17
    • Allard, R.1    Faubert, J.2
  • 2
    • 0022364212 scopus 로고
    • Spatial and temporal selectivity of the human motion detection system
    • Anderson S.J., Burr D.C. Spatial and temporal selectivity of the human motion detection system. Vision Research 1985, 25:1147-1154.
    • (1985) Vision Research , vol.25 , pp. 1147-1154
    • Anderson, S.J.1    Burr, D.C.2
  • 3
    • 0033178809 scopus 로고    scopus 로고
    • Central neural mechanisms for detecting second-order motion
    • Baker C.L. Central neural mechanisms for detecting second-order motion. Current Opinion in Neurobiology 1999, 9:461-466.
    • (1999) Current Opinion in Neurobiology , vol.9 , pp. 461-466
    • Baker, C.L.1
  • 4
    • 0016231987 scopus 로고
    • The electrical response of turtle cones to flashes and steps of light
    • Baylor D.A., Hodgkin A.L., Lamb T.D. The electrical response of turtle cones to flashes and steps of light. Journal of Physiology 1974, 242:685-727.
    • (1974) Journal of Physiology , vol.242 , pp. 685-727
    • Baylor, D.A.1    Hodgkin, A.L.2    Lamb, T.D.3
  • 5
    • 0020001036 scopus 로고
    • Response latency of brisk-sustained (X) and brisk-sustained (Y) cells in the cat retina
    • Bolz J., Rosner G., Wassle H. Response latency of brisk-sustained (X) and brisk-sustained (Y) cells in the cat retina. Journal of Physiology 1982, 328:171-190.
    • (1982) Journal of Physiology , vol.328 , pp. 171-190
    • Bolz, J.1    Rosner, G.2    Wassle, H.3
  • 6
    • 0031689327 scopus 로고    scopus 로고
    • Reaction time to motion onset of luminance and chromatic gratings is determined by perceived speed
    • Burr D.C., Fiorentini A., Morrone M.C. Reaction time to motion onset of luminance and chromatic gratings is determined by perceived speed. Vision Research 1998, 38:3681-3690.
    • (1998) Vision Research , vol.38 , pp. 3681-3690
    • Burr, D.C.1    Fiorentini, A.2    Morrone, M.C.3
  • 7
    • 0030780094 scopus 로고    scopus 로고
    • Linearity and normalization in simple cells in macaque primary visual cortex
    • Carandini M., Heeger D.J., Movshon J.A. Linearity and normalization in simple cells in macaque primary visual cortex. Journal of Neuroscience 1997, 17:8621-8644.
    • (1997) Journal of Neuroscience , vol.17 , pp. 8621-8644
    • Carandini, M.1    Heeger, D.J.2    Movshon, J.A.3
  • 8
    • 0024893590 scopus 로고
    • Motion: The long and short of it
    • Cavanagh P., Mather G. Motion: The long and short of it. Spatial Vision 1989, 4:103-129.
    • (1989) Spatial Vision , vol.4 , pp. 103-129
    • Cavanagh, P.1    Mather, G.2
  • 9
    • 0024117651 scopus 로고
    • Drift-balanced random stimuli: A general basis for studying non-Fourier motion perception
    • Chubb C., Sperling G. Drift-balanced random stimuli: A general basis for studying non-Fourier motion perception. Journal of the Optical Society of America A 1988, 5:1986-2007.
    • (1988) Journal of the Optical Society of America A , vol.5 , pp. 1986-2007
    • Chubb, C.1    Sperling, G.2
  • 12
    • 0027290796 scopus 로고
    • Discriminating the direction of second-order motion at short stimulus durations
    • Derrington A.M., Badcock D., Henning B. Discriminating the direction of second-order motion at short stimulus durations. Vision Research 1993, 33:1785-1794.
    • (1993) Vision Research , vol.33 , pp. 1785-1794
    • Derrington, A.M.1    Badcock, D.2    Henning, B.3
  • 14
    • 0023203123 scopus 로고
    • Simple reaction time to sinusoidal grating and perceptual integration time: Contributions of perceptual and response processes
    • Ejima Y., Ohtami Y. Simple reaction time to sinusoidal grating and perceptual integration time: Contributions of perceptual and response processes. Vision Research 1987, 27:269-276.
    • (1987) Vision Research , vol.27 , pp. 269-276
    • Ejima, Y.1    Ohtami, Y.2
  • 15
    • 0037371596 scopus 로고    scopus 로고
    • Longer VEP latencies and slower reaction times to the onset of second-order motion than to the onset of first-order motion
    • Ellemberg D., Lavoie K., Lewis T.L., Maurer D., Lepore F., Guillemot J.-P. Longer VEP latencies and slower reaction times to the onset of second-order motion than to the onset of first-order motion. Vision Research 2003, 43:651-658.
    • (2003) Vision Research , vol.43 , pp. 651-658
    • Ellemberg, D.1    Lavoie, K.2    Lewis, T.L.3    Maurer, D.4    Lepore, F.5    Guillemot, J.-P.6
  • 16
    • 0029869681 scopus 로고    scopus 로고
    • Perceived velocity of luminance, chromatic and non-Fourier stimuli: Influence of contrast and temporal frequency
    • Gegenfurtner K.R., Hawken M.J. Perceived velocity of luminance, chromatic and non-Fourier stimuli: Influence of contrast and temporal frequency. Vision Research 1996, 36:1281-1290.
    • (1996) Vision Research , vol.36 , pp. 1281-1290
    • Gegenfurtner, K.R.1    Hawken, M.J.2
  • 17
    • 0031855360 scopus 로고    scopus 로고
    • Second-order motions contribute to vection
    • Gurnsey R., Fleet D., Potechin C. Second-order motions contribute to vection. Vision Research 1998, 38:2801-2816.
    • (1998) Vision Research , vol.38 , pp. 2801-2816
    • Gurnsey, R.1    Fleet, D.2    Potechin, C.3
  • 18
    • 0026515756 scopus 로고
    • Two temporal channels of three? A re-evaluation
    • Hammett S.T., Smith A.T. Two temporal channels of three? A re-evaluation. Vision Research 1992, 32:285-291.
    • (1992) Vision Research , vol.32 , pp. 285-291
    • Hammett, S.T.1    Smith, A.T.2
  • 19
    • 0018174683 scopus 로고
    • Reaction time as a function of suprathreshold grating detection
    • Harwerth R.S., Levi D.M. Reaction time as a function of suprathreshold grating detection. Vision Research 1978, 18:1579-1586.
    • (1978) Vision Research , vol.18 , pp. 1579-1586
    • Harwerth, R.S.1    Levi, D.M.2
  • 20
    • 0026798825 scopus 로고
    • Temporal properties of human visual filters: Numbers, shapes and spatial covariation
    • Hess R.F., Snowden R.J. Temporal properties of human visual filters: Numbers, shapes and spatial covariation. Vision Research 1992, 32:47-59.
    • (1992) Vision Research , vol.32 , pp. 47-59
    • Hess, R.F.1    Snowden, R.J.2
  • 21
    • 0026786292 scopus 로고
    • The relation between velocity of visual motion and reaction time to motion onset and offset
    • Hohnsbein J., Mateeff S. The relation between velocity of visual motion and reaction time to motion onset and offset. Vision Research 1992, 32:1789-1791.
    • (1992) Vision Research , vol.32 , pp. 1789-1791
    • Hohnsbein, J.1    Mateeff, S.2
  • 22
    • 29144503987 scopus 로고    scopus 로고
    • Sensitivity to spatial and temporal modulations of first-order and second-order motion
    • Hutchinson C.V., Ledgeway T. Sensitivity to spatial and temporal modulations of first-order and second-order motion. Vision Research 2006, 46:324-335.
    • (2006) Vision Research , vol.46 , pp. 324-335
    • Hutchinson, C.V.1    Ledgeway, T.2
  • 23
    • 3042529776 scopus 로고    scopus 로고
    • First- and second-order information in natural images: A filter-based approach to image statistics
    • Johnson A.P., Baker C.L. First- and second-order information in natural images: A filter-based approach to image statistics. Journal of the Optical Society of America A 2004, 21:913-925.
    • (2004) Journal of the Optical Society of America A , vol.21 , pp. 913-925
    • Johnson, A.P.1    Baker, C.L.2
  • 24
    • 0015852090 scopus 로고
    • Psychophysical evidence for sustained and transient detectors in the human vision
    • Kulikowski J.J., Tolhurst D.J. Psychophysical evidence for sustained and transient detectors in the human vision. Journal of Physiology 1973, 232:149-162.
    • (1973) Journal of Physiology , vol.232 , pp. 149-162
    • Kulikowski, J.J.1    Tolhurst, D.J.2
  • 25
    • 0036065430 scopus 로고    scopus 로고
    • Failure of direction-identification for briefly presented second-order motion stimuli: Evidence for weak direction-selectivity of the mechanisms encoding motion
    • Ledgeway T., Hess R.F. Failure of direction-identification for briefly presented second-order motion stimuli: Evidence for weak direction-selectivity of the mechanisms encoding motion. Vision Research 2002, 42:1739-1758.
    • (2002) Vision Research , vol.42 , pp. 1739-1758
    • Ledgeway, T.1    Hess, R.F.2
  • 26
    • 17444393231 scopus 로고    scopus 로고
    • The influence of spatial and temporal noise on the detection of first-order and second-order orientation and motion direction
    • Ledgeway T., Hutchinson C.V. The influence of spatial and temporal noise on the detection of first-order and second-order orientation and motion direction. Vision Research 2005, 45:2081-2094.
    • (2005) Vision Research , vol.45 , pp. 2081-2094
    • Ledgeway, T.1    Hutchinson, C.V.2
  • 27
    • 38549161059 scopus 로고    scopus 로고
    • Choice reaction times for identifying the direction of first-order and different varieties of second-order motion
    • Ledgeway T., Hutchinson C.V. Choice reaction times for identifying the direction of first-order and different varieties of second-order motion. Vision Research 2008, 48:208-222.
    • (2008) Vision Research , vol.48 , pp. 208-222
    • Ledgeway, T.1    Hutchinson, C.V.2
  • 28
    • 0028043113 scopus 로고
    • Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision
    • Ledgeway T., Smith A.T. Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision. Vision Research 1994, 34:2727-2740.
    • (1994) Vision Research , vol.34 , pp. 2727-2740
    • Ledgeway, T.1    Smith, A.T.2
  • 29
    • 0028905073 scopus 로고
    • The perceived speed of second-order motion and its dependence on stimulus contrast
    • Ledgeway T., Smith A.T. The perceived speed of second-order motion and its dependence on stimulus contrast. Vision Research 1995, 35:1421-1434.
    • (1995) Vision Research , vol.35 , pp. 1421-1434
    • Ledgeway, T.1    Smith, A.T.2
  • 30
    • 3242749732 scopus 로고    scopus 로고
    • The influence of spatial frequency and contrast on saccade latencies
    • Ludwig C.J.H., Gilchrist I.D., McSorley E. The influence of spatial frequency and contrast on saccade latencies. Vision Research 2004, 44:2597-2604.
    • (2004) Vision Research , vol.44 , pp. 2597-2604
    • Ludwig, C.J.H.1    Gilchrist, I.D.2    McSorley, E.3
  • 31
    • 0038121855 scopus 로고    scopus 로고
    • Temporal properties of the visual responses to luminance and contrast modulated noise
    • Manahilov V., Calvert J., Simpson W.A. Temporal properties of the visual responses to luminance and contrast modulated noise. Vision Research 2003, 43:1855-1867.
    • (2003) Vision Research , vol.43 , pp. 1855-1867
    • Manahilov, V.1    Calvert, J.2    Simpson, W.A.3
  • 32
    • 0021705057 scopus 로고
    • A three channel model of temporal frequency perception
    • Mandler M.B., Makous W. A three channel model of temporal frequency perception. Vision Research 1984, 24:1881-1887.
    • (1984) Vision Research , vol.24 , pp. 1881-1887
    • Mandler, M.B.1    Makous, W.2
  • 34
    • 0026483257 scopus 로고
    • Visual response latencies in striate cortex of the macaque monkey
    • Maunsell J.H.R., Gibson J.R. Visual response latencies in striate cortex of the macaque monkey. Journal of Neurophysiology 1992, 68:1332-1344.
    • (1992) Journal of Neurophysiology , vol.68 , pp. 1332-1344
    • Maunsell, J.H.R.1    Gibson, J.R.2
  • 35
    • 0642341029 scopus 로고    scopus 로고
    • Contrast coding and magno/parvo segregation revealed in reaction time studies
    • Murray I.J., Plainis S. Contrast coding and magno/parvo segregation revealed in reaction time studies. Vision Research 2003, 43:2707-2719.
    • (2003) Vision Research , vol.43 , pp. 2707-2719
    • Murray, I.J.1    Plainis, S.2
  • 36
    • 0030820183 scopus 로고    scopus 로고
    • Dual multiple-scale processing for motion in the human visual system
    • Nishida S., Ledgeway T., Edwards M. Dual multiple-scale processing for motion in the human visual system. Vision Research 1997, 37:2685-2698.
    • (1997) Vision Research , vol.37 , pp. 2685-2698
    • Nishida, S.1    Ledgeway, T.2    Edwards, M.3
  • 37
    • 2942733491 scopus 로고    scopus 로고
    • Overlapping confidence intervals or standard error intervals: What do they mean in terms of statistical significance
    • Payton M.E., Greenstone M.H., Schenker N. Overlapping confidence intervals or standard error intervals: What do they mean in terms of statistical significance. Journal of Insect Science 2003, 3:1-6.
    • (2003) Journal of Insect Science , vol.3 , pp. 1-6
    • Payton, M.E.1    Greenstone, M.H.2    Schenker, N.3
  • 38
    • 0033763651 scopus 로고    scopus 로고
    • Neurophysiological interpretation of human visual reaction times: Effect of contrast, spatial frequency and luminance
    • Plainis S., Murray I.J. Neurophysiological interpretation of human visual reaction times: Effect of contrast, spatial frequency and luminance. Neuropsychologia 2000, 38:1555-1564.
    • (2000) Neuropsychologia , vol.38 , pp. 1555-1564
    • Plainis, S.1    Murray, I.J.2
  • 39
    • 0032871143 scopus 로고    scopus 로고
    • Response latency of macaque area MT/V5 neurons and its relationship to stimulus parameters
    • Raiguel S.E., Xiao D.-K., Marcar V.L., Orban G.A. Response latency of macaque area MT/V5 neurons and its relationship to stimulus parameters. Journal of Neurophysiology 1999, 82:1944-1956.
    • (1999) Journal of Neurophysiology , vol.82 , pp. 1944-1956
    • Raiguel, S.E.1    Xiao, D.-K.2    Marcar, V.L.3    Orban, G.A.4
  • 40
    • 0035590266 scopus 로고    scopus 로고
    • On judging the significance of differences by examining overlap between confidence intervals
    • Schenker N., Gentleman J.F. On judging the significance of differences by examining overlap between confidence intervals. The American Statistician 2001, 55:182-186.
    • (2001) The American Statistician , vol.55 , pp. 182-186
    • Schenker, N.1    Gentleman, J.F.2
  • 41
    • 34250018283 scopus 로고    scopus 로고
    • Asymmetric transfer of the dynamic motion after-effect between first- and second-order cues and among different second-order cues
    • doi: 10.1167/7.8.1
    • Schofield A.J., Ledgeway T., Hutchinson C.V. Asymmetric transfer of the dynamic motion after-effect between first- and second-order cues and among different second-order cues. Journal of Vision 2007, 7:1-12. doi: 10.1167/7.8.1.
    • (2007) Journal of Vision , vol.7 , pp. 1-12
    • Schofield, A.J.1    Ledgeway, T.2    Hutchinson, C.V.3
  • 42
    • 0033046172 scopus 로고    scopus 로고
    • Does early non-linearity account for second-order motion?
    • Scott-Samuel N.E., Georgeson M.A. Does early non-linearity account for second-order motion?. Vision Research 1999, 39:2853-2865.
    • (1999) Vision Research , vol.39 , pp. 2853-2865
    • Scott-Samuel, N.E.1    Georgeson, M.A.2
  • 43
    • 0028469060 scopus 로고
    • Correspondence-based and energy-based detection of second-order motion in human vision
    • Smith A.T. Correspondence-based and energy-based detection of second-order motion in human vision. Journal of the Optical Society of America A 1994, 11:1940-1948.
    • (1994) Journal of the Optical Society of America A , vol.11 , pp. 1940-1948
    • Smith, A.T.1
  • 44
    • 0001202110 scopus 로고
    • The detection of second-order motion
    • Academic Press, London, A.T. Smith, R.J. Snowden (Eds.)
    • Smith A.T. The detection of second-order motion. Visual detection of motion 1994, 145-176. Academic Press, London. A.T. Smith, R.J. Snowden (Eds.).
    • (1994) Visual detection of motion , pp. 145-176
    • Smith, A.T.1
  • 45
    • 0028372385 scopus 로고
    • Direction identification threshold for second-order motion in central and peripheral vision
    • Smith A.T., Hess R.F., Baker C.L. Direction identification threshold for second-order motion in central and peripheral vision. Journal of the Optical Society of America A 1994, 11:506-514.
    • (1994) Journal of the Optical Society of America A , vol.11 , pp. 506-514
    • Smith, A.T.1    Hess, R.F.2    Baker, C.L.3
  • 46
    • 0031027114 scopus 로고    scopus 로고
    • Separate detection of moving luminance and contrast modulations: Fact or artifact?
    • Smith A.T., Ledgeway T. Separate detection of moving luminance and contrast modulations: Fact or artifact?. Vision Research 1997, 37:45-62.
    • (1997) Vision Research , vol.37 , pp. 45-62
    • Smith, A.T.1    Ledgeway, T.2
  • 47
    • 0032008309 scopus 로고    scopus 로고
    • Sensitivity to second-order motion as a function of temporal frequency and eccentricity
    • Smith A.T., Ledgeway T. Sensitivity to second-order motion as a function of temporal frequency and eccentricity. Vision Research 1998, 38:403-410.
    • (1998) Vision Research , vol.38 , pp. 403-410
    • Smith, A.T.1    Ledgeway, T.2
  • 49
    • 0026507467 scopus 로고
    • Motion coherency rules are form-cue invariant
    • Stoner G.R., Albright T.D. Motion coherency rules are form-cue invariant. Vision Research 1992, 32:465-475.
    • (1992) Vision Research , vol.32 , pp. 465-475
    • Stoner, G.R.1    Albright, T.D.2
  • 50
    • 0020039118 scopus 로고
    • Motion tuning in peripheral vision: Reaction time and perceived velocity
    • Tynan P.D., Sekuler R. Motion tuning in peripheral vision: Reaction time and perceived velocity. Vision Research 1982, 22:61-68.
    • (1982) Vision Research , vol.22 , pp. 61-68
    • Tynan, P.D.1    Sekuler, R.2
  • 51
    • 0029848970 scopus 로고    scopus 로고
    • Impairment of the perception of second-order motion but not first-order motion in a patient with unilateral focal brain damage
    • Vaina L.M., Cowey A. Impairment of the perception of second-order motion but not first-order motion in a patient with unilateral focal brain damage. Philosophical Transactions of the Royal Society of London, Series B 1996, 263:1225-1232.
    • (1996) Philosophical Transactions of the Royal Society of London, Series B , vol.263 , pp. 1225-1232
    • Vaina, L.M.1    Cowey, A.2
  • 52
    • 0032890313 scopus 로고    scopus 로고
    • Perception of first- and second-order motion: Separable neurological mechanisms?
    • Vaina L.M., Cowey A., Kennedy D. Perception of first- and second-order motion: Separable neurological mechanisms?. Human Brain Mapping 1999, 7:67-77.
    • (1999) Human Brain Mapping , vol.7 , pp. 67-77
    • Vaina, L.M.1    Cowey, A.2    Kennedy, D.3
  • 53
    • 0032031428 scopus 로고    scopus 로고
    • The selective impairment of the perception of first-order motion by unilateral cortical brain damage
    • Vaina L.M., Makris N., Kennedy D., Cowey A. The selective impairment of the perception of first-order motion by unilateral cortical brain damage. Visual Neuroscience 1998, 15:333-348.
    • (1998) Visual Neuroscience , vol.15 , pp. 333-348
    • Vaina, L.M.1    Makris, N.2    Kennedy, D.3    Cowey, A.4
  • 54
    • 0345303972 scopus 로고    scopus 로고
    • First-order and second-order motion: Neurological evidence for neuroanatomically distinct mechanisms
    • Vaina L.M., Soloviev S. First-order and second-order motion: Neurological evidence for neuroanatomically distinct mechanisms. Progress in Brain Research 2004, 144:197-212.
    • (2004) Progress in Brain Research , vol.144 , pp. 197-212
    • Vaina, L.M.1    Soloviev, S.2
  • 55
    • 0034616035 scopus 로고    scopus 로고
    • A lesion of cortical area V2 selectively impairs the perception of the direction of first-order visual motion
    • Vaina L.M., Soloviev S., Bienfang D.C., Cowey A. A lesion of cortical area V2 selectively impairs the perception of the direction of first-order visual motion. NeuroReport 2000, 11:1039-1044.
    • (2000) NeuroReport , vol.11 , pp. 1039-1044
    • Vaina, L.M.1    Soloviev, S.2    Bienfang, D.C.3    Cowey, A.4
  • 56
    • 0033805740 scopus 로고    scopus 로고
    • Response latency of a motion-sensitive neuron in the fly visual system: Dependence on stimulus parameters and physiological conditions
    • Warzecha A.-K., Egelhaaf M. Response latency of a motion-sensitive neuron in the fly visual system: Dependence on stimulus parameters and physiological conditions. Vision Research 2000, 40:2973-2983.
    • (2000) Vision Research , vol.40 , pp. 2973-2983
    • Warzecha, A.-K.1    Egelhaaf, M.2
  • 57
    • 0026891007 scopus 로고
    • Psychophysically motivated model for two-dimensional motion perception
    • Wilson H.R., Ferrera V.P., Yo V. Psychophysically motivated model for two-dimensional motion perception. Visual Neuroscience 1992, 9:79-97.
    • (1992) Visual Neuroscience , vol.9 , pp. 79-97
    • Wilson, H.R.1    Ferrera, V.P.2    Yo, V.3
  • 58
    • 0028534658 scopus 로고
    • A model for two-dimensional motion perception: Coherence and transparency
    • Wilson H.R., Kim J. A model for two-dimensional motion perception: Coherence and transparency. Visual Neuroscience 1994, 11:1205-1220.
    • (1994) Visual Neuroscience , vol.11 , pp. 1205-1220
    • Wilson, H.R.1    Kim, J.2
  • 59
    • 0026798826 scopus 로고
    • Perceived direction of moving two-dimensional patterns depends on duration, contrast and eccentricity
    • Yo V., Wilson H.R. Perceived direction of moving two-dimensional patterns depends on duration, contrast and eccentricity. Vision Research 1992, 32:135-147.
    • (1992) Vision Research , vol.32 , pp. 135-147
    • Yo, V.1    Wilson, H.R.2
  • 60
    • 0027254951 scopus 로고
    • A processing stream in mammalian visual cortex neurons for non-Fourier responses
    • July 2
    • Zhou Y.-X., Baker C.L. A processing stream in mammalian visual cortex neurons for non-Fourier responses. Science 1993, July 2, 261:98-101.
    • (1993) Science , vol.261 , pp. 98-101
    • Zhou, Y.-X.1    Baker, C.L.2


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.