Abstract: In response to a request from a content server to forward an encrypted document to a recipient user, a forwarding engine in the content server prepares an e-mail message that contains a link to the document publisher and an identifier for the document. Upon receiving the e-mail, the recipient user can log onto a content server in the publisher and the publisher content server resolves the link, downloads a secure viewer program and an encrypted version of the requested document to the viewer program. Subsequently, the secure viewer program requests a decryption key for the encrypted document and decrypts the document. The recipient user can then view the document content in secure viewer but cannot copy or print the document without permission from the publisher.

Abstract: A networked computer system for storing and presenting multimedia data distributes that data among multiple storage devices of the system. The system includes a plurality of computers, each of which supports at least one viewing station. Each viewing station has access to any file on any of the storage devices and can retrieve and display any file on demand. To provide an efficient system and, at the same time, reduce the probability that the viewing of multimedia data may be interrupted, the system allocates resources, prioritizes access to files, and buffers data prior to the data's delivery to video adapters.

Abstract: A distributed program history database system is designed for use on a client-server network. The system consists of a plurality of program history servers which maintain version information for various program components. A program developer, upon logging into a client terminal on the network, establishes a workspace or project and connects with one of the history servers. After connection to the history server has been made, a draft of the program configuration is retrieved from the server. The configuration draft may include information for constructing some of the program components and "bridge" information identifying other program history servers where additional program components are located. The workspace uses the component information to assemble components and the bridge information to connect to other servers and retrieve the remaining components in order to assemble the complete source code for a program in the workspace.

Abstract: A method and system for formatting numerical information. An object-based operating system provides various number formatting services. Some objects scan text and convert the text to numerical information, and convert non-text numerical information to text, and convert between different numerical formats and languages. The system provides a common ground from which application programs can speak a seemingly common numerical language without specifying the details of converting numerical information between systems of representation. The present system relieves application developers of the burden of handling details of numerical information, and provides ease of information transfer between monetary systems and cultures having differing languages. The system also provides for conversion between number formats to allow for easier processing and/or comprehension of the numerical information, and normalization and alignment of any textual representation of numeric information.

Abstract: Digitized audio information is compressed by retrieving a first audio sample from a digitized audio signal and storing it in its entire, uncompressed, form. The next audio sample is then retrieved and a signed difference between the first audio sample value and the next audio sample value is computed. If this difference value can be represented in fewer data segments than would be required to represent the next audio sample, the difference value is stored, rather than the value of the next sample, otherwise the next sample is stored. The invention proceeds in this fashion until the entire PCM audio signal is compressed and stored. The compressed data stream is decompressed to generate an output data stream by retrieving a stored sample and examining it to ascertain whether it is a difference value or a flag which indicates that the following data represents a coded amplitude value.

Abstract: A method and system for providing synchronization of the timing of various multimedia events, including an audio event is disclosed. Clock objects are defined in the storage and associated with an internal or external source of current time. The clock objects are able to be displayed on the display, but can be hidden once their linkages are defined. One or more multimedia objects representative of audio, visual or other multimedia events, including an audio object, are defined and linked to a particular clock object or clock objects. Then, a processor synchronizes the multimedia objects, including a MIDI data object, with the associated clock object or objects. Finally, the various multimedia events are performed in synchronization with their associated clocks. The multimedia objects, including the audio object, may include external multimedia sources managed by the computer system.

Abstract: A method and apparatus for testing software programs systematically generates test data by removing from a potential test data candidate pool data which is syntactically incorrect for proper operation with the software program and then data which is semantically incorrect for the software program. The resulting reduced data collection is applied to the collection of components to generate output values which are then checked against post condition rules to verify that the software program operated correctly.

Abstract: An digital video image processing system employs codes of various lengths to encode the luminance information within the digital video images. The inventive method and apparatus divides a video image into non-overlapping regions containing a plurality of pixels with luminance values. Within each region, the method computes the total luminance variation across the region, the direction of greatest luminance change within the region, the base, or lowest, luminance value within the region and the location and type of luminance transition within the region. Depending on the variation of the luminance values within a region and on the quality desired in the decoded image, the computed information is used to encode the luminance values in short, medium, or long codes. The luminance codes may be predetermined and unchanging or they may vary from image to image or within given images.

Abstract: An image-compression/decompression system employs a variable spatial-frequency encoder to encode the chrominance information contained within a video image. The system divides the video image into non-overlapping regions and partitions each region into sub-regions. Within each region, the system computes a weighted average of the chrominance values in each sub-region, and compares the weighted average value associated with each sub-region to the weighted average values associated with the other sub-regions within the region. If differences between the average values are less than a predetermined threshold amount, the system assigns a single chrominance encoded value to the entire region. If, on the other hand, the differences between the weighted average values is more than the predetermined threshold amount, the system assigns individual chrominance values to each of the sub-regions.

Abstract: The method serves for actively damping vibrations on a paper-making machine. The kinematic quantities which describes the movements of the paper-making machine or parts thereof produced by the vibrations are measured and are processed as measurement signals. Between relatively movable masses, at least one of which belongs to the vibratable structure of the paper-making machine, is provided at least one servo motor which is controlled by a control unit. Movement of this servo motor is produced in such a way that it is directed opposite to the vibrational movement to be damped. The movement produced in this way for damping the vibrations can be produced both between parts of the paper-making machine and between part of the paper-making machine and a movable additional mass provided expressly for this purpose. A damper which can also be incorporated into the servo motor can be provided to reduce the vibrational energy.

Abstract: Digital apparatus for generating video characters with various kinds of edging is disclosed. The apparatus employs a plurality of digital delay registers which are used to generate a replica of the video information which is delayed by a preselected number of scan lines. The video information together with the delayed signals produced by the delay registers are provided to a pair of shift registers which generate fixed background patterns depending on the kind of edge information which is selected and a character body signal. The background pattern and the character body signal are then combined to produce the final video character output.

Abstract: A dynamic filter circuit used to process analog position error information in a disk drive head-positioning servo system is disclosed. The filter circuit monitors the velocity of the disk drive carriage and dynamically increases the gain and bandwidth of the filter as the carriage velocity increases. Specifically, an operational amplifier in feedback configuration is used in which the feedback networks are switched in response to the velocity signal. At low carriage velocity the filter has low gain and reduced bandwidth and therefore helps to decrease sensitivity of the system to noise. At high carriage velocities the gain and bandwidth of the filter are increased to minimize the effects of missing servo data.

Abstract: A circuit for filtering electrical waveforms in which the useful information is contained in patterns and spacing of zero-voltage crossings is disclosed. Illustratively, a disk memory system is disclosed in which the voltage peaks developed by the disk memory read-transducers are converted into zero-voltage crossing waveforms by differentiation. To eliminate false zero-voltage crossings caused by noise, the digital filter generates a linear ramp waveform whose magnitude is proportional to the time duration between successive zero-voltage crossings. False zero crossings typically have a short time duration between successive crossings. They are eliminated from the integrated ramp waveform by a comparator which only responds when the integrated waveform reaches a predetermined threshold level indicating the time between successive zero-voltage crossing exceeds a minimum time duration.

Abstract: A data processing arrangement is disclosed including a central processing unit, a plurality of peripheral units coupled to a peripheral bus, a memory access controller, a first memory bus, and a second memory bus. The first memory bus serves a first plurality of memory units and the second memory bus serves a second plurality of memory units. The memory access controller selects which of the peripheral units may use the peripheral bus to access a memory bus during a particular time interval. If use of a particular memory bus is requested by a peripheral unit for an interval in which that memory bus is required by the central processing unit, the memory access controller preempts the usage of that memory bus by the peripheral unit for the interval.

Abstract: A telephone station circuit is disclosed with restriction circuitry which allows a noncoin phone to be placed in a public location by preventing the generation of dial pulses on a call from the station except when a dialed number is preceded illustratively by an initial dialed "0." The call is thereby routed to an operator for appropriate charging procedures. The disclosed circuit utilizes an ordinary noncoin rotary dial telephone with a relay which is operated to enable called number dial pulsing from the noncoin phone by a special cam arrangement. The cam arrangement in turn is actuated by the dial mechanism of the phone upon the dialing of an initial 0 digit. The restriction relay is connected in series with the station line and has a pair of normally closed contacts which shunt the dial pulse contacts to prevent normal dialing. When the station goes off-hook, the relay is prevented from operating by a separate pair of contacts, associated with the dial mechanism which contacts shunt the relay coil.

Abstract: A conference circuit is disclosed for use in a time division switching system which has an incoming and an outgoing time division bus connected by a summing amplifier. During a conference call, a different group of conferee stations is connected to the incoming and outgoing buses by the switching system controller in each of a plurality of time slots dedicated to that call. Output signals from the connected stations are then applied to the incoming bus. The conference circuit is connected to the incoming and outgoing buses and includes storage and transfer circuitry. In each conference time slot, the storage circuitry stores the output signals generated by conferee stations connected during that time slot. Signals from conferee stations which were stored by the storage circuitry during previous time slot are combined by a combining means and the resulting sum is placed on the incoming bus.

Abstract: A self-checking read and write circuit interfaces a control circuit with a plurality of peripheral circuits. The read and write circuit receives address and data commands from the control circuit, decodes the commands and produces a driving signal to operate relays in the peripheral circuits. The read and write circuit also receives inputs from the peripheral circuits indicating the state thereof, multiplexes and inputs and forwards them to the control circuit under control of address signals. The circuit is self-checking in that a readout multiplexor which scans for state changes in the peripheral circuits has its even parity inputs connected at the outputs of the drive signal decoder and its odd parity inputs connected to the scanned points. A parity check circuit on the multiplexor address leads determines whether the address has even or odd parity. If the parity is even, the output of the multiplexor is compared to the output of the drive signal decoder.