Publications Archive

2010

A. Khasawneh, S. A. Alvarez, C. Ruiz, S. Misra, and M. Moonis. "Discovery of Sleep Composition Types using Expectation-Maximization", Proc. 23rd IEEE International Symposium on Computer-Based Medical Systems (CBMS 2010), Perth, Australia, Oct. 12-15, 2010.

S. Floyd, C. Ruiz, S. A. Alvarez, J. Tseng, G. Whalen. "Model selection meta-learning for the prognosis of pancreatic cancer", full paper (acceptance rate: 46/410 = 11.2%), Proc. Third International Conference on Health Informatics (HEALTHINF 2010), in conjunction with the Third International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2010), Valencia, Spain, Jan. 20-23, 2010, 29-37.

J. Hayward, S. A. Alvarez, C. Ruiz, M. Sullivan, J. Tseng, and G. Whalen. "Machine Learning of Clinical Performance in a Pancreatic Cancer Database", Artificial Intelligence in Medicine, special issue on Data Mining Approaches to the Study of Disease Genes and Proteins (Sun Kim, ed.), vol. 49, issue 3, July 2010, 187-195. DOI: 10.1016/j.artmed.2010.04.009.

Michael A. Kiebish, Rob Bell, Kui Yang, Toan Phan, Zhongdan Zhao, William Ames, Thomas N. Seyfried, Richard W. Gross, Jeffrey H. Chuang, and Xianlin Han. J. "Dynamic simulation of cardiolipin remodeling: Greasing the wheels for an interpretative approach to lipidomics", J. Lipid Res., doi:10.1194/jlr.M004796.

Soonmin Bae and Hao Jiang, "Building a Videorama with Shallow Depth of Field", IEEE International Conference on Pattern Recognition (ICPR 2010). To appear.

Hao Jiang, "3D Human Pose Reconstruction Using Millions of Exemplars", IEEE International Conference on Pattern Recognition (ICPR 2010). To appear.

Hao Jiang, Mark S. Drew and Ze-Nian Li, "Action Detection in Cluttered Video with Successive Convex Matching", IEEE Transactions on Circuits and Systems for Video Technology. Jan. 2010.

Howard Straubing, Pascal Tesson and Denis Thérien, "Weakly iterated block products and applications to logic and complexity", International Journal of Algebra and Computation, 20(2) 319-341 (2010).

2009

M. Bojanczyk, H. Straubing, and I. Walukiewicz, "Wreath prodcucts of forest algebras, with applications to tree logics", Proc. 24th IEEE Symposium on Logic in Computer Science (LICS) (2009) 255-263.

H. Jiang and S. X. Yu, "Linear Solution to Scale and Rotation Invariant Object Matching", IEEE Conference on Computer Vision and Pattern Recognition, Miami Beach, Florida, June 2009.

C. Pavlopoulou, D. Martin, S. X. Yu and H. Jiang, "Learning from Disagreements: Discriminative Performance Evaluation", The 11th IEEE International Workshop on Performance Evaluation of Tracking and Surveillance, Miami Beach, Florida, June 2009.

2008

E. Sciore, Database Design and Implementation. John Wiley, October 2008.

J. Hayward, S. A. Alvarez, C. Ruiz, M. Sullivan, J. Tseng, and G. Whalen. "Knowledge Discovery in Clinical Performance of Cancer Patients", to appear in Proceedings of the 2008 IEEE International Conference on Bioinformatics and Biomedicine, Philadelphia, PA, USA, Nov. 3-5, 2008.

H. Straubing and D. Thérien, "Modular Quantifiers", E. Grädel, J. Flum and T. Wilke (eds.), Logic and Automata: History and Perspectives, vol. 2 of the series Texts in Logic and Games, Amsterdam University Press, 2008, pp. 613-628.

M. Bojanczyk, L. Segoufin and H. Straubing, "Piecewise Testable Tree Languages", to appear in Proceedings of 23rd IEEE Symposium on Logic in Computer Science (LICS 2008).

H. Jiang and D. Martin, "Global Pose Estimation Using Non-tree Models", Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2008).

H. Jiang and D. Martin, "Finding Actions Using Shape Flows", European Conference on Computer Vision, Marseille, October 2008.

2007

S. A. Alvarez, C. Ruiz, and T. Kawato. "More Efficient Mining over Heterogeneous Data using Neural Expert Networks", in Multimedia Data Mining and Knowledge Discovery (V.A. Petrushin and L. Khan, eds.), Springer-Verlag, 2007.

S. Floyd, S. A. Alvarez, C. Ruiz, J. Hayward, M. Sullivan, J. Tseng, and G. Whalen. "Improved Survival Prediction for Pancreatic Cancer using Machine Learning and Regression", Society for the Surgery of the Alimentary Tract 48th Annual Meeting (SSAT 2007), in conjunction with Digestive Disease Week, Washington DC, USA, May 19-23, 2007.

J. Hayward, S. A. Alvarez, C. Ruiz, J. Tseng, M. Sullivan, and G. Whalen. "Survival of Pancreatic Cancer Patients Predicted using Machine Learning", Society of Surgical Oncology 60th Annual Cancer Symposium, Washington DC, USA, March 15-18, 2007.

H. Jiang, S. Fels and J. Little, A Linear Programming Approach for Multiple Object Tracking Computer Vision and Pattern Recognition 2007 (CVPR'07).

H. Jiang, M. S. Drew and Ze-Nian Li, Matching by Linear Programming and Successive convexification, IEEE Transaction on Pattern Analysis and Machine Intelligence, June, 2007.

H. Jiang and M. S. Drew, Shadow Resistant Object Tracking using Inertia Constraints Pattern Recognition, July, 2007.

H. Jiang, Ze-Nian Li and Mark S. Drew, Recognizing Posture in Pictures with Successive Convexification and Linear Programming, IEEE Multimedia, April, 2007.

A. Roy and H. Straubing, Definability of Languages by Generalized First-Order Formulas over (N; +), SIAM Journal on Computing, 37 (2), 502{521, 2007.

R. Signorile, "Integrating Planning Agents and Simulation into a Dynamic Decision Support System for Controlling the Logistics of a Transportation System", Proceedings of the Conceptual Modeling and Simulation (CMS) February, 2007.

2006

P. Laxminarayan, S. A. Alvarez, C. Ruiz, and M. Moonis. "Mining Statistically Significant Associations for Exploratory Analysis of Human Sleep Data", IEEE Transactions on Information Technology in Biomedicine, vol. 10, no. 3, July 2006, 440–450.

A. Roy and H. Straubing, Defineability of First Order Languages over (N; +), by 23rd Annual Symposium on Theoretical Aspects of Computer Science (STACS), 2006. Appeared in Lecture Notes in Computer Science (LNCS) 3884, 489-499.

E. Duenez, S. Miller, A. Roy and H. Straubing, Incomplete Exponential Sums in Several Variables, by Journal of Number Theory, 116 (2006), no. 1, 168-199.

R. Signorile, "Simulation, Logistics and Transportation for Energy Plants", Workshop on Logistics and Transportation", Milan, Italy, November, 2006.

Borowsky, E., Logan, A. and R. Signorile, "Leveraging the client-server model in P2P: Managing concurrent file updates in a P2P system", International Conference on Internet and Web Applications and Services (ICIW'06), February 23-25, 2006 Guadeloupe, French Caribbean.

H. Straubing, "Inexpressibility Results for Regular Languages in Nonregular Settings", in C. de Felice, A. Restivo (eds.), Developments in Language Theory, LNCS 3572, (2005) 69-77. (with D. Thérien) "A Note on Mod p-Mod m Circuits", Theory of Computing Systems 39 (2006) 699-706.

L. Chaubard, J. E. Pin and H. Straubing, "First-order Formulas with Modular Predicates", Proceedings of 2006 21st IEEE Symposium on Logic in Computer Science, (2006), 211-220.

L. Chaubard, J. E. Pin and H. Straubing, "Actions, Wreath Products of C-varieties, and Concatenation Product", Theoretical Computer Science 356 (2006), 73-89.

2005

P. Laxminarayan, C. Ruiz, S. A. Alvarez, and M. Moonis. "Mining Associations over Human Sleep Time Series", Proc. 18th IEEE International Symposium on Computer-Based Medical Systems (IEEE CBMS 2005), Dublin, Ireland, June 2005.

F. Green, A. Roy, H. Straubing, Bounds on an Exponential Sum arising in Boolean Circuit Complexity, Comptes Rendus Mathematique, C.R. Acad. Sci. Paris, Ser I 341 (2005), 279-282.

R. Signorile," Multi-Agent Peer to Peer System for Supply Chain Simulation", Conceptual Modeling and Simulation Conference (CMS'2005), Marseilles, France, October 20-22, 2005.

R. Signorile, "A Decision Support System For Inventory Control Using Planning And Distributed agents", 18th International Conference on Industrial & Engineering Applications of Artificial Intelligence & Expert Systems, June 22-25, 2005, Bari, Italy.

H. Straubing and D. Thérien, "Regular Languages Defined by Generalized First-order Formulas with a Bounded Number of Bound Variables", Theory of Computing Systems 36 (2003) 29-69. (with J. E. Pin) "Some Results on C-varieties", RAIRO: Theoretical Informatics, 39 (2005) 239-262.

H. Straubing "Inexpressibility Results for Regular Languages in Nonregular Settings", in C. de Felice, A. Restivo (eds.), Developments in Language Theory, LNCS 3572, (2005) 69-77. (with D. Thérien) "A Note on Mod p-Mod m Circuits", Theory of Computing Systems 39 (2006) 699-706.

2004

S. A. Alvarez, "A Theory of Frame Transformations for Belief Combination", Annals of Mathematics and Artificial Intelligence, vol. 40, no. 3/4, 187–213, March 2004 Sergio A. Alvarez

E. Sciore, "Enabling Collaborative Administration and Safety Fences: Factored Privileges in SQL Databases" (with A. Rosenthal). IEEE Data Engineering Bulletin 27:1, March 2004, pp. 42-47. Invited Submission.

R. Signorile, "Combining Cellular Automata and Multi-Agents in a Unified Simulation System for Crowd Control ", 16th European Simulation Conference, Oct. 17-20, 2004, Budapest, Hungary.

2003

S. A. Alvarez, C. Ruiz, and V. Dignum. "Data Mining and Web Knowledge Management", in Web Knowledge Management and Decision Support: Selected Papers from the Fourteenth International Conference on Applications of Prolog, LNCS 2543, Springer-Verlag, 2003.

S. A. Alvarez, T. Kawato, and C. Ruiz. "Mining over Loosely Coupled Data Sources using Neural Experts", Fourth International Workshop on Multimedia Data Mining (MDM/KDD2003), in conjunction with the Ninth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD2003), Washington, DC, Aug. 2003.

S. A. Alvarez. "Chi–Squared Computation for Association Rules: Preliminary Results", Technical Report BC-CS-03-01, Computer Science Department, Boston College, July 2003.

R. Muller, Inferring Annotated Types for Inter-procedural Register Allocation with Constructor Flattening, with Torben Amtoft, to appear in the Proceedings of the 2003 Workshop on Types in Language Design and Implementation (TLDI'03), New Orleans, LA, January, 2003.

R. Signorile and A. Bruzzone, "Harbor Management using Simulation and Genetic Algorithms", Port Technology International, Edition 18, January 2003.

R. Signorile and J. Pearlin, "Simulation of a Distributed Mutual Exclusion Algorithm Using Multicast Communication", Proceedings of the ESS2003,October 26-29, 2003 Delft, The Netherlands.

R. Signorile, "Distributed Simulation Using JINI", Proceedings of the 7th IEEE DS-RT'2003 International Symposium on Distributed Simulation and Real Time Applications October 23-26, 2003 Delft, The Netherlands.

R. Signorile, "Simulation for Logistics and Supply Chains", Proceedings of the 2003 Summer Simulation Multiconference, July 20–24, 2003 Montreal, Canada.

2002

W.-Y. Lin, S. A. Alvarez, and C. Ruiz. "Efficient Adaptive–Support Association Rule Mining for Recommender Systems", Data Mining & Knowledge Discovery, 6(1), 83-105, Jan. 2002.

S. A. Alvarez. "An Exact Analytical Relation among Recall, Precision, and Classification Accuracy in Information Retrieval", Technical Report BC-CS-02-01, Computer Science Department, Boston College, July 2002.

R. Muller, A Calculus with Polymorphic and Polyvariant Flow Types, with J. B. Wells, Allyn Dimock and Franklyn Turbak. 44 Pages. Journal of Functional Programming, 12 (3):183-227, May 2002.

R. Signorile, A System Dynamic Simulation of Logistics and Customer Service for Business Enterprises, Special issue of the Journal—Simulation - Simulation of Supply Chains, 2002.

R. Signorile, "The Wireless Mobility Integration Protocol for Using TCP/IP over Wired and Wireless Networks, Proceedings of the ESS2002 Modeling and Simulation conference, Dresden, Germany, October 22-25, 2002.

R. Signorile, "Using Distributed Simulation in Logistics and Supply Chain Management", Proceedings of the HMS2002 Conference, Bergeggi, Italy, Oct. 2002.

H. Straubing and D. Thérien, "Weakly Iterated Block Products of Finite Monoids", in Proceedings of LATIN 2002, Lecture Notes in Computer Science 2286 (2002).

H. Straubing "On the Logical Description of Regular Languages", Proceedings of LATIN 2002, Lecture Notes in Computer Science 2286 (2002).

2001

C. Shoemaker, M. Sao Pedro, M. Pungliya, C. Ruiz, S. A. Alvarez, M. Ward, E.F. Ryder, and J. Krushkal. "Computational Methods for Single Point and Multipoint Analysis of Genetic Variants Associated with Simulated Complex Disorder in a General Population", Genetic Epidemiology, vol. 21 (Suppl. 1): S738-S745, Nov. 2001.

M. Streeter, M. Ward, and S. A. Alvarez. "N2VIS – An Interactive Visualization Tool for Neural Networks", Conference on Visual Data Exploration and Analysis VIII, Proc. SPIE Vol. 4302, San Jose, CA, Jan. 2001.

R. Muller, Functioning Without Closure: Type-Safe Customized Function Representations for Standard ML, with Allyn Dimock, Ian Westmacott, Franklyn Turbak and Joe Wells, in the Proceedings of the ACM International Conference on Functional Programming, Florence, Italy, September, 2001.

A. Bruzzone and R. Signorile, Container Terminal planning by using Simulation and Genetic Algorithms, Journal of Maritime Harbor and Port Management, Fall 2001.

R. Signorile, Using Simulation to Optimize the Operations of an Emergency Room, Proceedings of the ESS 2001 Modeling and Simulation conference, Marseilles, France, October 16-21, 2001.

R. Signorile, "A System Dynamic Simulation of Logistics and Customer Service for Business Enterprises", Special Session on Simulation Aided Decision Support and Planning at the Proceedings of the International Conference on Information Systems, Analysis and Synthesis, Orlando, FL, July 2001.

H. Straubing, "Languages Defined by Modular Quantifiers", Information and Computation 166 (2001) 112-132.

2000

R. Signorile, "Multi-Agent Simulation", Proceedings of the International Conference on Systemics, Cybernetics and Informatics, July 2000.

R. Signorile, "Using Simulation for Business Decision Analysis", Proceedings of the International Conference on Information Systems, Analysis and Synthesis, July 2000.

R. Signorile, "Inventory Management Simulation with Agents", Proceedings of the HMS, Genova, Italy, Oct. 2000.

R. Signorile., "Distributed Intelligent Agents For A Collaborative Web-based Simulation", Proceedings of the International Conference on Web-Based Modeling and Simulation, San Diego, CA, January 2000.

H. Straubing, "When Can One Finite Monoid Simulate Another?", in J.C. Birget, S. Margolis, J. Meakin and M. Sapir (eds.) Algorithmic Problems in Groups and Semigroups, Birkh¨auser (2000) 267-288.

1999

E. Sciore, "First Class Views: A Key to User-Centered Computing" (with A. Rosenthal). SIGMOD RECORD, September 1999, pp. 29-36.

R. Signorile, "A framework for distributed intelligent agents in the simulation of external logistics of an enterprise", Proceedings of the HMS, Genova, Italy, Oct. 1999.

R. Signorile, "Simulating the Use of Intelligent Agents in an Automated Distributed Multi-Constrained Scheduling System", Proceedings of the 11th ESS, September, 1999.

A. Bruzzone and R. Signorile, "Crowd Control Simulation in a Java Based Environment", Proceedings of the International Conference on Web-Based Modeling and Simulation, San Francisco, CA, January 1999.

D. Barrington and H. Straubing, "Lower Bounds for Modular Counting by Circuits with Modular Gates", Computational Complexity 8 (1999) 258-272.

1998

Bruzzone, A. and R. Signorile, "Simulation and Genetic Algorithms for Ship Planning and Shipyard Layout", in the Special Issue SIMULATION on Harbor and Maritime Simulation, Oct. 1998.

R. Signorile, "A Study in the Use of Distributed Intelligent Agents in the Simulation of a Flexible Manufacturing Environment", Proceedings of the International the 10th European Simulation Conference, Oct. 1998.

R. Signorile, "Introducing simulation to the small businesses manager: a real live case", Proceedings of the ASTC '98, Boston, MA April 1998.

P. P´eladeau, H. Straubing and D. Thérien, "Finite Semigroup Varieties Defined by Programs", Theoretical Computer Science, 180 (1997) 325-339 "Languages Defined with Modular Counting Quantifiers", Proceedings of 15th Annual Symposium on Theoretical Aspects of Computer Science, Lecture Notes in Computer Science 1373, Springer, Berlin (1998) 332-343.

1997

R. Muller, Strongly Typed Flow-Directed Representation Transformations (Extended Abstract), with Allyn Dimock, Franklyn Turbak and J. B. Wells, in the Proceedings of the ACM International Conference on Functional Programming, Amsterdam, The Netherlands, June, 1997.

R. Muller, A Typed Intermediate Language for Flow-Directed Compilation (Extended Abstract), with J. B. Wells, Allyn Dimock and Franklyn Turbak, in Formal Aspects of Software Engineering, Theoretical Aspects of Programming and Software Engineering, Lille, France, April, 1997.

R. Muller, Compiling with Polymorphic and Polyvariant Flow Types, with Franklyn Turbak, Allyn Dimock and Joe Wells, in the Proceedings of the First International Workshop on Types in Compilation, Amsterdam, The Netherlands, June, 1997.

R. Signorile and Signorile, D., "Using Simulation As a Planning Tool for A Cytology Laboratory", 9th Annual European Simulation Conference, Oct. 1997.

H. Straubing "Finite Models, Automata, and Circuit Complexity" in N. Immerman and P. Kolaitis (eds.) Descriptive Complexity and Finite Models, DIMACS Series in Discrete Mathematics and Theoretical Computer Science, American Mathematical Society (1997) 63-96.

1996

A. Bruzzone and R. Signorile, "Genetic Algorithms and Simulation As Support for Planning a Port Terminal", Proceedings of the International 8th Annual European Simulation Conference, Oct. 1996.

R. Signorile and R. Perry, "A Graduate School Admission Process: An Exercise in Business Process Reengineering", 8th Annual European Simulation Conference, Oct. 1996.

R. Signorile, "An integrated Decision Support System Combining Simulation and Expert Systems", IASTED International Conference on Modeling, Simulation and Optimization, May 1996.

1995

M.H. Safizadeh and R. Signorile, "Optimization of Simulation via Quasi-Newton Methods", ORSA Journal On Computing, Fall 1995.

D. A. Mix Barrington and H. Straubing, "Lower Bounds for Modular Counting by Circuits with Modular Gates", in Proceedings of the 2nd Latin American Symposium on Theoretical Computer Science, Lecture Notes in Computer Science 911 Springer, Berlin (1995), 60-71.

H. Straubing, D. Thérien and W. Thomas, "Regular languages defined with generalized quantifiers", Information and Computation 118 (1995) 289-301. (with R. Beigel) "The Power of Local Self-Reductions", in Proceedings of the Tenth IEEE Conference on Structure in Complexity Theory, 1995.

H. Straubing, D. Thérien and W. Thomas, "Logics for Regular Languages, Finite Monoids, and Circuit Complexity", in J. Fountain (ed.), Semigroups, Formal Languages and Groups, Kluwer Academic Publishers (1995), 119-146.

1994

R. Muller, A Staging Calculus and its Application to the Verification of Translators (Preliminary Report), in Proceedings of the 21st Annual ACM SIGPLAN– SIGACT Symposium on Principles Of Programming Languages, Portland, Oregon, January, 1994.

E. Sciore, "Context Interchange in a Client/Server Architecture" (with M. Siegel and S. Madnick). Journal of Systems and Software (27:3), December 1994, pp. 223-232.

E. Sciore, "Query Abbreviation in the Entity-Relationship Data Model." Information Systems (19:6), November 1994, pp. 493-513.

E. Sciore, "Using Semantic Values to Facilitate Interoperability Among Heterogeneous Information Systems" (with M. Siegel and A. Rosenthal). ACM Transactions on Database Systems (19:2), June 1994, pp. 254-290.

E. Sciore, "Versioning and Configuration Management in an Object-Oriented Data Model." VLDB Journal (3:1), January 1994, pp. 77-106.

D. A. Mix Barrington and H. Straubing, "Complex polynomials and circuit lower bounds for modular counting", in Proceedings of LATIN '92 conference, Lecture Notes in Computer Science 583, Springer, Berlin (1992) 24-31; journal version in Computational Complexity 4 (1994) 325-338.

H. Straubing, P. Tesson and D. Thérien, "Weakly Iterated Block Products and Applications to Logic, Circuits and Communication Complexity", accepted for publication in International Journal of Algebra and Computation, Book Finite Automata, Formal Logic, and Circuit Complexity, Birkha¨user, Boston, 1994.

1992

E. Sciore, "Automatic Rule Derivation for Semantic Query Optimization" (with M. Siegel and S. Salveter). ACM Transactions on Database Systems (17:4), December 1992, pp. 563-600.

E. Sciore, "A Universal Relation Model with Semantic Abstractions" (with T. Chang). IEEE Transactions on Knowledge and Data Engineering (4:1), February 1992, pp. 23-33.

E. Sciore, "Using Semantic Values for Semantic Interoperability." Proc. Scientific Data Management Workshop (Salt Lake City UT, 1992).

D. A. Mix Barrington, K. Compton, H. Straubing and D. Thérien, "Regular Languages in NC1, J. Comp. Syst. Sci. 44 (1992) 478-499.

H. Straubing and P.Weil, "On a conjecture concerning dot-depth two languages", Theoretical Computer Science 104 (1992) 161-183.

J.E. Pin, H. Straubing and D. Thérien, "New Results on the Generalized Star-Height Problem", Information and Computation 101 (1992).

K. J. Compton and H. Straubing, "Characterizations of the regular languages in low-level complexity classes", Bulletin of the European Association for Theoretical Computer Science 48 (1992) 134-142.

H. Straubing "Circuit complexity and the expressive power of generalized first-order formulas", in Proceedings of ICALP 92, Lecture Notes in Computer Science 623 Springer, Berlin (1992) 16-27.

1991

E. Sciore, "Using Annotations to Support Multiple Kinds of Versioning in an Object-Oriented Database System." ACM Transactions on Database Systems (16:3), September 1991, pp. 417-438.

E. Sciore, "An Extended Universal Instance Model." Information Systems (16:1), January 1991, pp. 21-34.

E. Sciore, "Modular Rule-Based Query Optimization" (with J. Sieg). TR BCCS-91-15 Boston College, 1991.

H. Straubing "Constant-depth periodic circuits", International J. Algebra and Computation, 1 (1991), 49-87.

H. Straubing "Automata, logic and computational complexity", in Monoids and Semigroups with Applications, (J. Rhodes, ed.), World Scientific, (1991) 467-492.

D. A. Mix Barrington and H. Straubing, "Superlinear lower bounds for bounded-width branching programs", in Proc. 6th IEEE Structure in Complexity Theory Conference (1991) 305-314; journal version to appear in J. Comp. Syst. Sci.

1990

D.A. Mix Barrington, N. Immerman and H. Straubing, "On uniformity in NC1", J. Comp. Syst. Sci. 41 (1990), 274-306.

D. A. Mix Barrington, H. Straubing and D. Thérien, "Non-Uniform automata over groups", Information and Computation. 89 (1990) 109-132.

H. Straubing and D. Thérien, "Finite automata and computational complexity" in Formal Properties of Finite Automata and Applications, (J.E. Pin, ed.) Lecture Notes in Computer Science 386, Springer, Berlin (1990) 199-223.

H. Straubing "The wreath product and its applications" in Formal Properties of Finite Automata and Applications, (J.E. Pin, ed.) Lecture Notes in Computer Science 386, Springer, Berlin (1990) 15-24.