Code obfuscation can help software developers protect technological secrets. Code readability is greatly enhanced with object-oriented technology that represents dynamic binding using instance method invocation. Therefore, dismantling instance methods is proposed in this paper as a critical obfuscating technique for object-oriented programs. The interception classes are interpolated first into the project. The static images and the up forwarders are then created. For each virtual function system and each interface function system, a respective dispatching function is set up. By properly arranging the class identifiers and binding identifiers, the switch statement in the dispatching function can be compiled into constant-time low-level code. After using dispatching functions to simulate virtual function system or interface function system invocations, all original instance methods in the project will be removed. Interception functions and export functions are indispensable in supporting the operation of callback methods. A prototype of our obfuscation system was implemented and successfully tested on some practical scale applications. Copyright © 2013 John Wiley & Sons, Ltd.

The behavior of ordered binary decision diagrams (OBDD) for general Boolean functions is studied. A tight upper bound of (2/sup n//n)(2+ epsilon ) for the worst case OBDD size is derived. Although the size of an OBDD is dependent on the ordering of decision variables, it is shown that almost all functions are not sensitive to variable ordering.>

The problem of automatic diagnosis of digital circuits with efficiency is studied. Two improvements over the method of J.C. Madre et al. (1989) are developed to enhance the efficiency of diagnosis. Specifically, the dominance relation in circuit topology is utilized to reduce the search space of possibly correctable gates. In the authors' experiment, the search space is reduced to about one-half. A novel divide-and-conquer technique to determine the correct gate function is proposed.>

In this paper, an interactive verification and diagnosis system for VHDL [Vm88], VVDS, is presented. In VVDS, hybrid simulation, which simulates with both numerical and symbolic data, is implemented to achieve an effective compromise of the enormous quantity of input test data in the conventional simulation and the complexity of symbolic expression in the symbolic execution. To support efficient user interface in the verification and diagnosis process, both on-line programming of commands and micro-probing capability to passively and actively probe any level of design hierarchy are provided.