On the Practical Performance of Minimal Hitting Set Algorithms from a Diagnostic Perspective

Minimal hitting sets (MHSs) meliorate our reasoning in many applications, including AI planning, CNF/DNF conversion, and program debugging. When following Reiter’s ”theory of diagnosis from first principles”, minimal hitting sets are also essential to the diagnosis problem, since diagnoses can be characterized as the minimal hitting sets of conflicts in thebehavior of a faulty system. While the large amount of application options led to the advent of a variety of corresponding MHS algorithms, for diagnostic purposes we still lack a comparative evaluation assessing performance characteristics. In this paper, we thus empirically evaluate a set of complete algorithms relevant for diagnostic purposes in synthetic andreal-world scenarios. We consider in our experimental evaluation also how cardinality constraints on the solution space, as often established in practice for diagnostic purposes, influence performance in terms of run-time and memory usage.

Innovation of CNC machining education at the Faculty of Technology

The paper describes the ongoing educational project, which is focused on increasing the quality of teaching and making the study more attractive by introducing new selective courses: CNC technology in bachelor study programs and programming of CNC technology in engineering study programs at the Faculty of Technology of the Technical University in Zvolen, Slovakia. The solution of the project is also to create a background for building a CNC machining workplace. Teaching programming takes place in professional CNC emulators that are commonly used in praxis. These emulators allow program debugging, tests, trajectory drawing and optimising and collision checking of tool and workpiece. Altogether 23 students successfully completed the introduced course. Within the project solution, five theses were defended. Keywords: CNC programming, CNC simulators, teaching, innovation, workplace building.

Spectrum-based Fault Localization Techniques Application on Multiple-Fault Programs: A Review

Software fault localization is one of the most tedious and costly activities in program debugging in the endeavor to identify faults locations in a software program. In this paper, the studies that used spectrum-based fault localization (SBFL) techniques that makes use of different multiple fault localization debugging methods such as one-bug-at-a-time (OBA) debugging, parallel debugging, and simultaneous debugging in localizing multiple faults are classified and critically analyzed in order to extensively discuss the current research trends, issues, and challenges in this field of study. The outcome strongly shows that there is a high utilization of OBA debugging method, poor fault isolation accuracy, and dominant use of artificial faults that limit the existing techniques applicability in the software industry.

A Semantic Framework for Program Debugging

This work aims to build a semantic framework for automated debugging. A debugging process consists of tracing, locating, and fixing processes consecutively. The first two processes are accomplished by a tracing procedure and a locating procedure, respectively. The tracing procedure reproduces the execution of a failed test case with well-designed data structures and saves necessary information for locating bugs. The locating procedure will use the information obtained from the tracing procedure to locate ill-designed statements and to generate a fix-equation, the solution of which is a function that will be used to fix the bugs. A structural operational semantics is given to define the functions of the tracing and locating procedure. Both procedures are proved to terminate and produces one fix-equation. The main task of fixing process is to solve the fix-equation. It turns out that for a given failed test case, there exist three different types of solutions: 1. the bug is solvable, there exists a solution of the fix-equation, and the program can be repaired. 2. There exists a non-linear error in the program, the fix-equation generated at each round of the locating procedure is solvable, but a new bug will arise when the old bug is being fixed. 3. There exists a logical design error and the fix-equation is not solvable.

Implementation of a MIX Emulator: A Case Study of the Scala Programming Language Facilities

Implementation of an emulator of MIX, a mythical computer invented by Donald Knuth, is used as a case study of the features of the Scala programming language. The developed emulator provides rich opportunities for program debugging, such as tracking intermediate steps of program execution, an opportunity to run a program in the binary or the decimal mode of MIX, verification of correct synchronisation of input/output operations. Such Scala features as cross-compilation, family polymorphism and support for immutable data structures have proved to be useful for implementation of the emulator. The authors of the paper also propose some improvements to these features: flexible definition of family-polymorphic types, integration of family polymorphism with generics, establishing full equivalence between mutating operations on mutable data types and copy-and-modify operations on immutable data types. The emulator is free and open source software available at www.mix-emulator.org.