Abstract: An adaptive linear predictor is used to predict samples, and residuals from such predictions are encoded using Golomb-Rice encoding. Linear prediction of samples of a signal which represents digitized sound tends to produce relatively low residuals and those residuals tend to be distributed exponentially. Accordingly, linear prediction combined with Golomb-Rice encoding produces particularly good compression rates with very efficient and simple implementation. A code length used in Golomb-Rice, which is typically referred to as the parameter k, is adapted for each sample in a predictable and repeatable manner to further reduce the size of a Golomb-Rice encoding for each sample. An infinite incident response filter of processed residuals automatically reduces influences of previously processed residuals upon such adaptation as additional samples are processed. The efficiency of Golomb-Rice encoding is improved by limiting the predicted samples to an efficient range.

Abstract: A document delivery server dynamically customizes the format of a document to be delivered, based on the capabilities of the recipient and the type of document to be delivered. The server enables transparent delivery of formatted documents, regardless of the capabilities of the recipient. For example, the recipient platform could be a desktop computer, a network computer, a printer, a fax machine, or a personal digital assistant. The server attempts to maintain the information contained in the document in a high level representation and defers the decision of when to convert to a lower level representation, thereby maximizing the potential set of options and function at each step in the delivery process.

Abstract: A listener's ability to recognize and identify similar sounds is improved by forming exaggerated sounds which differ in spectral/temporal energy distribution from one another more than the similar sounds differ from one another and in generally the same way in which the similar sounds differ and testing the listener's ability to recognize and identify the exaggerated sounds. The exaggerated sounds are formed as follows: The similar sounds are spectrally transformed into a coordinate space and a linear function is projected between a pair of points representing the similar sounds in the coordinate space. Between the pair of points, the linear function represents a continuum of sounds between the similar sounds. To exaggerate the sounds, points are extrapolated outward from the pair of points along the linear function.

Abstract: An interactive multimedia application executes in a debug mode in which a tester can specify a particular classification of user event and a user event satisfying the particular classification is emulated. For example, classifications can include correct and incorrect responses. To emulate a correct response, an interactive module of the interactive multimedia application determines correct criteria and provides those criteria to a debug manager upon request. In addition, characterization of user events is performed by a user interface module which communicates user events in the form of event messages to the interactive module. The debug manager emulates a user event of the particular category by retrieving the classification criteria from the interactive module, forming an event message representing an event satisfying the criteria for the particular classification, and sending the event message to the interactive module.

Abstract: An interactive multimedia application executes in a debug mode in which previously recorded user events are retrieved from memory and emulated in sequence. Each user event is represented by a record which specifies a particular classification of user event. Accordingly, a user event satisfying the particular classification is emulated. The debug manager emulates a user event of the particular category by retrieving the classification criteria from the interactive module, forming an event message representing an event satisfying the criteria for the particular classification, and sending the event message to the interactive module. Accordingly, the interactive module receives an event message which could have come from either the debug manager or the user interface module. As such, the particular computer instructions executed by the interactive module in response to the event are the same regardless of whether the event is emulated.

Abstract: A method and system are provided for secure document delivery over a wide area network, such as the Internet. A sender directs a Delivery Server to retrieve an intended recipient's public key. The Delivery Server dynamically queries a certificate authority and retrieves the public key. The public key is transmitted from the Delivery Server to the sender. The sender encrypts the document using a secret key and then encrypts the secret key using the public key. Both encrypted document and encrypted secret key are uploaded to the Delivery Server, and transmitted to the intended recipient. The intended recipient then uses the private key associated with the public key to decrypt the secret key, and uses the secret key to decrypt the document. In an alternative, equally preferred embodiment of the invention, the sender uses the public key to encrypt the document. In yet another embodiment, the server transmits the document to the Delivery Server for encryption.

Abstract: A student user of a client computer system uses a teaching process to promote development of cognitive skills of the student, and a supervisor uses a second client computer to remotely monitor the progress of the student. The teaching process presents various types of stimuli to the student and records student response data which correspond to the stimuli. In addition, the teaching process forms evaluation data from the student response data where the evaluation data represents a correlation between the student response data for respective stimuli and predetermined correct response data for respective stimuli. Furthermore, the teaching process modifies its own behavior according to the evaluation data to thereby tailor the behavior of the teaching process to the cognitive abilities of the student. The student response data is uploaded to a global student database which is accessible to a supervisor user.

Abstract: An adaptive predictor is used to predict samples, and residuals from such predictions are encoded using Golomb-Rice encoding to thereby compress a digital signal which includes the samples. The adaptive predictor adapts to residuals between actual and predicted samples at a particular rate. The rate of adaptation is itself adapted periodically to ensure optimum performance of the compression. A number of samples are repeatedly compressed using different adaptation rates, and the adaptation rate which produces the best compression results is used. The adaptation rate can be an exponential power of 2 such that incrementing the adaptation rate effectively doubles the rate at which the predictor is adapted and decrementing the adaptation rate effectively halves the rate at which the predictor is adapted. Accordingly, fewer trials are needed to find a relatively optimal adaptation rate for the predictor.

Abstract: A task scheduling computer program retrieved from a server computer system through a computer network and executed by a client computer system which can be a network computer having no persistent, writeable storage. In executing the task scheduling computer program, a collection of one or more execution schedules are retrieved. The collection of execution schedules can be retrieved from the client computer system, from the server computer system, or from another computer system coupled to the client computer system through the computer network. The collection can be uniquely identified within the computer network by a universal resource locator (URL). Each execution schedule of the collection specifies one or more execution times and a task to be performed by the client computer system at the one or more execution times. For each of the one or more execution schedules, the client computer system performs the specified task at the one or more execution times.

Abstract: An adaptive linear predictor is used to predict samples, and residuals from such predictions are encoded using Golomb-Rice encoding. Linear prediction of samples of a signal which represents digitized sound tends to produce relatively low residuals and those residuals tend to be distributed exponentially. Accordingly, linear prediction combined with Golomb-Rice encoding produces particularly good compression rates with very efficient and simple implementation. A code length used in Golomb-Rice, which is typically referred to as the parameter k, is adapted for each sample in a predictable and repeatable manner to further reduce the size of a Golomb-Rice encoding for each sample. An infinite incident response filter of processed residuals automatically reduces influences of previously processed residuals upon such adaptation as additional samples are processed.

Abstract: A listener's ability to recognize and identify similar sounds is improved by testing the listener's ability to recognize and identify exaggerated sounds that are formed from pairs of similar sounds. The exaggerated sounds differ from one another in spectral/temporal energy distribution more that the similar sounds differ from one another and in generally the same way in which the similar sounds differ. The exaggerated sounds are formed as follows: the similar sounds are spectrally transformed into a coordinate space and a linear function is projected between a pair of points. To exaggerate the sounds, points are extrapolated outward from the pair of points along a linear function. The listener is challenged to repeatedly identify each of the exaggerated sounds. When the listener has demonstrated proficiency, the degree to which the exaggerated sounds differ from the similar sounds is reduced and the listener is again challenged.

Abstract: A history mechanism is provided in which user data, which represents signals generated by a user, are stored for subsequent recall and regeneration in a history database in one of two or more categories associated with two or more respective component symbols of the user data. For example, in one embodiment, user data includes alphabetic symbols and a respective category is formed for each letter of the alphabet. User data is parsed into components and stored in the history database in each category corresponding to the initial letter of each component of the user data since the initial letter of each component of the user data is prominent. The user recalls and regenerates the user data by selecting a category corresponding to a letter of the alphabet which is the initial letter of any component of the user data. The user then selects the previously generated user data from a list of previously generated user data classified under the selected category.

Abstract: A student user of a client computer system uses a teaching process to promote development of cognitive skills of the student and a supervisor uses a second client computer to remotely monitor the progress of the student. The teaching process presents various types of stimuli to the student and records student response data which correspond to the stimuli. In addition, the teaching process forms evaluation data from the student response data where the evaluation data represents a correlation between the student response data for respective stimuli and predetermined correct response data for respective stimuli. Furthermore, the teaching process modifies its own behavior according to the evaluation data to thereby tailor the behavior of the teaching process to the cognitive abilities of the student. The student response data is uploaded to a global student database which is accessible to a supervisor user.

Abstract: Symmetry in a filter is used to reduce the complexity of an interpolator or a decimator and to simplify derivation of resulting discrete samples. In particular, an inverse relationship between weights applied to two samples is recognized and exploited. An inverse relationship is recognized when a first weight is associated with a first of the samples and a second weight is associated with a second of the samples and a weight which is equivalent to the first weight is associated with the second sample and a weight which is equivalent to the second weight is associated with the first sample. The inverse relationship is exploited by forming two composite weights of the first and second weights and weighting composite sample signals with the composite weights. A first of the composite weights has a value which is one-half of the sum of the values of the first and second weights. A second of the composite weights has a value which is one-half of the difference of the values of the first and second weights.

Abstract: Mapping of pixels of a graphical object to a destination graphical image buffer is achieved by precalculating relative weights of object pixels near a subject pixel and storing the precalculated relative weights in a table and by determining weights of specific object pixels during processing by a table lookup of the predetermined weights according to a fractional portion of an object pixel address. A partitioned coefficient, which represents the relative weights of two or more object pixels, is retrieved from the weight table and used in a partitioned multiplication operation in a processor to weight each of the two or more object pixels substantially simultaneously. Weights associated with two or more object pixels are formed by partitioned multiplication of a partitioned horizontal weight word and a partitioned vertical weight word.

Abstract: Each node of a failing distributed computer system, e.g., as a result of a split-brain failure, races to achieve a quorum by successfully reserving two shared storage devices which are designated quorum controllers. During normal operation of the distributed computer system, each of the quorum controllers is associated with and reserved by a respective node. During the race for quorum in response to a detected failure of the distributed computer system, each node which has not failed forcibly reserves the quorum controller which is associated with the other node. If a node simultaneously holds reservations for both quorum controllers, that node has acquired a quorum. The forcible reservation of a shared storage device does not fail even if another node holds a valid reservation to the same storage device. Accordingly, a failed node which does not relinquish a reservation to the node's quorum controller cannot prevent another node from acquiring a quorum.

Abstract: A number of multiple-band pixels are stored in a number of data words and the multiple-band pixels are merged and sorted such that all components of each band of the pixels are stored contiguously and in the order in which the multiple-band pixels are originally stored in the data words. As a result, the pixels are converted from an interleaved format to a planar format. The data words are essentially divided in half and the halves are merged such that the pixel components are interleaved in a number of intermediate data words. By repeatedly dividing the intermediate data words in half and merging the respective halves, the components of all the pixels corresponding to each band are stored contiguously in a number of data words. The contiguous components of each band are sorted such that the components of each band are stored in the order in which the multiple-band pixels are originally stored in the data words.

Abstract: A system clock generator for a computer system to efficiently transfer data from a source subsystem to a destination subsystem of the computer system. The system clock generator generates a globally synchronized clock signal for the source subsystem and the destination subsystem. The source subsystem includes a clock generator for generating a source clk (SRC.sub.-- CLK) signal and a source-synchronous clock (SRC.sub.-- SYN.sub.-- CLK) signal for the source subsystem and destination subsystem, respectively. The SRC.sub.-- SYN.sub.-- CLK signal is generated whenever data is transferred from the source subsystem to the destination subsystem. Upon receiving the data and SRC.sub.-- SYN.sub.-- CLK signal from the source subsystem, the data is synchronized at the destination subsystem using the SRC.sub.-- SYN.sub.-- CLK signal. Since the source and destination subsystems are synchronized by the system clock signal, an incoming data stream can be synchronized within one system clock cycle.

Abstract: A parallel processor which is capable of partitioned multiplication and partitioned addition operations convolves multiple pixels in parallel. The parallel processor includes a load and store pipeline of a load and store unit which retrieves data from and stores data to memory and one or more arithmetic processing pipelines of an arithmetic processing unit which aligns data and performs partitioned multiplication and partitioned addition operations. A patch of pixels from a source image are convolved substantially simultaneously in the arithmetic processing pipeline of the processor by execution of the partitioned multiplication and partitioned addition operations. At substantially the same time, a subsequent patch of pixels from the source image are read by the load and store unit of the processor.

Abstract: To simulate a bus of a circuit, a number of virtual bus stubs ("VBSs") each post simulated bus signals as a single step and execution of the simulation system which includes such a VBS continues. As a subsequent, separate step, the VBS substantially immediately thereafter reaps a resolved simulated bus state. Synchronization in such a system is achieved by grouping into zones all VBSs which collectively represent the simulated state of a single bus. Each VBS has one of four states, namely, reap running, reap stopped, post running, post stopped. When a VBS posts, it is determined whether any other VBS of the same zone has yet to reap a previously resolved simulated bus state. If such a VBS exists, the posting VBS moves from reap running state to a post stopped state and execution of the simulation system containing the posting VBS is suspended until the last VBS of a zone reaps the previously resolved simulated bus state.