Abstract: Methods, systems and machine-readable instructions for processing an electronic document are described. In one aspect, logical blocks that were extracted from the electronic document, including a text block comprising text lines each encompassed by a respective bounding rectangle, are received. Edges of ones of the bounding rectangles are extended to at least one boundary without changing layout relationships among the logical blocks in the electronic document. A text layout boundary is generated from extended and unextended edges of the bounding rectangles. A description of the text layout boundary is stored in a machine-readable medium.

Abstract: A computer-implemented method determines the resemblance of data objects such as Web pages. Each data object is partitioned into a sequence of tokens. The tokens are grouped into overlapping sets of the tokens to form shingles. Each shingle is represented by a unique identification element encoded as a fingerprint. A minimum element from each of the images of the set of fingerprints associated with a document under each of a plurality of pseudo random permutations of the set of all fingerprints are selected to generate a sketch of each data object. The sketches characterize the resemblance of the data objects. The sketches can be further partitioned into a plurality of groups. Each group is fingerprinted to form a feature. Data objects that share more than a certain numbers of features are estimated to be nearly identical.

Abstract: A computer-implemented method determines the resemblance of data objects such as Web pages. Each data object is partitioned into a sequence of tokens. The tokens are grouped into overlapping sets of the tokens to form shingles. Each shingle is represented by a unique identification element encoded as a fingerprint. A minimum element from each of the images of the set of fingerprints associated with a document under each of a plurality of pseudo random permutations of the set of all fingerprints are selected to generate a sketch of each data object. The sketches characterize the resemblance of the data objects. The sketches can be further partitioned into a plurality of groups. Each group is fingerprinted to form a feature. Data objects that share more than a certain numbers of features are estimated to be nearly identical.

Abstract: A computer implemented method detects concurrency errors in programs. Machine executable images of multiple program threads are instrumented to locate and replace instructions which affect concurrency states of the threads. Concurrency state information is recorded in a memory while the multiple threads are executing. The recorded concurrency state information is analyzed, and inconsistent dynamic concurrency state transitions are reported as concurrency errors.

Abstract: A distributed computer system includes a multiplicity of concurrently active processes. Each object is owned by one process. Objects are accessible to processes other than the object's owner. Each process, when it receives a handle to an object owned by any other process, sends a first "dirty" message to the object's owner indicating that the object is in use. When a process permanently ceases use of an object handle, it sends a second "clean" message to the object's owner indicating that the object is no longer in use. Each object's owner receives the first and second messages concerning usage of that object, stores data for keeping track of which other processes have a handle to that object and sends acknowledgement messages in return. The receiver of an object handle does not use the handle until its first message is acknowledged.