Application of psychophysical techniques to haptic research

IEEE Transactions on Haptics

Volumn 6, Issue 3, 2013, Pages 268-284

  Jones, Lynette A ^a   Tan, Hong Z ^b,c  

^a Massachusetts Institute of Technology   (United States)

^b MICROSOFT RESEARCH ASIA   (China)

^c Purdue University   (United States)

Author keywords

Evaluation methodology; haptic I O; input devices and strategies; user interfaces

Indexed keywords

DIFFERENCE THRESHOLD; EVALUATION/METHODOLOGY; HAPTIC I/O; HUMAN HAPTIC PERCEPTIONS; INPUT DEVICES AND STRATEGIES; PERCEPTUAL PROCESSING; PSYCHOPHYSICAL METHODS; SIGNAL DETECTION THEORY;

COMPUTER APPLICATIONS; HAPTIC INTERFACES; HUMAN COMPUTER INTERACTION;

USER INTERFACES;

COMPUTER INTERFACE; HUMAN; PERCEPTIVE THRESHOLD; PHYSIOLOGY; PSYCHOPHYSICS; RESEARCH; TOUCH;

HUMANS; PSYCHOPHYSICS; RESEARCH; SENSORY THRESHOLDS; TOUCH PERCEPTION; USER-COMPUTER INTERFACE;

EID: 84883771294     PISSN: 19391412     EISSN: None     Source Type: Journal    
DOI: 10.1109/TOH.2012.74     Document Type: Article

References (112)

1. G.A. Gescheider, Psychophysics: The Fundamentals, third ed. Lawrence Erlbaum, 1997.
2. S.A. Klein, "Measuring, Estimating, and Understanding the Psychometric Function: A Commentary," Perception and Psychophysics, vol. 63, pp. 1421-1455, 2001. (Pubitemid 33610265)
3. M.R. Leek, "Adaptive Procedures in Psychophysical Research," Perception and Psychophysics, vol. 63, pp. 1279-1292, 2001. (Pubitemid 33610256)
4. L.A. Jones and S.J. Lederman, Human Hand Function. Oxford Univ. Press, 2006.
5. S.J. Lederman and R.L. Klatzky, "Haptic Perception: A tutorial," Attention, Perception and Psychophysics, vol. 71, pp. 1439-1459, 2009.
6. R.M. Friedman, K.D. Hester, B.G. Green, and R.H. LaMotte, "Magnitude Estimation of Softness," Experimental Brain Research, vol. 191, pp. 131-142, 2008.
7. S.J. Lederman, "The Perception of Surface Roughness by Active and Passive Touch," Bull. Psychonomic Soc., vol. 18, pp. 253-255, 1981.
8. R.T. Verrillo, S.J. Bolanowski, and F.P. McGlone, "Subjective Magnitude Estimate of Tactile Roughness," Somatosensory and Motor Research, vol. 16, pp. 352-360, 1999. (Pubitemid 30006509)
9. E.E. Brodie and H.E. Ross, "Jiggling a Lifted Weight Does Aid Discrimination," Am. J. Psychology, vol. 98, pp. 469-471, 1985.
10. M.A. Plaisier, W.M. Bergmann Tiest, and A.M.L. Kappers, "Haptic Object Individuation," IEEE Trans. Haptics, vol. 3, no. 4, pp. 257-265, Oct.-Dec. 2010.
11. S.J. Lederman and R.L. Klatzky, "Relative Availability of Surface and Object Properties during Early Haptic Processing," J. Experimental Psychology: Human Perception and Performance, vol. 23, pp. 1680-1707, 1997. (Pubitemid 127456197)
12. J.C. Craig and K.O. Johnson, "The Two-Point Threshold: Not a Measure of Tactile Spatial Resolution," Current Directions in Psychological Science, vol. 9, pp. 29-32, 2000.
13. K.O. Johnson and J.R. Phillips, "Tactile Spatial Resolution: 1. Two- Point Discrimination, Gap Detection, Grating Resolution, and Letter Recognition," J. Neurophysiology, vol. 46, pp. 1177-1191, 1981. (Pubitemid 12196183)
14. H.Z. Tan, N.I. Durlach, G.L. Beauregard, and M.A. Srinivasan, "Manual Discrimination of Compliance Using Active Pinch Grasp: The Roles of Force and Work Cues," Perception and Psychophysics, vol. 57, pp. 495-510, 1995.
15. K.O. Johnson, T. Yoshioka, and F. Vega-Bermudez, "Tactile Functions of Mechanoreceptive Afferents Innervating the Hand," J. Clinical Neurophysiology, vol. 17, pp. 539-558, 2000. (Pubitemid 32039325)
16. K.O. Sofia and L.A. Jones, "Mechanical and Psychophysical Studies of Surface Wave Propagation during Vibrotactile Stimulation," to be published in IEEE Trans. Haptics.
17. L.E. Krueger, "Reconciling Fechner and Stevens: Toward a Unified Psychophysical Law," Behavioral and Brain Sciences, vol. 12, pp. 251-320, 1989.
18. G.R. Lockhead, "Psychophysical Scaling: Judgments of Attributes or Objects," Behavioral and Brain Sciences, vol. 15, pp. 543-601, 1992.
19. H.E. Ross, "On the Relations between Discriminability and Apparent Magnitude," British J. Math. and Statistical Psychology, vol. 50, pp. 187-203, 1997.
20. G.A. Gescheider, J.H. Wright, and R.T. Verrillo, Information- Processing Channels in the Tactile Sensory System. Taylor and Francis, 2009.
21. R.H. LaMotte and M.A. Srinivasan, "Surface Microgeometry: Tactile Perception and Neural Encoding," Information Processing in the Somatosensory System, O. Franzen and J. Westman, eds., pp. 49- 58, Macmillan, 1991.
22. J.W. Morley, A.W. Goodwin, and I. Darian-Smith, "Tactile Discrimination of Gratings," Experimental Brain Research, vol. 49, pp. 291-299, 1983. (Pubitemid 13185458)
23. R.J. Sinclair and H. Burton, "Tactile Discrimination of Gratings: Psychophysical and Neural Correlates in Human and Monkey," Somatosensory and Motor Research, vol. 8, pp. 241-248, 1991.
24. I.E. Gordon and V. Morison, "The Haptic Perception of Curvature," Perception and Psychophysics, vol. 31, pp. 446-450, 1982.
25. A.W. Goodwin, K.T. John, and A.H. Marceglia, "Tactile Discrimination of Curvature by Humans Using Only Cutaneous Information from the Fingerpads," Experimental Brain Research, vol. 86, pp. 663-672, 1991.
26. K.O. Johnson, I. Darian-Smith, C. LaMotte, B. Johnson, and S. Oldfield, "Coding of Incremental Changes in Skin Temperature by a Population of Warm Fibers in the Monkey: Correlation with Intensity Discrimination in Man," J. Neurophysiology, vol. 42, pp. 1332-1353, 1979. (Pubitemid 10229769)
27. K.O. Johnson, I. Darian-Smith, and C. LaMotte, "Peripheral Neural Determinants of Temperature Discrimination in Man: A Correlative Study of Responses to Cooling Skin," J. Neurophysiology, vol. 36, pp. 347-370, 1973.
28. R.S. Johansson and A.B. Vallbo, "Detection of Tactile Stimuli. Thresholds of Afferent Units Related to Psychophysical Thresholds in the Human Hand," J. Physiology, vol. 297, pp. 405-422, 1979. (Pubitemid 10166928)
29. J. Mei, R.P. Tuckett, D.A. Poulos, K.W. Horch, J.Y. Wei, and P.R. Burgess, "The Neural Signal for Skin Indentation Depth. II Steady Indentations," J. Neuroscience, vol. 3, pp. 2652-2659, 1983. (Pubitemid 14187140)
30. G.K. Essick, O. Franzen, and B.L. Whitsel, "Discrimination and Scaling of Velocity of Stimulus Motion across the Skin," Somatosensory and Motor Research, vol. 6, pp. 21-40, 1988. (Pubitemid 19042917)
31. O. Franzen and J. Nordmark, "Vibrotactile Frequency Discrimination," Perception and Psychophysics, vol. 17, pp. 480-484, 1975.
32. D.A. Mahns, N.M. Perkins, V. Sahai, L. Robinson, and M.J. Rowe, "Vibrotactile Frequency Discrimination in Human Hairy Skin," J. Neurophysiology, vol. 95, pp. 1442-1450, 2006.
33. M. Rothenberg, R.T. Verrillo, S.A. Zahorian, M.L. Brachman, and S.J. Bolanowski, "Vibrotactile Frequency for Encoding a Speech Parameter," J. Acoustical Soc. of Am., vol. 62, pp. 1003-1012, 1977. (Pubitemid 8199289)
34. A.J. Brisben, S.S. Hsiao, and K.O. Johnson, "Detection of Vibration Transmitted through an Object Grasped in the Hand," J. Neurophysiology, vol. 81, pp. 1548-1558, 1999. (Pubitemid 29262486)
35. J.C. Craig, "Difference Threshold for Intensity of Tactile Stimuli," Perception and Psychophysics, vol. 11, pp. 150-152, 1972.
36. E. Francisco, V. Tannan, Z. Zhang, J. Holden, and M. Tommerdahl, "Vibrotactile Amplitude Discrimination Capacity Parallels Magnitude Changes in Somatosensory Cortex and Follows Weber's Law," Experimental Brain Research, vol. 191, pp. 49-56, 2008.
37. H.Z. Tan, B. Eberman, M.A. Srinivasan, and B. Cheng, "Human Factors for the Design of Force-Reflecting Haptic Interfaces," Proc. Am. Soc. of Mechanical Eng.: Dynamic Systems and Control Conf., vol. 55-1, pp. 353-359, 1994.
38. E.E. Brodie and H.E. Ross, "Degrees of Freedom of Movement in Weight Discrimination: Effect of Stimulus Intensity," Int'l Soc. for Psychophysics Fechner Day 86, pp. 15-20, 1986.
39. L.A. Jones, "Matching Forces: Constant Errors and Differential Thresholds," Perception, vol. 18, pp. 681-687, 1989. (Pubitemid 20052370)
40. X.D. Pang, H.Z. Tan, and N.I. Durlach, "Manual Discrimination of Force Using Active Finger Motion," Perception and Psychophysics, vol. 49, pp. 531-540, 1991.
41. H.E. Wheat, L.M. Salo, and A.W. Goodwin, "Human Ability to Scale and Discriminate Forces Typical of Those Occurring during Grask and Manipulation," J. Neuroscience, vol. 24, pp. 3394-3401, 2004. (Pubitemid 38451905)
42. W. Bergmann Tiest and A.M.L. Kappers, "Cues for Haptic Perception of Compliance," IEEE Trans. Haptics, vol. 2, pp. 189- 199, 2009.
43. L.A. Jones and I.W. Hunter, "A Perceptual Analysis of Stiffness," Experimental Brain Research, vol. 79, pp. 150-156, 1990. (Pubitemid 20040424)
44. W. Bergmann Tiest, A.C.L. Vrijling, and A.M.L. Kappers, "Haptic Perception of Viscosity," Proc. Int'l Conf. Haptics: Generating and Perceiving Tangible Sensations (EuroHaptics '10), pp. 29-34, 2010.
45. L.A. Jones and I.W. Hunter, "A Perceptual Analysis of Viscosity," Experimental Brain Research, vol. 94, pp. 343-351, 1993. (Pubitemid 23220007)
46. W.B. Knowles and T.B. Sheridan, "The "Feel" of Rotary Controls: Friction and Inertia," Human Factors, vol. 8, pp. 209-215, 1966.
47. W.R. Provancher and N.D. Sylvester, "Fingerpad Skin Stretch Increases the Perception of Virtual Friction," IEEE Trans. Haptics, vol. 2, no. 4, pp. 212-223, Oct.-Dec. 2009.
48. G.B. Rollman, "Electrocutaneous Stimulation: Psychometric Functions and Temporal Integration," Perception and Psychophysics, vol. 5, pp. 289-293, 1969.
49. G.R. Hawkes, "Information Transmitted via Electrical Cutaneous Stimulus Duration," J. Psychology, vol. 51, pp. 293-298, 1961.
50. J.G. Kreifeldt and M.-C. Chuang, "Moment of Inertia: A Psychophysical Study of an Overlooked Sensation," Science, vol. 206, pp. 588-590, 1979. (Pubitemid 10192169)
51. H.E. Ross and A.J. Benson, "The Weber Fraction for Moment of Inertia," Int'l Soc. for Psychophysics, Fechner Day 86, pp. 71-76, 1986.
52. E.H. Weber, The Sense of Touch. Academic Press, 1834/1978.
53. N.I. Durlach, L.A. Delhorne, A. Wong, W.Y. Ko, W.M. Rabinowitz, and J. Hollerbach, "Manual Discrimination and Identification of Length by the Finger-Span Method," Perception and Psychophysics, vol. 46, pp. 29-38, 1989. (Pubitemid 19164538)
54. H.Z. Tan, M.A. Srinivasan, C.M. Reed, and N.I. Durlach, "Discrimination and Identification of Finger Joint-Angle Position Using Active Motion," ACM Trans. Applied Perception, vol. 4, 2-1-2- 14, 2007.
55. W.A. Simpson, "The Method of Constant Stimuli Is Efficient," Perception and Psychophysics, vol. 44, pp. 433-436, 1988.
56. F.A. Wichman and N.J. Hill, "The Psychometric Function: 1. Fitting, Sampling and Goodness of Fit," Perception and Psychophysics, vol. 63, pp. 1293-1313, 2001. (Pubitemid 33610257)
57. T.N. Cornsweet, "The Staircase Method in Psychophysics," Am. J. Psychology, vol. 75, pp. 485-491, 1962.
58. W.P. Tanner and J.A. Swets, "A Decision-Making Theory of Visual Detection," Psychological Rev., vol. 61, pp. 401-409, 1954.
59. N.I. Durlach, "A Decision Model for Psychophysics," Communication Biophysics Group, Research Laboratory of Electronics, MIT, Oct. 1968.
60. N.A. Macmillan and C.D. Creelman, Detection Theory: A User's Guide, second ed. Lawrence Erlbaum, 2004.
61. M. Kocsis, S. Cholewiak, R. Traylor, B. Adelstein, E.D. Hirleman, and H.Z. Tan, "Discrimination of Real and Virtual Surfaces with Sinusoidal and Triangular Gratings Using the Fingertip and Stylus," to be published in IEEE Trans. Haptics.
62. H. Robbins and S. Monro, "A Stochastic Approximation Method," Annals of Math. Statistics, vol. 22, pp. 400-407, 1951.
63. H. Levitt, "Transformed Up-Down Methods in Psychoacoustics," J. Acoustical Soc. of Am., vol. 49, pp. 467-477, 1971.
64. C. Kaernbach, "Simple Adaptive Testing with the Weighted updown Method," Perception and Psychophysics, vol. 49, pp. 227-229, 1991.
65. C. Kaernbach, "Adaptive Threshold Estimation with Unforced- Choice Tasks," Perception and Psychophysics, vol. 63, pp. 1377-1388, 2001. (Pubitemid 33610262)
66. S.A. Cholewiak, K. Kim, H.Z. Tan, and B.D. Adelstein, "A Frequency-Domain Analysis of Haptic Gratings," IEEE Trans. Haptics, vol. 3, no. 1, pp. 3-14, Jan.-Mar. 2010.
67. F. Barbagli, K. Salisbury, C. Ho, C. Spence, and H.Z. Tan, "Haptic Discrimination of Force Direction and the Influence of Visual Information," ACM Trans. Applied Perception, vol. 3, pp. 125-135, 2006.
68. W.R. Garner, Uncertainty and Structure as Psychological Concepts. Wiley, 1962.
69. H.-Y. Chen, J. Santos, M. Graves, K. Kim, and H.Z. Tan, "Tactor Localization at the Wrist," Proc. Sixth Int'l Conf. Haptics: Perception, Devices and Scenarios (EuroHaptics '08), pp. 209-218, 2008.
70. S.A. Cholewiak, H.Z. Tan, and D.S. Ebert, "Haptic Identification of Stiffness and Force Magnitude," Proc. Symp. Haptic Interfaces for Virtual Environment and Teleoperator Systems, 87-91, 2008.
71. L.A. Jones and K. Ray, "Localization and Pattern Recognition with Tactile Displays," Proc. Symp. Haptic Interfaces for Virtual Environment and Teleoperator Systems, pp. 33-39, 2008.
72. I. Oakley, Y. Kim, J. Lee, and J. Ryu, "Determining the Feasibility of Forearm Mounted Vibrotactile Displays," Proc. Symp. Haptic Interfaces for Virtual Environment and Teleoperator Systems, pp. 27- 34, 2006. (Pubitemid 44733144)
73. J.B.F. Van Erp, A.H.C. van Veen, C. Jansen, and T. Dobbins, "Waypoint Navigation with a Vibrotactile Waist Belt," ACM Trans. Applied Perception, vol. 2, pp. 106-117, 2005.
74. G.A. Miller, "The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information," Psychological Rev., vol. 63, pp. 81-97, 1956.
75. N.I. Durlach, H.Z. Tan, N.A. Macmillan, W.M. Rabinowitz, and L.D. Braida, "Resolution in One Dimension with Random Variations in Background Dimensions," Perception and Psychophysics, vol. 46, pp. 293-296, 1989.
76. H.Z. Tan, "Identification of Size Using the PHANToM: Towards a Set of Building Blocks for Rendering Haptic Environments," Proc. Sixth Int'l Symp. Haptic Interfaces for Virtual Environment and Teleoperator Systems, pp. 197-203, 1997.
77. G.A. Miller, "Note on the Bias of Information Estimates," Information Theory in Psychology, H. Quastler, ed., pp. 95-100, Free Press, 1954.
78. W.M. Rabinowitz, A.J.M. Houtsma, N.I. Durlach, and L.A. Delhorne, "Multidimensional Tactile Displays: Identification of Vibratory Intensity, Frequency, and Contactor Area," J. Acoustical Soc. of Am., vol. 82, pp. 1243-1252, 1987.
79. F.G. Ashby and J.T. Townsend, "Varieties of Perceptual Independence," Psychological Rev., vol. 93, pp. 154-179, 1986.
80. S.L. Campbell, "Uni- and Multidimensional Identification of Rise Time, Spectral Slope, and Bandwidth," PhD dissertation, Dept. of Speech and Hearing Sciences, Univ. of Washington, 1993.
81. G. Denesvich, "Identification of Frequency and Amplitude through Cutaneous Stimulation," BS thesis, Dept. of Electrical Eng. and Computer Science, MIT, 1995.
82. H.Y. Chen, J. Park, S. Dai, and H.Z. Tan, "Design and Evaluation of Identifiable Key-Click Signals for Mobile Devices," IEEE Trans. Haptics, vol. 4, no. 4, pp. 229-241, July/Aug. 2011.
83. N. Garcia-Hernandez, N.G. Tsagarakis, and D.G. Caldwell, "Feeling through Tactile Displays: A Study on the Effect of the Array Density and Size on the Discrimination of Tactile Patterns," IEEE Trans. Haptics, vol. 4, no. 2, pp. 100-110, Mar./ Apr. 2011.
84. C.M. Salisbury, R.B. Gillespie, H.Z. Tan, F. Barbagli, and J.K. Salisbury, "What You Can't Feel Won't Hurt You: Evaluating Haptic Hardware Using a Haptic Contrast Function," IEEE Trans. Haptics, vol. 4, no. 2, pp. 134-146, Mar./Apr. 2011.
85. B. Unger, R. Hollis, and R. Klatzky, "Roughness Perception in Virtual Textures," IEEE Trans. Haptics, vol. 4, no. 2, pp. 122-133, Mar./Apr. 2011.
86. S.S. Stevens, "On the Psychophysical Law," Psychological Rev., vol. 64, pp. 153-181, 1957.
87. R. Teghtsoonian, "On the Exponents in Stevens' Law and the Constant in Ekman's Law," Psychological Rev., vol. 78, pp. 71-80, 1971.
88. L.A. Jones, "Perception of Force and Weight: Theory and Research," Psychological Bull., vol. 100, pp. 29-42, 1986.
89. D. Laming, Sensory Analysis. Academic Press, 1986.
90. D. Laming, The Measurement of Sensation. Oxford Univ. Press, 1997.
91. C.E. Connor, S.S. Hsiao, J.R. Phillips, and K.O. Johnson, "Tactile Roughness: Neural Codes That Account for Psychophysical Magnitude Estimates," J. Neuroscience, vol. 10, pp. 3823-3836, 1990.
92. E.M. Meftah, L. Belingard, and C.E. Chapman, "Relative Effects of the Spatial and Temporal Characteristics of Scanned Surfaces on Human Perception of Tactile Roughness Using Passive Touch," Experimental Brain Research, vol. 132, pp. 351-361, 2000. (Pubitemid 30330210)
93. A.M. Kappers, "Large Systematic Deviations in the Haptic Perception of Parallelity," Perception, vol. 28, pp. 1001-1012, 1999.
94. R.P. Hellman and J.J. Zwislocki, "Monaural Loudness Function at 1000 cps Tone and Internal Summation," J Acoustical Soc. of Am., vol. 35, pp. 856-865, 1963.
95. R.N. Shepherd, "Psychological Relations and Psychophysical Scales: On the Status of 'Direct' Psychophysical Measurement," J. Math. Psychology, vol. 24, pp. 21-57, 1981.
96. E.C. Poulton, Bias in Quantifying Judgments. Lawrence Erlbaum, 1989.
97. G. Borg, "Psychophysical Bases of Perceived Exertion," Medicine and Science in Sports and Exercise, vol. 14, pp. 377-381, 1982. (Pubitemid 13215050)
98. D.P. Price, P.A. McGrath, A. Rafii, and B. Buckingham, "The Validation of Visual Analogue Scales as Ratio Scale Measures for Chronic and Experimental Pain," Pain, vol. 17, pp. 45-56, 1983. (Pubitemid 13004473)
99. L.M. Grierson and H. Carnahan, "Manual Exploration and the Perception of Slipperiness," Perception and Psychophysics, vol. 68, pp. 1070-1081, 2006.
100. A.M. Smith and S.H. Scott, "Subjective Scaling of Smooth Surface Friction," J. Neurophysiology, vol. 75, pp. 1957-1962, 1996. (Pubitemid 26159031)
101. E.C. Poulton, "Models for Biases in Judging Sensory Magnitude," Psychological Bull., vol. 86, pp. 777-803, 1979.
102. J.W. Morley and M.J. Rowe, "Perceived Pitch of Vibrotactile Stimuli: Effects of Vibration Amplitude, and Implications for Vibration Frequency Coding," J. Physiology, vol. 431, pp. 403-416, 1990.
103. W.S. Torgerson, Theory and Methods of Scaling. Wiley, 1958.
104. F.W. Young and R.M. Hamer, Theory and Applications of Multidimensional Scaling. Lawrence Erlbaum, 1994.
105. M. Hollins, R. Faldowski, S. Rao, and F. Young, "Perceptual Dimensions of Tactile Surface Texture: A Multidimensional Scaling Analysis," Perception and Psychophysics, vol. 54, pp. 697- 705, 1993.
106. N. Gaißert, S. Waterkamp, R.W. Fleming, and I. Bulthoff, "Haptic Categorical Perception of Shape," PLOS ONE, vol. 7, no. 8, article e43063, 2012.
107. W. Bergmann Tiest and A.M.L. Kappers, "Analysis of Haptic Perception of Materials by Multidimensional Scaling and Physical Measurements of Roughness and Compressibility," Acta Psychologica, vol. 121, pp. 1-20, 2006. (Pubitemid 43033470)
108. J. Luk, J. Pasquero, S. Little, K. MacLean, V. Levesque, and V. Hayward, "A Role for Haptics in Mobile Interaction: Initial Design Using a Handheld Tactile Display Prototype," Proc. SIGCHI Conf. Computer Human Interactions Conf., pp. 171-180, 2006. (Pubitemid 44032100)
109. K. MacLean and M. Enriquez, "Perceptual Design of Haptic Icons," Proc. EuroHaptics, pp. 351-363, 2003.
110. J. Pasquero, J. Luk, S. Little, and K. MacLean, "Perceptual Analysis of Haptic Icons: An Investigation into the Validity of Cluster Sorted MDS," Proc. Symp. Haptic Interfaces for Virtual Environment and Teleoperator Systems, pp. 437-444, 2006. (Pubitemid 44733208)
111. H.N. Ho and L.A. Jones, "Development and Evaluation of a Thermal Display for Material Identification and Discrimination," ACM Trans. Applied Perception, vol. 4, pp. 13-1-13-24, 2007.
112. H.Z. Tan, C.M. Reed, and N.I. Durlach, "Optimum Information- Transfer Rates for Communication through Haptic and Other Sensory Modalities," IEEE Trans. Haptics, vol. 3, no. 2, pp. 98-108, Apr.-June 2010.