Abstract: A method and apparatus for generating a covering set of test cases from a directed graph is provided. The directed graph includes nodes and edges connecting the nodes, and a test case is a path through the directed graph. To generate a partial set of test cases, a set of selected test cases is received. These test cases can be manually selected or they can be a maintained test case set. The edges or nodes on the directed graph (or requirements linked to nodes or edges) that are covered by the selected test cases are marked with an identifier. Test cases are then generated from the directed graph according to a coverage algorithm. Marked graph elements may, but need not, be included in the generated test cases. The resulting partial test case set together with the selected test cases satisfy the coverage criterion.

Abstract: A verification system for verifying that a software system satisfies a property by extracting a verification model from implementation level source code is provided. The extraction proceeds by translating source strings generated from the source code into strings belonging to a target language, and generating a verification model in the target language. The translation is guided by explicit mappings in a lookup table, optional user-defined data restrictions, and default type rules. Standard logic model checking is performed on the extracted verification model to check that the system satisfies (or can possibly violate) any given explicit or implicit logic system property.

Abstract: A verification system for verifying that a software system satisfies a property by extracting a verification model from implementation level source code. The extraction proceeds by translating source strings generated from the code subject to an externally-defined abstraction filter (a so-called conversion table). Standard logic model checking is performed on the extracted verification model to check that the system satisfies (or can possibly violate) any given explicit or implicit logic system property.

Abstract: Techniques and testers for testing a system U including the steps of (a) defining a formal specification of a logical property P that system U is required not to satisfy; (b) generating a passive testing module T based upon property P to monitor system U; (c) invoking a function F at specific invocation points during the execution of system U to compute an abstract representation of the state of system U at the current point of execution; (d) passing the abstract representation computed by function F to passive testing module T in order to determine whether the abstract representation of the execution of system U to the current point matches illegal property P; and (e) declaring a "fail" result if the abstract representation of the execution of system U to the current point matches illegal property P and declaring a "pass" result if the abstract representation of the execution of system U to the current point does not match illegal property P.

Abstract: An on-the-fly verification system which employs statically-available information to reduce the size of the state space required to verify liveness and safety properties of a target system consisting of asynchronous communicating processes. The verification system generates a verifier from a description of the target system and a specification of the property to be verified. The verifier models the target system as a set of finite state machines, constructs a state space containing a graph of nodes representing states of the target system and transitions between the states, and uses the state space to verify the property. The size of the state space is reduced by using information from the description and the specification to divide transitions from a node into per-process bundles and to determine which bundles of transitions must be included in the state space and which may be left out of the state space.

Abstract: The present invention involves a method of deriving the height and width of a graphic image from raw graphical image data stored in a computer system. It includes commencing execution of a height-width derivation program in the computer system and, at least once, operating the height-width derivation program to perform a series of steps. These include calculating the area of the image size, e.g. using the total number of bytes, and calculating the square root of the area to obtain a first value, and then determining by assumption a first assumed width and a first assumed height. For example, these assumptions may be achieved by calculating one half of the first value to obtain a first assumed width value and dividing the area by the first assumed width value to obtain a first assumed height value.

Abstract: An interactive image editor. Editing commands are interactively imputted to a computer by a user to form an image transformation function. The commands define how to alter the pixels of the image and the portions of the image to alter. The editor parses the commands and generates a program for performing the image transformation. The program is then executed, either by interpreting it or by first compiling it on-the-fly. In either case, each affected pixel of the image is transformed in accordance with the command statements.