MSC.Nastran Bibliography

Superelements/Large Problem Techniques/Substructuring

Arakawa, H.; Murakami, T.; Ito, H. Vibration Analysis of the Turbine Generator Stator Frame, The MSC 1988 World Users Conf. Proc., Vol. II, Paper No. 43, March, 1988. 

Arora, Tejbir; Birmingham, Lily. Application of MSC/NASTRAN Superelement Dynamic Reduction Techniques for the Vertical Launching System, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 39, March, 1988. 

Aslani, Chang; Yatheendar, Manicka; Visintainer, Randal, H.; Rohweder, David S.; Lopez de Alda, Juan. Simulation of Proving Ground Events for Heavy Truck Cabs Using Adams, MSC/NASTRAN, and P/FATIGUE, MSC 1994 World Users' Conf. Proc., Paper No. 5, June 1994. 

Bakhtiary, Nima; Rose, Ted L. Recommendations for Large Problem Solutions Using MSC/NASTRAN, The MSC 1992 World Users' Conf. Proc., Vol. II, Paper No. 62, May, 1992. 

Bellenda, R.; Miranda, D.; Pizzamiglio, M. GP-180 Aircraft: F.E.M. Design and Data Management, Proc. of the MSC/NASTRAN Eur. Users' Conf., April, 1985. 

Bereznak, R. M.; Sahota, C. S. Application of NASTRAN Level 16.0 Automated Multistage Substructuring Techniques, Sixth NASTRAN Users' Colloq., pp. 131-132, October, 1977, (NASA CP-2018). 

Bergere, G. Large Non-Linear Bearing Problems Solved with MSC/NASTRAN, NASTRAN User's Conf., Paper No. 4, June, 1981. 

Berthelon, T.; Capitaine, A. Improvements for Interpretation of Structural Dynamics Calculation Using Effective Parameters for Substructures, Proc. of the 18th MSC Eur. Users' Conf., Paper No. 9, June, 1991. 

Boroughs, Robert R. Development and Analysis of the Learjet 54/55 Fuselage NASTRAN Model Using Substructure Techniques, Ninth NASTRAN Users' Colloq., pp. 201-223, October, 1980, (NASA CP-2151). 

Brolliar, Steve; Bracklin, Joe. Nonlinear Analysis of the Solid Rocket Booster Aft Skirt Welds Using a Modified MSC/NASTRAN Superelement Approach, The MSC 1992 World Users' Conf. Proc., Vol. II, Paper No. 52, May, 1992. 

Brown, J. J.; Lee, J. M.; Parker, G. R.; Zuhuruddin, K. Procedure for Processing and Displaying Entire Physical Modes Based on Results Generated Through Component Mode Synthesis, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 15, March, 1988. 

Brunner, M.; Liebe, D. Module MERGEOFP2-A New Treatment of the Superelement Output for Postprocessing, Proc. of the 15th MSC/NASTRAN Eur. Users' Conf., October, 1988. 

Buchanan, Guy. Superelement Data Recovery via the Modal Acceleration Method, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 40, March, 1988. 

Buchanan, Guy. Hydroelastic Modeling Techniques in Superelement Analysis, The MSC 1988 World Users Conf. Proc., Vol. II, Paper No. 46, March, 1988. 

Butler, Thomas G. Transients by Substructuring with DMAP, Seventh NASTRAN Users' Colloq., pp. 301-334, October, 1978, (NASA CP-2062). 

Butler, Thomas G. Condensing Loaded Points for Transient by Substructuring, Eighth NASTRAN Users' Colloq., pp. 79-100, October, 1979, (NASA CP-2131). 

Calcagni, M.; Giordano, F.; Salvatore, R. MSC/NASTRAN Design Optimization: Applications to Aerospace Industry, MSC 1995 European Users' Conf. Proc., Italian Session, September, 1995. 

Carney, Kelly S.; Abdallah, Ayma A.; Hucklebridge, Arthur A. Implementation of the Block-Krylov Boundary Flexibility Method of Component Synthesis, The MSC 1993 World Users' Conf. Proc., Paper No. 26, May, 1993. 

Cattani, E.; Micelli, D.; Sereni, L.; Cocordano, S. Cylinder Block Eigenfrequencies and Eigenvectors Prediction with a Linear Brick and Wedge Finite Element Model, Proc. of the 19th MSC European Users' Conf., Paper No. 16, September, 1992. 

Cavalli, M. Esempi di Analisi di Grandi Strutture con Particolare Riferimento ai Problemi di Implementazione sulla Macchina, Proc. of the MSC/NASTRAN First Italian Users' Conf., October, 1987, in Italian. 

Chan, Gordon C.; Schmitz, Ronald P. Automated Multi-Level Substructuring for Sperry's Version of NASTRAN, Sixth NASTRAN Users' Colloq., pp. 133-154, October, 1977, (NASA CP-2018). 

Chong, Darryl G. Guide to MSC/NASTRAN V66B, International Business Machines Corporation, June, 1991. 

Coates, Dr. Tim. Static Analysis of the Wamira Aircraft Using External Superelements, The First Australasian MSC Users Conf. Proc., Paper No. 13, June, 1987. 

Cohen, Allan R.; Laurenson, Robert M. Application of a Substructure Technique for STS/Payload Coupled Modal Analysis, Proc. of the MSC/NASTRAN Users' Conf., March, 1979. 

Coleman-Curtis, Michelle; Gupta, Viney; Roche, Joseph M. Large-Scale Space Station Freedom FEM Modeling and Analyses Using Superelements, The MSC 1992 World Users' Conf. Proc., Vol. I, Paper No. 4, May, 1992. 

Cooke, Robert F. Superelement Planning, Data Management, and Multiple Boundary Conditions, MSC/NASTRAN Users' Conf. Proc., Paper No. 23, March, 1986. 

Darkis, M. Analysis of an Aircraft Engine Mounting Making Use of the Superelement and Material Non-linearity Capability in MSC/NASTRAN, The MSC 1988 World Users Conf. Proc., Vol. II, Paper No. 55, March, 1988. 

Del Basso, Steve; Singh, Sudeep; Lindenmoyer, Alan J. Component Mode Synthesis of Space Station Freedom Using MSC/NASTRAN Superelement Architecture, The MSC 1990 World Users Conf. Proc., Vol. II, Paper No. 48, March, 1990. 

Del Basso, Steve; Singh, Sudeep K.; Lindenmoyer, Alan J. Superelement Methodology for Coupled Loads Analysis of Space Station Freedom, 31st AIAA/ASME/ASCE/ AHS/ASC Structures, Structural Dynamics and Materials Conf., Part 4, pp. 2126-2142, April, 1990. 

Deloo, Ph.; Dunne, L.; Klein, M. Alter DMAPS for the Generation, Assembly and Recovery of Craig-Bampton Models in Dynamic Analyses, Actes de la 2ème Confèrence Française Utilisateurs des Logiciels MSC, Toulouse, France, September, 1995. 

Egashira, Yuji. Large Scale Vibration Analysis of Car Body Using Superelement Method, The Second MSC/NASTRAN User's Conf. in Japan, October, 1984, in Japanese. 

Farley, Mike. Pre- and Postprocessing Large Detailed MSC/NASTRAN Models, The MSC 1991 World Users' Conf. Proc., Vol. II, Paper No. 62, March, 1991. 

Ferragut, Nelson J. The Usage of Substructuring Analyses in the Get Away Special (GAS), Tenth NASTRAN Users' Colloq., pp. 204-215, May, 1982, (NASA CP-2249). 

Field, E. I.; Herting, D. N.; Herendeen, David L.; Hoesly, R. L. The Automated Multi-Stage Substructuring System for NASTRAN, NASTRAN: Users' Exper., pp. 571-592, September, 1975, (NASA TM X-3278). 

Field, Eric I. Unexpected Dividends from Level 16 Automated Substructuring, Sixth NASTRAN Users' Colloq., pp. 155-160, October, 1977, (NASA CP-2018). 

Filstrup, A. W. Normal Mode Analysis of a Rotating Group of Lashed Turbine Blades by Substructures, NASTRAN: Users' Exper., pp. 301-322, September, 1973, (NASA TM X-2893). 

Flanigan, Christopher C. Accurate and Efficient Mode Acceleration Data Recovery for Superelement Models, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 38, March, 1988. 

Flanigan, Christopher C. Accurate Enforced Motion Analysis Using MSC/NASTRAN Superelements, MSC 1994 World Users' Conf. Proc., Paper No. 25, June, 1994. 

Flanigan, Christopher C. Efficient and Accurate Procedures for Calculating Data Recovery Matrices for Superelement Models, The 1989 MSC World Users Conf. Proc., Vol. II, Paper No. 4, March, 1989. 

Fresko, D.; Neer, A. GIN (General Interface to NASTRAN): A Data Management System for MSC/NASTRAN Models, The MSC 1988 World Users Conf. Proc., Vol. II, Paper No. 49, March, 1988. 

Gibson, Warren C. Component Damping with Superelements, MSC/NASTRAN Users' Conf. Proc., Paper No. 8, March, 1985. 

Greenberg, Mitchell L. Use of MSC/NASTRAN General Elements in Complex Static Problems, MSC 1995 World Users' Conf. Proc., Paper No. 24, May, 1995. 

Grooms, H. R.; Yahata, S. Space Shuttle-The Need for Substructuring, NASTRAN: Users' Exper., pp. 769-778, September, 1971, (NASA TM X-2378). 

Hardman, E. S. Static and Normal Modes Analysis of an Aircraft Structure Using the NASTRAN External Superelement Method, Proc. of the MSC/NASTRAN Eur. Users' Conf., May, 1986. Paper no. 7.

Haenen, E. Building Block Approach for Truck Chassis Analysis Using a Superelement Library, Proc. of the 19th MSC European Users' Conf., Paper No. 25, September, 1992. 

Harstad, K.; Zemer, D. Finite Element Analysis for the Design Study of a 370 Metre High Reinforced Concrete Offshore Gas Platform, Proc. of the MSC/NASTRAN Eur. Users' Conf., April, 1985. 

Hennrich, Carl W.; Konrath, Edwin J. Jr. Substructure Analysis Techniques and Automation, NASTRAN: Users' Exper., pp. 323-394, September, 1973, (NASA TM X-2893). 

Housner, Jerrold M.; Aminpour, Mohammad A.; Dávila, Carlos G.; Schiermeier, John E.; Stroud, W. Jefferson; Ransom, Jonathan B.; Gillian, Ronnie E. An Interface Element for Global/Local and Substructuring Analysis, MSC 1995 World Users' Conf. Proc., Paper No. 25, May, 1995. 

Huang, J-Shan. The Optimal Design of Structural Systems by the Superelement Method, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 7, March, 1988. 

Irvine, M.; Brown, R. Full Vehicle Body Model Analysis Using Superelement Techniques, Proc. of the 15th MSC/NASTRAN Eur. Users' Conf., October, 1988. 

Kasai, Manabu. Generalized CMS Employing External Superelements, The Fourth MSC/NASTRAN User's Conf. in Japan, October, 1986, in Japanese. 

Kim, Hyoung M.; Bartkowicz, Theodoore J.; Van Horn, David A. Data Recovery and Model Reduction Methods for Large Structures, The MSC 1993 World Users' Conf. Proc., Paper No. 23, May, 1993. 

Kohno, Kazukiyo; Tsunada, Tomohiro; Seto, Hideyuki; Tanaka, Michio. Hybrid Stress Analysis of Boundary and Finite Elements by a Super-Element Method, Finite Elements in Analysis and Design, Vol. 7, No. 4, pp. 279-290, February, 1991. 

Komzsik, L.; Rose, T. Substructuring in MSC/NASTRAN for Large Scale Parallel Applications, Computing Systems in Engineering, Vol. 2, No. 2-3, pp. 167-173, 1991. 

Kubota, Minoru. Efficient Use of Component Mode Synthesis Using Image Superelements Applied to Dynamic Analysis of Crankshaft, MSC/NASTRAN Users' Conf. Proc., Paper No. 22, March, 1986. 

Kubota, Minoru. Response Spectrum Analysis of Underground Tank Dome Roof Using Image Superelement Method, The Fifth MSC/NASTRAN User's Conf. in Japan, October, 1987, in Japanese. 

Kurokawa, Kunihiko. Superelement Static Analysis for Jet Propulsion Engine Structure, The First MSC/NASTRAN User's Conf. in Japan, October, 1983, in Japanese. 

Lahey, R. S. Substructure Coupling-A Different Approach, Sixth NASTRAN Users' Colloq., pp. 161-174, October, 1977, (NASA CP-2018). 

Larkin, Paul A.; Miller, Michael W. MSC/NASTRAN Superelement Analysis, MSC/NASTRAN Users' Conf. Proc., Paper No. 10, March, 1982. 

Lawson, D. W.; Webster, J. L.; Overbye, V. D. MSC/NASTRAN Superelements in Structures with Reflective Symmetry, Proc. of the Conf. on Finite Element Methods and Technology, March, 1980. 

Lee, W. M. Substructure Mode Synthesis with External Superelement, The 2nd Annual MSC Taiwan User's Conf., Paper No. 16, October, 1990, in Chinese. 

Leuer, John P.; Chung, Y. T. A Superelement Approach to NSTS/Space Station Payload Coupled Loads Analysis Using MSC/NASTRAN V66, The MSC 1992 World Users' Conf. Proc., Vol. II, Paper No. 55, May, 1992. 

Levy, Alvin. NASTRAN Multipartitioning and One-Shot Substructuring, NASTRAN: Users' Exper., pp. 285-300, September, 1973, (NASA TM X-2893). 

Lu, Leo K. Coupled Blade-Disk Vibration Analysis by Superelement and Cyclic Symmetry Methods, MSC/NASTRAN Users' Conf. Proc., Paper No. 14, March, 1982. 

MacNeal, R. H.; McCormick, C. W. Computerized Substructure Analysis, World Conf. on Finite Element Methods, October, 1975. 

Maekawa, Seiyou. Advantage and Critical Points in Superelements Analysis, The Third MSC/NASTRAN User's Conf. in Japan, October, 1985, in Japanese. 

Mase, M.; Saito, H. Application of FEM for Vibrational Analysis of Grouped Turbine Blades, MSC/NASTRAN Users' Conf., March, 1978. 

Mazet, G. B.; Gillot, E. Static Analysis Using Super-Elements of a Part of an Aircraft Brake Assembly, Proc. of the 17th MSC Eur. Users' Conf., Paper No. 25, September, 1990. 

Mera, A. MSC/NASTRAN's Numerical Efficiency for Large Problems on CYBER Versus Cray Computer, Proc. of the MSC/NASTRAN Eur. Users' Conf., June, 1983. 

Nagy, L. I.; Campbell, G. C. Modeling Strategy and Semi-Automated Connectivity Checking for Large Size Finite Element Models, Proc. of the Conf. on Finite Element Methods and Technology, Paper No. 20, March, 1981. 

Narayanaswami, R. Applications of NASTRAN Substructuring, NASTRAN: Users' Exper., pp. 485-496, September, 1972, (NASA TM X-2637). 

Nees, H.; Schmid, R. Large Finite Element Model of Valve Structure Solved with NASTRAN Superelement Technique, Proc. of the MSC/NASTRAN Eur. Users' Conf., June, 1983. 

Palmieri, F. W. Analyzing Deployment of Spacecraft Appendages Using MSC/NASTRAN, The MSC 1990 World Users Conf. Proc., Vol. I, Paper No. 6, March, 1990. 

Patel, Hemant. Development of Superelement Design Sensitivity in MSC/NASTRAN, The MSC 1991 World Users' Conf. Proc., Vol. I, Paper No. 3, March, 1991. 

Patel, Magan P.; Shah, Lalit C. Dynamic Analysis Using Superelements for a Large Helicopter Model, Seventh NASTRAN Users' Colloq., pp. 335-354, October, 1978, (NASA CP-2062). 

Peters, Ken J.; Nelson, Brian H. A Multilevel Superelement Approach to the Analysis of Electronic Hardware, MSC/NASTRAN Users' Conf. Proc., Paper No. 21, March, 1985. 

Petesch, D.; Deuermeyer, D. Performance Considerations for Running Very Large MSC/NASTRAN Models on Current and Future Cray Research Supercomputers, Proc. of the 20th MSC European Users' Conf., September, 1993. 

Petesch, Doug. Efficient Execution of Very Large MSC/NASTRAN Models, Proc. of the 21st MSC European Users' Conf., Italian Session, September, 1994. 

Philippopoulos, V. G. Dynamic Analysis of an Engine-Transmission Assembly-Superelement and Component Mode Synthesis, Proc. of the Conf. on Finite Element Methods and Technology, Paper No. 3, March, 1981. 

Popham, B. Use of MSC/NASTRAN on the Olympus Satellite Project, Proc. of the MSC/NASTRAN Eur. Users' Conf., May, 1987. 

Poulter, J. The Use of MSC/NASTRAN External Superelements within an Automated Analysis Package, Proc. of the 15th MSC/NASTRAN Eur. Users' Conf., October, 1988. 

Radaj, D.; Schilberth, G. Efficiency of the Multilevel Superelement Technique, NASTRAN User's Conf., April, 1978. 

Redner, Keith H.; Hennrich, Carl W. Superelement Management in a Network Environment, The MSC 1990 World Users Conf. Proc., Vol. II, Paper No. 63, March, 1990. 

Reyer, H. Modal Synthesis with External Superelements in MSC/NASTRAN, Proc. of the MSC/NASTRAN Eur. Users' Conf., May, 1984. 

Rose, Ted. DMAP Alters to Apply Modal Damping and Obtain Dynamic Loading Output for Superelements, The MSC 1993 World Users' Conf. Proc., Paper No. 24, May, 1993. 

Rose, Ted L. Using Superelements to Identify the Dynamic Properties of a Structure, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 41, March, 1988. 

Rose, Ted L. Using Superelements for Response Spectrum and Other Handy Alters, The 1989 MSC World Users Conf. Proc., Vol. II, Paper No. 45, March, 1989. 

Sabahi, D.; Rose, T. L. Finite Element Analysis of the Twelve Foot Pressurized Wind Tunnel, Proc. of the 1989 ASME Int. Computers in Engineering Conf. and Exposition, Vol. 2, pp. 389-397, July, 1989. 

Sabahi, Dara; Rose, Ted. Special Applications of Global-Local Analysis, The MSC 1990 World Users Conf. Proc., Vol. II, Paper No. 49, March, 1990. 

Sabahi, Dara; Rose, Ted. MSC/NASTRAN Superelement Analysis of the NASA/AMES Pressurized Wind Tunnel, The MSC 1990 World Users Conf. Proc., Vol. II, Paper No. 50, March, 1990. 

Shah, Lalit C. Automated Multi-Stage Substructuring Analysis Compared with Superelement Analysis, NASTRAN: Users' Exper., pp. 593-594, September, 1975, (NASA TM X-3278). 

Shein, Shya-Ling. Generation of the Space Station Freedom On-Orbit Dynamic Loads Analysis Model Using MSC/NASTRAN V66A Superelements, The 2nd Annual MSC Taiwan Users Conf., Paper No. 7, October, 1990. 

Shein, Shya-Ling; Marquette, Brian; Rose, Ted. Superelement Technology Application and Development in Dynamic Analysis of Large Space Structures, The MSC 1991 World Users' Conf. Proc., Vol. I, Paper No. 26, March, 1991. 

Shyu, Bor-Lin; Fu, Hsueh-Horng; Chiang, Kuo-Ning. The Application of Sparse Iterative and Direct Solvers on Large-Scale FEM Models, The Sixth Annual MSC Taiwan Users' Conf. Proc., Paper No. 2, November, 1994. 

Singh, Sudeep K.; Engelhardt, Charlie. Dynamic Analysis of a Large Space Structure Using External and Internal Superelements, The MSC 1991 World Users' Conf. Proc., Vol. I, Paper No. 27, March, 1991. 

Smith, C. M. The Application of Reanalysis Techniques to Large Finite Element Models Through NASTRAN DMAP, The MSC 1988 World Users Conf. Proc., Vol. I, Paper No. 16, March, 1988. 

Spangler, N.; Raasch, I. Some Drawbacks in the Use of the Superelement Technique, Proc. of the MSC/NASTRAN Eur. Users' Conf., April, 1982. Paper No. 11. 

Steinmuller, G.; Wamsler, M. Experiences in the Application of NASTRAN Superelement Techniques for Large Structures, NASTRAN User's Conf., May, 1979. 

Stone, Mark J.; Genberg, Vic. Nonlinear Superelement Analysis to Model Assembly Processes, The MSC 1993 World Users' Conf. Proc., Paper No. 59, May, 1993. 

Storm, E.; Zemer, D. T. Structural Analysis and Design of an Automobile Joint Using the NASTRAN Superelement Method, Proc. of the MSC/NASTRAN Eur. Users' Conf., June, 1983. 

Swan, Jim. A DMAP Alter for Interface Loads Across Superelements in Dynamic Analyses, The MSC 1992 World Users' Conf. Proc., Vol. I, Paper No. 23, May, 1992. 

Ullio, R.; Marucchi-Chierro, P. C. A Methodological Study on Fluid/ Structure Interaction using Superelement Technique in Order to Control by Design the Induced Vibroacoustic Environment for Manned Space Modules, Proc. of the 20th MSC European Users' Conf., Paper No. 19, September, 1993. 

Vandepitte, D.; Wijker, J. J.; Appel, S.; Spiele, H. Normal Modes Analysis of Large Models, and Applications to Ariane 5 Engine Frame, Proc. of the 18th MSC Eur. Users' Conf., Paper No. 6, June, 1991. 

Vitiello, P.; Quaranta, V. SEA Investigation Via a FEM Based Substructuring Technique, MSC 1995 European Users' Conf. Proc., Italian Session, September, 1995. 

Wijker, J. J. Substructuring Technique Using the Modal Constraint Method, Proc. of the MSC/NASTRAN Eur. Users' Conf., June, 1983. 

Wilson, Charles T. Efficiency Improvements for Static Analysis with Superelements, MSC/NASTRAN Users' Conf., March, 1978. 

Wilson, Thomas L. A NASTRAN DMAP Alter for the Coupling Modal and Physical Coordinate Substructures, Sixth NASTRAN Users' Colloq., pp. 119-131, October, 1977, (NASA CP-2018). 

Wolf, M. Cyclic Symmetry and Superelements, A DMAP Coupling Algorithm, Proc. of the MSC/NASTRAN Eur. Users' Conf., May, 1984. 

Wu, H. T.; Diep, S. Q.; Gupta, V. K. Nonlinear Static Analysis of McDonnell Douglas MD90 Aircraft Using MSC/NASTRAN Superelement Database, The MSC 1991 World Users' Conf. Proc., Vol. II, Paper No. 38, March, 1991. 

Zaphir, Zvi. Crack Propagation Analysis Using NASTRAN Superelement Capability, MSC/NASTRAN Users' Conf. Proc., Paper No. 4, March, 1983. 

Zavareh, P.; McNamee, M. Inertia Relief Solutions of Large Finite Element Models with Applications of Multiple External Superelements, The 1989 MSC World Users Conf. Proc., Vol. II, Paper No. 46, March, 1989. 

Zemer, David T. A Direct Matrix Abstraction Procedure for a Static Solution During a Phase I Substructuring Analysis, Sixth NASTRAN Users' Colloq., pp. 105-119, October, 1977, (NASA CP-2018). 

Zemer, David T. Comparison of Several NASTRAN Analytical Techniques for Large Structures, Seventh NASTRAN Users' Colloq., pp. 355-364, October, 1978, (NASA CP-2062). 

Zemer, David T. Implementation of Superelement Analysis at the Production Level, Proc. of the MSC/NASTRAN Users' Conf., March, 1979. 

Zerenghi, A.; Intema, S. P. A.; Fanchi, L. Structural Design of an Antenna Reflector Assembly for Space Telecommunication Purposes Using MSC/NASTRAN, Proc. of the MSC/NASTRAN Eur. Users' Conf., May, 1984. 

Zerenghi, A. Structural Design of an Antenna Reflector Assembly for Space Telecommunications Purposes Using MSC/NASTRAN, Proc. of the MSC/NASTRAN First Italian Users' Conf., October, 1987. 

Zimmerman, D.; Dahm, R. NASTRAN Processing for Large Car Structures on Cray and Cyber Computers, Proc. of the MSC/NASTRAN Eur. Users' Conf., May, 1986. 

Zimmermann, D.; Ahmad, R. Superelement Technique Applied to Car Body Development, NASTRAN User's Conf., June, 1981. Paper No. 17.