Research Interests

Papers

TA Courses

Education

Contact Information



U of M Links:

Programming Productivity and Software Quality Research Group

Department of Computer Science and Engineering

University of Minnesota Software Engineering Center

Institute of Technology

University of Minnesota

Kai Xu

Research Interests:

• Execution Monitoring of Object Oriented Programs

  In Object Oriented programs, a functionality of an application is usually implemented as the interactions among different components (objects) of the application. Sometimes, such interaction scenarios can be very complicated. During testing or debugging, developers often need to perform execution monitoring to ensure that each important object interaction is implemented correctly. Execution monitoring means monitor the software interactions and checking (1) the sequencing constraints are enforced, and (2) each important interaction affects the program state as intended.

  To perform execution monitoring, extra programs will be constructed to observe the software interaction and checking if the design decisions are enforced. Manually writing such programs can be tedious and error prone. Thus, my advisor, Donglin Liang , and I proposed behavior view diagrams (BVD), a monitoring specification language that extends the UML 2 sequence diagrams.

  A BVD specification describes
  • How to identify involved objects in a particular interactio scenario
  • What's the sequencing constraints among different interactions
  • What action should be performed when a particular interaction is detected (e.g. checking the states of local variables)
  Monitoring and trace-visualization programs can be generated automatically from BVD specifications. By default, the execution trace is visualized in the same BVDs as the monitoring specification. When an interaction occurs in a wrong order, or the target program is in a wrong state, an error will be reported to facilitate the debugging. The information given by the execution monitoring allows bugs be narrowed and identified much faster.

  I am currently formalizing the semantics of BVDs and writing tools to support code generation from BVD specifications.

Papers:

Donglin Liang and Kai Xu, Program Execution Monitoring with Scenario Implementation Models,
Tech report 04-034, Dept. of CSE, Univ. of Minnesota, Nov 2004.
[Full text in PDF]

TA Courses:

• Spring 2007 - CSci5802: Software Engineering II
• Fall 2006 - CSci5801: Software Engineering I
• Spring 2006 - CSci5802: Software Engineering II
• Fall 2005 - CSci2011: Discrete Structures of Computer Science
• Spring 2004 - CSci 2011: Discrete Structures of Computer Science, CSci5802: Software Engineering II

Education:

• Ph.D., Computer Science at The University of Minnestoa, Twin Cities,
  (Expected Jan. 2009);
• M.S., Computer Science, University of Minnesota, Duluth, 2006;
• M.S., Applied Mathematics and Statistics, University of Minnesota, Duluth, 2003;
• B.A.. Computer Science & Networking, Shanghai Tiedao University, China
  (merged with Tongji University, Shanghai, China in 2000),1996.

Contact Information: