Research Contributions


  • Most scheduling problems are NP-complete. I found lower bounds for these algorithms (number of processors, time), which are computationally feasible and can be used to evaluate heuristic scheduling algorithms. This was part of my Ph. D. Dissertation. I also found procedures to evaluate those bounds in a convenient way. This work has been applied by others to parallel algorithms [Kas85], genetic algorithms [Gol02], robotics [Kas84], and manufacturing. It was also extended to consider message costs [Alm90].

  • When relational databases appeared there was very little emphasis on security. I called attention to this aspect through publications and talks. I wrote the first book on database security (Addison-Wesley, 1981). I developed one of the first models for authorization of relational database systems. This model extended the access matrix model with predicates appropriate to describe database concepts. The model included the concept of “implied authorization”, where rights defined for an aggregate apply to the components. Another aspect is the separation of administration from use rights, where the data belongs to the enterprise, not to the creator of a file. My ideas influenced the security of S/R, IBM Research’s relational database system, which later became the basis for the SQL standard and for the DB2 Database Management system. My book on database security has been used extensively by universities and practitioners and was the first to emphasize administrative aspects of security.

  • My ideas on implied authorization were used by the group at MCC (Microelectronic Computer Corporation, Austin, TX) that developed Orion, one of the first object-oriented databases. Several groups in the U.S. (University of Houston [Maj97], George Mason University), and Europe (University of Frankfurt, Germany, University of Nice, France, University of Essen, Germany, and University of New England, Australia {Eve04]) applied and expanded my authorization ideas. The recent version of Microsoft’s operating system, Windows 2000, incorporates implied object authorizations where authorizations are inherited by subclasses, thus implementing almost directly my ideas. The newest Microsoft framework, .NET, includes components that also use the idea of inherited or implied authorizations. This model is also mentioned in the Handbook of Information Security Management of 2003.

  • I applied these ideas to object-oriented databases (1988-1995). I developed a complete set of implied access right inheritance policies (implied rights now become inherited rights) as well as algorithms to decide access and studied the effect of schema changes on security. I also applied my models to Internet security (1993-1998). An object-oriented model of hypertext document security uses implied authorization and architectural levels to control access.

  • I led a group at IBM that studied the performance of virtual database buffers and the I/O traffic generated by database access. This work concluded that the Least Recently Used (LRU) replacement algorithm was the most appropriate. Teng and Gumaer [Ten84], describe database buffering for IBM’s DB2, and indicate that this system adopted the same strategy based on our results. Later work on the 801 system at IBM also used these results [Att87]. We also showed the value of a special processor for disk search. Research projects at the University of Maryland and at the University of California Berkeley (ISTORE [Bro]), used a similar approach as part of their intelligent storage architecture.

  • I developed the concept of Recovery Metaprogram for software security and fault tolerance. It has been used and extended by a group at the University of Genoa, Italy. A variation of the idea was used in IBM’s S/R to decouple access paths for better performance.

  • Object-oriented methodology. I have explored the combination of object-oriented and procedural approaches to software design. I extended the dynamic model of object-oriented methods by using Communicating Sequential Machines. Another paper explores models for real-time telemedical systems. My work on combining object-oriented and procedural programming was used at Raytheon, Portsmouth, RI, IBM Boca Raton, and NCS Pearson, in 2002.

  • My work on Role-Based Access Control and secure software development has influenced several researchers [Dom03, Neu02].

  • I developed the concept of Semantic Analysis Patterns, where a set of classes implementing a basic set of Use Cases is used as a building block to develop complex conceptual models, such as web-based systems. Several patterns from this work have been published at the PLoP (Pattern Languages of Programs) Conferences. These patterns have been used in practical systems and in several research projects. In particular, they have become well-known in China, and several of my patterns have been translated to Chinese [uml]. A group at Texas Tech has used this approach in a prototype tool CODASYS (COnceptual modeling tool for DAtabase SYStems), to help novice designers to build conceptual data models [tex].

  • Security patterns. These are recurrent design units found in well-designed secure systems. I developed this idea from my previous work on security, and wrote several papers with specific patterns. My current work on security patterns combines my work on security and my work on patterns to evolve a methodology for secure systems design. I am now editing a book putting together most of the known security patterns. IBM, Microsoft, the Open Group, and others are using extensively this concept and some of my patterns.

  • Web services security. Web services are components that can be accessed through the Internet. I wrote one of the first overviews of their security. I just completed a survey paper and I am developing now patterns for web services security. We are applying this work to wireless systems now, supported by an earmark grant.


    • References

    [Alm90] M.A. Al-Mouhamed, “Lower bound on the number of processors and time for scheduling precedence graphs with communication costs”, IEEE Trans. on Software Eng., Vol. 16, No 2, dec. 1990, 1390-1398.

    [Att87] C.R.Attanasio, “801 architecture support for database- A case study”, IBM Research Report RC 12416, Jan. 1987.

    [Bro] A. Brown, D. Oppenheimer, K. Keeton, R. Thomas, J. Kubiatowicz, and D.A. Patterson, “ISTORE: Introspective storage for data-intensive network services”.

    [Dom03] D. Domingos, A. Rito-Silva, and P.Veiga, “Workflow access control from a business perspective”, Procs. OOIS’2003, Workshop on Encapsulation and Access Rights in OOD&P (WEAR 2003).

    [Eve04] M. Evered and S. Boegeholz, “A case study in access control requirements for a health information system”, Procs. 2nd Workshop on Australasian Information Security, 2004, 53-61.

    [Gol02] M. Golub and S. Kasapovic, “Scheduling multiprocessor tasks with genetic algorithms”, Proceedings of the IASTED International Conference on Applied Informatics, February 18-21,2002, Insbruck, Austria, Acta Press, 2002, 273-278.

    [Jos02] J.B.D.Joshi, Z. K. Li, H. Fahmi, B. Shafiq, and A. Ghafoor, “A model for secure multimedia document database system in a distributed environment”, IEE Transactions on Multimedia, Vol. 4, No 2, June 2002, 215-234.

    [Kas84] H. Kasahara and S. Narita, “Practical multiprocessor scheduling algorithms for efficient parallel processing”, IEEE Trans. on Computers, Vol. C-33, No 11, November 1984, 1023-1029.

    [Kas85] H. Kasahara and S. Narita, “An approach to supercomputing using multiprocessor scheduling algorithms”, Procs. 1st IEEE Int. Conf. on Supercomputing Systems, 1985, 139-148.

    [Maj97] I. Majetic and E. L. Leiss, “Authorization and revocation in object-oriented databases”, IEEE Trans. on Knowledge and Data Eng., Vol. 9, No 4, July/August 1997, 668-672.

    [Neu02] G. Neumann and M. Strembeck, “A scenario-driven role engineering process for functional RBAC roles”, Procs. SACMAT’02, 33-42.

    [Ten84] J.Z.Teng and R.A.Gumaer, “Managing IBM Database 2 buffers to maximize performance”, IBM Systems Journal, vol. 23, No 2, 1984, 211-218.

    [tex] S. R. Antony and D. Batra, “CODASYS: a consulting tool for novice database designers”, ACM SIGMIS Database, 2002, vol. 33, No 3, 54-68

    [uml] http://www.umlchina.com
    http://www.mmmbook.com/xprogrammer/issue/28/resource.htm