Showing papers by "Hewlett-Packard published in 1988"

Method of monitoring changes in attribute values of object in an object-oriented database

Abstract: A method of monitoring objects in an interactive object-oriented database system. Any of a plurality of client programs can request monitoring of attributes of objects in the database. A record is kept of update transactions initiated by a client. When the client commits the changes, any client which has requested monitoring is notified of any change in the value of an attribute being monitored at the request of that client. The notification interrupts the client and invokes a predesignated client procedure. Overhead is minimized by creating partial view materialization paths and defining monitors ahead of time and by localizing the monitoring.

The triangle processor and normal vector shader: a VLSI system for high performance graphics

Abstract: Current affordable architectures for high-speed display of shaded 3D objects operate orders of magnitude too slowly. Recent advances in floating point chip technology have outpaced polygon fill time, making the memory access bottleneck between the drawing processor and the frame buffer the most significant factor to be accelerated. Massively parallel VLSI system have the potential to bypass this bottleneck, but to date only at very high cost. We describe a new more affordable VLSI solution. A pipeline of triangle processors rasterizes the geometry, then a further pipeline of shading processors applies Phong shading with multiple light sources. The triangle processor pipeline performs 100 billion additions per second, and the shading pipeline performs two billion multiplies per second. This allows 3D graphics systems to be built capable of displaying more than one million triangles per second. We show the results of an anti-aliasing technique, and discuss extensions to texture mapping, shadows, and environment maps.

Magnetostatic wave technology: a review

Abstract: Magnetostatic wave (MSW) technology has been under investigation for more than a decade. Using ferrimagnetic films such as liquid-phase epitaxial (LPE) yttrium iron garnet (YIG) films, MSW devices and subsystems offer instantaneous bandwidths of up to 1 GHz at operating frequencies in the microwave bands (0.5-26.5 GHz). Because MSWs travel with velocities two-to-four orders of magnitude slower than electromagnetic waves, compact devices can be built using hybrid and monolithic microwave integrated circuit (MMIC) techniques. These devices include delay lines, dispersive delay lines, filters, resonators, and directional couplers. Subsystems using these devices, such as electronically tunable delay lines channelized filter banks, delay-line discriminators, oscillators, and frequency multipliers can be used for applications in signal identification, control and processing directly at microwave frequencies. An overview of the MSW technology is presented and an assessment of the various devices and subsystems that can be built using thin and thick LPE-YIG films is provided. >

Service station for ink-jet printer

Abstract: The service station provides components for wiping and capping the orifice plate of an ink-jet pen that is installed in a printer that can carry more than one pen-type. Certain service station components are dedicated for use with only one type of pen and other components are dedicated for use with another type of pen, thereby avoiding ink contamination that may occur, where, for example, a single wiper is used to wipe pens of both type.

Reduction of kink effect in thin-film SOI MOSFETs

Abstract: Numerical simulation is used to show that potential and electric field distribution within thin, fully depleted SOI devices is quite different from that observed within thicker, partially depleted devices. Reduction of drain electric field and of source potential barrier brings about a dramatic decrease of kink effect. >

Pulse-doped AlGaAs/InGaAs pseudomorphic MODFETs

Abstract: MODFETs have been fabricated using heterojunctions consisting of AlGaAs and pseudomorphic InGaAs, grown on GaAs substrates. The large conduction band discontinuity (about 0.46 eV for 25% In and Al concentration) leads to a 2-D electron density as high as 2.3*10/sup 12/ cm/sup -2/, with electron mobilities of 7000 and 16000 cm/sup 2//V-s at 300 and 77 K, respectively. Such a high electron density in combination with reasonable transport properties leads to MODFETs with exceptional characteristics. Devices with 0.15-0.25- mu m gate length have room-temperature drain currents as high as 600 mA/mm and room-temperature transconductance as high as 500 mS/mm. The f/sub T/ is as high as 98 GHz, as determined by 20-dB/decade extrapolation of microwave data taken to 25 GHz. A comparison of the effect of bias on the total delay through standard and pseudomorphic MODFETs suggests that the excellent microwave performance exhibited by the pseudomorphic device arises from a reduction in parasitic and drain delays and not from a higher electron velocity under the gate. >

Statistical analysis of effective singular values in matrix rank determination

Abstract: A major problem in using SVD (singular-value decomposition) as a tool in determining the effective rank of a perturbed matrix is that of distinguishing between significantly small and significantly large singular values to the end, conference regions are derived for the perturbed singular values of matrices with noisy observation data. The analysis is based on the theories of perturbations of singular values and statistical significance test. Threshold bounds for perturbation due to finite-precision and i.i.d. random models are evaluated. In random models, the threshold bounds depend on the dimension of the matrix, the noisy variance, and predefined statistical level of significance. Results applied to the problem of determining the effective order of a linear autoregressive system from the approximate rank of a sample autocorrelation matrix are considered. Various numerical examples illustrating the usefulness of these bounds and comparisons to other previously known approaches are given. >

Secure messaging systems

Abstract: A secure communication system wherein encrypted messages are passed between selected pairs of user terminals in a secure messaging system. A link is first established between the two terminals of the pair, one terminal sending a request to a key distribution center (KDC), which then provides encrypting keys to both terminals so they can communicate with each other. (Messages involving the KDC are themselves protected by encryption). The keys sent out by the KDC are key transporting keys, which are used by the terminals solely to transport data transporting keys between each other. The data transporting keys are used to transport (encrypt) the actual messages, and for security are changed after a usage count is reached; a fresh data transporting key is then generated and transferred under the key transporting key. This minimizes the load on the KDC. A hierarchy or key transporting keys can be used. The KDC (but not the user terminals) maintains a log to enable recover after a system failure. A journey key can be generated to allow a user temporary access to a link from a third terminal.

Object management facility for maintaining data in a computer system

Abstract: A computer having a file management system is presented. The file management system includes a plurality of application programs, a plurality of data files a plurality of class data structures and a plurality of object data structures. Each class data structure includes a reference to an application program within the plurality of application programs. Each object data structure includes a reference to a class data structure from the plurality of class data structures and a reference to at least one data file from the plurality of data files. The use of object data structures adds a layer between a user of the computer and data files. This allows for the computer to refer to an object data structure and access file associated therewith using a tag which is inaccessible to the user. The user refers to an object based on the physical location of the object on the screen. The user may also give the object data structure a name, which is wholly unconnected to the value of the tag. This allows a user to, for instance, give two objects in the same directory, the same name. Additionally, the file management system includes a plurality of link data structures, each link data structure including a reference to a first object data structure in the plurality of object data structures which serves a parent object of the link, and including a reference to a second object data structure in the plurality of object data structures which serves as a child object of the link. Child objects and parent objects are not necessarily the same for each link data structure.

Ordered-defect structure in epitaxial YBa2Cu3O7-x thin films.

Abstract: An ordered defect structure in superconducting Y-Ba-Cu-O thin films has been characterized by both x-ray diffraction and transmission electron microscopy. The defect structure, which is observed growing epitaxially within the grains of normal $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}$ structure, has the diffraction characteristics of a distinct phase whose volume fraction can be correlated with changes in film composition. The diffraction characteristics are consistent with an orthorhombic unit cell ($a\ensuremath{\cong}b=3.86$ \AA{}, $c=27.19$ \AA{}) with space group Ammm. These are the characteristics to be expected from a structure in which extra copper-oxygen layers create fault planes, which are inserted at every unit cell in the parent $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}$ structure. The composition expected for the pure phase is ${\mathrm{Y}}_{2}{\mathrm{Ba}}_{4}{\mathrm{Cu}}_{8}{\mathrm{O}}_{20\ensuremath{-}x}$. Preliminary transport measurements on films containing this extra phase are characterized by lower normal-state resistances and a lower Hall constant.

View composition in a data base management system

Abstract: In a database management system that operates according to the Structured Query Language standard, a query containing a reference to a view is processed by dynamically materializing the view through execution of the view definition. Once the view is materialized, it is treated as any other base table. To enable a query optimization plan to refer to the materialized view, a view node is introduced into the execution plan. The view node includes a subquery that results in the creation of the virtual table defined by the view. This created table is temporarily stored in a memory. The query optimizer can treat view nodes in the same manner as stored base tables, and thereby overcomes restrictions that were placed upon views by previous view decomposition approaches.

Ink jet pen having improved ink storage and distribution capabilities

Abstract: An ink jet pen (10) (or other similar fluid delivery system) wherein primary and secondary ink reservoirs (12,26) and an ink jet printhead (36) are all interconnected by way of a porous ink-transfer member 24). The ink will pass directly from the primary ink reservoir (12) to the printhead (36) under a normal or predetermined range of temperatures and pressures. However, for temperatures and pressures outside this range, the secondary reservoir (26) will be brought into operation to give or receive ink to or from the porous ink transfer member (24) and thereby serve to maintain a substantially constant backpressure at the printhead (36).

Printhead-carriage alignment and electrical interconnect lock-in mechanism

Abstract: A printhead cartridge and carriage assembly (10) is provided comprising: a carriage (12); a snap-spring (62) for securing a printing cartridge (14) in postion on the carriage; and an interconnect strip (16) for supplying electrical signals to the cartridge, including a force loading spring pad (24) for urging a portion of the interconnect strip against a portion of the cartridge. The cartridge has top (32), bottom (34), sides (36, 38), front (40) and rear (42) surfaces and includes a printhead (44) on the bottom surface, an electrical contact strip (46) on the back surface connected to the printhead, referencing pads (56) on the side surface, and a lip (64) on the back surface for accepting the snap-spring. Referencing surface (60) are provided for receiving the referencing pads on the cartridge. The spring pad urges the interconnect strip against the electrical contact of the cartridge. The printhead cartridge/carriage assembly of the invention requires only one hand of the operator to both insert and lock the cartridge in position. Further, the cartridge/carriage assembly provides simultaneous alignment of the printhead in the X, Y, and Z directions. Finally, contact between the printhead and the interconnect strip is reliably made each time the cartridge is inserted and locked in position, thereby ensuring proper nozzle firing each time.

Generalized version control in an object-oriented database

Abstract: An important function of an engineering database management system is to support incremental and cooperative design in an orderly way. This calls for a version-control mechanism of some generality if it is to be appropriate to the design of complex objects. The authors consider the nature of design objects, and develop some functional requirements for version control of such objects. They outline the basic object-oriented database model, which they take as the foundation for their proposal. They then discuss the relationship between versions and the objects they exemplify, describe the mechanisms for the creation of versioned objects and the conversion of non-versioned objects to versioned form, study the impact on referencing and type checking in the object model, and arrive at a flexible notion of a context containing rules for version selection. Their implementation of some of these concepts is also described. >

Multi-chamber ink jet recording head for color use

Abstract: A multichamber ink jet pen has a printhead comprising a plurality of nozzle groups corresponding in number to the number of chambers. The nozzle groups are respectively in communication with the individual chambers for receiving ink. The multi-color ink jet pen is retrofittable in a single color printer to provide multicolor printing capability. The nozzles in the nozzle groups are formatted to correspond to the nozzle format in the printhead of the single color ink jet pen, including the same nozzle spacing, to take advantage of the single color printer control for that nozzle format. The nozzle groups each duplicate a different longitudinal segment of the single color nozzle column pattern. The nozzle groups are staggered in the scan direction and the end nozzles in the respective groups have the same longitudinal spacing therebetween as the nozzles in the nozzle columns to duplicate the nozzle spacing of the single color nozzle column pattern within and between the nozzle groups of the multi-color recording head.

Self-leveling membrane probe

Abstract: A self-leveling membrane probe [10] is disclosed. A carrier [12] supports a translation stage [18] through radial flexure pivots [14]. A flexible membrane [22] having a first and second side is stretched over the translation stage [28] and held in high tension across its central portion compared to the tension maintained in its outer portion. The membrane's [22] center of the first side faces a device under test (DUT) (not shown) and carries contact bumps [34] that relay electric signals in and out of the DUT. The second side opposite the contact bumps [34] is occupied by a receptacle [32] including a rotation plate [30] and a conical well [32b] designed to receive a pivot pin [26] enbedded in a reference plate [24] suspended from above by the translation stage [18]. The pin [26] and well [32b] function together as a bearing and provide an automatic compensating rotation in response to an alignment mismatch between the probe [10] and a device under test. When the contact bumps [34] encounter uneven test pads, one end of the rotation plate [30] is pushed upwards away from the test wafer. Since the pivot pin [26] is held in a constant vertical position by the fixed reference plate [24], the rotation plate [30] reacts to the imbalanced force applied from below by rotating about the pointed end [26a] of the pivot pin [26] which is seated at the bottom of the conical well [32b]. The resulting angular deflection of the rotation plate [30] aligns the contact bumps [34] on the membrane [22] to the inclined plane of the input-output pads.

Hydraulically tuned channel architecture

Abstract: The use of lumped resistive elements (28) in an ink feed channel (10) between an ink-propelling element, such as a resistor, (12) and an ink supply plenum (14) provides a means of achieving resistive decoupling and meniscus resonance control with a minimum of deleterious side effects and design compromises typical of prior art solutions. A secondary constriction (30) in the ink feed channel is defined by a width W2 sufficient to provide physical support for the resistive elements while avoiding resistance to ink refill. The printhead further comprises lead-in lobes (38) for assisting in purging any bubbles in the ink. The lobes are disposed between the projections and the plenum chamber and separate one pair of projections from a neighboring pair.

An interconnect structure for PC boards and integrated circuits

Abstract: An interconnect structure for electrically coupling conductive paths (14′,28′) on two adjacent, rigid substrates, such as PC boards or IC chips, comprises a number of buttons (16) formed on a first substrate (12), and a number of contacts (28) formed on a second substrate (26). The buttons are elastically deformable, and include a resilient core (18) made from an organic material such as polyimide, and a metallic coating (20) formed over the core. The two substrates are compressed (F) between mounting plates such that the buttons (16) are pressed against the contacts (28) to make electrical contact.

Integrated thermal ink jet printhead and method of manufacturing

Abstract: We describe an integrated thermal ink jet printhead and manufacturing process therefor which includes the successive build-up of an orifice plate, a first barrier layer, heater resistors, a second barrier layer, and an ink reservoir-defining layer on top of a reusable or "dummy" substrate. Lead-in conductors are formed integral with the heater resistors by controlling the cross-sectional areas of these components, and openings (passageways) are formed between ink reservoirs and the orifice plate to provide for ink flow under control of the heater resistors. The dummy substrate is stripped away from the adjacent orifice plate, and the ink reservoir defining layer may be secured to an ink supply tank which supplies ink to the individual ink reservoirs. Thus, the orifice plate, heater resistors and ink flow paths of the printhead are self aligned, and the heater resistors are removed from direct cavitational forces from ink ejected from the orifice plate.

Ink delivery system for inkjet printer

Abstract: Ink is flowed through an ink flow channel of an inkjet print head, in a volume far greater than the volume required for printing purposes. The excess ink cools the print head and also aids in purging bubbles from the head. Ink for printing is extracted from the flow channel by capillary channels and conveyed to the ejection mechanism of the print head. In operation, ink from a stationary reservoir is circulated by a low-pressure pump through a particle filter and gas separator, and to the print head by a low-pressure trailing tube system, with the excess ink returned to the reservoir. The pressure of the ink at the capillary is maintained below atmospheric pressure, preferably utilizing hydraulic pressure created by locating the vented ink reservoir at a level below the print head. Leakage of ink from the print head is thereby prevented, and a positive ejection force is required.

Analog/digital data device and method

Abstract: A data communications method and system is provided to facilitate the communication between a plurality of units of data terminal equipment (DTE) connected over communication lines. A first DTE unit is located in a digital network and a second DTE unit is located in either a digital network or in an analog network. When attempting to place a call from the first DTE unit in the digital network to the second DTE unit in either a digital network or an analog network, a first call is made to determine the characteristics of the second DTE unit called. If the second DTE unit called returns an indication that it also possesses digital capability, then the call is established. If, however, the indication from the second DTE unit called is that it does not have digital capability, then the first DTE unit places a second call through a modem within a terminal adapter within the system to the second DTE unit. The system is also capable of receiving a call made to the first DTE from outside the digital network. The system also has the capability of establishing an error-free connection between the first DTE and second DTE units.

Data base management system for real-time applications

Abstract: A real-time database provides the predictable, high speed data access required for on-line applications, while providing flexible searching capabilities. The data retrieval routines include the option to "read-through-lock" to access data in locked data tables, the capability to directly access to data using tuple identifiers, and the capability to directly access unformatted data from input areas which contain blocks of unformatted data. The data updating routines include an option to omit index updating when updating data and an option to update data in a locked data table. Multiple indexes can be defined for a data table. Thus, high speed searches can be performed based on a variety of data fields. The data storage and retrieval mechanisms are independent and there are hash index tables that connect the multiple index keys to the data tables. The data table structure includes a column defined for storing tuple identifier strings. These tuple identifiers can be used as pointers for chaining to related data stored in other data tables. The datas base has relatively small programmatic memory. There is a common structure for user data tables, index tables and system tables. The database includes a minimum number of routines with certain routines providing multiple functionality.

Membrane probe with automatic contact scrub action

Abstract: An apparatus [10] for providing an automatic lateral scrubbing motion when a test membrane [22] engages a device under test (DUT) (not shown). Included are a fixed length flexure pivot assembly [30] and a pair of variable length flexure pivot assemblies [38]. Signal traces, signal trace terminals, and contact bumps [23, 25, 60] are formed for communicating electrical signals between the apparatus [10] and the DUT. A membrane [22] is stretched and configured for carrying the signal traces, signal trace terminals, and contact bumps [23, 25 and 60]. A hexagonal translation stage [28] is formed with an upper surface [29] disposed for being coupled to at lesat one of the fixed and variable length flexure pivot assemblies [30 and 38], and formed with a lower surface [54]. Surface [54] is formed to define an aperture [51] through itself, formed for securing over itself the membrane [22] when stretched; it is disposed for being coupled to membrane [22]. Finally included is a carrier [12], formed for suspending the hexagonal translation stage [28] and fixed and variable length flexure pivot assemblies [30 and 38].

Frequency locking device

Abstract: An improved frequency locking circuit suitable for indirectly locking an optical frequency f 0 to a radio frequency f 1 or of locking the radio frequency to the optical frequency. A beam of optical frequency f 0 is modulated by a compound signal which is the sum of a signal at frequency f 2 and an FM subcarrier at frequency f 1 that is phase modulated at frequency f 3 to produce a phase modulated beam. The phase modulated beam is filtered by a filter having a transfer function having a characteristic frequency f f . A pair of control signals are generated that are proportional respectively to the amplitudes of two components of the filtered signal at frequencies f 2 , f 3 . These control signals are separately used in a pair of servo loops to separately establish fixed values of f 0 /f f and f 1 /f f . By using an optical cavity of the filter, the frequency locking circuit may be used for measuring the refractive index of a gas. The circuit may also be used for calibrating a multi-mode filter.

Cues and control in Expert-Client Dialogues

Abstract: We conducted an empirical analysis into the relation between control and discourse structure. We applied control criteria to four dialogues and identified 3 levels of discourse structure. We investigated the mechanism for changing control between these structures and found that utterance type and not cue words predicted shifts of control. Participants used certain types of signals when discourse goals were proceeding successfully but resorted to interruptions when they were not.

Ink-jet printer with printhead carriage alignment mechanism

Abstract: A novel ink-jet printer (10) is provided. The print provides both paper supply tray (12) and paper collection tray (18) in the front (14) of the printer for ease of paper handling and reduced footprint. The paper collection tray is provided with a pair of opposed output rails (22) which support a sheet of paper (16c) during printing to permit ink on a sheet of paper (16b) previously printed to dry. A paper handling mechanism is provided which eliminates a sheet pickup motor and associated elements. The paper handling mechanism is configured to pick off a sheet of paper from a stack of input paper, bring it around paper drive rollers (24) onto a platen (26), where the printing operation, employing a printhead cartridge (32), occurs. The printer further includes a service station (230) for clearing clogged nozzles in the printhead (33) and removing bubbles therefrom, for covering the nozzles with a protective cap (266), and for wiping contaminants off the nozzles. Reference pads (200) are provided for aligning and securing the printing cartridge in a carriage (35). The carriage is associated with a carriage guide (27), to which the carriage and print medium are referenced. The resulting printer is easy to manufacture, has reduced complexity by eliminating components in the paper drive mechanism and is lower in cost.

Test method for random defects in electronic microstructures

Abstract: A method for testing layering processes of integrated circuit construction for random defects. A test structure is employed having a plurality of micro-patterns covering a wafer, the patterns being fabricated in accord with a unit process of an integrated circuit manufacturing operation. The patterns are fabricated either with a lower conductive level covered by an insulative layer and an upper conductive level, all having pads which may be probed at the upper level, or a single conductive layer. By repeating tests in various unit processes, random defects can be isolated to individual unit processes. Nine patterns are disclosed which form a universal test set.