Journal Papers

Below is a list of journal articles produced by SSDL. These articles are only available through their respective publisher. In many cases a copy can be accessed or purchased from AIAA.

Journal Articles: 2018

Journal Articles: 2017

Journal Articles: 2016

Journal Articles: 2015

  • Stevenson, T.; Imken, T.; and Lightsey, E.G.; "Design and Testing of a Cold Gas Thruster for an Interplanetary CubeSat Mission," Journal of Small Satellites, Vol. 4, No. 2, pp. 371-386, October, 2015.
  • Johl, S.; and Lightsey, E.G.; "A Reusable Command and Data Handling System for University CubeSat Missions," Journal of Small Satellites, Vol. 4, No. 2, pp. 357-369, October, 2015.
  • Wolstencroft, M.; King, M.A.; Whitehouse, P.L.; Bentley, M.J.; Nield, G.A.; King, E.C.; McMillan, M.; Shepherd, A.; Barletta, V.R.; Bordoni, A.; Riva, R.E.M.; Didova, O.; and Gunter, B.C.; "Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the south-western Weddell Sea," Geophysical Journal International, Vol. 203, No. 1, pp. 737-754, October, 2015.
  • Mandalia, A.B.; and Braun, R.D.; "High-Altitude Divert Architecture for Future Robotic and Human Mars Missions," Journal of Spacecraft and Rockets, Vol. 52, No. 5, pp. 1311-1319, Sept-Oct, 2015.
  • Worthy, J.L.; and Holzinger, M.J.; "Incorporating Uncertainty in Admissible Regions for Uncorrelated Detections," AIAA Journal of Guidance, Control, and Dynamics, Vol. 38, No. 9, pp. 1673-1689, September, 2015.
  • Eldad, O.; and Lightsey, E.G.; "Propellantless Attitude Control of a Nonplanar Solar Sail," Journal of Guidance, Control, and Dynamics, Vol. 38, No. 8, pp. 1531-1534, August, 2015.
  • Mahzari, M.; Braun, R.D.; White, T.R.; and Bose, D.; "Inverse Estimation of the Mars Science Laboratory Entry Aeroheating and Heatshield Response,," Journal of Spacecraft and Rockets, Vol. 52, No. 4, pp. 1203-1216, July-August, 2015.
  • Steinfeldt, B.A.; and Braun, R.D.; "Extensibility of a Linear Rapid Robust Design Methodology," Engineering Optimization, July, 2015.
  • Mandalia, A.B.; and Braun, R.D.; "Supersonic Retropropulsion Thrust Vectoring for Mars Precision Landing," Journal of Spacecraft and Rockets, Vol. 52, No. 3, pp. 827-835, May-June, 2015.
  • Tangdamrongsub, N.; Steele-Dunne, S.C.; Gunter, B.C.; Ditmar, P.G.; and Weerts, A.H.; “Data assimilation of GRACE terrestrial water storage estimates into a regional hydrological model of the Rhine River basin,” Hydrology and Earth System Sciences, Vol. 19, No. 4, pp. 2079-2100, April, 2015.
  • Holzinger, M.J.; Scheeres, D.J.; and Hauser, J.; "Reachability Using Arbitrary Performance Indices," IEEE Transactions on Automatic Control, Vol. 60, No. 4, pp. 1099-1103, April, 2015, doi: 10.1109/TAC.2015.2391451.
  • Kazemba, C.D.; Braun, R.D.; Schoenenberger, M.A.; and Clark, I.G.; "Dynamic Stability Analysis of Blunt-Body Entry Vehicles Using Time-Lagged Aftbody Pitching Moments," Journal of Spacecraft and Rockets, Vol. 52, No. 2, pp. 393-403, Mar-Apr, 2015.
  • Miller, M.J.; Steinfeldt, B.A.; and Braun, R.D.; "Investigation of Drag Modulated Supersonic Inflatable Aerodynamic Decelerators for Use on Mesospheric Sounding Rocket Payloads," Journal of Spacecraft and Rockets, Vol. 52, No. 2, pp. 383-392, Mar-Apr, 2015.
  • Putnam, Z.R.; and Braun, R.D.; "Extension and Enhancement of the Allen-Eggers Analytic Ballistic Entry Trajectory Solution," Journal of Guidance, Control and Dynamics, Vol. 38, No. 3, pp. 414-430, March, 2015.
  • Grant, M.J.; and Braun, R.D.; "Rapid Indirect Trajectory Optimization for Conceptual Design of Hypersonic Missions," Journal of Spacecraft and Rockets, Vol. 52, No. 1, pp. 177-182, Jan-Feb, 2015.
  • Levinsen, J. F.; Khvorostovsky, K.; Ticconi, F.; Shepherd, A.; Forsberg, R.; Sørensen, L. S.; Muir, A.; Pie, N.; Felikson, D.; Flament, T.; Hurkmans, R.; Moholdt, G.; Gunter, B.C.; Lindenbergh, R. C.; and Kleinherenbrink, M.; “ESA Ice Sheets CCI: Derivation of the optimal method for surface elevation change detection of the Greenland Ice Sheet – Round Robin results,” International Journal of Remote Sensing, Vol. 36, No. 2, pp. 551-573, January, 2015.

Journal Articles: 2014

  • Holzinger, M.J.; "Using Magnetometers for Space Object Characterization in Space Situational Awareness Applications," Journal of Guidance, Control, and Dynamics, Vol. 37, No. 5, pp. 1397-1405, August, 2014.
  • Dutta, S; and Braun, R.D.;"Statistical Entry, Descent and Landing Performance Reconstruction of the Mars Science Laboratory," Journal of Spacecraft and Rockets, Vol. 51, No. 4, pp. 1048-1061, July-Aug, 2014.
  • Slobbe, D.C.; Klees, R.; and Gunter, B.C.; “Realization of a consistent set of vertical reference surfaces in coastal areas,” Journal of Geodesy, Vol. 88, No. 6, pp. 601-615, June, 2014.
  • Steinfeldt, B.A.; and Braun, R.D.; "Utilizing Dynamical Systems Concepts in Multidisciplinary Design," AIAA Journal, Vol. 52, No. 6, pp. 1265-1279, June, 2014.
  • Dutta, S.; Karlgaard, C.D.; and Braun, R.D.; "Uncertainty Quantification for Mars Entry, Descent, and Landing Reconstruction Using Adaptive Filtering," Journal of Spacecraft and Rockets, Vol. 51, No. 3, pp. 967-977, May-June, 2014.
  • Holzinger, M.J.; Alfriend, K.T.; Wetterer, C.J.; Luu, K.K.; Sabol, C.; and Hamada, K.; "Photometric Attitude Estimation for Agile Space Objects with Shape Uncertainty,"Journal of Guidance, Control, and Dynamics, Vol. 37, No. 3, pp. 921-932, May-June, 2014.
  • Putnam, Z.R.;Grant, M.J.;Kelly, J.R.;Braun R.D.; and Krevor, Z.C.;"Feasibility of Guided Entry for a Crewed Lifting Body Without Angle-of-Attack Control," Journal of Guidance, Control, and Dynamics, Vol. 37, No. 3, pp. 729-740, May, 2014.
  • Gunter, B.C.; Didova, O.; Riva, R.E.M.; Ligtenberg, S.R.M.; Lenaerts, J.T.M.; King, M.A.; van den Broeke, M.R.; and Urban, T.; “Empirical estimation of present-day Antarctic glacial isostatic adjustment and ice mass change,” The Cryosphere, Vol. 8, No. 2, pp. 743-760, April, 2014.
  • Dutta, S.;Braun, R.D.; and Karlgaard, C.D.; "Atmospheric Data System Sensor Placement Optimization for Mars Entry, Descent and Landing," Journal of Spacecraft and Rockets, Vol. 51, No. 1, pp. 163-174, Jan-Feb, 2014.
  • Putnam, Z.R. and Braun, R.D.; "Drag-Modulation Flight-Control System Options for Planetary Aerocapture," Journal of Spacecraft and Rockets, Vol. 51, No. 1, pp. 139-150, Jan-Feb, 2014.
  • Putnam, Z.R. and Braun, R.D.; "Precision Landing at Mars Using Discrete-Event Drag Modulation," Journal of Spacecraft and Rockets, Vol. 51, No. 1, pp. 128-138, Jan-Feb, 2014.

Journal Articles: 2013

  • Dutta, S.;Braun, R.D.;Russell, R.P.;Striepe, S.A.; and Clark, I.G.; "Comparison of Statistical Estimation Techniques for Mars Entry, Descent, and Landing Reconstruction," Journal of Spacecraft and Rockets, Vol. 50, No. 6, pp. 1207-1221, Nov-Dec, 2013.
  • Korzun, A.M.; and Braun, R.D.; "Conceptual Modeling of Supersonic Retropropulsion Flow Interaction and Relationships to System Performance," Journal of Spacecraft and Rockets, Vol. 50, No. 6, pp. 1121-1133, Nov-Dec, 2013.
  • Mahzari, M.;Braun, R.D.; and White, T.R.; "Reconstruction of Mars Pathfinder Aerothermal Heating and Heatshield Material Response Using Inverse Methods,"Journal of Spacecraft and Rockets, Vol. 50, No. 6, pp. 1171-1182, Nov-Dec, 2013.
  • Korzun, A.M.;Cordell, C.E.; and Braun, R.D.; "Computational Aerodynamic Predictions of Supersonic Retropropulsion Flowfields," Journal of Spacecraft and Rockets, Vol. 50, No. 5, pp. 950-960, Sept-Oct, 2013.
  • Korzun, A.M.; and Braun, R.D.; "Application of a Reynolds-Averaged Navier-Stokes Approach to Supersonic Retropropulsion Flowfields," Journal of Spacecraft and Rockets, Vol. 50, No. 5, pp. 961-980, Sept-Oct, 2013.
  • Meginnis, I.M.;Putnam, Z.R.;Clark, I.G.;Braun, R.D.; and Barton, G.H.; "Guided Entry Performance of Low Ballistic Coefficient Vehicles at Mars," Journal of Spacecraft and Rockets, Vol. 50, No. 5, pp. 1047-1059, Sept-Oct, 2013.
  • Gunter, B.C.; and Maessen, D.C.; "Space-Based Distributed Computing Using a Networked Constellation of Small Satellites", Journal of Spacecraft and Rockets, Vol. 50, No. 5, pp. 1086-1095, Sept-Oct, 2013.
  • Dec, J.A.; and Braun, R.D.; "Three-Dimensional Finite Element Ablative Thermal Response and Design of Thermal Protection Systems," Journal of Spacecraft and Rockets, Vol. 50, No. 4, pp. 725-734, July-Aug, 2013.
  • Bopp, M.S.;Ruffin, S.M.;Braun, R.D.;Clark, I.G.; and Theisinger, J.T.; "Multi-Fidelity Approach to Estimate Heating for Three-Dimensional Hypersonic Aeroshells," Journal of Spacecraft and Rockets, Vol. 50, No. 4, pp. 754-762, July-Aug, 2013.
  • Cordell, C.E.; and Braun, R.D.; "Analytical Modeling of Supersonic Retropropulsion Plume Structures," Journal of Spacecraft and Rockets, Vol. 50, No. 4, pp. 763-770, July-Aug, 2013.
  • Mahzari, M.; and Braun, R.D.; "Time-dependent Mars Entry Aeroheating Estimation from Simulated In-Depth Heat Shield Temperature Measurements," Journal of Thermophysics and Heat Transfer, Vol. 27, No. 3, pp. 435-446, July 2013.

Journal Articles: 2012

  • Clark, I.G.; Braun, R.D.; and Ruffin, S.M.; "Validation of Computational Analyses for Supersonic Tension Cone Static Aerodynamic Performance," Journal of Spacecraft and Rockets, Vol. 49, No. 3, pp. 483-495, May-June, 2012.
  • Dec, J.A.; Braun, R.D.; and Laub, B.; "Ablative Thermal Response Analysis Using the Finite Element Method," Journal of Thermophysics and Heat Transfer, Vol. 26, No. 2, pp. 201-212, Apr-Jun, 2012.
  • Lafleur, J.M.; Fleming, E.S.; and Saleh, J.H.; "Response Surface Equations for Expendable Launch Vehicle Payload Mass Capability," Journal of Spacecraft and Rockets, Vol. 49, No. 1, pp. 185-189, Jan-Feb, 2012.

Journal Articles: 2011

  • Lafleur, J.M. and Cerimele, C.J.; "Mars Entry Bank Profile Design for Terminal State Optimization," Journal of Spacecraft and Rockets, Vol. 48, No. 6, pp. 1012-1024, Nov-Dec, 2011.
  • Bonfiglio, E.; Adams, D.; Craig, L.; Spencer, D.; Arvidson, R.; and Heet, T.; "Landing Site Dispersion Analysis and Statistical Assessment for the Mars Phoenix Lander," Journal of Spacecraft and Rockets, Vol. 48, No. 5, pp. 784-797, Sept-Oct, 2011.
  • Dubos, G.F. and Saleh, J.H.; "Spacecraft Technology Portfolio: Probabilistic Modeling and Implications for Responsiveness and Schedule Slippage," Acta Astronautica, Vol. 68, No. 7-8, pp. 1126-1146, Apr-May, 2011.
  • Marsh, C.L. and Braun, R.D.; "Fully Propulsive Mars Atmospheric Transit Strategies for High-Mass Missions," Journal of Spacecraft and Rockets, Vol. 48, No. 2, pp. 271-282, Mar-Apr, 2011.
  • Dubos, G.F. and Saleh, J.H.; "Comparative Cost and Utility Analysis of Monolith and Fractionated Spacecraft Using Failure and Replacement Markov Models," Acta Astronautica, Vol. 68, No. 1-2, pp. 172-184, Jan-Feb, 2011.

Journal Articles: 2010

  • Lafleur, J.M. and Saleh, J.H.; "Survey of Mission Evolution and Flexibility in the Space Shuttle Program," Space Policy, Vol. 26, No. 4, pp. 236-245, Nov, 2010.
  • Arora, N. and Russell, R.P.; "A Fast, Accurate, and Smooth Planetary Ephemeris Retrieval System," Celestial Mechanics and Dynamical Astronomy, Vol. 108, No. 2, pp. 107-124, Oct, 2010.
  • Korzun, A.M. and Braun, R.D.; "Performance Characterization of Supersonic Retropropulsion for High-Mass Mars Entry Systems," Journal of Spacecraft and Rockets, Vol. 47, No. 5, pp. 836-848, Sept-Oct, 2010.
  • Dubos, G.F.; Castet, J.F.; and Saleh, J.H.; "Statistical Reliability Analysis of Satellites by Mass Category: Does Spacecraft Size Matter?," Acta Astronautica, Vol. 67, No. 1-2, pp. 584-595, July-Aug, 2010.
  • Dubos, G.F. and Saleh, J.H.; "Risk of Spacecraft On-Orbit Obsolescence: Novel Framework, Stochastic Modeling, and Implications," Acta Astronautica, Vol. 67, No. 1-2, pp. 155-172, July-Aug, 2010.
  • Lafleur, J.M. and Saleh, J.H.; "Survey of Intra- and Inter-mission Flexibility in Space Exploration Systems," Acta Astronautica, Vol. 67, No. 1, pp. 97-107, July-Aug, 2010.
  • Grant, M.J.; Steinfeldt, B.A.; Braun, R.D.; and Barton, G.H.; "Smart Divert: A New Entry, Descent and Landing Architecture," Journal of Spacecraft and Rockets, Vol. 47, No. 3, pp. 385-393, May-June, 2010.
  • Korzun, A.M.; Dubos, G.F; Iwata, C.K.; Stahl, B.A.; and Quicksall, J.J; "A Concept for the Entry, Descent, and Landing of High-Mass Payloads at Mars," Acta Astronautica, Vol. 66, No. 7-8, pp. 1146-1159, April-May, 2010.
  • Castet, J.F. and Saleh, J.H.; "Beyond Reliability, Multi-State Failure Analysis of Satellite Subsystems: a Statistical Approach," Reliability Engineering and System Safety, Vol. 95, No. 4, pp. 311-322, Apr, 2010.
  • Castet, J.F. and Saleh, J.H.; "Single Versus Mixture Weibull Distributions for Nonparametric Satellite Reliability," Reliability Engineering and System Safety, Vol. 95, No. 3, pp. 295-300, Mar, 2010.
  • Steinfeldt, B.A.; Grant, M.J.; Matz, D.A.; Braun, R.D.; and Barton, G.; "Guidance Navigation and Control System Performance Trades for Mars Pinpoint Landing,"Journal of Spacecraft and Rockets, Vol. 47, No. 1, pp. 188-198, Jan-Feb, 2010.

Journal Articles: 2009

  • Brathwaite, J. and Saleh, J.H.; "Value-Centric Framework and Pareto Optimality for Design and Acquisition of Communication Satellites," International Journal of Satellite Communications and Networking, Vol. 27, No. 6, pp. 330-348, Nov-Dec, 2009.
  • Castet, J.F. and Saleh, J.H.; "Satellite and Satellite Subsystems Reliability: Statistical Data Analysis and Modeling," Reliability Engineering and System Safety, Vol. 94, No. 11, pp. 1718-1728, Nov, 2009.
  • Castet, J.F. and Saleh, J.H.; "Satellite Reliability: Statistical Data Analysis and Modeling," Journal of Spacecraft and Rockets, Vol. 46, No. 5, pp. 1065-1076, Sept-Oct, 2009.
  • Korzun, A.M.; Braun, R.D.; and Cruz, J.R.; "A Survey of Supersonic Retropropulsion Technology for Mars Entry, Descent and Landing," Journal of Spacecraft and Rockets, Vol. 46, No. 5, pp. 929-937, Sept-Oct, 2009.
  • Theisinger, J.E.; and Braun, R.D.; "Multiobjective Hypersonic Entry Aeroshell Shape Optimization," Journal of Spacecraft and Rockets, Vol. 46, No. 5, pp. 957-966, Sept-Oct, 2009.
  • Saleh, J.H. and Dubos, G.F.; "Responsive Space: Concept Analysis, Critical Review, and Theoretical Framework," Acta Astronautica, Vol. 65, No. 3-4, pp. 376-398, Aug-Sept, 2009.
  • Lafleur, J.M. and Saleh, J.H.; "System-Level Feasibility Assessment of Microwave Power Beaming for Small Satellites," Journal of Propulsion and Power, Vol. 25, No. 4, pp. 976-983, July-Aug, 2009.
  • Russell, R.P. and Brinckerhoff, A.T.; "Circulating Eccentric Orbits Around Planetary Moons," Journal of Guidance, Control, and Dynamics, Vol. 32, No. 2, pp. 424-436, Mar-Apr, 2009.
  • Clark, I.M.; Hutchings, A.L.; Tanner, C.L.; and Braun, R.D.; "Supersonic Inflatable Aerodynamic Decelerators for Use on Future Robotic Missions to Mars," Journal of Spacecraft and Rockets, Vol. 46, No. 2, pp. 340-352, Mar-Apr, 2009.

Journal Articles: 2008

  • Korzun, A.M.; Braun, R.D.; Wagner, E.B.; Fulford-Jones, T.R.; Deems, E.C.; Judnick, D.C.; and Keesee, J.E.; "Mars Gravity Biosatellite: Engineering, Science and Education," Acta Astronautica, Vol. 63, No. 4, pp. 8-19, July-Aug, 2008.
  • Dubos, G.F.; Saleh, J.H.; and Braun, R.D.; "Technology Readiness Level, Schedule Risk, and Slippage in Spacecraft DesignJournal of Spacecraft and Rockets, Vol. 45, No. 4, pp. 836-842, July-Aug, 2008.
  • Rohrschneider, R.R. and Braun, R.D.; "Static Aeroelastic Analysis of a Thin-Film Clamped Ballute for Titan Aerocapture," Journal of Spacecraft and Rockets, Vol. 45, No. 4, pp. 785-801, July-Aug, 2008.
  • Clark, I.G. and Braun, R.D.; "Ballute Entry Systems for Lunar Return and Low-Earth-Orbit Return Missions," Journal of Spacecraft and Rockets, Vol. 45, No. 3, pp. 619-630, May-June, 2008.
  • Wilhite, A.W.; Gholston, S.E.; Farrington, P.A.; and Swain, J.J.; "Evaluating Technology Projections and Weight Prediction Method Uncertainty of Future Launch Vehicles,"Journal of Spacecraft and Rockets, Vol. 45, No. 3, pp. 587-591, May-June, 2008.
  • Putnam, Z.R.; Bairstow, S.H.; Braun, R.D.; and Barton, G.H.; "Improving Lunar Return Entry Footprints Using Enhanced Skip Trajectory Guidance," Journal of Spacecraft and Rockets, Vol. 45, No. 2, pp. 309-315, Mar-Apr, 2008.
  • Christian, J.A.; Manyapu, K.; Wells, G.W.; Lafleur, J.M.; Verges, A.M.; and Braun, R.D.; "Sizing of an Entry, Descent, and Landing System for Human Mars Exploration,"Journal of Spacecraft and Rockets, Vol. 45, No. 1, pp. 130-141, Jan-Feb, 2008.

Journal Articles: 2007

  • Wooster, P.D.; Braun, R.D.; Ahn, J.; and Putnam, Z.R.; "Mission Design Options for Human Mars Missions," MARS: The International Journal of Mars Science and Exploration, Vol. 3, pp. 12-28, Aug, 2007.
  • Braun, R.D. and Manning, R.M.; "Mars Entry, Descent and Landing Challenges," Journal of Spacecraft and Rockets, Vol. 44, No. 2, pp. 310-323, Mar-Apr, 2007.
  • Putnam, Z.R.; Braun, R.D.; Rohrschneider, R.R.; and Dec, J.A; "Entry System Options for Human Return from the Moon and Mars," Journal of Spacecraft and Rockets, Vol. 44, No. 1, pp. 194-202, Jan-Feb, 2007.
  • Rohrschneider, R. and Braun, R.; "A Survey of Ballute Technology for Aerocapture,"Journal of Spacecraft and Rockets, Vol. 44, No. 1, pp. 10-23, Jan-Feb, 2007.

Journal Articles: 2006

  • Braun, R.D.; Wright, H.S.; Croom, M.A.; Levine, J.S.; and Spencer, D.A.; "Design of the ARES Mars Airplane and Mission Architecture," Journal of Spacecraft and Rockets, Vol. 43, No. 5, pp. 1026-1034, Sept-Oct, 2006.
  • Reeves, D.M.; Scher, M.D.; Wilhite, A.W.; and Stanley, D.O.; "Apollo Lunar Orbit Rendezvous Architecture Decision Revisited," Journal of Spacecraft and Rockets, Vol. 43, No. 4, pp. 910-915, July-Aug, 2006.
  • Shelton, J.D.; Frederick, R.A.; and Wilhite, A.W.; "Launch Vehicle Propulsion Design with Multiple Selection Criteria," Journal of Spacecraft and Rockets, Vol. 43, No. 4, pp. 893-902, July-Aug, 2006.

Journal Articles: 2005

  • Olds, J.; McCormick, D.; Charania, A.; and Marcus, L.; "Space Tourism: Making it Work for Fun and Profit," Journal of the British Interplanetary Society (JBIS), Vol. 58, No. 7-8, pp. 241-256, July-Aug, 2005.

Journal Articles: 2004

  • Budianto, I.A. and Olds, J.R.; "The Design and Deployment of a Satellite Constellation Using Collaborative Optimization," Journal of Spacecraft and Rockets, Vol. 41, No. 6, pp. 956-963, Nov-Dec, 2004.

Journal Articles: 2002

  • Ledsinger, L.A. and Olds, J.R.; "Optimized Solutions for Kistler K-1 Branching Trajectories Using Multidisciplinary Design Optimization Techniques," Journal of Spacecraft and Rockets, Vol. 39, No. 3, pp. 420-429, May-June, 2002.

Journal Articles: 2001

  • Way, D.W. and Olds, J.R.; "Space Transfer-Vehicle Concept for Deploying Solar-Power Satellites," Journal of Aerospace Engineering, Vol. 14, No. 2, pp. 65-71, Apr, 2001.
  • Olds, J.R. and Bradford, J.E.; "SCCREAM: A Conceptual Rocket-Based Combined-Cycle Engine Performance Analysis Tool," Journal of Propulsion and Power, Vol. 17, No. 2, pp. 333-339, Mar-Apr, 2001.

Journal Articles: 1999

  • Olds, J.R.; "Two Options for Flight Testing Rocket-Based Combined-Cycle Engines,"Journal of Spacecraft and Rockets, Vol. 36, No. 5, pp. 693-700, Sept-Oct, 1999.
  • Rowell, L.F.; Braun, R.D.; Olds, J.R.; and Unal, R.; "Multidisciplinary Conceptual Design Optimization of Space Transportation Systems," Journal of Aircraft, Vol. 36, No. 1, pp. 218-226, Jan-Feb, 1999.