Real-Time Object-Oriented Research


Distributed Real-Time 
Collaborative Services
System Services
All "TR" papers are University of Rhode Island Department of Computer Science and Statistics Technical Reports.
Last Updated May 2001

Real-Time CORBA

Real-Time Object Oriented Databases

  • TR96-247 (PDF)

  • Object-Based Semantic Real-Time Concurrency Control with Bounded Imprecision
    L. Cingiser DiPippo, V. Fay Wolfe
    Feb. 1997
    This paper describes how semantic object-based concurrency control can bound logical imprecision in the database. It contains a set of sufficient conditions for achieving epsilon serializabilty and proof that they are sufficient. A version has appeared in IEEE Transactions on Knowledge and Data Engineering vol. 9 no. 1.
  • TR97-257(PDF)

  • SMOS: A Memory-Resident Object Store
    Yong Yuan
    Jan 1997
    This paper describes an implementation of Open OODB replacing Exodus disk-resident memory with shared memory.
  • TR95-245 (PDF)

  • Performance of Object-Based Semantic Real-Time Concurrency Control
    L. Cingiser DiPippo and V. Fay Wolfe
    Oct 1996
    This paper presents performance results for object-based semantic real-time concurrency control. The protocol is compared with other object locking techniques which use varying degrees of semantic knowledge. Overall, the semantic locking technique misses fewer deadlines and reads less temporally inconsistent data than the other techniques.
  • TR97-258 (PDF)

  • Extending the Priority Ceiling Protocol Using Read/Write Affected Set Semantics
    Michael Squadrito
    April 1996
    This thesis presents the Affected Set Priority Ceiling Protocol (ASPCP) for concurrency control in real-time object-oriented systems. The ASPCP uses the semantic information of objects in a real-time system to provide a higher potential for concurrency than existing Priority Ceiling protocols.  It also presents proofs that the protocol still prevents deadlock and bounds priority inversion.   Finally, this thesis describes a prototype implementation on which tests were conducted, and analyzes the results.
  • TR96-250 (PDF)

  • The Affected Set Priority Ceiling Protocol For Real-time Object-Oriented Databases
    M. Squadrito, L. Cingiser DiPippo, and V. Fay Wolfe
    Mar 1996
    This paper describes adding priority ceilings to our earlier work on semantic concurrency control. This extension elminates deadlock, bounds priority inversion, and is simpler to implement than our original semantic concurrency control technique.  A version of this paper appears in the Proceedings of the First International Workshop on Real-Time Databases, March 1996.
  • TR96-249 (PDF)

  • Real-Time Databases
    L. Cingiser DiPippo and V. Fay Wolfe
    May 1995
    This long paper surveys real-time database research and technology.  This paper appears as a chapter in Database Systems Handbook, Multiscience Press, 1997.
  • Dissertation (PDF)

  • Semantic Real-Time Object-based Concurrency Control
    L. Cingiser DiPippo
    May 1995
    This dissertation presents and analyzes (including simulations) semantic real-time object-based concurrency control.
  • TR94-236 (PDF)

  • The Design of Real-Time Extensions to the Open Object-Oriented Database System
    V. Fay Wolfe, L. Cingiser DiPippo, J. J. Prichard, J. M. Peckham, P. Fortier
    June 1994
    This is a shorter version of our initial implementation of a real-time object-oriented database in Texas Instruments Open Object-Oriented Database system. A version of this paper appeared in the Proceedings of the Workshop on Object-Oriented Real-Time Dependable Systems, October, 1994.
  • TR94-231 (PDF)

  • RTSORAC: Design of a Real-Time Object-Oriented Database System
    J. Peckham, V. Fay Wolfe, J. J. Prichard, L. Cingiser DiPippo
    Feb. 1994
    This is a detailed description of our first implementation of the a real-time object-oriented database using the RTSORAC model and semantic concurrency control.
  • TR93-219 (PDF)

  • Real-Time Semantic Object-based Concurrency Control
    L. Cingiser DiPippo and V. Fay. Wolfe
    Dec. 1993
    This paper describes real-time semantic object-based concurrency control. A version appeared in The Proceedings of IEEE Real-Time Systems Symposium. Dec. 1993.
  • TR93-216 (PDF)

  • A Model for Real-Time Object-Oriented Databases
    V.Fay Wolfe,L. Cingiser, J. Peckham, J. Prichard
    Jan. 1993
    This paper describes the basic RTSORAC real-time object-oriented model used in all of our work. A version appeared in the Conference on Database and Expert Systems Applicaitons, Greece, Sept. 1994.

Distributed Real-Time Collaborative Systems

  • TR99-274  (PDF)

  • A UML Package for Specifying Real-Time Objects
    L. DiPippo and L. Ma
    Nov. 1999
    The Unified Modeling language provides a robust set of tools for modeling software systems.  However, these tools do not directly address the requirements of real-time systems.  Many real-time systems require the specification of data that has strict timing constraints.  This paper presents a UML package for specifying real-time objects called RT-Object.  The constructs in the package are based on the objects of the RTSORAC (Real-Time Semantic Objects Relationships And Constraints) model.  The RT-Object package has been used to design real-time objects in a Real-Time Multi-User Virtual Environment in which widely distributed users collaborate in time-critical planning and decision making.  A version of this paper appears in Computer Standards and Interfaces 22 (2000) 307-321.
  • TR99-268 (PDF)

  • Integration of Real-Time Objects into a Distributed Multi-User Virtual Environment
    Ling Ma
    May 1999
    This thesis describes the design and implementation of real-time objects in the C2MUVE multiuser virtual environment.  The design involves integrating real-time features into UML data objects.  The implementation places these objects into a Java-based CORBA environment.
  • ONR Report (PDF)

  • Real-Time Collaborative Planning and Multi-User Environment
    L. DiPippo and R. Johnston
    Dec. 1998
    This report specifies the design objectives of the Distributed Real-Time Collaborative Systems (DRTCS) effort at URI and SPAWAR.  It includes the integration of real-time objects, real-time CORBA, real-time object-oriented databases, real-time scheduling, and real-time agents into a collaborative environment such as C2MUVE.

Real-Time Multi-Agent System Services
  • TR01-281(PDF)

  • Expressing Quality of Service in Agent Communication
    L. C. DiPippo and L. Nair
    June 2001
    This paper presents extensions to a well-known agent communication language for the expression of quality of service.  It describes the semantics of the extensions, while allowing quality of service to be interpreted as broadly as possible.  The paper then describes the specific extensions to KQML through added performative parameters.  A prototype implementation of the extended language is also discussed.  A version of this paper appears in the Proceedings of the 2001 International Conference on Aritficial Intelligence, Las Vegas, Nevada, June 2001.
  • TR00-279(PDF)

  • Extending ACL to Support Communication in a Real-Time Multi-Agent System
    Lekshmi S. Nair
    Dec. 2000
    This thesis describes extensions to an agent communication language to support real-time communication. It describes the implemention of the extended ACL in KCOBALT, an agent communication tool-kit based on KQML and CORBA. The extensions we have made to KQML are equally applicable to FIPA ACL .
  • TR00-280 (PDF)

  • A Real-Time Multi-Agent System Architecture for E-Commerce Applications
    L. C. DiPippo, V. F. Wolfe, L. Nair, E. Hodys, O. Uvarov
    Dec. 2000
    This paper describes an architecture for real-time multi-agent systems (RTMAS) that builds upon an existing real-time CORBA architecture.  The RTMAS architecture provides real-time agent services for real-time agent communication, real-time agent scheduling and real-time agent facilitation.  These services work together to allow for the expression and enforcement of real-time agent interactions.  The paper describes the design of these services, along with a prototype implementation of the RTMAS architecture that is based upon an existing agent communication implementation.  A shorter version of this paper will appear in the Proceedings of the The Fifth International Symposium on Autonomous Decentralized Systems, March 2001.
  • TR00-275 (PDF)

  • A Scheduling Algorithm for a Real-Time Multi-Agent System
    Ethan Hodys
    Aug. 2000
    This thesis describes the design of a model and scheduling algorithm for real-time multi-agent systems.  The scheduling model is based upon the assumption that real-time agents provide multiple execution strategies for solving a given problem, with varying execution times and quality of results.  The algorithm schedules by EDF unless an overload condition occurs.  In this case, a load reduction heuristic is employed to reduce the execution time, and therefore expected quality, of currently scheduled agent tasks.
  • TR99-273 (PDF)

  • Towards a Real-Time Agent Architecture - A Whitepaper
    L. DiPippo, B. Thuraisingham, E. Hodys
    Nov. 1999
    Applications such as military training simulations, and electronic commerce can benefit from the flexible and responsive nature of multi-agent systems.  These applications have inherent timing constraints on the operations and interactions that the agents might perform.  This paper presents a real-time agent architecture in which agents communicate, cooperate, coordinate and negotiate to meet the goals of a particular application under specified timing constraints.  The architecture provides a real-time CORBA layer to handle underlying real-time communication.  It also has a real-time agent communication layer in which agents interact via a real-time extension of a well-known agent communication language.  A version of this paper will appear in the Proceedings of the Fifth International Workshop on Object-oriented Real-time Dependable Systems.

Real-Time Object-Oriented Applications

  • TR96-251 (postscript)

  • The Design of an Open System with Distributed Real-Time Requirements
    R. Ginis, J.J. Prichard, and V. Fay Wolfe
    June 1996
    This paper describes the real-time requirements of the C3I system of the US Navy's New Attack Submarine. It presents a CORBA wrapper for a COTS real-time database. A version appeared in the Proceedings of the IEEE Real-Time Technology and Applications Symposium, June, 1996.
  • TR93-214 (postscript)

  • Real-Time Object-Oriented Database Support for Intelligent Program Stock Trading
    V. Fay Wolfe, K.F. Lau
    Jan. 1993
    This paper applies our RTSORAC model to porgrammed stock trading with real-time constraints. Timed atomic commitment is also employed. A version of this paper appeared in The Journal of Database Management, Fall, 1995.
  • TR93-215

  • Real-Time Considerations in Submarine Target Motion Analysis (No electronic version. Must be ordered from URI Dept. of Computer Science Secretary)
    G.A. Bussiere, J. Oblinger, V. Fay Wolfe
    Jan. 1993
    This paper describes the real-time aspects of the MATE submarine tracking application. A version appeared in the Proceedings of the IEEE Workshop on Real-Time Applications, May, 1994.

Real-Time SQL
  • Dissertation (PDF)

    J.J. Prichard
    July 1995
    This dissertation presents and analyzes (including a prototype implementation) real-time extensions to SQL.
  • TR94-241 (postscript)

  • Real-Time SQL: Extensions for Support of Real-Time Database Systems
    J. J. Prichard, P. J. Fortier, Victor Fay Wolfe
    Oct. 1994
    This is a RTSQL "whitepaper" that was presented to ANSI for the working draft of real-time extensions to SQL.
  • TR94-235 (postscript)

  • Flexible Real-Time SQL Transactions
    P. Fortier, J. J. Prichard, V. Fay Wolfe
    May 1994
    This is a short paper describing flexible real-time transaction design as specified in real-time SQL. A version of this paper appeared in the Proceedings of the IEEE Real-Time System Symposium, December, 1994.

Return to Real-Time Object-Oriented Research Homepage