Patents Represented by Attorney, Agent or Law Firm Douglas W. Cameron
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Patent number: 5532657Abstract: Disclosed is a high speed coaxial contact and signal transmission element which comprises an inner conductor element 1, an outer conductor element 6 and a dielectric area 4 between the inner conductor element 1 and the outer conductor element 6. The inner conductor element 1 is a continuous element and consists of a core 2 of hardened conductive material exhibiting good elastic properties surrounded by a metal shell 3. A filament 5 of low dielectric constant material is wrapped around the inner conductor element 1 and fixed on the surface of the inner conductor element 1. The outer conductor element 6 consists of a metal shield. These high speed coaxial contact and signal transmission elements are used for the transmission of high speed electrical signals in high density fashion and for contacting and testing electrical devices with minimal dimensions.Type: GrantFiled: May 23, 1995Date of Patent: July 2, 1996Assignee: International Business Machines CorporationInventors: Roland Stoehr, Rudolf Kratt
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Patent number: 5533020Abstract: A method and apparatus for scheduling the transmission of a number of data streams over a common communications link, where each of the data streams conforms to a corresponding set of flow control parameters. Each of the data streams to be transmitted on the communications link is stored in a corresponding queue. The status of each queue is maintained, and a target transmission time is calculated for each queue. Signals are then generated for each queue at a time at least after the target transmission time, and these signals are used to indicate to a corresponding queue that is can transmit a cell on the link. Upon reception of a corresponding signal, a queue then transmits at least one cell onto the communications link.Type: GrantFiled: October 31, 1994Date of Patent: July 2, 1996Assignee: International Business Machines CorporationInventors: Jonathan W. Byrn, Gary S. Delp, Philip L. Leichty, Baiju V. Patel, Kevin G. Plotz, Frank A. Schaffa, Marc H. Willebeek-LeMair
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Patent number: 5530757Abstract: A method and apparatus for determining when a original document has been altered. With this invention the original information in the document is hashed using a one-way hash function. The hashed information is then encoded into a number of fingerprint pieces which are then transmitted to a number of locations. To verify the originality of the document a minimum number of fingerprint pieces are decoded and the purported genuine document is hashed using the one-way hash function. If the results of the latter hash equal the results of decoding the minimum number of fingerprint pieces, then the purported document is accepted as the genuine document.Type: GrantFiled: June 28, 1994Date of Patent: June 25, 1996Assignee: International Business Machines CorporationInventor: Hugo M. Krawczyk
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Patent number: 5530893Abstract: A data processing system having a built-in keyboard and an external input device which are alternately activated. If there is no command from the external keyboard (106), the external keyboard is invalidated (108). If there is a command from the built-in keyboard, it is transmitted to the CPU (110-114). If there is a command from the external keyboard (106) and the command is RESEND a previous command is transmitted to the CPU. If the command is not RESEND, the command from the external keyboard is transmitted to the CPU.Type: GrantFiled: June 9, 1994Date of Patent: June 25, 1996Assignee: International Business Machines CorporationInventor: Haruo Sugi
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Patent number: 5528616Abstract: An apparatus is described for obtaining single frequency laser operation in a coupled waveguide configuration without using a diffraction grating. More specifically, this invention is a laser structure for oscillating light in single longitudinal mode. This structure has a pair of coupled but dissimilar waveguides that are collinear with each other and separated by a mirror in contact with each of the guides. The length of the waveguides are adjusted so that frequency selective coupling between the waveguides can discriminate between wavelengths corresponding to different longitudinal modes.Type: GrantFiled: April 24, 1995Date of Patent: June 18, 1996Assignee: International Business Machines CorporationInventors: Jeffrey A. Kash, Bardia Pezeshki, Franklin F. Tong
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Patent number: 5528763Abstract: A method and apparatus for admitting packets into the buffer of an attachment of a communications adapter. More specifically, a discard bit is maintained in a table of the attachment to indicate whether a cell of a packet was previously discarded because of a buffer full condition. All subsequently received cells of a packet are automatically discarded if the discard bit is in the state indicating that a cell was previously discarded because the buffer was full.Type: GrantFiled: September 14, 1993Date of Patent: June 18, 1996Assignee: International Business Machines CorporationInventor: Dimitrios N. Serpanos
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Patent number: 5524136Abstract: A method and apparatus for efficiently tracking the location of a mobile station in a cellular network, especially in cellular networks having nonuniform traffic distribution. A mobile station reports to a base station only upon entering selected reporting cells. When communication with a mobile station is desired, the station is searched for in the vicinity of the last reporting cell in which the station appeared. The vicinity of a reporting cell is defined as the set of all intersecting cells reachable from the reporting cell without passing through another reporting cell.Type: GrantFiled: April 20, 1992Date of Patent: June 4, 1996Assignee: International Business Machines CorporationInventors: Amotz Bar-Noy, Ilan Kessler
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Patent number: 5521601Abstract: This invention provides a tag identification system and method for identifying tags in the range of a reader station where the tags are divided into smaller groups, where the tags are identified one group at a time so as to save power by powering off the tags that are not in the group currently being identified. Each tag puts itself in a group by performing calculations from parameters stored in itself and from parameters received from the reader station. In another variation of this invention, only tags which configure themselves to be activated at a final frequency are identified. The set of tags which configure themselves to be activated at the final frequency changes with each identification round until all tags in the range of the reader have been identified.Type: GrantFiled: April 21, 1995Date of Patent: May 28, 1996Assignee: International Business Machines CorporationInventors: Dilip D. Kandlur, Arvind Krishna
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Patent number: 5519796Abstract: A monolithically integrated equalization optical equalization device having an optical demultiplexer for demultiplexing an optical signal into a number of individual channels and a number of optical connections for connecting the terminals of the demultiplexers to an optical multiplexer. Metallic strips of varying lengths are deposited on the optical connections so that the optical signal is equalized over the channels at the output terminals of the optical multiplexer.Type: GrantFiled: March 6, 1995Date of Patent: May 21, 1996Assignee: International Business Machines CorporationInventors: Chung-Sheng Li, Franklin F.-K. Tong
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Patent number: 5515361Abstract: A method and apparatus for monitoring links in an optical star network along with means for taking down a link in the event of a failure without disruption to other parts of the network, bringing back the link into operation once the failure is corrected, while adhering to eye-safety regulations. More specifically, when one link of a pair of links connecting a station to a star coupler fails, the failure is detected by a monitor and the links of the pair are connected to each other by a switch. This connection of the two links provides a look from the transmitter of the station through the pair of links and to the receiver of the station. This connection also disconnects the station from the star network. When the pair of links again become operable, a signal is detected as passing from the transmitter through the loop and back to the receiver. Detection of the signal by the receiver then results in switching the pair of links back to the star coupler, thereby reconnecting the station to the star network.Type: GrantFiled: February 24, 1995Date of Patent: May 7, 1996Assignee: International Business Machines CorporationInventors: Chung-Sheng Li, Rajiv Ramaswami
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Patent number: 5495475Abstract: A method for resolving race conditions in cascaded switches. More specifically, cross links between the cascaded switches are assigned preferred directions relative to each of the switches. A connection request or a response emanating from a switch will always use a send preference cross link if such link is available.Type: GrantFiled: February 27, 1995Date of Patent: February 27, 1996Assignee: International Business Machines CorporationInventors: Peter A. Franaszek, Martin W. Sachs
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Patent number: 5493652Abstract: A memory management system for maximizing the number of contiguous free buffers to reduce the required number of free buffer pointers. Accordingly, with this invention a buffer memory is divided into two disjoint areas with one area having only contiguous free buffers while the other area has a combination of free and used buffers. This invention also has a means for maximizing the number of contiguous free buffers by using the buffers in the area having only contiguous free buffers only if there are no free buffers in the other area having both used and free buffers.Type: GrantFiled: April 29, 1994Date of Patent: February 20, 1996Assignee: International Business Machines CorporationInventors: Odysseas Koufopavlou, Ahmed Nasr-El-Din Tantawy
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Patent number: 5490139Abstract: A method of routing packets through a fixed source routing communications network from and to mobile units. With this invention an initial access point is determined when a communications session is established to or from a mobile unit through the network. Location information is updated each time the mobile unit moves out of the range of one access point and into the range of another access point of the network. When packets for the session are to be transmitted to the mobile unit from the wired network, the packets are forwarded from the initial access point to a current access point, which by definition is in the range of the mobile unit. When packets for the session are to be transmitted from the mobile unit and to the wired network, the access point intercepts these packets and routes them to their destination and/or initiates route discovery to those destinations. When packets are to be transmitted between mobiles at different access points.Type: GrantFiled: September 28, 1994Date of Patent: February 6, 1996Assignee: International Business Machines CorporationInventors: Murray C. Baker, Partha P. Bhattacharya, Jeane S.-C. Chen, Roger Y. M. Cheung, Arvind Krishna, Peter E. Reissner, Mahmoud Naghshineh
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Patent number: 5454079Abstract: A computer workstation runs an application 12 which generates data for transmission over a network. The workstation includes a communications subsystem 14 which is responsible for actually sending data generated by the application onto the network. The application therefore passes data 22 for sending to the communications subsystem, along with the identification 24 of the channel over which that data is to be sent, and compression information 26. In a first embodiment the communications subsystem contains a variety of compression routines 40, and the compression information indicates which of these routines is most appropriate for the data in question. In a second embodiment, the compression information is a call-back function 92, whereby the communications subsystem can call back to the application program to perform the compression itself.Type: GrantFiled: September 28, 1993Date of Patent: September 26, 1995Assignee: International Business Machines CorporationInventors: Michael I. Roper, Lawrence S. Evans, Graham D. Wallis, Anthony Fyles, Andrew Key, Vincent Sethi
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Patent number: 5422898Abstract: This invention covers an apparatus for generating multiple wavelengths of light, where the intensity of each wavelength is separately controlled, and where all the wavelengths exit the device from the same aperture. Structurally, this multiple wavelength source consists of a passive waveguide coupled to an active tapered resonator. The light generated in the resonator couples to the passive waveguide and exits from the ends of the device. By pumping different regions of the resonator, different wavelengths can be obtained.Type: GrantFiled: October 29, 1993Date of Patent: June 6, 1995Assignee: International Business Machines CorporationInventors: Jeffrey A. Kash, David W. Kisker, Bardia Pezeshki, Franklin F. Tong
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Patent number: 5423032Abstract: A method and apparatus for extracting multi-word technical terms from a text file in a computer system. Word strings are selected from the text that have at least two words, that have at most a specified maximum number of words, that include none of a special set of selected tokens, and that only include selected characters. Word string which occur less than a specified minimum number of times in the text file are deleted. The remaining strings form a set of word strings very likely to be multi-word technical terms. Improvements on the quality of the set of word strings can be accomplished by deleting word strings which do not satisfy certain grammatical constraints.Type: GrantFiled: January 3, 1992Date of Patent: June 6, 1995Assignee: International Business Machines CorporationInventors: Roy J. Byrd, John S. Justeson, Slava M. Katz
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Patent number: 5390234Abstract: A method of tracking mobile stations in a cellular network. A mobile station will report to a base station only when the mobile station is turned on and only after having made a minimum number of intercellular movements. When communications with a mobile station is desired, the mobile station is searched for only in the neighborhood of the most recent current cell, which is the last cell from which the mobile station reported to the base station.Type: GrantFiled: April 20, 1992Date of Patent: February 14, 1995Assignee: International Business Machines CorporationInventors: Amotz Bar-Noy, Ilan Kessler
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Patent number: 5390359Abstract: A method and apparatus for determining whether a record, or an edited version thereof, is stored in a computer system. With this invention, whenever a record is stored in the system a hash function is applied to subsets of a key representing the record to be stored to generate multiple hash addresses. A copy of the key, or pointer thereto, is stored at each of the generated hash addresses. Whenever one wishes to determine whether a key is stored in the system, a hash function is applied to subsets of the test record to generate multiple hash addresses. The key for the test record then compared with the key stored in each of the generated hash addresses. If the key for the test record is sufficiently close to anyone of the keys found at the hash addresses, the test record is assumed to be stored in the system.Type: GrantFiled: March 20, 1992Date of Patent: February 14, 1995Assignee: International Business Machines CorporationInventor: Frederick J. Damerau
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Patent number: 5371890Abstract: A method and apparatus for providing non-privileged state cross-memory communications between application programs in disjoint communication memory domains. Appropriate operating systems store a table indicating which communication memory domains and which operations are permitted by a corresponding application program in a corresponding communication memory domain.Type: GrantFiled: October 30, 1991Date of Patent: December 6, 1994Assignee: International Business Machines CorporationInventors: Gerald P. Bozman, John A. Pershing, Jr., Joann Ruvolo-Chong
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Patent number: 5369705Abstract: A method and apparatus for providing authentication among a dynamically selected group of users in a communication system with a dynamically changing network topology. With this invention, freshness information and alleged identity information are transmitted from each of the users in the group using available paths in the network. A group key is then generated, and coded information, derived from the group key and the above transmitted information, is sent to each of the users. Each unit of coded information is accompanied by an identifying tag so as to identify which of the users is to use the appropriate unit of coded information. Each alleged user will then extract the group key from a corresponding coded information unit only if it shares an appropriate secret with a server. Without knowledge of the group key, a user cannot be authenticated.Type: GrantFiled: June 3, 1992Date of Patent: November 29, 1994Assignee: International Business Machines CorporationInventors: Raymond F. Bird, Amir Herzberg, Philippe A. Janson, Shay Kutten, Refik A. Molva, Marcel M. Yung